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Another 130xe memory issue


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Pin one does NOT connect anywhere so good to go. Can you wash the board with 90+% isopropyl alcohol in order to clean up rosin, flux residue? Sometimes they produce a battery of sorts with the mixture of metals involved and that can cause a good soldering job to perform in the strangest manner, especially completely brain dead. Use a toothbrush to scrub around some while sloppy wet with the alcohol. I always tried to use my sisters toothbrush if at all possible, but you can buy one too. Pin one would have a purpose if the chips for a 256K expanded memory were installed. 64K just doesn't need pin 1.

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@moonlight_mile  also do all the trace/via continuity tests check out for the top side of the board? I am out and about at the mo so can't check but one of my own topics posts a few months back highlighted an issue I had after socketing all the ram on an XL I believe where I missed a tiny bad via /trace connection which was causing a whole line of pins not to connect. 

Edited by Beeblebrox
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I was working on cleaning up the board some more. I have 91% iso and a toothbrush. Been lightly scrubbing with the alcohol but the board where I was working is still pretty sticky from the flux. I have cleaned it with the iso about 10 times. Is there something else I can use to remove the sticky flux residue?  I have goo gone but I think that is a mild acid so I don’t know if that would be safe or not. 
 

any suggestions?

 

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1 hour ago, moonlight_mile said:

I was working on cleaning up the board some more. I have 91% iso and a toothbrush. Been lightly scrubbing with the alcohol but the board where I was working is still pretty sticky from the flux. I have cleaned it with the iso about 10 times. Is there something else I can use to remove the sticky flux residue?  I have goo gone but I think that is a mild acid so I don’t know if that would be safe or not. 
 

any suggestions?

 

I've used the citrus smelling Goo Gone many times to remove flux.  Generally followed up by super hot water and if needed, Dawn dish soap.  I don't worry about how wet the board ever gets, I have an air compressor I use for drying.

 

P.S.

Cleaned PCBs like this for years when I was working at an assembly place running their wave soldering machine.  Hundreds of PCBs at a time, went right from the wave solder into the sink.

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That worked. All clean and dry now. Still red screen. Actually it started as a green screen but now it is steady red screen. Tried the syschek. Goes right to red screen. 
 

Left it on for a while. The 6502 is the only chip that even got warm. (The first time). Then I left it on again and the 6502 and the antic was getting slightly warm. 
 

Remarkably, my 6502 is socketed. Checked my backup 130, nothing is socketed. So I checked my 800xl. 6502 is socketed but I have the U1M lines soldered to the chip and really don’t want to fool with this, since my 800xl works perfectly. (Knock on wood). 
 

so… I figure it would be a good idea to have a backup 6502. I found this on on ebay. Obviously, it doesn’t have the c0180xxx Atari chip number. But it is a 6502. Will this work?  Want to double check before I order it. 
 

Here is the link:

https://www.ebay.com/itm/372746009184

 

also for shits and giggles I checked my mt ram with a 4164/41256 dram tester I bought years ago. Only 1 mt ram was bad. But I know they are a timebomb. Just figured I would use my ram tester since I think I have used it a total of 2 times since I got it. Lol. 
 

let me know what you guys think. 

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the A8 6502 is different to the standard one - Atari requested an additional HALT function.

i think its called a 6502B but check first before you spend any dough

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On 4/25/2022 at 2:13 PM, moonlight_mile said:

That worked. All clean and dry now. Still red screen. Actually it started as a green screen but now it is steady red screen. Tried the syschek. Goes right to red screen. 
 

Left it on for a while. The 6502 is the only chip that even got warm. (The first time). Then I left it on again and the 6502 and the antic was getting slightly warm. 
 

Remarkably, my 6502 is socketed. Checked my backup 130, nothing is socketed. So I checked my 800xl. 6502 is socketed but I have the U1M lines soldered to the chip and really don’t want to fool with this, since my 800xl works perfectly. (Knock on wood). 
 

so… I figure it would be a good idea to have a backup 6502. I found this on on ebay. Obviously, it doesn’t have the c0180xxx Atari chip number. But it is a 6502. Will this work?  Want to double check before I order it. 
 

Here is the link:

https://www.ebay.com/itm/372746009184

 

also for shits and giggles I checked my mt ram with a 4164/41256 dram tester I bought years ago. Only 1 mt ram was bad. But I know they are a timebomb. Just figured I would use my ram tester since I think I have used it a total of 2 times since I got it. Lol. 
 

let me know what you guys think. 

I just watched a video where  flashjazzcat was repairing a 130XE with a red screen also. He tried a couple of things and what happened to complicate this is that he had inadvertently  replaced the bad RAM with more bad RAM. He swapped it out with another batch of RAM and then it booted up fine. Did you test the known good RAM to make sure that there were no duds? 

