Klyball
Experienced Member
Does anyone have have any photo's of the top and bottom of the original power supply board?
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Altair 8800 power supply photos
- Thread starter Klyball
- Start date
MicrocomputerSolutions
Veteran Member
- Joined
- Jul 30, 2012
- Messages
- 563
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.
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.
Klyball
Experienced Member
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
If possible could some one measure the dimensions of the pcb, that would be a start
Klyball
Experienced Member
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.
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.
pcjunky
Experienced Member
Looks great. Just like the PS in my 8800A.
Klyball
Experienced Member
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.
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.