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NTSC Atari 600xl Black Screen


Sinjinhawke

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I picked up an "as is" Atari 600xl on the cheap.  Figured if it does not work I can make use of parts if needed for my working Atari 600xl and 800xl.

 

When it arrived I plugged it in and nothing.  TV didn't change and keyboard LED did not come on.  I'm not technical but I tried a few things.

I pulled the BASIC, OS ROM, PIA, SALLY, ANTIC, GTIA, MMU and put them in the working 600xl and they worked so those chips seem fine.

I have not tried swapping the POKEY as my working 600XL has a BOT ENGINEERING 64K upgrade which covers the POKEY.  I can take it from my 800XL and try that later.

 

After I put the chips back in their non working ATARI 600XL I tried powering it on again and this time I got a black screen and the LED on the keyboard lit up.  Seems reseating the chips helped a little.

 

I tried using my SYS-CHECK v2.2 but still only get a black screen.   I put the SIDE3 in to see if it lights up and there is the slightest green flicker then nothing.  Also tried a Star Raiders cart.

 

The bottom of the case has what looks like a dried rust puddle almost perfectly in the centre and the paper in the shielding looks like it was wet at some time.  Shielding has rust.

 

I don't need to get this working since I have 3 working machines but if anyone has any suggestions on what I can try it would be appreciated.

 

On the bright side it came with the box and styrofoam which I haven't had since I was a kid.

IMG_2314.thumb.jpg.ff8f19b27bf7aabbd39c707a443e4e63.jpgIMG_2315.thumb.jpg.2f97163312a601478557ce873ddb316b.jpg

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Rust is conductive. First order of business clean the board of rust...

next order of business is a possible line of broken traces on the lower left side of you bottom pcb picture...

easy to bridge if cracked or broken

that same crack is near the keyboard connector area of the pcb... you need to bridge those cracked joints as well

did the crack happen as you pulled the pcb out of the case... or is there evidence of twist and crush damage to the computers shell?

 

looks good to repair... just bridge the broken cracked traces. drill at the ends of the pcb cracks in places that contain no traces to stop the spread... epoxy/resin glues can firm things up.

 

Edited by _The Doctor__
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When it arrived it had no screws holding the main case together.  Owner may have opened it to dry it out back in the day.  The shields were still screwed together.  
 

I’ll try the delay line swap and cleaning up some of the rust this weekend.  The keyboard appears to be fully functional and the IC’s all work so if it ends up as parts it was a great value.   

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9 hours ago, bfollowell said:

Is it just,me, or do you guys see the ugly bunch of globbed together solder joints on the right, underside of the motherboard, about halfway down? Something about all those solder bridges doesn't look quite right.

 

 

Capture.thumb.JPG.26dbaa8f69223dfd9e2625270dfa9e30.JPG

 

The blobbed ones are all connected together by traces anyway.

 

The rust is right between GND and the 5V trace running around the outside of the board, though, so an intermittent dead short is quite possible, especially since the power LED didn't initially come on.

Edited by flashjazzcat
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I took my daughter's toothbrush (old one, I'm not a monster) and some alcohol and did some light scrubbing.  Also swapped the delay line. 

 

No effect but no worries.  I was having some issues with my working 600xl.  One of the issues was it wasn't reading anything on the SIO.  Dr Venkman suggested the POKEY so I pulled it from the black screen machine and put it in the working one and SIO problem resolved.  The old POKEY is damaged at the R/W I/O Control pin.  Not sure how that happened as I have never removed the pin before.  The only incident in recent history was the old power supply went bad and maybe fried that pin?  Possible?  Wild guess?   

 

So I guess I will just use the black screen board for parts and as backup keyboard as I don't have another POKEY to replace the broken one with.

 

Thank you for the suggestions.  I enjoyed making the effort to get it up and running.

IMG_2317.jpg

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You can scrub that pin with Deoxit or other electrical cleaner, then solder on a leg snipped from a donor chip like a cheap logic chip or another dead or damaged IC you might be able to find. That would likely salvage your POKEY. You’d just have to be careful inserting and removing it in the future but it will probably be good indefinitely. 

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16 minutes ago, DrVenkman said:

You can scrub that pin with Deoxit or other electrical cleaner, then solder on a leg snipped from a donor chip like a cheap logic chip or another dead or damaged IC you might be able to find. That would likely salvage your POKEY. You’d just have to be careful inserting and removing it in the future but it will probably be good indefinitely. 

 

I've been thinking of picking up a can of that. I see they have several products. Which do you guys use? Deoxit D5? Deoxit Gold G5?

 

 

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11 minutes ago, bfollowell said:

 

I've been thinking of picking up a can of that. I see they have several products. Which do you guys use? Deoxit D5? Deoxit Gold G5?

 

 

Standard D5. The “Gold” version is intended for cleaning gold contacts, though to be honest, that’s mostly marketing. Gold won’t tarnish so there’s no corrosion to remove anyway - just surface dirt, nicotine, dried aerosols, etc. In my experience the regular D5 cleans it perfectly.

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to further that explanation, gold contacts are not pure gold, they are an alloy... they can tarnish in most cases because of the mixture of metals... the standard stuff does a great job as stated as the alloy contains the normal base metals that it works on anyway.

 

that being said, the gold series stuff has it's use... it isn't just a cleaner, it is also a preventive. Consider it a finishing solution.

it helps reduce wear and prevent oxidation from reforming as quickly among other things. I've used the gold series stuff on low voltage and current connectors that are problematic and it solves recurring problems at those points.

 

I never use the gold series for the initial cleaning, just the finish up / touch up.

 

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1 hour ago, tjlazer said:

How can reseating chips make the power LED come on?  Sounds like a bad trace on the board and not a bad chip seating issue.

