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Beeblebrox

600XL - red screen - FIXED now fully working - Multiple issues - upgraded to 64k and U1MB - S-video enabled - Sharing as may help others in their 600XL troubleshooting

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I have a confession - I think I am addicted to fixing Atari 8-bits!:grin: We may well have to set up an alternative to AA (Alcoholics Anonymous) for Atari hardware addicts!:P

 

This latest fix involved another PAL 600XL, (my 2nd 600XL), and has almost been as tricky as my earlier 130XE from the dead fix, although that was a mammoth one I must admit as it was virtually totally dead and I was way outta my depth. AA users were incredibly helpful as ever and that one was a steep learning curve as it also involved passive components as well as ICs. Still that 130XE is doing well despite undergoing major surgery. (I am relatively new to this after all.)

 

So with this 600XL I am pleased to say after perhaps a week or so of tinkering I've just this minute managed to completely restore it.

 

It had 3 x established issues in the end, and is now upgraded with U1MB as well as S-video.  Such a relief as I thought I'd exhausted everything.

 

I thought sharing what I have done may well help any others with either similar problems or some aspects of the issues I came across.

 

This was a case of a series of problems that were contributing to several issues, where only fixing one issue then enabled me to work out the other issues.

 

Of course as usual I made some newbie mistakes on the way. (All of this seems to be the norm when hardware trouble shooting on the A8s and especially when you aren't an expert. Although I know it can happen to those who are seasoned experts in it as well... least that what I'll keep telling myself heh heh!:D).

 

It'll all become clear..... read on if you can be bothered - it's a big post. :grin:

 

Anyway, this 600XL was a recent aquisition as part of a bundle of Atari hardware I just couldn't resist. (I do love the 600XL:lust:):

 

image.thumb.png.75284237b683ec5cd0d17b0b3b5eb6cd.png

 

It was bought relatively cheaply with a known issue - namely it just displayed a red screen on power up:

 

image.png.8579d68763f00def81a50cb5f504ce50.png

 

My first reaction these days is to assume bad ram chips as a minimum.

Additionally since I planned to install a brand new U1MB module that's been sitting for a couple of month waiting for a host (euuuuuww!:P),  if I ever fixed this 600XL I would need to order the RAM to upgrade it to 64K initially. So I placed an order for 2 x 41464C - 12 (120ns), chips on Ebay UK for peanuts.

 

A quick look at the 600XL service manual was the starting point and unfortunately had no details relating to a red screen.

 

However I have picked up from reading AA threads and fixing an 800XL with a similar issue that a red colour screen can indicate one or more of the following:

 

Bad Ram chip(s)

Bad MMU

Bad OS chip

Bad Basic chip

Bad CPU

Bad GTIA or ANTIC chips

 

My first tool in the arsenal was to initially test things using my trusty Sys Check II.

 

Unfortunately in diagnostic mode and any of the other modes I initially tried I didn't get a display, (either the same red screen or garbage). So at this stage it wasn't gonna help. (That's not to say later on when the first issue was solved it then didn't come in handy).

 

So - what next?

 

Well as mentioned I had ordered some replacement 41464C 18pin RAM chips so those were on their way at least.

 

So I opened her up, and hilariously found what was unlikely to be the cause of any issues, but rather the antics of a child sometime in the 80's...

 ...namely a brown colouring pencil rattling around inside:):

 

image.thumb.png.89bf7f97ff1da4eaa7cc69892715effe.png 

 

Anyways, I removed the shielding, remembering to unscrew the hidden release screw, handily indiated in the above picture in the hole just above the pencil tip.;)

(With my first 600XL disassembly I spent ages racking my brain trying to work out why the PCB and sheilding wouldn't come away from the base - having at the time removed what I assumed were all the screws. Sneaky Atari engineers! Anyhoo I digress.)

 

(BTW it had a nice AWC keyboard which I AFAIK is standard with 600XLs, unlikey the variety of keyboards you get with 800XL.)

 

Wires

 

Straight away is was clear someone had undertaken one of the 64K upgrades, given at a quick glance the wiring was in place for it on both sides of the board. Frustratingly the two 18pin ram chips were unmarked with the model number and rating rubbed off ....which didn't help. (Why do people erase these?!:?)

image.thumb.png.060f38058d873c07d3a8a707565b94f1.png      image.thumb.png.63360b0ea61cc1d95d8672789d1688a3.png  

 

However on closer inspection of the upgrade it appeared one of the soldered wires coming from pin 3 of the 74 logic chip U5, (74LS158), had become detached from it's original solder point.

image.thumb.png.aa7babaac6a0bcc0eed376a8a636e75d.png

 

Seemed this was it - a simple loose wire!! 

 

I did a quick search of my past notes, AA, etc given I've already successfully upgraded my other 600XL to 64K for that U1MB upgrade, and decided I'd mirror the latter wiring/setup.