The video in question is this one. He discovers this about 1:031:35 into the video

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I did watch his video the other day.

At this point the ram I have in there was tested a few years ago but hasn’t been tested recently. I will run all those chips through my ram tester again tomorrow see if any of them went bad. Below is a pic of my ram
Testere5408f5eacbfac79311fc9ff1615f48b.jpg

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Posted (edited)

I re-tested all my Samsung (I think that is the brand) ram. All passed the tests. 
 

I haven’t done too much with this. Waiting on my new 6502. But since you guys have better eyes than this old guy, here are pics of the board. Please be gentle on the soldering skills. Lol. 
 

Let me know if you see anything I really botched up. 

yes I know the one chip is backwards. But that is because I just put them back in. I fixed that. And they were all in the correct way when I tested the board. 

thanks again!  

1C31DEA2-84ED-4627-B707-05AA13ABCF05.jpeg

A1F4BB1B-279B-48FC-8348-2ED51791971D.jpeg

C8A575F5-6333-4570-8F70-14DB2481661E.jpeg

B67904BD-65D8-46D9-B615-58FBBC5C921F.jpeg

Edited by moonlight_mile
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Ok.

This all arose a few years ago when I got an side2 cart. It would not boot. Jazzcat felt there was something wrong because the cart needed the extra ram or something.

It ran fine as is. It just didn’t have the extra bank of 64k. I think I used the 512k on the syschek once and it all worked. So it was possibly a ram issue.

With the resistors not switched everything passed with syschek.

I flipped the resistors and every chip came up bad. (I have tested all the chips that I pulled out and only the 1 tests bad but that doesn’t necessarily mean much with the mt chips).

So, I put in the sockets on the 2nd bank since this was definitely part of the issue. 1st bank tests fine.

Once all was done and I plugged it in I got the red screen. I haven’t bothered to switch the resistors back to see if the computer boots as of yet.

Left it on for a while. The 6502 is the only thing that warms up. 2nd time I left it on the 6502 and antic started getting warm. Neither were hot.

So, that is where I am, ordered a newish 6502 from myatari on eBay. Just waiting for that to get shipped. I am just started with the 6502 since it is socketed.

The other atari I have with a socketed 6502 is the 800xl and the u1m is installed in there and I really don’t want to fool around with that too much since it is working fine.

I don’t have an oscilloscope (I really want one but it is have to substantiate the cost for a very rare use) but I have a logic probe. I have never had much luck with the probe but I am going to give it a shot in the next day or two.

I am pretty sure the power is fine on the board. It has been a while since I tested it but I will test that again when I probe around.

So. That is kinda where I am with this project.

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beeblebrox will laugh as i fought against it with my own XE project, but id get the memory checked by switching over first, and i wouldnt trust the first bank of MT isnt the problem.

but for sake of ease and for a few quid changing the CPU isnt a bad shout to rule it out

 

Do you have a star raiders? does it work?

 

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beeblebrox will laugh as i fought against it with my own XE project, but id get the memory checked by switching over first, and i wouldnt trust the first bank of MT isnt the problem.

but for sake of ease and for a few quid changing the CPU isnt a bad shout to rule it out

 

Do you have a star raiders? does it work?

 

 

red screen only happened after you swapped memory?

sounds like you broke a track/bad solder or something static fried...

 

you only really need check the continuity down the whole bank of ram by checking pin to pin on the top and bottom chips (as they are linked via the rest), on most pins

 

my gut feeling is its smethign wrong with your ram or ram install

 

 

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I think my traces are ok. What I did was placed one probe on the leg of the chip and the other probe elsewhere on the board. Thinking if the leg of the chip goes through the socket to the pad and then to its destination that the traces are good. Here are my results. 
 

Legs 9-16 all connect to each other. 
Leg 2 on all the chips connect to various pins on the cpu

Legs 3,4,5,6,7,8 all tone out to various pins on the Freddie chip

Leg 1 (as previously indicated) goes no where. 
 

Am I on the right track in my process of checking the traces?

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16 minutes ago, Beeblebrox said:

@ugliestgolf this is completely off topic but I gotta ask. I know AA forum pseudonym's can be anything, but I am curious ... is there any significance to yours? ? Are you an avid golfer?  

Maybe he drives this?

CGTalk - Vw Golf Mk1 1979, Grid (3D)

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Yes i do play golf

 

and it’s a randomly generated xbox live name from back in the og xbox days when the only online game was links golf…

been my name ever since..

if ud seen me play you’d understand…my golf is ugly

effective but ugly/not pretty

Edited by ugliestgolf
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