[GL1zdA]

I have a Personal IRIS which I know was working. I disassembled it once, but haven't had time to work on it, so it was lying for 2 years in parts. Recently, I've reassembled it, and it doesn't work anymore. There are no signs of life: I'm switching the power on and nothing happens, I can't hear even a single fan. The power cord is connected. I think I've connected everything, but maybe this is I should check something? I've tried to find a disassembly guide, but it seems it is gone: https://web.archive.org/web/200310101502.../piris_td/ .

[jan-jaap]

The PSU of the Personal IRIS is straightforward. No soft power on/off etc, if mains voltage goes in then +5, +12 etc comes out on the other side. If it doesn't, it's broken. This happened to me as well a while ago, and you can read HERE how I replaced it using a compatible donor PSU and some handy work. There's a similar story based an an AT PSU (so pre-ATX) on sgistuff.net, but using a donor PSU that old is maybe not such a good idea in 2021.

[Raion]

One note: don't try ATX. Many of our computers use negative voltages and these are not supplied by an ATX. This can cause all sorts of issues.

[GL1zdA]

The PSU of the Personal IRIS is straightforward. No soft power on/off etc, if mains voltage goes in then +5, +12 etc comes out on the other side. If it doesn't, it's broken. This happened to me as well a while ago, and you can read HERE how I replaced it using a compatible donor PSU and some handy work. There's a similar story based an an AT PSU (so pre-ATX) on sgistuff.net, but using a donor PSU that old is maybe not such a good idea in 2021.

I remember your story. Do you know any other replacement PSUs? I found the PFC375-4000, but it would cost me around $500.

One note: don't try ATX. Many of our computers use negative voltages and these are not supplied by an ATX. This can cause all sorts of issues.

The problem with ATX would be to find one, that supplies over 40 A on 5 V, so I didn't even think about using one. But it's good to know that there are other issues with them.

[weblacky]

The PSU of the Personal IRIS is straightforward. No soft power on/off etc, if mains voltage goes in then +5, +12 etc comes out on the other side. If it doesn't, it's broken. This happened to me as well a while ago, and you can read HERE how I replaced it using a compatible donor PSU and some handy work. There's a similar story based an an AT PSU (so pre-ATX) on sgistuff.net, but using a donor PSU that old is maybe not such a good idea in 2021.

 From your experience, do these Personal Iris PSUs bench-start automatically (assuming they are correctly loaded)?  While we might not be there yet, repairing PSUs that we KNOW how to bench start lowers the bar to repair...considerably.

[jan-jaap]

The PSU of the Personal IRIS is straightforward. No soft power on/off etc, if mains voltage goes in then +5, +12 etc comes out on the other side. If it doesn't, it's broken. This happened to me as well a while ago, and you can read HERE how I replaced it using a compatible donor PSU and some handy work. There's a similar story based an an AT PSU (so pre-ATX) on sgistuff.net, but using a donor PSU that old is maybe not such a good idea in 2021.

 From your experience, do these Personal Iris PSUs bench-start automatically (assuming they are correctly loaded)?  While we might not be there yet, repairing PSUs that we KNOW how to bench start lowers the bar to repair...considerably.

I still had a working PSU, so here's the original and the partially rebuilt PSU:





Notice the brown jumper wire on the white/black wires. That's where the power switch should be. Wired like this, the PSU starts up without any hassle (I tried). There's a sense wire going back from the IP6/IP10 and a power fail signal, but that's it.

The problem is that L-shaped bracket that covers the solder side of the PCB. It is used as a heat sink for several components, so unless you attach something else to help cool these you can't poke around in the live internals.

I don't need to explain to you that troubleshooting these PSUs can be a rather time consuming affair. I was already familiar with PowerOne (from the big iron) so I simply looked for a replacement in their catalogue that would fit the Personal IRIS form factor. That's how I came up with the PFC375 series. I was able to source the PowerOne PFC375-4000 unit for very little money, new in box, but some others (PFC-3000?) will work as well. IIRC the '4000 has a -5V output and the '3000 doesn't. The original PSU doesn't supply -5V either.

So, between an impractical and time consuming repair and a cheap, reliable replacement, I chose the latter.

NB: Here's the label from the original PSU. It's an L&H Research type CM-E2348A, 5V@45A, 12V@9A and (-)12V@2A.  SGI part 9430801