Faulty 130XE?

[Particle Man]

I got a 130XE used some years back. Never used it that much, just fooled around with it a bit. I noticed at first that some games seemed to mess up, and I attributed it to it being a 130XE, thinking maybe some 800/800XL games would just crash due to some incompatibility. Now as I've used it more, I am starting to think it is just faulty. However, I don't know what component it could be, or how to test it.

 

Usually a game will load fine but within some number of minutes (10 minutes? it's very unpredictable) the game will freeze, with a frozen sound (whatever sound is being played at the time) and sometimes with colored lines on the screen. I tried switching to another power adapter and it SEEMED to improve it, but the crashes were still present, and I don't know if it really even improved it or if it was just coincidence.

 

I'm running a memory test on it now, it seems to pass fine. I even left it running for 40 minutes, no apparent problems (though I didn't watch the whole time, so I'm not sure if it erases the red blocks once it cycles?) Anyway, any suggestions on how I can test my system to see one way or the other whether it's hardware or software?

[Rybags]

Might be a bad RAM chip.

 

One symptom is that it can get hot, so maybe try running it for half an hour, then check each of them for undue warmth compared to the rest.

[Almost Rice]

Might be a bad RAM chip.

 

 

I agree. I opened up a few of my 130xe and everyone of them had Micron Technology ram, except for the top leftmost chip. That 1 chip had NEC, Samsung or some other Japanese fab.

 

The solution is probably to replace the MT ram or do 1 of the internal upgrades available.

[Jmk]

With my RAM-troubled 130XE the red blocks stayed up, so you don't have to worry about missing them when you're not watching. Note that there are two BIOS versions of the memory test. The earlier one just tests the first 48K (it shows 48 blocks on screen) and the later one tests the full 128K. If you have the earlier BIOS then it is possible to pass the memory test with bad RAM higher up.

 

If you can, download this, get systest.atr and put it onto a disk or use a SIO2SD/PC cable and run CPS SUPER SALT:

 

Link

 

Run it like this:

LOA SUPERSAL.COM

 

This has a rather good RAM tester, although it will only check the first 64K of memory. If you're having non-128K software problems then something should still show up.

[MEtalGuy66]

Yeah. It's 90% likely bad ram.. 130xe's are famous for it.. especially the earlier models that had 16 ram chips and used the "MT" (Micron Technologies) branded ram.. Ive probably fixed 50 of them or more in the last 22 years or so..

The next most likeley culprit is crappy solder joints.. Ive also seen the EMMU chips fail on quite a few occasions, and occasionally the MMU or FREDDIE chip..

 

The factory ram test is crap.. I have seen it report "all good" many times when ram was in fact defective..

 

Bad thing is, All the chips are soldered in (unless you got real lucky), and the boards are real easy to lift traces when desoldering chips..

 

Get someone with some experience to replace the RAM for you. If it's Micron ram, you migth as well socket & replace all of it..

Edited July 17, 2010 by MEtalGuy66

[Rybags]

What's the deal with the mixing of brands or speeds on the 1-bit RAM machines?

 

I've read here people recommending it, but just don't get the logic behind the scheme.

[MEtalGuy66]

I don't think anyone has ever actually RECCOMENDED mixing brands of RAM in a machine. I have seen many 130xe machines in which ATARI did it at the factory. Usually this is where the machine failed the RAM test on the assembly line, and they went back and replaced one or more chips. Sometimes they even installed a socket under the chip(s) that they replaced. It's actually pretty common on the "16-chip" RAM models..

[sloopy]

I don't think anyone has ever actually RECCOMENDED mixing brands of RAM in a machine. I have seen many 130xe machines in which ATARI did it at the factory. Usually this is where the machine failed the RAM test on the assembly line, and they went back and replaced one or more chips. Sometimes they even installed a socket under the chip(s) that they replaced. It's actually pretty common on the "16-chip" RAM models..

 

x2,

 

absolute best situation is matched DRAMs, but it isnt really necessary on these machines, as long as all the DRAM's supply the bit before the machine reads it...

 

but the two things i wont do are mix speeds, or mix brands within a byte. i have seen this done, and it can work, especially when the DRAMs all have speeds well

under 150ns (i.e. 2@70ns, 3@80ns, last 3@100ns )

 

sloopy.