(As is commonly known there are several ways you can do the 64K upgrade which all amount to the same connections I've learnt.

 

I went with one the legend that is Tf_hh kindly advised me on at the time. It was only a slight tweak to the wiring already in place.

(Incidentally on the underside of the board is a jumper wire for U18 pins 8 and 10 - and you don't need the IC in place anymore.)

 

image.thumb.png.e527a5313bf3c866e93d89925d8a647e.png  


So with the wiring re-established/checked both sides of the board and triple checked for shorts as well as continuity to ensure it mirrored my working 600XL's 64K upgrade, I booted up the machine hoping to see some progress.

Nada! Red screen.:mad:

 

I left the machine running and checked for any hot chips. Some different ICs ran slightly warmer than others but I've learnt that is to be expected. Nothing stood out.

 

BTW I'd decided to use brand new replacement 74LS158 ICs for U5 and U6 but this made no difference.

 

I also replace the notorious 74LS08 chip with a new 74F08 chip just in case. No difference at this stage at least, (wasn't expecting it to for a red screen).

 

Incidentally whilst looking on the underside of the board I spied a large blob of old solder, (not from my work), which looked like it was clearly shorting two solder points. I removed it but it made no difference - so was a bit of a red herring but good to catch:

image.png.0beae169deb09715b69d3d669bf94d6a.png

 

So at this stage I had to rule out the initial disconnected wire as the cause. Knew it wouldn't be that easy!:roll:

 

Ram

 

I popped the working ram chips from my other working 600XL into the sockets. Nothing - Red screen.  Hmmm.

 

I popped the Ram chips from this non working 600XL into my working 600XL - they were good and it booted.

So the original Ram appeared ok. Hmmmmmmmmmmmmmmm.

 

So next on my list was to systematically unseat and reseat all the main ICs individually to see if there was a bad/broken/bent pin or oxidisation, etc causing a break. I did this one chip at a time testing after each. No change.

I did this for all the 40pin, 28pin, 24pin, 18pin, 16pin ICs. Nothing. Red screen still.:?

 

I also did the usual and check for continuity with sockets and IC legs/pins, check traces for continuity around them, looking for bad solder points, and also to see of any of the passive components (especially caps), looked dodgy. It all looked ok.

At this stage I wasn't about to start checking the passive components with my multimeter.

 

Next move was to pop the CPU, ANTIC, and GTIA chips from this 600XL into my working 600XL, and visa versa - all one at a time testing between swaps.

The "bad" 600XL's 40pin chips were all confirmed working in the working 600XL and with the working 600XL's chips in the "bad" 600XL, I still got the red screen. So it wasn't the CPU, or graphics chips themselves at fault.

 

I did the same for the OS ROM chips swapping between machines. Still a red screen. Not the OS chip.

 

I then did the same for the delay line, MMU, 4050 and all the 74 logic chips (aside U5 and U6 which were already new ICs). Red screen persisted.

 

I replaced the old 74LS74 chip with a brand new one. No change.

 

Sockets

 

So at this stage I now was thinking it was a bad socket somewhere.

 

So I systematically removed the following 40Pin sockets from the board starting with the CPU, then GTIA, ANTIC, testing after each one. I checked the vias, traces and continuity between nearby points at the time of removing old sockets and installing the new precision ones. With the sockets checked I tried with the original 40pin chips as well as other CPUs, GTIA, ANTIC. Still a red screen. 

 

I did the same for the MMU socket. Red screen.

 

I decided I'd wait until the new RAM chips arrived even though I knew the original RAM had worked on my other 600XL when exchanged.

 

A few days passed and with the new chips having dropped through the letter box I popped em in. Still a red screen which I expected.

 

Then I noticed that one of these new RAM chips was running hotter than it's partner. Just my luck, at least one of the new RAM chips was likely bad.

Given I didn't know what rating the original unmarked ram chips were (12, 10?), I didn't want to risk mixing and matching existing and new RAM chips. I don't have an 18pin RAM chip tester, just a 16pin DRAM tester). 

 

 

OK - what hadn't I looked at? Not really thinking it would be a likely cause I removed the PIA chip and popped it in my working 600XL. Boom....I got a red screen on my working 600XL!!!! (Odd feeling seeing your "good" computer fail and being happy about it!) Bad PIA chip!!:music:

 

Another one to chalk up to experience

 

Ok, so the PIA is bad. I hadn't realised the PIA would cause a red screen.

In fact same for the Pokey. I'd not realised either of these 40pin ICs would be a problem in this context so I'd not swapped them out.

 

Joy was short lived because with a working PIA from my other 600XL in place my bad 600XL it now powered up to a black screen! I tried another PIA from another machine. Same black screen.

 

I decided to replace the PIA socket with a precision one just in case....

image.thumb.png.d805b6785039ec095c3024f2f9735156.png

 

Still a black screen.

