• Please review our updated Terms and Rules here

Apple //e aux RAM issue

agentb

agentb

Experienced Member
Joined
Apr 22, 2021
Messages
364
Location
Philly, USA
I recently came upon an enhanced Apple //e that had been in storage for decades at an old school. Seems to work pretty well, but fails self-test with:
*RAM 0 0 1 0 0 0 0 0

I believe the * references the extra 64k not the base 64k. And the order of the bits is opposite the order on the ram card or motherboard.

Can someone confirm that indicates Chip 6 on the aux ram board?

I ordered a few 4164 chips and piggybacked one on to Chip 6 but that doesn’t solve the self-test and once I got the error MMU with the piggybacked RAM.

Not sure if piggybacking is really fool proof? So should I desolder Chip 6 and replace with a socket and new 4164 chip? Don’t want to bother if the problem is elsewhere. Any other suggested tests, please let me know.

RAM test fails on 2nd pass which I think may be aux RAM: at address 91A4 bit 5 which seems to concur with the self-test indicating Chip 6.

Thanks for any help you can offer. It’s been forever since I’ve played with an Apple II, my first computer was an Apple ][plus.21D642D8-49F3-4E08-AD79-66A57DEC5905.jpeg5C3D148F-D2B9-4C36-9B11-E1430AB1B5B5.jpeg
 
its the ram on the aux slot board. usually the 64k 80 col card. yes ram #6

If you take out the aux ram card and rerun the diagnostics they should pass unless you have bad onboard ram as well which is unlikely but completely possible.

I never had luck piggybacking. its just a waste of time. Pull the card and run the test again
. if it passes you know the ram on the card is bad.. which ram card do you have? share a photo.
 
Thanks for the reply. Yes without the card the test passes. I’ll look to replace that chip 6.

B01FA540-AF3E-47E5-A5D3-833C67B07C95.jpeg
 
agentb said:
I recently came upon an enhanced Apple //e that had been in storage for decades at an old school. Seems to work pretty well, but fails self-test with:
*RAM 0 0 1 0 0 0 0 0

I believe the * references the extra 64k not the base 64k. And the order of the bits is opposite the order on the ram card or motherboard.

Can someone confirm that indicates Chip 6 on the aux ram board?

I ordered a few 4164 chips and piggybacked one on to Chip 6 but that doesn’t solve the self-test and once I got the error MMU with the piggybacked RAM.

Not sure if piggybacking is really fool proof? So should I desolder Chip 6 and replace with a socket and new 4164 chip? Don’t want to bother if the problem is elsewhere. Any other suggested tests, please let me know.

RAM test fails on 2nd pass which I think may be aux RAM: at address 91A4 bit 5 which seems to concur with the self-test indicating Chip 6.

Thanks for any help you can offer. It’s been forever since I’ve played with an Apple II, my first computer was an Apple ][plus.
Click to expand...
It's definitely not fool proof but it was successful for me the one time I tried it.
 
Verault is correct, remove the card and test the system. That will isolate the source. Have you tried to PR#3 it? Does it go into 80 columns? If it had a bad ram it probably won’t. Some people are pro piggybacking and some are against it. I’ve only tried it once on my memory card and I had good luck. You’ll need to form your own opinion. 4164s and 4264s are perfectly interchangeable. It probably doesn’t matter but personally I’d keep the speed the same as the others. Yes that is location 6. Remove (both) ICs at location 6 and install a socket for the new IC.
 
Self-test without the card works fine. With the card in place, PR#3 does indeed go into 80 columns, AppleWorks in 80 columns also seemed to work. Next step I'll tackle replacing chip 6 on the mem card.
 
huzzah! Replacing Chip 6 on the aux mem board did the trick! Both the self-test and the RAM test program now both pass. And most importantly, Maniac Mansion now loads properly. Previously there was some corruption on the title screen and weird behavior.

I used a desolder tool with a push-button spring-loaded suction. Really tempted to get one of those desolder power suction vacuums after this. Would have made it a lot easier. Thanks for the help.
 
Desoldering tools are nice. I use one constantly. My advice is dont buy the cheap ones. I bought one of those cheap blue chinese ones and it broke within 2 weeks. The iron broke free from the body, it was just connected via plastic!

A hakko FR301 is fantastic. I use the FR300 but they are pretty much the same.. Worth every penny.
 
Absolutely. I was nervous on the price. Paid like 30 or $40 for the chinese garbage and $300 for the hakko. Heater burned out on the hakko at 3 months. They replaced it free of charge and gave me 20 free ceramic paper filters for my inconvenience so I know they stand behind thier product,. I use it all the time. I have bought extra tips and let me give some advice. Replace the tips ONLY when HOT! They have a special tool included for swapping the hot tips. I tried doing it cold on a well used one and the solder inside made a seal and it broke my heater. So I had to buy and install another heater a couple months back.. but that was all my own fault.
 
And the gentleman that’s praising the Hakko is who had me get one and I don’t know how you could even be in this hobby without one. I had ZERO luck with those cheap “suckers”. You use this tool once and you’ll never know how you got by without it.
 
I was thinking about how you told me you dont like solder suckers the other day when i decided to use one on a quick job of fixing an apple ii softcard. It worked great. I like solder suckers but the hakko is still a million times better.

I still hate solder braid for through hole stuff. its ok for SMD work and removing excess solder.
 
Thanks for the tip on the hot tips. I’ll have to order up one of these. Seems well worth it if I need to desolder in the future.
 
agentb said:
huzzah! Replacing Chip 6 on the aux mem board did the trick! Both the self-test and the RAM test program now both pass. And most importantly, Maniac Mansion now loads properly. Previously there was some corruption on the title screen and weird behavior.

I used a desolder tool with a push-button spring-loaded suction. Really tempted to get one of those desolder power suction vacuums after this. Would have made it a lot easier. Thanks for the help.
Click to expand...
I think you're referring to a SOLDAPULLT:

www.edsyn.com

The Original Deluxe SOLDAPULLT

Check out the deal on The Original Deluxe SOLDAPULLT at EDSYN Inc.
www.edsyn.com

I have one of these and it works quite well. The only problem is the "violence" from the release tends to cause the tip to move pushing the soldering iron tip across the PCB and marring the silk screen a little. Not the end of the world but annoying (to me).

I also have the Hakko 301 (per Veraults recommendation). Really nice and what I use for most of my desoldering needs. I wouldn't spend the money on one unless you have a critical project or expect to do a lot of desoldering. I ended up purchasing a smaller tip for it as I feel it works better for my desoldering needs.
 
Yeah I don’t have any immediate desoldering needs, so hard to justify the expense. But oh yes, in my mind totally worth it for the next cap replacement or whatnot.
 
If you arent going to do much desoldering work than thst msy be all you need. I do tons of work so I can justify it. If you buy that heated aolder pump do me a favor and open a thread to review it. it would be good to kbow if it works especially for those who dont need an expensive deaoldering gun.
 
You must log in or register to reply here.
Back
Top