View Full Version : Altair 8800 power supply photos

February 8th, 2016, 10:32 AM
Does anyone have have any photo's of the top and bottom of the original power supply board?


February 9th, 2016, 08:32 PM
Does anyone have have any photo's of the top and bottom of the original power supply board?


Here are some photos that maybe help.

February 9th, 2016, 11:12 PM
I have two Altair power supplies sitting here that I'm working on refurbishing for a customer.

The problem that I see is that I don't think there are many people that know what an original Altair power supply looks like. The Altair that I have sitting here with a spare power supply is what I've been told are second series, or improved power supplies. They are supposed to have more output than the original Altair power supplies and as a consequence, are a little bigger.

From what I've been told, the problem is that the original bypass transistors were too small, and have a tendency to fail.

February 10th, 2016, 09:12 AM
Those sound like 8800b supplies , as the first ones had no bypass transistors.
If possible could some one measure the dimensions of the pcb, that would be a start

March 13th, 2016, 09:35 AM
i was able to finish what i think is a very successful power supply replica. originally i wanted to do something that was more robust but decided to go the original route. I did use beefier diode's and wiring. I decided that i would not expand the motherboard as i wanted to leave it in the stock configuration and any expansion would be a single card ram rom serial all in one type design.

The biggest stumbling block was finding the 24/8 volt transformer that was pretty much a no go. I had originally designed a bigger supply using just 2 transformers, and that design got me thinking and when i looked at the finished circuit board i found the solution. Buy Cutting one trace and adding 1 jumper i could use off the shelf transformers with the same look and foot print as the originals and still leaving all the components the same so visually a exact replica.
Unfortunately the machine once power was applied does not function. I found a shorted cap in the 12v reg on the cpu card and after that was fixed still no joy. But that would have been just to easy.


March 15th, 2016, 05:44 AM
Looks great. Just like the PS in my 8800A.

May 16th, 2016, 03:40 PM
I now have my Altair ready for display, i want to just leave it stock minus the replica supply. i have extra card guides and sockets but i won't install them. i doubt i will hook up a drive or any other devices but wanted to have it do a little more then kill the bit so i made a memory /serial board, basically a 88-2SIO minus the current loop with 64k rom and or sram. keeping along the retro line with a couple of semi modern upgrades with parts on hand to keep the chip count down but still giving the vintage feel.
I have 4 extra boards, if any one is interested just PM me. Any way here are a couple of shots of the finished machine , i will put the card slots and guides along with the 88-1MCS in a display with the unit.