 

I also replaced the Pokey chip with a working one and tested the Pokey in my good 600XL. Pokey was ok when in my good 600XL.  So it's wasn't the Pokey chip at least.

 

However just in case replaced the Pokey socket with a new one, did checks, etc etc....

image.png.ab7ae7e6389b10301a5f89b923d0d9df.png

 

Still a black screen. So it wasn't the socket. At least now I have a precision socket for a potential Pokeymax upgrade.

 

According to the field service manual a black or grey screen can indicate a power/voltage problem. Also in threads and videos I've watched I've seen for 800XL and also XE machines a black screen can indicate bad ram or bad CPU as well as GTIA or ANTIC issues but I'd already ruled these out as possiblities.

 

I tried another CPU, GTIA and ANTIC again just in case. Black screen.

 

I then replaced the RAM sockets, tested - black screen still.

Then I replaced a few other 74 logic chip sockets and checked after each install. Black screen.

 

OS ROM

 

At this stage I decided to try the Sys check II again.

 

Whilst I got the same black screen with the diagnostic setting, (which disables the machines RAM and OS ROM), and garbage on another setting...:

 

image.thumb.png.3a7ea39c571f36309835b1c1a5e7bbbf.png

 

 

.... on one of the other settings which used the RAM on the machine but the OS rom on the Sys check II all of a sudden displayed and started testing!;-)

 

The RAM checked out ok...

 

image.thumb.png.58d0fa6470b4325b6e4884d72f19fcc4.png

 

....but the OS was reporting as bad.  (Neglected to take a pic of that).

 

Now it's worth noting I've had a false report before of the OS rom testing bad on a 65XE where a faulty 74 logic chip was causing it to report as such. I remember with that machine I tested 4 x OS ROM chips at the time and all of them reported as bad. It wasn't until I relaced the 74 logic chip in question did the same 4 x OS ROM chips test ok.

So with this 600XL I wasn't 100% convinced the problem was the OS rom chip. But I had still had faith in the Sys Check II. 

 

So maybe during this whole process the OS rom chip, which may have been on the edge of going bad(?), finally gave up the ghost.... because I had checked it earlier in my other 600XL and it looked like it was working?!?!

Who knows!?!:?:

 

So I had two spare OS chips left.

First one I tried made no difference - black screen with Sys check II unplugged and with it in place it still reported a bad OS chip.

 

The second OS ROM chip I popped in worked - bingo - Sys check II reported a good OS rom chip and without Sys check II plugged in I got a ready prompt popping up! OMG at last!!!!

 

So it then looks like one of my spares was bad.

 

Colour


Of course being connected to my LG TV via the composite and 600XLs not having Chroma/luma be default I was getting a greyscale/black and white image.

With the S-video cable I wasn't getting an image at all - to be expected.

 

So I reinstated the Chroma and luma circuit with a 100ohm resistor and 220uf Cap, etc, (as I'd done before on my other 600XL) and voila:thumbsup::

 

image.thumb.png.86cf245704b04f594f53f7a39f049ff9.png    image.thumb.png.7b9598df3742b469fd138b03219e12be.png   

 

 

I ran the A8's bog standard Self test memory test run, all apeared to look ok:

 

image.thumb.png.f90aa1993a722da404e12b27d3f465ac.png

 

Ok - so could this be all fixed?:D....

 

Well of course not, the universe isn't that kind!! :mad::???:

 

My go to check after reviving an A8 after tinkering like this has been to pop the SIDE3 cart in, which I did......

 

....I got this in loader mode... a complete crash:?:

 

image.thumb.png.d39505de8d0c8fe7a65094cabba25e57.png    image.thumb.png.476551cdae3bba25c3aee14303e99127.png    

 

Oddly in SpartaDOS-X mode I got this and it didn't crash:

 

image.thumb.png.8902c579c163952a69cd61329ab50770.png

 

So the cartridge was at least communicating with the 600XL.

 

I checked traces and vias, pin connections with the cart slot and they all checked out.

 

One thing I'd noticed a few times with no cartridge plugged in was that after a cold boot of a few seconds, it appeared that the memory lingered with the Ready prompt on boot up.

In other words turning the computer back on even after 5 seconds of it being off went directly to the ready prompt instantly, no "farting" sound.......it was just there straight away as if the machine hadn't been turned off. Got me thinking as to whether the RAM was a low rating of 10 (100ns) or less - if indeed there is a rating less than 10(?)...  and it was taking longer for it to "wipe itself" of residual data. (sorry - I don't know the terminology).

 

Please with progress albeit a bit jaded I took a day's break from it all.

 

So at this stage with all the work I'd done so far the board looks like this:

 

image.thumb.png.0e727a621ed643dd42dc619517e15a3f.png

 

Incidentally it's worth pointing out at this stage I could get my stock 1050 Happy drive to load the Mecenary game. 

