Question on '71B Hardware Interfaces

[Garth Wilson]

(06-18-2018 12:20 AM)rprosperi Wrote:  

(06-17-2018 11:36 PM)Garth Wilson Wrote:  I have a 64KB front-port RAM module from CMT, but I've never seen one on eBay. I also have a 96KB from them for the card-reader port, and they also had 128KB and 160KB but I didn't have the budget for those. These all had lithium backup batteries so you could remove them (assuming they're FREEPORTed) without losing data.

All front port modules (4K from HP, 32K, 64K from CMT) as well as Card Reader RAM modules (96K, 128K and 160K from CMT and 32K, 64K, 96K RAM, and 32K RAM/32K EPROM from HHP) have been sold on eBay in the last few years (sometimes bundled with a 71B), but they are all quite-to-very expensive - a lowly 32KB front port RAM module goes for anywhere between $100-200, usually towards the high end. Although this is still far cheaper than they were back in the day (e.g. 32K was $395), it's still high for hobby accessories!

Garth - Do you have any idea where to get replacement Lithium batteries that fit the CMT front port 64K module?

I didn't pay that much, but I could probably only dream of getting one in the early production time until SRAM prices came down from the original prices.

I don't have any idea where to get that thin postage-stamp-like battery for the front port RAM. I might have taken mine out a few years ago just to make sure it wouldn't leak in the computer, after it was nearly 30 years old but was apparently not dead yet. I think I put heat-shrink tubing over the one in the card reader port RAM module. I don't remember. I have no real interest in removing and reinstalling, so keeping the memory when they're out of the computer is irrelevant.