Pole Position - CPU Board Battery Replacement?

[kentmurphy]

Folks,

I know this question has been posted before (see below),

http://forums.ace.com/ubbthreads/showfla...rt=all&vc=1

but I still need some help. In the above post, Mark recommended replacing the 6116 CMOS RAM at location 7E on the CPU PCB with a Simtek STK25C48 NVSRAM and the 0.1 uF 25v ceramic disk cap at C67 with a 100uF 25v ceramic disk cap.

Since the Simteks are no longer produced and Mark apparently doesn't have anymore in stock, what other options do I have? My CPU board has the original battery and I am getting nervous.

Thanks,
Kent

 

[jrok]

Since the Simteks are no longer produced and Mark apparently doesn't have anymore in stock, what other options do I have? My CPU board has the original battery and I am getting nervous.

Remove the battery completely and put in a Dallas DS1220AB-200 or an ST M48Z02-200 battery backed SRAM at location 7E. The M48Z parts are normally cheaper than the Dallas parts and both Mouser or Digikey stock them.

- James

 

[kentmurphy]

Thanks Jrok. Any tips on removing the battery and replacing the chip you mentioned? I suspect it will be straightforward. Correct?

Thanks,
Kent

 

[cdjump]

i'd cut the battery off immediately if its the original battery. They're known for leaking and corroding the board, making them quit working. If you see green stuff on your board, then take some vinegar cut by half with water and a toothbrush and scrub the green stuff to neutralize it before it eats a trace up and your boards go south. PP's aren't cheap to have fixed- ask me how i know. lol.

 

[cdjump]

installing the memory should just be removing the old chip, and reinstalling the new one, making sure that you get the notch, or dot, or whatever is used to denote pin 1 positioned the same way as the original was.
Mouser doesn't have the M48Z02-200, but digikey has 234 in stock. I think i may buy one for my PP2 since i need to order anyway.

edit - not sure if 7e is socketed from the factory or not. If not, you'll have to remove the old chip, solder in a socket and install the new chip.
Ok, i just looked on one of my boardsets - 7E on the cpu is a socketed 5517 memory chip, so it should be pull and replace, no soldering involved.

 

[mspaeth]

I've still got several hundred Simteks.

 

[kentmurphy]

Surgery complete. Tumor removed and patient is doing fine.

Patient
Tumor in Patient
Tumor Removed
Tumor

Thanks cdjump.

Kent

 

[kentmurphy]

I've still got several hundred Simteks.

I sent a pm several weeks ago? ... Help me ... Is there any difference between the chips Jrok recommended and the Simteks?

Thanks,
Kent

 

[mspaeth]

The DS1220s and M48Z02s are just battery backed low-power SRAMs, rather than 'true' nonvolatile RAMs. Battery life should be many years on them.

 

[cdjump]

Surgery complete. Tumor removed and patient is doing fine.

Patient
Tumor in Patient
Tumor Removed
Tumor

Thanks cdjump.

Kent

glad to help, or at least try to. Thats the only battery on a PP that i've seen that wasn't leaking, and with an '83 date code, its a small miracle. Consider yourself lucky to have one of a very few un-acid damaged PP boardsets. (or just PP's that work. lol.)

 

[kentmurphy]

I have been so involved with my Star Wars that I forgot to update this post. About 2 weeks ago I replaced the IC at 7E with the Dallas battery-backed SRAM. All is well. Wish I would have taken pictures, but I didn't (damn). Anyway, I want to thank everyone who provided advice. Couldn't have done it without you.

Thanks again,
Kent

 

[kentmurphy]

Per request here are two pictures with the battery removed and the IC at 7E replaced with a Dallas battery-backed SRAM.

http://webpages.charter.net/kentmurphy/images/poleposition/batterysram1.jpg
http://webpages.charter.net/kentmurphy/images/poleposition/batterysram2.jpg

Thanks,
Kent

 

[Leinhit]

Thanks... did you have to solder in a socket or anything.. or just plug and play basically..

thanks for the link.. I'll get looking at it to get one..

 

[kentmurphy]

No soldering ... just pulled the old IC and seated the new one ... just make sure you line up the pins correctly ... if you look at the Dallas IC you can see it has a circle which indicates pin 1 ... just install as you see it in my picture and you should be ok ...

Kent

 

[FrizzleFried]

No soldering ... just pulled the old IC and seated the new one ... just make sure you line up the pins correctly ... if you look at the Dallas IC you can see it has a circle which indicates pin 1 ... just install as you see it in my picture and you should be ok ...

Kent

Sorry to dig up an old thread but where did you get these Dallas IC's, and what model number specifically? A link would absolutely rock...

Thanks!

 

[TheDrewster]

I too would like to know where to get these ICs. Anybody?

 

[Phetishboy]

I too would like to know where to get these ICs. Anybody?

I got mine from Spaeth.

 

[FrizzleFried]

If anyone has a part number/name for this chip, at least I could try to Google it... or if Mark's around??

EDIT: Is this the proper IC? http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail&name=DS1220AB-200+-ND

 

[veldkamp]

Sorry to dig up an old thread but where did you get these Dallas IC's, and what model number specifically? A link would absolutely rock...

Thanks!

Here is the M48Z02. The 200ns part is obsolete, but the faster 70ns is still available (as is the 150ns).

Edit: or, if you really want the 200ns part, it looks like Digikey still has them.

 

[FrizzleFried]

Here is the M48Z02. The 200ns part is obsolete, but the faster 70ns is still available (as is the 150ns).

Edit: or, if you really want the 200ns part, it looks like Digikey still has them.

Thank you VERY much! I picked up the Mouser part linked and just installed them in both PP and PPII. They work like a charm. No more lugging around the remote battery packs... KICKASS. Thanks again!