Atari 130 XE - black screen except for Pitfall II

[NickFolino]

So my 130 stopped working.  Black screen on power on.  I've tried a couple dozen cartridges.

But...

Pitfall II works fine.

The 400/800 diag cart loads, but the jkli keys don't work.  ROM test fails, as I think it should.  40k of RAM passes tests.

Shamus loads to the start screen and plays a steady tone, but nothing else.

 

Everything else just shows a black screen.  To list a few:  BASIC, Pilot, Assembler Editor, Robotron, Midnight Magic, Ernie's Magic Shapes, Pole Position, Cloudburst...

A bunch of different cartridges from different manufacturers, all black screen.

 

Would this be an OS ROM failure?  Could anything else cause this problem?

 

Nick

[Paul Westphal]

Open it up. If you see " MT " stamped on the ram, start there.

 

Atari knew they were buying cheap crappy ram, so sometimes you will see a single Japanese ram in the first slot then the rest would be MT.

The MT ram has the propensity to not reset after power down.

 

This problem is very frequent in the entire XE line.

[Beeblebrox]

@NickFolino  Could be the ANTIC is on it's way out and starting to fail

 

EDIT: sorry - missed that you said RAM test looks ok but Rom test failed. So as Paul mentioned it could be a bad ram chip(s) causing issues. I've had Sys check II report a bad rom chip falsly when it was bad RAM all along. Soon as I fixed the ram it worked and the OS rom started reporting ok.

 

Failing that if Pitfall II is working then I think you can rule out the Y1 crystal as if that had gone you would get a black screen for everything.

 

If it were another component in the video circuit you would also not get any game to run. So I think that rules out the likes of L4-L8. 

 

EDIT: Sounds like i could also be a graphics related issue, hence if not RAM as Paul states in the first instance my money is on ANTIC next.

 

130XE service manual (attached) symptom checklist states:

 

 

Also check out: http://www.atarimania.com/documents/130XE-Reference-Manual.pdf

 

and

 

http://www.atarimania.com/documents/130XE - Sams ComputerFacts.pdf

 

 

130xe Hardware Manual.pdf

Edited February 21, 2022 by Beeblebrox

[NickFolino]

8 minutes ago, Paul Westphal said:

Open it up. If you see " MT " stamped on the ram, start there.

 

Atari knew they were buying cheap crappy ram, so sometimes you will see a single Japanese ram in the first slot then the rest would be MT.

The MT ram has the propensity to not reset after power down.

 

This problem is very frequent in the entire XE line.

Interestingly the first chip is different and is a 4164.  The rest are MT 4264.  I have a ton of 4164 chips.  I assume it's safe to use them instead of the 4264.

One of them is getting pretty warm, so I'll start with him...

 

Thanks!

Nick

[Beeblebrox]

@NickFolino  a single RAM chip getting warm is defo a clear sign of failure.

 

4164s and 4264s are fine to use. What rating are the ones you plan to put in?  120ns or 150ns perhaps (12 or 15 at the end of the stamped number?)

 

Also don't put MT branded chips back if you can avoid it.

 

Are your Ram chips socketed then? Or are you looking to desolder the chip from the board and install a socket? 

 

EDIT: it is quite common it seems for the first chip at the top to be a different number to the rest I've found.

Edited February 21, 2022 by Beeblebrox

[NickFolino]

1 minute ago, Beeblebrox said:

@NickFolino  a single RAM chip getting warm is defo a clear sign of failure.

 

4164s and 4264s are fine to use. What rating are the ones you plan to put in?  120ns or 150ns perhaps (12 or 15 at the end of the stamped number?)

 

Are your Ram chips socketed then? Or are you looking to desolder the chip from the board and install a socket? 

 

They're soldered in.  I'll add a socket when I replace them.  The ones I'll put in are 150ns.

[Beeblebrox]

@NickFolino  Great - sounds like you know what you are doing? 

 

150ns sounds good.

 

Just to say I have socketed a good few XE and XLs in the past year, in particular ram. XE board traces are always generally considered less robust than XL.

 

Saying that I had a stroke of bad luck the other week having desoldered all 8 chips from an Atari 800XLF I was fixing because of a couple bad ram chips and as it transpired some other issues.

