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New owner needs help :(


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#26 Pheonix OFFLINE  

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Posted Wed Jul 11, 2018 9:56 PM

I hadn't gotten that far yet.  I had just gone through their web site to see if they listed it anywhere.



#27 ACML OFFLINE  

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Posted Wed Jul 11, 2018 10:14 PM

The bar is there, just not pictured.  Was bent when it first arrived, but managed to carefully straighten it out.  it slides through a channel under where the HI-TEK patent text is on the plastic.  The bar sits nicely and doesn't tilt much when the ends are pressed.  Though it does tilt a bit.  I did notice (testing the tilt amount, about 5 degrees at a guess,) that the bar works when press anywhere to the right of the 'M' key.  So maybe the bar needs more straightening??  Looks rather straight, though.

 

Oh, I also did a thorough cleaning when I first got it.  Took it apart and cleaned board, connectors, keys, etc... 

From the photos I can see that you have the white plungers on the keyboard so it is a Hi Tek.  I think I may have a suggestion.  What may be happening is that solder pad #57 on the back of the keyboard has cracked, but has not yet fallen out.  This is a common failure of the Hi Tek.  Repeated pounding on the spacebar transfers the load in the Hi Tek into the green PCB and solder pad #57 is one of the two space bar points.  There is a theory that too many enthusiastic rounds of Defender causes the user to smack the space bar too hard.  Cycle fatigue eventually wins and the solder pad breaks and the pin eventually falls out.  Flip the keyboard over and look for solder pad #57 near the space bar area (it's to the right of the ribbon cable points and has a #57 next to it).  It may look OK, but resolder that pad.  Don't add too more more solder, just get it to re-flow. Try it and see if that solves your problem.


Edited by ACML, Wed Jul 11, 2018 10:17 PM.


#28 Pheonix OFFLINE  

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Posted Wed Jul 11, 2018 10:59 PM

I'll give that a try when I replace L101.  Waiting to hear back from Best Electronics right now (15 hours before they next open & counting.)  Depending on what their answer is, I'll either track down other items they have to total it out to their minimum order, or I'll go with one of the not-quite-the-right-values ones off of eBay.  With the hopes that it'll work anyways.  I'm hoping the 0.85-1.15 uH one will work.  It comes the closest to the 0.85-1.2 uH stats one of the sources I came across quoted.  If, it acts as a low-pass filter, though, not being able to confirm the 4.5 Mhz mentioned in the Sam's manual, may cause other problems.

 

The actual solder work, though, will have to wait till I'm having a good day after the part arrives.



#29 BillC ONLINE  

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Posted Thu Jul 12, 2018 4:07 PM

Yes, I used that book extensively.  Other than a couple of mistakes I figured out (R148 isn't marked on the schematics, just a resister symbol without the numbers,) it was quite helpful in attempting to track down the signal loss.  Would have done me more good if I had an oscilloscope instead of just an analogue volt-ohm meter.  Even a more modern digital multi-meter would have been helpful :(

 

From the same page, I pulled the SAMs service manual & the Field service manual for the 800 as well.

Even when the parts value isn't listed in the schematic, it can usually be found in the parts list near the back of the Field Service Manual. The image below is clipped from page 201.

 

14-5221.jpg


Edited by BillC, Thu Jul 12, 2018 4:16 PM.


#30 Pheonix OFFLINE  

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Posted Sat Jul 14, 2018 1:23 PM

Have the inductor on its way :)  Working on next issue....  But a quick catch up:

 

1) Got the 800XL up and running smoothly now.  Started with a red/brown screen, so followed the field service manual & replaced all the listed chips without effect :(  Then started swapping out the other chips that I could.  Turns out the 6502C Sally (C014806,) was causing the problem.  So I have a full set of U2-5, U18, U19, U28, & U30 that all work just fine.  The spare BASIC chip is Rev.B as I went ahead and left the Rev.C chip I bought in the system.  Had a brief problem with the 'F' key remaining triggered at all times, but cleaned the mylar layers and that problem went away.... A brief note:  I really wish the instruction sites I visited on cleaning the mylar had warned me of the 62 tiny springs that aren't being held in by anything.  I "thought" I had found them all and put them back, but turns out I had missed one when the "break" key stopped working.  Got that taken care of, though it took several hours of scanning my floor inch by inch to find the bloody spring.

 

2) Got my second 800 main board up and running :)  it still has it's inductor.  Turns out, in this case, that the POKEY chip was stopping it.  It's own POKEY, constant reboot.  POKEY from the mb with the broken inductor, boots just fine.  So, I'll have 2 working mb's & 2 working power boards when the inductor gets here & I replace it :)

 

3) Got my 800 space bar working fine too.  Turns out that each side of the space bar has 2 holes for the metal support bar.  I had been putting the bar in the same hole on each side.  When I put it in different ones, the space bar started working just fine.

 

4) Giving up on the 1010 tape drive.  It records just fine but doesn't play back.  I just don't have the tools to test correctly.  Nothing appears damaged.  I'll probably try to find someone with the right tools willing to buy it so they can fix it.  But, starting next month, I'll be looking for a 1010 again.  Prefer one with a pass through, or I'd be looking for a 1010 or a 410.