 

My thinking at this point is that having identified a bad PIA and OS ROM issue and confirming the RAM appeared to be ok, was as follows:

 

  • That there was either an issue with a 74 logic chip somewhere
  • Or perhaps the aforementioned ram quirk was at the very least contributing to something.

 

However since both Sys check II AND self test memory test checks repeatidley indicating me the RAM wasn't bad, my money was one or more of on the logic chips causing an issue.

 

So I decided to make sure the issue wasn't the 74LS158 chips U5 and U6 sockets which I replaced. I replaced a few other logic IC socketed, checking after each install.

I also popped a precison socket for the MMU in advance of the planned U1MB install.

No change - still has the same issue with SIDE3 cart menu glitching.

 

I tried my Rescue on Fractalus (ROF) cart and just got a black screen on boot up.

 

I replaced the OS rom socket with a precision one and BASIC chip socket with a dual wipe one just in case.

 

Still the SIDE3 loader menu and ROF cart glitching persisted.:x

 

I decided to order some new RAM chips as I could get some HM50464P 12 (120ns) chips very cheaply and thought it good to have spares. (Ebay has been amazing in that respect).

This was despite the installed original RAM reporting ok. My thinking was at least I'd be getting some known 12 (120ns) rated RAM chips and I've read the HM50464P are highly recommended as reliable equivilants.

 

Today is a good day

 

So this morning whilst I waited for the new RAM chips to arrive I decided I may as well install U1MB. Besides, with the U1MB upgrade you remove the MMU and OS ROM chips. I thought if there was still some issue with these at least I'd be taking these two ICs out of the equation.

 

The U1MB didn't take too long to install and it booted up with no issues.

However no change in terms of SIDE3 loader and ROF carts just booted to black screens. :roll:

And now it didn't even get to the glitching SIDE3 loader menu anymore.

 

Still it was great to see U1MB it was up and running at least:

 

image.thumb.png.8a13fda5a1341155c82db48aa9b29554.png

 

I took a mucn needed break and popped into town, had a decent mid afternoon lunch, (as I'd neglected to eat breakfast such was my obession with the morning's tinkering), and being British .....a bottle of Punk IPA.:D

 

On returning home the postie had delivered the new RAM chips:

 

image.thumb.png.b158adb37151142121e27b19e1b08c1c.png

 

I popped them in the sockets honestly fully expecting to see no change.......

 

image.thumb.png.8219f03a1c6b1737bbc87fb59f958561.png

 

...popped in the SIDE3 cart and powered up.................. OMG........ you have got to be kidding me..........only bl00dy worked!!:-o:lol::music::)

 

image.thumb.png.7faecdf26d50c1f7e6c37c7ee4b74840.png

 

So - despite countless checks on the original RAM with self test's memory testing, (which I know is rudamentry), AND Sys check II multiple runs confirming the RAM was ok, there was clearly something with the original RAM chips that wasn't quite right. 

 

Could it be that whomever did the memory upgrade mixed up some of the chips?  I assume you have to run the same rating of RAM chip? There was no way of knowing as the markings were erased.

 

Incidentally I am not trying to lay blame on Sys check II at all - it is an amazing bit of kit that's saved me a lot of pain with previous fixes and is highly regarded. However I fully understand it can't pick up on everything regarding the RAM.

 

So, to recap, the issues with this 600XL were definitely at the very least:

 

  • BAD PIA chip causing the initial RED screen
  • A recently failed BAD OS ROM chip causing the next issue of a black screen
  • Quirky/malfunctioning RAM chips of unknown brand and rating causing the SIDE3 cart and ROF cart not to boot.

 

It's worth noting I used a USB power supply for all my A8s and it was no difference with this 600XL. I never use original Atari (brick) PSUs.

 

Now it has U1MB with the latest FJC firmware flashed and Chroma Luma and gives a good picture on both composite and S-video (the latter helped by the excellent Hercules workshop double shielded cable I recently received from Canada):

 

image.thumb.png.b53ae2a06ca5e9ec0e9dd9d900f03d58.png      image.thumb.png.be27fabb2a1d9ed1f4a7453c76ad20c2.png    image.thumb.png.88488017ba7d6b9eb34089b844ba95ae.png    image.thumb.png.ca6d589c2f01164565ec8443492f5cea.png           

 

Whether anything else I've done in the process by way of removing sockets, installing new precision sockets or double wipe ones, replacing some of the usual suspect logic chips (74LS74 with a new one and the notorious 74LS08 with74F08), etc has fixed anything else I couldn't say for sure.

 

I am pretty exhausted but I think given my experience so far with several A8 fixes of this nature, and especially my experience with the Dead 130XE in September, I've learnt you have to go through several stages and revisit things several times. The investigative nature of the process is what drives ya I guess....... albeit both rewarding and hugely frustrating simultaneously!

