[Working, Never-Serviced Centris 650] What do I need to fix/replace before it explodes?

[sinisterpisces]

Hello,

I've got a Centris 650 that I know turns on and works--or at least doesn't have a problem that I've found yet. The previous owner showed it working and fitted it with a Zulu SCSI, but I've not yet turned it on or plugged it in because I'm not sure if the PSU has a RIFA in it.

However, I suspect that, aside from replacing the battery (with another battery that can leak), it was never serviced by the previous owner.

So, I'm trying to figure out what I need to address before something potentially explodes, leaks, or otherwise damages the system. Am I leaving anything out of this list?

1. Replace battery with coin cell (with an adapter of some sort).
2. Replace or recap PSU. The potential for cap leaking aside, I live in a carpeted apartment with windows that don't open. A RIFA blowing on me would be an actual catastrophe.
3. Replace or recap the CD-ROM. I'm pretty sure this will have caps on it that will leak or have leaked.
4. Replace or recap the floppy drive. Same as above. Though, I like the idea of replacing it with an internal BlueSCSI.

Am I missing any obvious potential explosions/leaks?

Thanks!

 

[CptSkyfox]

I'm surprised there's no responses.

Well, i'm no expert, but I'll tell you what I know.

1. Replacing the battery holder really isn't neccessary, as long as you don't leave the battery in there for 10 years. You can just pull it out when you're not planning on using it for years. Plus, CR2032s are a little undervolted for the spec, and have much lower capacity. So they run down fast.
2. The PSUs in 650 are the same ones found in the 7100. I'm not sure if there is a drop in replacement for the guts of these models. I don't think there is. So recapping might be your best option, and these models are known to have all the usual issues. There's some safety caps in them, though I think less than older models. All the caps are likely aging and may be going out of spec, so a recap may be necessary anyway to keep it working in the future.
3. Replacing the CD may be hard, because it's a caddy model on the Centris 650, and the chasis is fit for a caddy rather than tray. The caps on these tend to go bad way less, but yeah you could recap it if you wanted to be safe.
4. The caps on the floppy are typically the last thing to go bad. Rather, there's a ton of other things that need work, including a tiny gear that likes to break. These old floppies are worth restoring, though, because they have a motorized insertion mechanism. Honestly, I'd say keep the floppy, fix it up, and replace the HDD with a BlueSCSI. That's the bit that always irreparably breaks down, anyway.

Am I missing any obvious potential explosions/leaks?

The wombat (Quadra/Centris 650/800) boards are all tantalums, so they don't leak.

There is however a capacitor on the audio circuit that's sitting on 12v, that isn't properly derated, and is known to occasionally pop. It's a 16v cap, and for 12v it should be using 25v because tantalums are sensitive to voltage spikes.

Here's a picture of the cap, pardon the dust:



It can be fine, but if you're already in there and modding things (this model has a huge amount of mods that can be done) you might want to replace this cap with a 10uF 25v polymer tantalum.