ATARI 130XE Ram test Failure

[Madi]

I purchased an Atari 130XE through eBay. When I turned it on, it went directly to ram test . All ram boxes (cells) showed red color except for the box 1, 13 ,21 and 22. when I inserted a CART, it always go to ram test screen only. Is it mainly a ram failure issue?

If I get a ram extension model such as RAM320XE will be suffice?

 

Thnx

[Kyle22]

Hi Madi,

 

I think you need to replace the RAM chips inside the computer. Depending on what version of the XE you have, there will be either 4 or 16 RAM chips. RAM is cheap (these days), the only thing you have to be careful of is the circuit board itsself. Atari went cheap on the XEs and the pads and traces will EASILY lift if you apply too much heat when desoldering / soldering.

 

Any competent electronics tech should be able to help you. Also, if your power supply is part # C061982, ask the tech to use a voltmeter and check the output of your power supply. These are known to fail and go over 5 volts, and a common casualty is the RAM (usually along with buzzing sound, and distorted screen).

 

Good luck,

 

-Kyle

[Xuel]

I have an Atari 800XL that powers on to a black screen unless I connect my RAM320XL to it, so I'm thinking the RAM320XL is substituting for the faulty internal RAM, like you say, but I don't know for sure if that's true or even possible. In my research for my own PBI device I was under the impression that it would be possible for the external device to ignore EXTENB and assert the EXTSEL signal even for accesses to internal memory thus making it possible to stand in for the internal RAM.

[Kyle22]

Interesting..... I don't know for sure. I don't own a RAM320 (I'm a 1200XL guy). There must be some RAM320 owners who could say for certain. I just don't like the idea of having bad RAM in the machine, and 'covering up' the problem by using an external solution.

 

-K

[Madi]

Thank you Kyle for the information.

 

I opened the 130XE and found 16 ram chips 15 of them marked with µT 4264-20 and only one was marked with m 3764_15RS (OKI).

I tested the power supply voltage on pins 1,4,6 of the C061982 power supply and it read +5v.

 

It is not clear to me which is the best RAM replacement technique:

Should I buy the same chip ratings (64k) ?

or can I replace them with compatible 256K for example?

Is it possible to mount the new ram chips on top of original ones (piggybacked) to be safer?

What are the recommended RAM brand(s)

 

Madi

 

[Madi]

Just to add more testing results.

I turned the 130XE on for 10 mins,then measured the temperature of all chips on board with gun (laser) thermometer

 

All RAM chips (16) were of normal room temperature (25 +1 or 2 C) except for:

C014806C (Atari SALLY 6502C) ? and C021697 (ANTEC 'E') ? which are the only socketted chips.

The temperature of both was 41 C.

I thought, that temperature goes very high for damaged RAM chips

Madi

[russg]

Thank you Kyle for the information.

 

I opened the 130XE and found 16 ram chips 15 of them marked with µT 4264-20 and only one was marked with m 3764_15RS (OKI).

I tested the power supply voltage on pins 1,4,6 of the C061982 power supply and it read +5v.

 

It is not clear to me which is the best RAM replacement technique:

Should I buy the same chip ratings (64k) ?

or can I replace them with compatible 256K for example?

Is it possible to mount the new ram chips on top of original ones (piggybacked) to be safer?

What are the recommended RAM brand(s)

 

Madi

 

Those MT DRAMs are known to fail, if memory serves. It isn't easy, but replacing them is required. I think cutting the pins, with say, a dremel type cutting disc, makes

removeing them easier.

Edited October 28, 2013 by russg

[+Roydea6]

Just to add more testing results.

I turned the 130XE on for 10 mins,then measured the temperature of all chips on board with gun (laser) thermometer

 

All RAM chips (16) were of normal room temperature (25 +1 or 2 C) except for:

C014806C (Atari SALLY 6502C) ? and C021697 (ANTEC 'E') ? which are the only socketted chips.

The temperature of both was 41 C.

I thought, that temperature goes very high for damaged RAM chips

Madi

Since the two hot chips are socketed. I would try swapping those two chips with replacements first and if not fixed then move onto more difficult DE-soldering of other chips.

[Almost Rice]

I second russg diagnosis. Those ram chips need replacement or buy the 320xe ram upgrade and dont worry about internal ram

[Kyle22]

It would be very unusual for the 6502 or ANTIC to show RAM failure in the self-test. If either of those were bad, I would expect a blank screen.

 

Careful use of a dremel to cut off the pins as close to the chip as possible, then carefully heat and pull out each one. After that, careful use of de-soldering wick to clean up the holes. Please install sockets while you have the chance, it makes it much easier later if you have a problem.

 

There are memory upgrades which use 256K chips. 320K is a common setup, that's 1 row of 64K, 1 row of 256K. There are some extra (small) chips and wiring involved, or, you can put 2 rows of 64K (like original) and use the Ultimate 1M upgrade. U1M gives you 1MB RAM, SpartaDOS-X, Clock, and more. All inside.