 

Certainly I which I'd checked the PIA regarding red screen earlier on in my investigations, but that is hindsight for ya. :grin:

 

Besides there was still the OS rom and RAM issues anyway... and who knows what else.:P

 

If you survived reading this post.... well done!;-)

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

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nicely done! tenacity is the secret ingredient for success 😎 its satisfying when you finally see the ordinary ready prompt!

in case youre not aware - or for future reference - the PIA is an off-the-shelf part, you just need to get a particular version to guarantee compatibility. heres the research topic:

 

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2 minutes ago, xrbrevin said:

nicely done! tenacity is the secret ingredient for success 😎 its satisfying when you finally see the ordinary ready prompt!

in case youre not aware - or for future reference - the PIA is an off-the-shelf part, you just need to get a particular version to guarantee compatibility. heres the research topic:

 

@xrbrevin  thanks. Actually I'd asked about sourcing Pia chips in another post so many thanks for linking the above. I wouldn't mind getting a couple of spares from mouser.co.uk.

 

I'll read the thread. 

 

The 600XL is looking very happy. Will clean it up a bit tmrw as the casing is pretty dirty. 

 

Next to get to grips with all things sio2pc and I've a couple of 1050 drives which need some attention. 

 

😁

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Excellent read.  I have 3 NTSC 600xl machines.  1 does not work.  I one day hope to try and revive it and these well documented stories shared by AA users will be the guide.

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8 hours ago, Sinjinhawke said:

0Excellent read.  I have 3 NTSC 600xl machines.  1 does not work.  I one day hope to try and revive it and these well documented stories shared by AA users will be the guide.

@Sinjinhawke

Thanks, kind of you to say. :D  I wish ya luck fixing it.

 

I have greatly benefited from AA posts documenting many troubleshooting issues, fixes and upgrades. Not to mention certain YouTube videos, (flashJazzcat's (FJC's), in particular:D).

 

As I've mentioned in previous posts I am certainly no expert. Also this time around rather than start the topic thread as I was going through the process, (which has helped in the past), I felt I'd amassed enough knowledge to try any nail it myself, then document it all post fix. (Of course assuming I'd fix it).  Just didn't quite expect it to be such a monumentally lengthy post when I started typing it yesterday heh heh.:D

 

Sure I went down some rabbit holes during the fix and again if I'd caught the PIA earlier it would have save me some effort. (However it still had some quirky issues and it definitely wasn't a clear cut case. Still don't know what the brown coloring pencil is supposed to be soldered too..... :rolling:;))

 

Then again hindsight is a wonderful thing, and you learn by making mistakes of course. I don't think I did too badly with this one and quite enjoyed it. Hughly satisfying to play AtariBlast! on it i can tell ya... damn I love the colours in that game!;-)

 

What really helps me generally aside Google, Youtube and AA threads of course, is the following:

 

  • My previous experience as a newbie fixing A8s over the last few months in particular, and knowledge gained from AA member's help/expertise and a lot of reading.
  • Having another working 600XL and XLs in general for parts to exchange and to test this XL's ICs on. 
  • Socketed ICs from the get go - I've done fixes on non-socketed A8s (XE's mainly but some 800XLs) - and it's a major pain!!
  • As a starter always lift each IC and reseat it from it's socket first, whilst at the time checking for broken IC pins/legs, and broken sockets. Check after you do each one rather than doing them all. You can easily make things worse by accidentally bending a leg, (or worse), without realising and then you won't know which IC component is the culprit if another issue surfaces immediately or later on.
  • When removing sockets there are several ways. I've seen some use professional desoldering stations and or a combo of a heat gun to pre-heat the sockets from underneath, (and sometimes on top). I am no expert but I opt for using an iron at around 200c with a small to medium tip and using a solder sucker to remove as much solder from the vias and legs as possible from the underside of the board. I sometimes add solder to a via to reflow before then using the solder sucker again. You can check to see if the socket's legs are loose/semi loose each time. Then very gently try prying up the socket from the topside with a tool, (being careful not to damage any other components). Go slow and any resistance, stop immediately to check to see if you still have solder top side of the via(s). You can easily pull up a trace if you don't and that can be incredibly tricky to fix, especially given these go under sockets. (I've done so once or twice this year on previous A8's boards and manage to fix them all thankfully using either offcuts from resistor legs or wires from old ribbon cables, narrow heat shrink where needed, etc.) Reheat said vias from the underside and try prying at the same time. Sometimes the sockets pins will pull clean from the plastic recess and remain in the board. Tweezers and the soldering iron soon gets rid of them. 
  • A multimeter is a must have.
  • Have a pair of arched tweezers helps a lot, as does a set of tailored soldering tools to lever ICs, etc out. (they cost peanuts):

image.png.3166defaaf4ddc273f642fed326df36d.pngimage.png.4074b1be2743c983abb07a78e49bbc97.png   

       