 

At the time I very carefully soldered in 8 x new round precision sockets, checked everything in doing so. (I am very mindful to remove the solder with a solder sucker to allow the chips to pop out to minimise the strain on their vias/traces). However it seems I still damaged a trace on the underside with the iron, which I found relatively soon, but topside I'd overlooked one side of a single trace connecting to a via on pin 9 of the socket for the ram chip U13 where there was a very tiny visually imperceptible break in the trace, severing the continuity all the way down the line. (Must had occured when removing the chip from the board topside).

 

Long story short aside the other issues I'd found and fixed, (a handful of damaged traces socketing the entire board, bad OS rom, 2 x bad ram chips, PIA and a DIN Power socket), I was puzzled for days why the machine wasn't working. I eventually found said broken trace on a 3rd or so continuity check. Jumpered the pins underneath and all of a sudden it booted.

 

Reason I'm saying this is I suppose it might be worth socketing/replacing the bad chip first and testing it worked before you socket and replace the others Then maybe just socket them one at a time and test after each socket and new ram chip is in place.  That way if you are unlucky at least if there is a failure, you'll know it is liley to do with the last socketed Ram chip.

 

Just a thought.

 

More info regarding my XLF fix here if you are interested.

Edited February 21, 2022 by Beeblebrox

[NickFolino]

She's back up and running!

Thanks for the help!

It was U26, the RAM chip that was getting hot.  I lifted the trace on pin 3 and broke one of the ceramic caps, but they were easy to fix.

I'll have to remember to always check RAM on these.  I thought for sure it was one of the ROMs just based on symptoms.

 

Thanks again!

Nick

[Beeblebrox]

@NickFolino Great. Easily done. Glad it's up and running.

If you can get yourself a Sys Check II unit made by Tf-hh. Excellent tool plus it gives you 512K of RAM as well. Your 130XE just needs to have an ECI port. (XEGS and rare XE models donr have ECI ports).

 

@Paul Westphal good call. ?

Edited February 22, 2022 by Beeblebrox

[Paul Westphal]

The XE line is the main reason I purchased a $300 Hakko de-soldering gun.  

[NickFolino]

2 minutes ago, Paul Westphal said:

The XE line is the main reason I purchased a $300 Hakko de-soldering gun.  

It wasn't nearly as bad as older Kenwood audio equipment.  Their traces lift and run off when they smell a soldering iron heating up!

[Almerian]

18 hours ago, Paul Westphal said:

Open it up. If you see " MT " stamped on the ram, start there.

 

Atari knew they were buying cheap crappy ram, so sometimes you will see a single Japanese ram in the first slot then the rest would be MT.

The MT ram has the propensity to not reset after power down.

 

Off topic: "....The first recorded lawsuit over the soaring memory chip prices has been brought against Micron Technology Corp, Boise, Idaho by Atari Corp, Sunnyvale, California. Atari’s suit charges Micron with unlawful exploitation of the dynamic random access memory circuits shortage created by federal restrictions on importation of the circuits from Japan and seeks damages for breach of contract, bad faith and violation of federal antitrust laws. It’s a crazy situation, said president Sam Tramiel – First Micron pleads with the government to impose sanctions on the Japanese for selling low-cost DRAM chips, then they raise their own prices to several times their cost of manufacturing the circuits. Atari contends that Micron agreed to sell it 256Ks at $3.75 each, nearly triple Micron’s cost of production and then repudiated the contract in the hope of commanding even higher prices......"
There you go, Micron Technology. Expensive shitty products from a shitty company.

Edited February 22, 2022 by Almerian
spelling

[lbaeza]

BTW, the Shamus cart requires OS-B, it won't pass the welcome screen on XL/XE computers.

 

Regards, 

Luis.

[Paul Westphal]

On 2/22/2022 at 9:47 AM, lbaeza said:

BTW, the Shamus cart requires OS-B, it won't pass the welcome screen on XL/XE computers.

 

Regards, 

Luis.

I believe Shamus will run on XL machines if you hold down either OPTION or SELECT ( can't remember which ) when you turn the machine on. It will skip the title screen, but runs.