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Any way to replace 5160/5161 power supply?

Great Hierophant said:
Does anyone know the best size of torx security bits to use with the 5150 and 5160 power supplies?
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Buy a kit, will probably have 3 sizes minimum, one of them will fit. I've never had to specifically hunt out a certain size.
Make sure it's a security torx not just torx though, the bit needs to have the hole in the middle.
 
Thanks again for the recurring suggestions (and the note about the adapter cable, had no idea that existed!).

After the purchase of a cheap security torx set, I was able to get it apart. I pulled out the only fuse I could see and it appears intact; it's not burnt or broken. I also couldn't find anything wrong with the components, although I completely admit I don't know what I'm looking at.

Here's a video, complete with rambling:


When I tested, it was with the power supply connected to an IDE drive, as I read from minuszerodegrees.net that the power supply requires a little bit of load to turn on.

Unless someone has further suggestions, I'm leaning towards the adapter cable + a new PS, and I would wire up the Big Red Switch to the switch leads on the cable. This seems like the least risky way for me to get power inside my 5161 while still retaining the vintage external appearance.
 
May I borrow your thread for a question which is not entirely off topic. I should replace the mains cable receptacle in my XT but I understand that there could be high voltages lurking inside the PSU even when unplugged. At least there are some warning stickers suggesting so. My question is, What Should Every Man Know Before Opening a PSU, just not to do any harm to himself and the hardware?
 
Ecky said:
May I borrow your thread for a question which is not entirely off topic. I should replace the mains cable receptacle in my XT but I understand that there could be high voltages lurking inside the PSU even when unplugged. At least there are some warning stickers suggesting so. My question is, What Should Every Man Know Before Opening a PSU, just not to do any harm to himself and the hardware?
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I'm not actually an electrical engineer, but I have repaired PSUs before and know enough that I'm not scared of them any more.

First of all, turn off the power.

With the power off, the only parts of the PSU that have dangerous voltages will be the mains capacitors (the big round cylinders that say 400V or so on them). There are usually two. Sometimes there are resistors to discharge the capacitors when power is removed, but I've worked on PSUs where they were missing or broken so don't rely on it.

Some people suggest just shorting the two terminals of each capacitor with a screwdriver (one with a plastic handle and metal blade, obviously). This works, but makes a big loud spark that could damage something. So I prefer the less violent method of taking a mains powered incandescent lamp (test it first), and just touching the prongs of the plug to the capacitor terminals. This discharges the capacitor into the lamp, briefly lighting it. Then short it with a screwdriver as well just to be sure that it is safe.

One other precaution you can take is to work with one hand behind your back. That way, if you do get a shock the current is less likely to go through your heart.
 
Small update: evildragon took me up on my offer for payment-for-services so the PS is on its way to him. Once he/I know what was wrong with it, I'll update the thread.

This thread is a nice summary of options; going to bookmark it!
 
I just wanted to update this thread. I got the PSU today in the mail, and I have begun diagnosing. The problem seems to be happening very early in the AC stage, because it happens well before the power is even getting rectified to DC.

I have zeroed the problem down to the small board mounted in the back of the PSU, right above of the power connector, and on the same board as the fuse. The fuse without a doubt is fine, because at 1v AC, it's not going to blow. ;) The transformer appears fine, however the problem appears to be one of those orange blob capacitors. There's so much ripple and so little power, it's no wonder the poor thing won't power up.

http://img.photobucket.com/albums/v395/Evilweredragon/IMG_1886_zps19f7ac78.jpg

I'm just hoping that ripple didn't cause more damage. I will be hunting down these capacitors, and their values on that little board, and we will see how this goes! :D
 
Those caps look like plain old film capacitors--they rarely go bad. If you do replace them, be sure to check for an "X", "X1" or "X2" mark on them and replace them with similar types--those are "safety" caps, made to fail in a defined way.

What does the relay do on this PSU?
 
I'm not sure of what the relay does, but I just finally got that board unmounted and scoped out the two caps. One of them is definitely faulty.

When I scope on the other side of the cap, I get this beautiful sine (and the scope is misreading it as 12v but it's really 120v. It's because my probe had to be on X10 because my scope can't see 120v): http://img.photobucket.com/albums/v395/Evilweredragon/IMG_1887_zps143128f2.jpg

So that cap needs to go. I'm going to look at one of my AT PSU's I use for parts. I may have this exact cap on it since it's filtering line current. I wonder how the cap went though? It's connected directly to the AC outlet connector it seems..
 
Chuck(G) said:
Those caps look like plain old film capacitors--they rarely go bad. If you do replace them, be sure to check for an "X", "X1" or "X2" mark on them and replace them with similar types--those are "safety" caps, made to fail in a defined way.

What does the relay do on this PSU?
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No X mark on it.

cap_zps56bce9a0.jpg


I'm going to try and get as much as original replacement as possible. May not be the same brand, but I'm going to match the specs.
 
Whatever, just note that this cap is rated for 125VAC, so don't try to use a polarized cap. Any modern cap is likely to be physically smaller, so you might go to a 250VAC cap to get the same physical size. Try a Nichicon QXL2E104KTPT or a Panasonic ECQ-E2A104MW.
 
I wouldn't plan on using polarized anyway. The two pins on this cap are directly connected across the AC outlet. DC cap would let out the smoke quite quickly if I did.

The only capacitor I have at my disposal right now is 275V~, however it's 1.0MFD, not 0.1MFD like the original is, so I can't use that.

I'm going to go to my local electronics surplus store, they should have a few nichicon caps of this type like you recommended.

EDIT: Found a compatible replacement in my drawer. It's a 250v~(AC) 0.1uF..
 
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Right across the AC line? So its funciton is EMI suppression. So it's either shorted or open. If it's shorted, magic smoke. If it's open, the PSU should work anyway.
 
Chuck(G) said:
Right across the AC line? So its funciton is EMI suppression. So it's either shorted or open. If it's shorted, magic smoke. If it's open, the PSU should work anyway.
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Yea, after I noticed it was straight across, I started to suspect something else.

I was able to find that the transformer on that board, it's solder pad had lifted just enough to disconnect. So I patched up the trace, and used the original capacitor, and viola, the PSU now makes it's relay clicks when turned on, and 120v AC is now going all the way to the main PSU board.

However, the fan still won't spin, and no drives connected turn on. About how much load do these PSU's need to test them? I have a feeling I'm going to need to dig out my 286 motherboard as another test load.

EDIT: Got the main PSU board out. Oh man there's a LOT of cold solder joints. I'm going to be busy tonight!
 
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First of all, I can't thank you enough. If I could transform into an anime teenage girl and jump up and down clapping without seeming pervy, I would do that in a heartbeat.

Secondly, thank you for the close-up shots of what popped cold soldier joints look like, as well as what testing voltage with a multimeter looks like. I am less scared of electronics now, and if I had known that repairing popped joints was just a matter of heating up the soldier and reflowing it, I might have taken that on. In fact, I think the next time I have something like this happen, I will likely use it as an excuse to buy an iron and just give it a shot.
 
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