  • Owning a Sys Check II - I can't praise this bit of kit enough and it's more than paid itself back.
  • Being methodical but accept you will go down the wrong rabbit holes - it's an investigative process after all and no-one is infallable.
  • Revisit things you have already tested if you see progress or a change. You'll definitely go off on tangents and more often than not it is helpful/informative is some way.
  • Go slow and never do more than one thing before testing. (I could have easily saved time and gone ahead and re-socketed all of the 40pin sockets at the same time before testing, but it's better to test after each change). Pretty obvious really.
  • Accept you are likely in for the long haul and will throw tantrums at times when you have powered the damn thing up to a red or black screen for the 50th time that day!! :x:lol:
  • Taking photos along the way for your own reference - (for me this is an obsolute must especially if you are doing this over a long period of time). I've got a really bad short term (and long term memory for starters)....................... I've got a really bad short term (and long term memory for starters)... (sorry, couldn't resist)......:lolblue: At the very least take notes.
  • IMHO don't use the A8's original brick power supply - get a modern USB one - in the UK you can get them for £10 on Ebay. The power supply maybe a cause of an issue for starters. Plus for me they are cumbersome and take up valuable floor space. Ditch the brick!!;-)

 

Getting a hold of the annotated images of the A8's motherboard in question is very helpful, as is sourcing the service manual, and getting a hold of the silkscreen, (blueprint map of the motherboard layout as it were). This is a good place, and in my earlier reply above I mentioned this too. Schematics also very useful - bit of a learning curve for me as had never looked at one before I did my 130XE fix last month.

(AA members have been very helpful in the past with all of these, and Google nearly always leads to a pge, PDF or image somewhere).

 

I'll say it again - look at FJC's videos on YouTube. I've picked up a lot from him, and also discussions with AA members.:thumbsup:

 

The 600XL has one of the better boards as the IC reference numbers aren't so much obscured by the ICs or sockets themselves, unlike XE boards.

 

Just to mention - In terms of cost I already own the soldering equipment. Component wise, (if you exclude the cost of the U1MB in this particular project), it's cost me about £25 in components to fix this all in, (RAM chips, some replacement 74 logic chips and sockets I'd already bought in mini bulk orders for a previous A8 fix. I always have spare wires and a stash of resistors, and some capacitors from previous upgrades).

 

Plus I got a free brown colouring pencil out of it!! :lol:

 

TBH it's not so much about the cost as I've learnt some more about the hardware, for the most part enjoyed the process. Besides I can waste £25 in the blink of an eye on a round of drinks here in the UK so I'd rather spend it on an Atari :D

 

Here I go again.... I only meant to say thanks:roll::lolblue:

 

EDIT: BTW I realised that aside many typos I'd neglected to mention in my main post yesterday that at the time of lifting and reseating various ICs, I had also obviously done the same with all the 14pin ICs as well, which of course covers a lot of the 74 logic chips. Just in case anyone wondered.

 

 

Edited by Beeblebrox
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Fortunately I do have a Sys-Check and a little experience removing chips.  My 130xe has no sockets and had bad MT RAM so it was my first ever desoldering (and soldering) experience.  Removed the whole first row, put in sockets and new chips and it passes all the tests.  2nd row also has MT but it seems to pass all the extended ram tests I throw at it so I'm not going to pull those just yet.

 

Knowm (non-working) 600xl issues

- The POKEY has one corroded leg which seems to prevent anything working when plugged into the SIO so I will need to try and attach a new leg since POKEYs' are becoming far too rare to give up on to easily.  

- It also has a bad keyboard connector but I recently acquired replacements thanks to tf_hh.  

- It also needs a new 600xl mylar.  I bought the Retronics one and it works when I plug it in and test it with my fingers but does not work when pressed by keystrokes, quite odd.

 

I do need to understand how to use my meter to understand what readings I should be seeing (and where) when the board is powered.  Right now I only know enough on how to check for continuity.

 

Will be a nice project once I have several days off with nothing to do.  A 600xl is a terrible thing to waste.

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33 minutes ago, Sinjinhawke said:

Fortunately I do have a Sys-Check and a little experience removing chips.  My 130xe has no sockets and had bad MT RAM so it was my first ever desoldering (and soldering) experience.  Removed the whole first row, put in sockets and new chips and it passes all the tests.  2nd row also has MT but it seems to pass all the extended ram tests I throw at it so I'm not going to pull those just yet.

 

Knowm (non-working) 600xl issues

- The POKEY has one corroded leg which seems to prevent anything working when plugged into the SIO so I will need to try and attach a new leg since POKEYs' are becoming far too rare to give up on to easily.  

- It also has a bad keyboard connector but I recently acquired replacements thanks to tf_hh.  

- It also needs a new 600xl mylar.  I bought the Retronics one and it works when I plug it in and test it with my fingers but does not work when pressed by keystrokes, quite odd.

 

I do need to understand how to use my meter to understand what readings I should be seeing (and where) when the board is powered.  Right now I only know enough on how to check for continuity.