[Particle Man]

OK. This is the OP, I've tried some of the tests. First I ran M. Pascher's ANALYZE.COM. It gave "Fehler" (fault or failure I imagine) during the following tests:

 

1. Address Test

B1 ADR1 B2 ADR2

00 4000 00 5000

 

2. Refresh Test

BK ADR

00 5000

 

3. Walking

BK ADR

00 5000

 

4. Random Test

BK ADR

00 4000

 

5. (other random test)

BK ADR

00 4000

 

Next I tried "Extended RAMtest". It said the following:

Bank 11100011 $E3 OK

Bank 11100111 $E7 Err

Bank 11101011 $EB OK

Bank 11101111 $EF Err

 

The thing is, I don't know how to interpret these. The 'errors' returned are very quick and reliable, not intermittent at all. Are these genuine errors or just nonexistent RAM it's trying to check? Again it's a 130XE with (I assume) 128K of RAM. If anyone can interpret this I'd appreciate it, thanks.

 

** I also just tried "Super Salt". No detected problems. And since the onboard memtest ram for 40 minutes with no red blocks apparent, I'm not sure what to think.

Edited July 22, 2010 by Particle Man

[Jmk]

OK. This is the OP, I've tried some of the tests. First I ran M. Pascher's ANALYZE.COM. It gave "Fehler" (fault or failure I imagine) during the following tests:

 

I've tried analyze.com before and I've no idea what it's supposed to do. But those same figures show up when you try it on an emulator.

 

Next I tried "Extended RAMtest". It said the following:

Bank 11100011 $E3 OK

Bank 11100111 $E7 Err

Bank 11101011 $EB OK

Bank 11101111 $EF Err

 

The thing is, I don't know how to interpret these. The 'errors' returned are very quick and reliable, not intermittent at all. Are these genuine errors or just nonexistent RAM it's trying to check? Again it's a 130XE with (I assume) 128K of RAM. If anyone can interpret this I'd appreciate it, thanks.

 

** I also just tried "Super Salt". No detected problems. And since the onboard memtest ram for 40 minutes with no red blocks apparent, I'm not sure what to think.

 

Well, E3, E7, EB and EF are the 4 extra 16K banks available in the 130XE. From that, I would guess that you have a fault in the upper 64K of RAM.

 

This would suggest that your first 64K is fine, which is hard to believe as hardly any games (certainly the original games) used the upper 64K... If your chips are socketed then you could swap the first 64K over with the second and either end up going straight to the memory test or you could get a useful result in Super Salt. But they probably aren't socketed...

 

As I'm not an Atari expert, I'll leave it to others to comment before I suggest you break out the soldering iron.

 

----------

 

The left (outer) 8 chips (U16-U09) hold the first 64K of RAM, which Super Salt says is OK. The right (inner) 8 chips (U33-U26) hold the second 64K of RAM. (Although other motherboards with a different number of RAM chips were used).

 

Here is a terrible table, which I believe was accurate for my 130XE (but is not 100% confirmed):

1st 64K   2nd 64K   Bit Held
============================
U16       U33       Bit 7
U15       U32       Bit 6
U14       U31       Bit 5
U13       U30       Bit 4
U12       U29       Bit 3
U11       U28       Bit 2
U10       U27       Bit 1
U09       U26       Bit 0

[Defender II]

If they aren't socketed, and you aren't good at desoldering, you risk a great possibility of lifting traces on 130XEs. I recommend taking/sending it to someone who has the skills to do it for you. If you insist on doing it yourself get a good desoldering tool, MEtalGuy66 posted about a good one not too long ago just do a quick search.

 

Yeah, MG that Micron Technologies RAM is garbage. I got eight pieces I just yanked.

 

If you have MT RAM trash it all and install sockets & new RAM.

First cut the leads on all the MT RAM with a dikes near the top of the chip. Once the chip is out of the way you have better access to desolder.

 

WARNING!

To reduce the chance of lifting traces apply the iron for very short periods of time until the solder flows. If it doesn't work the first time go to a pin on the other side or another chip and allow it to cool before retrying.

You only want to apply the iron to the pin, if possible. (Unlike when you make a solder joint you want to touch the pin and trace.) If the solder won't flow readily you may need to touch the pin & trace (This is required to remove larger wires & items like RF modules, but they usually have a larger ground trace that is less prone to lift.)

 

Next use your soldering iron to straighten any pins on the back side of the RAM. Put the board in a stand vertically and hold the pin with needle-nose pliers. Apply the desolderer or soldering iron to THAT pin on the back side of the board. When solder flows on the front side the pin should come out fairly easily. DON'T YANK IT! If it doesn't come out easily you may not have straightened it enough or your didn't get the solder to flow all the way around the pin and through the board. Let it cool and go to a pin on the other side or another chip. When you come back to that pin you may need to add solder to it to get it to flow all the way through.

Once you have removed all of the pins use the desolderer or soldering iron & a solder sucker to clean up the holes. Don't desolder holes next to each-other unless you allow them to cool first.

 

Install your sockets.

 

Install you new RAM.

Edited July 24, 2010 by Defender II