 

More info here http://atariage.com/forums/topic/211158-ultimate-1mb-installation-questions/

 

4164 chips on ebay http://www.ebay.com/itm/D4164C-15-Dynamic-RAM-Memory-64K-x-1-Bit-UPD4164C-15-/310127868116

 

41256 chips on ebay http://www.ebay.com/itm/RAM-KM41256AP-12-Samsung-16-Pin-DIP-41256P-41256AP-/370291917418?pt=LH_DefaultDomain_0&hash=item56371e426a

 

Good luck

 

-Kyle

[+bob1200xl]

This works pretty well. Those are 4 1/2" Xcelite cutters.

 

Bob

 

 

[1050]

It is not clear to me which is the best RAM replacement technique:

Should I buy the same chip ratings (64k) ?

Yes for the left or outside row especially since they are the ones being tested in the built in ROM/RAM test and showing as bad. The right row or inside row are your 4 extended memory banks and can not be tested with your current version of OS ROM that didn't have that in there yet. Upgrading to the last ROM OS for the 130XE that does do the extended memory test only tests the standard 4 banks and not the rest if you go for bigger (why not while you are in there?) so it becomes less than desirable to do the last ROM OS upgrade all said and done. Your box, you stuff it with what you want.

 

or can I replace them with compatible 256K for example?

Right row only and then for a larger extended memory, but yes. Even larger can be done by piggybacking the left row except for the -CAS pin on all those chips as they still need that -CAS signal from the right row in order to work as extended memory. Otherwise the two rows have the same signals and you can check this with a voltmeter pin for pin.

 

Is it possible to mount the new ram chips on top of original ones (piggybacked) to be safer?

People do it, but I don't understand why or even how it works unless the original chip is dead somehow (new one on me and never seen this myself) and this is the fault showing in the test. Having the new chips 'pinch' the legs of the old ones first without using any solder and trying the ram test again and having good results would be the only way I would proceed with this technique. Then soldering the new ones in place to ensure solid sound connections. Since I can do this kind of work without too much fear, I would go ahead and take the old chips out, put in machine sockets and be done with it.

 

Your temperature readings show dead chips, active ones would be quite warm but not blazing hot. Please verify those low temps with your finger. The 40 pin jobs run hot as a matter of course, if they were bad, you would not be looking at a built in RAM test screen, you would have only shades of colors if lucky and nothing else.

 

Shorted RAM chips from an over voltage power supply will raise a blister on your finger they run so much hotter than 'good' running chips, you got that part right. But if they just up and die and are just lumps on a log then they won't show any signs of extra heat and they should if they are working. Too hot or too cold equals a bad chip.

 

What are the recommended RAM brand(s)

Anything other than MT or more correctly, uT as you have noticed seems to be the consensus. Stay away from those stinkers and you'll do just fine.

[+tf_hh]

Hi,

 

Should I buy the same chip ratings (64k) ?

or can I replace them with compatible 256K for example?

Is it possible to mount the new ram chips on top of original ones (piggybacked) to be safer?

What are the recommended RAM brand(s)

 

As already told, the Micron (MT) DRAMs are often faulty. But it could be happen, that only one item is really damaged. If no one of the DRAMs gets very hot, it seems to be a "normal" failure - Some times some silly people plug in a Commodore C64 power supply into an Atari XL/XE, this kills mostly instantly all DRAMs first (because the C64 uses 9 volts AC and 5 volts DC, Atari XL/XE only 5 volts DC),

 

You can try to swap the banks, this is an easy test. In the attached picture I mark two resistors - the CAS_MAIN and CAS_BANK signals are there. Just swap the ends of both resistors (just choose one end, it´s not important which one) to each other, so that the resistors are not in parallel like in your picture, they have to be crossed like an X.

 

If the second bank is okay, then your 130 XE will start. Of course the extended memory is faulty now, but you can live without it - or better insert an U1MB :-)

 

Regards, Jurgen

 

[atari8warez]

and if you can get the first bank working as suggested by Jurgen above, you can then boot the computer from a drive and test the rest of the memory (extended RAM) with this program. This is an .atr so you will either need an SIOxxx device to boot from or somehow convert that to a real disk.

Memory Test Radon Boot.atr

Edited October 30, 2013 by atari8warez

[Madi]

Thank you all for info and suggestions, that I learned a lot.

 

When I swapped the banks as suggested by Jurgen, I got a black screen (with some twisted grey vertical lines).

I switched back to the original connections of resistors R110 and R111 and the test ram screen came alive again (all bad except 3 boxes).

 

I guess that I will wait for the ram chips I did order yesterday and let you know of the outcome. (a simple eBay purchase turned into a project ).

Unfortunately, orders take 18-25 days to arrive.

 

BTW, Almost Rice had mentioned a 320xe ram upgrade. I though it is still a beta project. I would appreciate it if some one put the link.

 

Regards

Madi

[fibrewire]

This works pretty well. Those are 4 1/2" Xcelite cutters.

 

+1 for Diagonal cutters. When working with electronics, involuntary muscle spasms are much harder to correct when using a dremel