 

5) Second CPU card still not working.  It now has all known-to-be-good chips in it (including the Sally chip borrowed back from the 800XL.)  But the 800 still won't boot with it.  Cannot find any broken traces or obviously damaged resistors or diodes (that's all the components aside from the socketed chips.)  Can't seem to find if there is anything I need to change on the 800 to upgrade from the C014360 to the C015500 card.  Is there any such change that needs to be made?

 

6) Got the Axlon 32K card working most of the time.  The card edge connector is still a little loose, but I'm working on it.  This second MB may be better, I'll give that a try later.  But, as long as I have the 16K card in slot 1 (slot 0 for the OS card,) and the Axlon in slot 2 (and sitting right,) it works just fine at 48K RAM :)  Put the Axlon in slot 1 or 3 (regardless of what's in the other slots,) and it doesn't work (won't even boot.)

 

7) Still cannot get anything from the Mosaic 32K card.  Been looking for a manual, as everything I've read implies I will need to alter the mb for it to work.  I just don't know in what way, and would prefer not to experiment.

 



#31 _The Doctor__ OFFLINE  

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Posted Sat Jul 14, 2018 10:15 PM

um nope my 800 uses old 6502, not sally if you want old school goodness.

 

sally has halt.... old 6502 does not


Edited by _The Doctor__, Sat Jul 14, 2018 10:16 PM.


#32 Pheonix OFFLINE  

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Posted Sat Jul 14, 2018 10:34 PM

The C015500 CPU card was an updated version that dropped 2 of the chips from the card and used the Sally instead.  But, the card is bad.  Tested the chips & pulled them (they're good.)  Going to put this CPU card with the non-working 1010.  Eventually, will find someone who will want to try and fix them.  Figure $5 + shipping & PP fees for either or for both ($5 to cover packing materials mostly.)  The chips themselves I'm either going to store for future replacement or sell to someone that needs them.  Once I've finished testing everything that is.



#33 Pheonix OFFLINE  

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Posted Wed Jul 18, 2018 4:38 AM

I owe ACML an apology.  It seems there was a loose solder pad after all.  Caused the problem to be intermittent.  Was working just fine for about 2 days, then stopped working again.  Got the inductor in, and pulled the KB to check, and noticed that one of the solder joints was loose and would visibly  move when the space bar was pressed.  So, after attaching the inductor, I heated the solder joint to reset.  Only the space bar stopped working completely after words.  Used a desolder gun to clean the solder out completely only to discover that the pin that connects the switch to the board was completely missing on one side.  Used a piece of a new resistor leg to remake the connection, and testing showed that it was making a good connection.  Only, after putting it back together, it again stopped working.  pulled it apart again, to discover that the pad on the board itself had come completely off (still haven't found the piece of resister leg & missing pad.)  Ended up attaching an extremely thin wire further down on the connection point, and then running it around and into the post.  It's working OK, but I'm not happy with it (talk about jury rigged.)  So, now I'm looking for a replacement KB.



#34 _The Doctor__ OFFLINE  

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Posted Wed Jul 18, 2018 11:58 AM

check your solder sucker for the copper.... it probably stuck in the there some where... or in a solder blob.  I had a friend who did the same thing... that is where I found his, I used tiny tweezer tool to hold the copper lead contact in the correct position and soldered it back in. (late 80's)

I don't think the board number was mentioned before but it's cool you have the updated one. Sorry if I misssed it


Edited by _The Doctor__, Wed Jul 18, 2018 11:59 AM.


#35 xrbrevin OFFLINE  

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Posted Wed Jul 18, 2018 12:45 PM

damn those pesky de-bonding solder pads...

although they do test your tenacity and resourcefulness when it comes to repairing them!



#36 ACML OFFLINE  

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Posted Wed Jul 18, 2018 3:32 PM

  It seems there was a loose solder pad after all.  

Don't give up just yet.  The way I fix this is to use a very thin wire like a lead from an 1/8 watt resistor or my favorite go to is those Christmas hooks that you hang your ornomants on.  They are thin and flexible.  I insert the wire and wiggle it around while pressing the space bar and checking continuity between the two solder pads.  When I get a consistent beep (continuity with bar pressed and no beep when not pressed), I very carefully solder the pad taking great care to not move the wire.  Test it again when the solder hardens and if it doesn't work, re-heat and re-position. 


Edited by ACML, Wed Jul 18, 2018 3:34 PM.


#37 Pheonix OFFLINE  

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Posted Wed Jul 18, 2018 3:42 PM

I tried that, but the surface pad is actually gone as well, just bare PCB.  The solder won't stick to that.  Looking into alternate ways of making a permanent connection without a wire having to stick out of the post.  May have to get some PCB glue and just glue a wire in place then go from there.



#38 _The Doctor__ OFFLINE  

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Posted Wed Jul 18, 2018 4:37 PM

remake the trace using copper foil and high temp. epoxy...  readily searchable and purchasable. easy peasy....  go to youtube and watch the videos on trace repair with those materials.. last... thing to to a couple days later... apply pcb mask...  also searchable and purchasable....






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