No idea.  It’s just observed behaviour between initial power on attempt and subsequent attempt after trying all the chips in my other 600xl.  
 

Maybe removing it from the case and shielding did something. Maybe the board warming up from the cold did something.  

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6 hours ago, DrVenkman said:

You can scrub that pin with Deoxit or other electrical cleaner, then solder on a leg snipped from a donor chip like a cheap logic chip or another dead or damaged IC you might be able to find.

Just wanted to confirm this approach.  I managed to snap a pin off of a POKEY while I was practicing desoldering/socketing as part of my current retro Atari computer binge, and was indeed able to graft on a lead.

 

Tip One: I've been hanging on to leads from resistors and capacitors and such as I snip them off, if they are long enough to seem worth it.  They are pretty handy for sticking in a breadboard hole to bring out a signal so you can clip a probe or whatever to it.  Anyway, many of them are really thin and wimpy, especially in modern resistors.  But, maybe 1/4 of the lead fragments I had stashed were noticeably thicker and suitable for pin replacement surgery.  You can always snip one off yourself from an easily replaceable discrete component if you don't happen to have a suitable wire fragment laying around.  I found posts that recommend using 30 AWG solid core wire for this, but I can't confirm that.  Anything that seems solid enough to hang in there and about the same diameter as a pin should be fine.

 

Tip Two: Don't trim the lead fragment or wire or what have you to fit until after soldering is done and satisfactory.  It's hard enough to keep the IC and wire stable without also trying to manage a 1/8" or 1/16" piece of wire and a hot soldering iron!  Also easier to see the length you need after it's on and you can just eyeball it against the intact pins.  I also wouldn't recommend using a leg from a donor chip unless you can cut it a little longer than is strictly needed, so you have a bit more to hang on to.

 

Tip Three: You need to hold the pin and the IC very stable to do this.  So if you don't have 4-5 hands, it helps to have something like Helping Hands or the like.  Even with that, things tend to skitter away when you touch them with the iron or the solder.  It can definitely be done, I've done it twice now, but it wasn't fun either time.  Really the actual tip here is, please be careful not to burn yourself!

 

If you already knew all of this or it was obvious, sorry.  I'm just very excited at learning how to do all this sort of stuff, so trying to help where it seems like maybe I can.  Lord knows I've gotten a lot of help from the people here.

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An alternative is to use a machine pin socket, insert the chip into the socket then solder a connection to any broken pins(wire may be required). This solves the issue of keeping the chip/pin stable and also reduces the risk of the replacement pin breaking off if removing the chip, just remove the chip/socket as a unit.

 

This method only works if there is sufficient height clearance.

Edited by BillC
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12 hours ago, DrVenkman said:

You can scrub that pin with Deoxit or other electrical cleaner, then solder on a leg snipped from a donor chip like a cheap logic chip or another dead or damaged IC you might be able to find.

 

3 hours ago, BillC said:

An alternative is to use a machine pin socket, insert the chip into the socket then solder a connection to any broken pins(wire may be required). This solves the issue of keeping the chip/pin stable and also reduces the risk of the replacement pin breaking off if removing the chip, just remove the chip/socket as a unit.

 

This method only works if there is sufficient height clearance.

 

It's funny. I worked as a bench tech for a couple of years, but didn't work with a lot of discrete components outside of the classroom and labs. I've been a bench hobbyist for the past several years. Still neither of these fixes had ever occurred to me. I'm usually pretty good at thinking out of the box, but both of these are really great ideas. Personally, the older I get, the shakier I get, so I think BillC's option would work better for me, assuming I had the clearance for the extra height, but both are really great ways to fix the problem.

 

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3 hours ago, BillC said:

An alternative is to use a machine pin socket, insert the chip into the socket then solder a connection to any broken pins(wire may be required). This solves the issue of keeping the chip/pin stable and also reduces the risk of the replacement pin breaking off if removing the chip, just remove the chip/socket as a unit.

 

This method only works if there is sufficient height clearance.

I have a FTe '816 board with gold pins that was inserted and removed several times, with several pins that have broken off because they are so soft... and a spare low profile socket.  Thank you for the great idea!

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4 hours ago, BillC said:

An alternative is to use a machine pin socket, insert the chip into the socket then solder a connection to any broken pins(wire may be required). This solves the issue of keeping the chip/pin stable and also reduces the risk of the replacement pin breaking off if removing the chip, just remove the chip/socket as a unit.

I thought about doing something along those lines, either soldering the pin to the board or putting a stub in the socket and soldering to that, but I was trying to see if I could fix my POKEY in such a way that I might be able to swap it out again later if need be.  I guess you could still do it with your solution, you'd just have to un-solder the one connection to remove it.

 

Agree that your way would be more stable.  I am not really that happy with the structural integrity of the two chips I fixed via graft (the POKEY and a Delay Line).  They do work though, so that's something at least.

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6 minutes ago, Dr Memory said:

I thought about doing something along those lines, either soldering the pin to the board or putting a stub in the socket and soldering to that, but I was trying to see if I could fix my POKEY in such a way that I might be able to swap it out again later if need be.  I guess you could still do it with your solution, you'd just have to un-solder the one connection to remove it.

 

Agree that your way would be more stable.  I am not really that happy with the structural integrity of the two chips I fixed via graft (the POKEY and a Delay Line).  They do work though, so that's something at least.

I wasn't talking about removing the chip from the socket it is soldered to, but using it as a permanent attachment which then plugs into the socket on the PCB. If vertical clearance is limited using low profile sockets for both would reduce the increase in height, Millmax makes low-profile sockets. Below is a link from a post I made, the links are for the German website but Mouser is international.

 

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