another dead 130... what could be the problem?

[Marius]

Hi folks,

 

Today I received an ebay bought 130xe.

 

When I opened the package I was VERY happy. This XE is brandnew. Perfect Grey. Keyboard in mint state. And inside the xe also all shiny and now dust or other dirt or traces.

 

So far so good.

 

The XE does do: turning on results in a red power led, and a BLACK SCREEN and some hisssssssssssssss noise from the speaker (very soft). I use a good PSU, and a good cable.

 

What could be the cause.

 

It does do a little thing (the black screen looks like the black screen a healthy atari gives when turned on...) So I think:

 

CPU might be ok.

 

Perhaps OS? But a dead OS results most of the time in a RED screen here.

 

Any ideas? I have tested this with MONITOR cable. On NTSC and PAL.

 

It does NOT boot.

 

Perhaps the bankswitch chip? Or does an atari 130 xe with a bad bankswitch chip still startup right?

 

Thanks

Marius

 

p.s. It only did cost 3,50 euro. So I'm glad with a brandnew case and keyboard for that money. But a working atari 130XE brandnew.... that would be better

[Rybags]

Tried it with a cart?

 

Something like Star Raiders, which takes control immediately.

 

 

I guess open it up. Check the capacitors for leakage/swelling. Check for broken traces on the PCB.

 

Nice that you scored it for 3.50 - mine was $5 but the case/keys have that sickly yellow/brown suntan effect.

[mimo]

Bad RAM

[MEtalGuy66]

oops.. see next post..

Edited October 8, 2007 by MEtalGuy66

[MEtalGuy66]

Bad RAM

 

Well, that would be the classic fault to expect. And apon inspection of the inside of the machine, if it is a revision that uses the 16-chip DRAM arrangement, I would definitely reccomend replacing any DRAM chips marked "MT" (Micron Technologies).

 

However, usually bad base RAM or OS ROM (or faulty connection thereto) produces a green screen.

Bad RAM in the extended bank will not in any way inhibit the machine from booting up normally.

 

 

 

130xes are famous for crap solder joints throughout...

 

Try this.. Lift it about 2 feet above the desk surface, and drop it on the desk. Then plug everything back in and see if anything changed.

 

I swear that back in the mid-late 80s, a guy that worked at an atari authroized service center told me that this was an actual "first step" used in their diagnostic approach for flakey 130xes. He said that more often than not, this would temporarily cause the machine to either work right, or drastically change the failure symptoms- In which case, they would immediately suspect faulty solder connections..

 

I personally have seen quite a few 130xes that did not even have enough solder applied to wick through the holes to the component side. And I mean on LARGE percentages of the board. Some revisions are definetely worse about this than others.

 

All 3 of my 130xes have had their boards completely stripped and rebuilt with decent solder, new caps, and sockets for everything.

[Marius]

Thanks for you very interesting contribution.

 

I did contact the seller, and now he told me he tried that Atari with some other brand PSU!!!!!

 

Hey simply KILLED the atari with a wrong PSU.

 

I don't know what happened. Or +/- swapped, or bad voltage :s....

 

Anyway I think I let this one go. I have really PLENTY of atari 130XE's and I'll strip it for nice chips like the bankswitching pal. Let's hope that one is still alive.

 

That 130XE came in a brandnew case and brandnew keyboard. So I'm still glad...

 

 

If any has an idea what could be damaged due to a wrong PSU. He told me it was a commodore 64 PSU, but as far I know that one does not fit in the atari PSU connector....

 

Marius

[carmel_andrews]

As the xe you've just received is the new one...why don't you desolder the bad ram (if that is the prob.) and get some new ram (from an xe (or xl) not in use, but working) and re solder that ram back into the new xe and see if that sorts out the problem

Edited October 8, 2007 by carmel_andrews

[classics]

I've seen black screen 130XEs that had a bad FREDDIE, though its a very unusual failure. The problem with 130XEs is usually RAM.

 

If he plugged it into a C-64 power supply then expect multiple chips to be burned out.

 

Steve

Edited October 8, 2007 by classics

[philburnite]

Yes definetly faulty Ram , sometimes you can touch each memory chip while the machinre is switched on and feel which ones are getting abnormally hot this works sometimes but what I would do is remove the whole lot and find a working machine and socket one ram chip but leave the chip out so you have 7 rams and one socket then test each 130xe chip individualy youll know which ones are bad when you either get lots of garbage on the screen or a black screen it would help if you did this test procidure with a cartrige game plugged into the working machine .

[MEtalGuy66]

Yes definetly faulty Ram , sometimes you can touch each memory chip while the machinre is switched on and feel which ones are getting abnormally hot this works sometimes but what I would do is remove the whole lot and find a working machine and socket one ram chip but leave the chip out so you have 7 rams and one socket then test each 130xe chip individualy youll know which ones are bad when you either get lots of garbage on the screen or a black screen it would help if you did this test procidure with a cartrige game plugged into the working machine .

 

If the Ram chips say "MT" on them, you may as well consider them bad.

 

Just desolder all 16 of them and install sockets.

 

The "x1256" dram chips used in 90% of old 286,386,or XT motherboards and RAM cards work just fine as "drop in" replacements.

 

These are 256kx1 DRAMs. The extra adress line pin is orphaned on the atari motheboard, so it doesnt matter. They work just fine as a 64kx1 bank.

 

And if you ever want to go to 320k, just "daisy chain" pin 1 of all the chip in the extended bank, add a 33ohm resistor on the end of this new adres line, to the mux'd output of a 74ls158... hook the two corresponding inputs to pins 15 and 16 of the PIA chip, and the select input to pin 30 of the GTIA.. Hook up power and ground, and pull the enable line hi with a hot wire, and you have a 320k XE. One of the easiest and most common ram expansions out there..