PDA

View Full Version : Is the CPU board in this Altair legit?



falter
July 17th, 2016, 08:37 AM
Currently saving up for an Altair and whilst doing so trying to familiarize myself a bit.

I keep seeing this one on ebay.. and wondering if it's the real deal or a clone. Obviously it's missing its RAM board. The thing that has me wondering is the condition.. and the cpu card. I note the cpu card's silskcreen for parts placement is black rather than yellow? All the Rev 0 boards I've found thus far are yellow. Just wondering.

glitch
July 17th, 2016, 08:54 AM
I don't see a picture or link in your original post, but at some point MITS did transition to black silkscreen.

falter
July 17th, 2016, 09:00 AM
Whoops.. here's the link:

http://www.ebay.com/itm/131839492235

Chuck(G)
July 17th, 2016, 09:02 AM
Looks just like the one I have--and I built that one myself.

roberttx
July 17th, 2016, 09:24 AM
This listing (131839492235) has been removed, or this item is not available.

It's gone now.

SomeGuy
July 17th, 2016, 09:56 AM
The link still works for me, but the last few days I have seen that "This listing has been removed" error pop up quite a bit even when they are still there. Hitting reload usually fixes that.

smp
July 17th, 2016, 10:18 AM
The link works for me, too.

I'm drooling over the good shape this system seems to be in!

Too rich for my blood, though.

smp

falter
July 17th, 2016, 01:02 PM
You *do* have to have the original RAM board to operate it though don't you? That's the minimum system?

Chuck(G)
July 17th, 2016, 01:23 PM
Which original RAM board? I seem to recall that there was a static RAM board and then a DRAM board using 4Kx1 3-rail 22-pin DRAMs.

But any S100 RAM board should do the trick.

roberttx
July 17th, 2016, 01:23 PM
The link still works for me, but the last few days I have seen that "This listing has been removed" error pop up quite a bit even when they are still there. Hitting reload usually fixes that.

With my work account, in Firefox, I consistently get the error message. Refresh doesn't change anything, but searching on the item # brings up the listing.

With my personal account, in Edge, the link works fine and brings the listing right up.

More ebay weirdness...

falter
July 17th, 2016, 01:53 PM
In the manual the reference an '8800 memory board' that uses 8101 rams.

Chuck(G)
July 17th, 2016, 02:17 PM
Same as 2101 SRAM. 256x4 22-pin +5 single-rail. Power hungry beasts--1W per package. The board gave very little memory (1K maybe?) It was already obsolete by the time the 8800 was shipping. MITS came out with the 4K DRAM (miserable thing) at about the same time to improve the memory picture.

smp
July 17th, 2016, 02:24 PM
In the manual the reference an '8800 memory board' that uses 8101 rams.

Hi falter,

Yes, the Altair documentation will refer only to Altair boards for memory and I/O. As Chuck said, pretty much any S-100 RAM board will fill the bill for a generic system. If you are going for all 100% Altair, then you will need one of the Altair memory boards. IIRC, when I built mine (so long ago) I had the 1K static RAM board, with the entire load of 1K. It consisted of four pairs of 8101 (or 2101) static RAM chips, each containing 256 x 4 bits, so you needed at least one pair of chips for 256 x 8 bits. I had all eight chips, for the entire 1K.

smp

Chuck(G)
July 17th, 2016, 02:46 PM
I'll add that third-party RAM boards were by far one of the best sellers in the early days. I've got a couple that use 2102L/91L02 1Kx1 SRAMS--64 of them for a grand total of 8K per board.

Makes today's gigabyte RAM seem almost ridiculous in comparison.

MicrocomputerSolutions
July 17th, 2016, 03:45 PM
The link works for me, too.

I'm drooling over the good shape this system seems to be in!

Too rich for my blood, though.

smp



Good Shape?

Did you miss the rust on the inside (top) of the rear panel (and the components) ?

smp
July 17th, 2016, 04:12 PM
Good Shape?

Did you miss the rust on the inside (top) of the rear panel (and the components) ?

Yes, I missed that. Sorry for my enthusiasm.

smp