 

Will be a nice project once I have several days off with nothing to do.  A 600xl is a terrible thing to waste.

@Sinjinhawke

Great, sounds like ya good to go.

 

Regarding soldering the Pokey leg on, I guess providing you have a protruding pin/leg which you can clean up a little, you might have some luck soldering a little piece of metal to it. (Perhaps a leg from an old socket?) I've tried before and it was tricky. I was always worried it would fall off and short something and also the heat soldering it on would damage the Pokey. 

 

Not sure re the 600XL's mylar as no experience of them.

 

Great re keyboard connector - good ol tf_hh.

 

cheers :D

 

ps EDITED and removed some content as had my XE head on for a second so irrelavent)

 

Edited by Beeblebrox
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1 hour ago, Sinjinhawke said:

The POKEY has one corroded leg

white vinegar is good at lifting corrosion - very non-invasive to the base material

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20 hours ago, xrbrevin said:

white vinegar is good at lifting corrosion - very non-invasive to the base material

Corroded and partially disintegrated, no longer has length to make the connection.   I would probably need to run a wire out of the socket to the corroded leg after cleaning it with vinegar.  Anyway that is a long way off as the board is still dead ATM and maybe a new source of POKEY's will show up.  Someone will find a warehouse just filled with Atari 7800 Ballblazer carts to harvest.

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2 hours ago, Sinjinhawke said:

Corroded and partially disintegrated, no longer has length to make the connection.   I would probably need to run a wire out of the socket to the corroded leg after cleaning it with vinegar.  Anyway that is a long way off as the board is still dead ATM and maybe a new source of POKEY's will show up.  Someone will find a warehouse just filled with Atari 7800 Ballblazer carts to harvest.

@Sinjinhawke

Absolutely. Sounds like a new Pokey chip might be required. I've heard of people sucessfully scraping the side of the chip near the entry point for said leg until there is enough of a stump to adhere to.  I've tried before and failed but that's not to say it can't work.

 

Which pin/leg is the culprit btw?

 

The other thing is to bite the bullet and get a pokey max to go stereo (highly recommended - I have stereo on 3 x of my Ataris and the difference is amazing)

 

 

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5 hours ago, Sinjinhawke said:

Corroded and partially disintegrated, no longer has length to make the connection.   I would probably need to run a wire out of the socket to the corroded leg after cleaning it with vinegar.  Anyway that is a long way off as the board is still dead ATM and maybe a new source of POKEY's will show up.  Someone will find a warehouse just filled with Atari 7800 Ballblazer carts to harvest.

If you want to salvage the pokey chip, you could use a second chip socket. Put the Pokey chip in the socket and then solder what is left of the leg to the leg of the corresponding leg  of the socket. Then, you can just put this into another socket on the motherboard. This would make it easier to replace in case the pokey chip dies.

 

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Hey @Beeblebrox,

 

Thanks for the great info! I am also in the process repairing 8bit systems too. I am looking to get a good multimeter. I only have a very cheap basic one. Which one do you use?  

 

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13 minutes ago, scorpio_ny said:

Hey @Beeblebrox,

 

Thanks for the great info! I am also in the process repairing 8bit systems too. I am looking to get a good multimeter. I only have a very cheap basic one. Which one do you use?  

 

Hi @scorpio_ny

 

Thanks. What have you got in the way of Atari's?

 

I am not an electronics expert so just picked up a cheap one here on Amazon in the UK. Has good reviews: 

https://www.amazon.co.uk/gp/product/B07GNL1PKW/ref=ppx_yo_dt_b_search_asin_image?ie=UTF8&psc=1

 

 

On one of my other fixes topic thread some of the more experienced electronics expert forum member's talked about a brand called Fluke multimeters:

 

 

I just needed something cheap and simple/reliable.

 

I've also gone for one of these to compliment it so I can quickly test passive components:

https://www.ebay.co.uk/itm/363205440012?var=632374798011

 

image.thumb.png.64602f01f125b73e55c9baddaf940846.png

 

 

Edited by Beeblebrox

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51 minutes ago, scorpio_ny said:

Hey @Beeblebrox,

 

Thanks for the great info! I am also in the process repairing 8bit systems too. I am looking to get a good multimeter. I only have a very cheap basic one. Which one do you use?  

 

 

You can't beat Fluke meters for quality and features. You do pay for those though. They do have some cheaper models though, if you don't need a full-blown industrial meter. They have quite a few that would be good for an electronics workbench for $100-$150. I've heard some decent things about some of the Extech meters, and many of those have capacitor/diode/transistor checking capability and are considerably cheaper than most Flukes, but I have no direct experience with them myself.

 

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4 hours ago, Beeblebrox said:

@Sinjinhawke

BTW just Googled this... not sure if up-to-date but $20 for a POKEY chip ain't bad.

https://www.best-electronics-ca.com/custom-i.htm

 

 

 

You can't just check there, because those links to the main listings never change. You also need to check the addendum page to see if the stock status or the price has changed. The link is below.

