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O2 PSU disassembly and refurb - Printable Version

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O2 PSU disassembly and refurb - Raion - 01-14-2020

So at 4AM i've had a sudden urge to try and figure out the O2's PSU and break out my old soldering kit to see if I can do it, for a few reasons:

1. It's all through the hole.

2. the parts seem readily available online

3. While documentation exists out there about the O2 PSU characteristics, no refurbishment information has surfaced

4. Nobody even knows how to take apart the damn things

I'm gonna document the process with parts I use to replace all electrolytics on board, images of the boards, and detailed takedown instructions. This is all a learning process for me, and I'm fully anticipating the possibility of failure. All the same, the sacrificial lamb has been chosen, and thankfully it's not an Octane.

RE: O2 PSU disassembly and refurb - shrek - 01-14-2020

Keep us posted. I have an O2 that’s in questionable condition and I know for a fact the PSU is broken. If you make guides or something I’ll try to repair mine following them.

RE: O2 PSU disassembly and refurb - Raion - 01-14-2020

So first thing I did:

The panaflo fan is held in place by a plastic rivet that i think is impossible to preserve. I drilled it out. With the PSU facing the fan and in the install orientation it's at the 2 o'clock position. I'll post a detailed guide once this is all said and done, with images. I drilled that out with a simple hand drill.

There are five screws holding the side panel of the case on. They are all visible so just undo every screw you can and the pieces should come apart. Set the panel aside, it has nothing of interest.

The first thing to always test is the fuse. With the multimeter in continuity mode, you can easily verify this.

Slide the fan out after releasing the two pin molex header. Then you can access the five screws and ground lug holding both boards in. Everything has to come out as one, including the system connector. To remove that, take some needlenose pliers and press the two plastic studs in and push them out of the frame. Removing all screws (theres one inside the hole for the heavy metal tab) you should be able to gently slide out the boards.

Now, cleaning the boards won't happen until I get all of the old electrolytics out. I'm gonna take some high res pics hopefully and try to roughly mark out what goes where, as well as have a table of parts you'll need with links to mouser for replacements. Due to the big transformers, I'm hesitant to dishwash the board, I'm not sure how we can dry transformers and if they contain oil inside that could be ruined by water, so I'm gonna remove all the electrolytics, clean the board with Windex and isopropanol, and scrub all of the windings, mosfets. Voltage regularors etc really well.

Some are not going to be easy to get to for desoldering, so I'm gonna use snips to cut them out, then desolder the leads, then hopefully I can get them back in correctly afterwards.

As I said, this is all a learning experience. And with ATX PSUs in almost all cases being unsuitable, I'm going to be documenting this with pinouts and my own graphics if I can. I'm not good at any of this, but one of my resolutions is to stop being lazy and learn some damn skills.

RE: O2 PSU disassembly and refurb - Raion - 01-14-2020

Partial list of caps (locations will be added once I can see them all on silkscreen):

4 x 10,000uf 6.3V Axial 105C rated capacitors
1 x 22uf 50V Axial 105C rated capacitor
2 x 2200uf 25V Axial 105C rated capacitor
2 x 2200uf 6.3V Axial 105C rated capacitor
2 x 220uf 16V Axial 105C rated capacitor

These make up the capacitors on the connector side of the O2 PSU. I will be doing the other side and the board stuck up at a right angle next, once I can extract the caps, mark their locations, ratings, etc.

Because these are part of a switching PSU, conventional wisdom goes you want low ESR (equivalent series resistance) parts. I will confirm this and I promise I will do my best to provide the proper parts for replacement.

My goal is to make it so that anyone can do work on their O2 PSU, and also to document it for myself because I wouldn't mind doing a few jobs at low cost to members here; if that is of interest once I'm done.

I will of course be doing Indy PSUs once I'm done here assuming all goes well, including a cooling mod to Sony PSUs to make them cool far better. A stopgap until either an open plan for replacement PSUs comes out, or the promised PSU replacements materialize. (Not that I have any lack of confidence in the people doing it, with all due respect, just we've had enough vaporware in the community over the years, including from myself, so my goal now is "Don't announce anything until you have something to show for it.)

RE: O2 PSU disassembly and refurb - Raion - 01-15-2020

Okay, got the capacitors out and took some measurements. No idea if these will come in handy, but I did the ones that looked unusual/I don't seem them often. Unfortunately my hand solder sucker and wick aren't cutting it, so looks like the actual lead removal will have to wait until I have one of those fancy vacuum things or something unless someone has better ideas, I've also tried pulling the leads out from the top and they're not budging for the bigger ones. I think my iron may be shot, which is possible, it's nearly 15 years old. Gonna test it and callibrate the base just to be sure, but we'll see.

Images thus far are here: https://siliconimage.irixnet.org/User-Albums/Raion/o2-psu-refurb

Comments? I know I'm amateur and ghetto and there's gonna be flux residue everywhere and stuff. I'm not a pro, and I hate soldering, but I need to contribute documentation, and there's reasons that I feel rolling my own is best.

RE: O2 PSU disassembly and refurb - Raion - 01-17-2020

Small update:

Still working on removing components. It's definitely not easy, and there's a chance that I fried the board in the process, but we'll see.

RE: O2 PSU disassembly and refurb - shrek - 01-17-2020

Looks like you’re making some decent progress. I’ve seen others repair Indigo2 PSUs and do replacements for Fuels but this is the first time I’ve seen someone attempt an O2 PSU repair.

RE: O2 PSU disassembly and refurb - Raion - 01-19-2020

I got most of the DC side cap legs out. Before I go any further, I'm gonna put this on hold until I can afford a desoldering vacuum gun. This is getting on my nerves. I'll be ordering replacement caps probably later this month.

RE: O2 PSU disassembly and refurb - dexter1 - 01-19-2020

The solder can be hard to remove, because of its high melting point of about 400 Celsius.
I've had my fair share of frustration from lithium cell replacements on Indigo1 motherboards...

Try adding leader solder to it first, then wick it or suck it out. Ideally a solder remover gun will be best to get components out cleanly.

I often watch Adrian's digital basement on youtube for these matters, he seems to have good results reworking through-hole systems like C64's and Apple II systems

RE: O2 PSU disassembly and refurb - KayBee - 02-19-2020

Raion, this may sound stupid, but if you send me the parts I can try my desoldering gun on them. I live in Los Angeles though. All of our O2 power supplies will need love eventually, so good to figure it out. Anyway, happy to help, I speak fluent solder.