 

Luckily, the Pokey chips still show in stock, though limited to 1, and still for $20.

 

https://www.best-electronics-ca.com/addendum.htm
 

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2 hours ago, scorpio_ny said:

If you want to salvage the pokey chip, you could use a second chip socket. Put the Pokey chip in the socket and then solder what is left of the leg to the leg of the corresponding leg  of the socket. Then, you can just put this into another socket on the motherboard. This would make it easier to replace in case the pokey chip dies.

 

I have seen this done before but completely forgot about it.   Silly old brain of mine.  

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3 hours ago, scorpio_ny said:

If you want to salvage the pokey chip, you could use a second chip socket. Put the Pokey chip in the socket and then solder what is left of the leg to the leg of the corresponding leg  of the socket. Then, you can just put this into another socket on the motherboard. This would make it easier to replace in case the pokey chip dies.

 

@scorpio_nyNow why didn't I think of that?!! Great idea. :D:):thumbsup: I mihgt try that on a couple of 40pin ICs I'd almost written off with multiple stumped legs.

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5 hours ago, Beeblebrox said:

Hi @scorpio_ny

 

Thanks. What have you got in the way of Atari's?

Well, I four NTSC 800XL's, one NTSC 600XL and a NTSC 130XE. One of the 800XL's has been upgraded with an Ultimate 1MB and Sophia 2 chip. I just got my Pokeymax 3 which I have to schedule some time to install on that same machine. My 600 XL has been upgraded to 64K and has the UAV video upgrade plus the missing the 5 DIN socket. I also have a 1050 and XF551 in storage which I have to go get to see if they still work. The upgraded 800XL and the 130XE, along with the disk drives are my actual childhood computers. I had kept them and now I am enjoying using them again.

 

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5 hours ago, bfollowell said:

 

You can't beat Fluke meters for quality and features. You do pay for those though. They do have some cheaper models though, if you don't need a full-blown industrial meter. They have quite a few that would be good for an electronics workbench for $100-$150. I've heard some decent things about some of the Extech meters, and many of those have capacitor/diode/transistor checking capability and are considerably cheaper than most Flukes, but I have no direct experience with them myself.

 

@bfollowell,

 

I have heard the same thing about the Fluke meters. I will check out the Extech as well to see if they suit my needs.

 

Thanks! 👍

 

 

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9 hours ago, scorpio_ny said:

Well, I four NTSC 800XL's, one NTSC 600XL and a NTSC 130XE. One of the 800XL's has been upgraded with an Ultimate 1MB and Sophia 2 chip. I just got my Pokeymax 3 which I have to schedule some time to install on that same machine. My 600 XL has been upgraded to 64K and has the UAV video upgrade plus the missing the 5 DIN socket. I also have a 1050 and XF551 in storage which I have to go get to see if they still work. The upgraded 800XL and the 130XE, along with the disk drives are my actual childhood computers. I had kept them and now I am enjoying using them again.

 

@scorpio_ny

Niiiiice. I have several U1MB modules installed in various A8 models.  (see my signature) I also have UAV rev D installed in my main driver A8, (a heavily modded 800XL). I have a couple of stereo enhanced A8s and also a new pokeymax 2 module waiting to be installed in one of my A8s.

 

I have most of the newer models of A8 although I may just about have secured an 800. (They are incredibly expensive to aquire these days).

 

I resurrected my only original A8 (the 130XE) from my teenage years but as yet have not managed to locate my original beloved 800XL. Horrible feeling I sold it in the 90s. I had 3 x other XEs I had bought late 90s, (sold one recently) but other than those all the A8s and drives I've aquired since to either fix and/or upgrade.

 

My fav was always the 800XL and recently since I've gotten 2 x 600XLs it's close. I also have a soft spot for the XE design, just the cart port is in a stupid place. 800/600XL cart port is perfect for access.

 

Great time to get back into the Atari scene, with amazing games like Flob and ports like PoP, Giana sisters, ADM, etc etc.

 

I can't wait to test FJC's SIDE3 FAT firmware sometime in the coming weeks.

 

 

Edited by Beeblebrox

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On 10/11/2021 at 5:48 PM, scorpio_ny said:

@bfollowell,

 

I have heard the same thing about the Fluke meters. I will check out the Extech as well to see if they suit my needs.

 

Thanks! 👍

 

 

Check this out: https://youtu.be/hGBwC0y-pnE 

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On 10/16/2021 at 11:56 AM, hasanc said:

Check this out: https://youtu.be/hGBwC0y-pnE 

Thanks @hasanc! I happen to follow Jan Beta's channel as well!. I also repair the Commodore 8-bits. I am looking at the Fluke 17B or the Fluke 117. There is a big difference in price.  The latter, though more expensive,  I know I will have the Fluke warranty in case of any issues with the device.

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