Old Compaq Armada internal PSU repair

[yuuki47]

Re: Old Compaq Armada internal PSU repair

Yeah, 680 uF should be fine if you could get those to fit.

But don't go ordering new caps for these just quite yet, unless that somehow saves you on shipping costs.

OK. Got it! I'll order the cap for now and replace it to see if it runs. Until then, I'll focus on other things. It should be here within 1-3 days.

The supply says "Nagano Japan Radio Company" on the back of PCB btw. The fact that its Japanese puts me a bit more at ease.

But all this cap talk makes me nervous. I have a Toshiba 310CDT that still works strongly even with the original hard drive (though it's been making a lot of parking noises lately) so maybe I should re-cap these before bad things happen.

The saddest part is that there also the tiny SMD caps. If one of those fails, it's not like its specs are printed on them, so there's no way to know what to replace them with unless you've got a schematic.

Sad to think that these laptops will die like that one day...

[momaka]

Re: Old Compaq Armada internal PSU repair

They are 560uf, and it's a weird size, so I can't find replacements. Can I use a higher capacitance or will that cause bad things to happen? My guess is that it won't, since they are just the output caps. But I'm not an expert, just a hobbyist.

Yeah, 680 uF should be fine if you could get those to fit.

But don't go ordering new caps for these just quite yet, unless that somehow saves you on shipping costs. Reason I say this is because they are likely not the issue. Usually bad caps on the output will only cause the voltage to be slightly lower and not really become unstable until a load is put on there. So I think it's either the startup cap or something else.

Actually, while waiting for the replacement startup cap, you could re-install back the caps and heat the adapter with a hair dryer until it's somewhere around 45-50C. Then plug it in and see if the voltage comes up. The heat will cause the ESR of the caps to drop, so that's one easy way to test if the issue is with the capacitors or not (though this trick tends to work only if the caps are not too badly failed... which in your case, they aren't.)

Dont worry I am aware of things like these. I may not be knowledgeable but I know electronic safety pretty well, and why AC is a no-no.

AC is actually your friend - especially very high frequency stuff, because the higher the frequency, the less current that would try to pass through your body and the more it will try to pass through the outermost layer of your body/skin (making it less likely to pass high current through the heart.) On the other hand, AC will conduct through your skin at a much lower voltage compared to DC.

On that regard, the PSU is turning on, its just that it outputs 1.2v instead of 18v. But maybe that's considered "not turning on".

Well, it's neither and both in a way.

BTW, the startup cap has like plastic protective sleeves on the legs probably for insulation. Should I re-use those? I can slide them off...

Wouldn't hurt to.
I think they were installed due to the proximity of this cap to the leads of the big cap next to it. And probably also to raise the cap a little away from the board so that it doesn't run as hot.
The glue on the PCB looks like something Astec would use. Same in regards to the output capacitor choices (Nichicon PL). It might actually be an Astec-made PSU... and Astec is pretty good quality (and a big PSU OEM back then.)

[stj]

Re: Old Compaq Armada internal PSU repair

i wonder if it's so they can lean it away from that vertical board?
it clearly overlaps the space marked for the cap

[yuuki47]

Re: Old Compaq Armada internal PSU repair

Here's also the PSU where the cap was (you can see the pads)



These are all high-res images if you want to zoom

I wish I could get closer but my camera is not very good. As soon as I get too close, it can't focus.

[yuuki47]

Re: Old Compaq Armada internal PSU repair

you mean it's raised from the board? are the holes the same spacing as the cap wires?

Yes they are the same space and straight. There's also a lot of glue there.

But whether it was raised from the board I don't know. It was too cramped and dark in there to know. Here's a photo:

[stj]

Re: Old Compaq Armada internal PSU repair

you mean it's raised from the board? are the holes the same spacing as the cap wires?

[yuuki47]

Re: Old Compaq Armada internal PSU repair

If they are 560 uF caps (weird cap size, yes)

They are 560uf, and it's a weird size, so I can't find replacements. Can I use a higher capacitance or will that cause bad things to happen? My guess is that it won't, since they are just the output caps. But I'm not an expert, just a hobbyist.

BTW, since the PSU is not powering ON, MAKE SURE TO DISCHARGE THE PRIMARY CAPACITOR(S) BEFORE starting work on the PSU

Dont worry I am aware of things like these. I may not be knowledgeable but I know electronic safety pretty well, and why AC is a no-no.

I got shocked as a kid by a sketchy appliance and I jumped so high I reached the ceiling. The switching voltage contracted my muscles so bad they acted like springs

On that regard, the PSU is turning on, its just that it outputs 1.2v instead of 18v. But maybe that's considered "not turning on".

BTW, the startup cap has like plastic protective sleeves on the legs probably for insulation. Should I re-use those? I can slide them off...

[momaka]

Re: Old Compaq Armada internal PSU repair

BTW, for the startup cap, I'm thinking getting these. They should be good right? They are Panasonic FR's

Looks good to me.

For the output caps, I can't seem to find any readily available replacements at that exact spec. Hmmm... I have one of those M-Testers. Should I pull them out and measure their ESR and capacitance? Is that a good enough test?

Usually yes.

for the startup i would raise it to 47uf
longer life and cheaper and more common than 33uf.

I wouldn't.

Sure going from 33 uF to 47 uF is likely not going to cause issues... but I found in a few cases, it does mess with the short-circuit / OL protection time, so I choose not to mess with these unless I really don't have any proper replacements available.

In regards to the 47 uF lasting longer than the 33 uF... not really. If they are both 5x11 mm case size, it won't make any significant difference even 10-15 years down the road.

So stick with what the manufacturer used. The price difference between 33 uF and 47 uF is almost non-existent, even when buying huge quantities like manufacturers do. So I doubt they went with 33 uF to save on costs.

you cant use regular barrel plugs from stuff like radio's because they can only handle one or two amps

Depends on their size and how well they are made.
I'd trust an old scavenged barrel plug from a router (or similar) more than a "100% brand new and high quality" junk from China.

But is that REALLY a good idea? Is it really safe to use a 20+ year old PSU, even if I re-cap it and it outputs a stable 18v? I'm nervous it'll fail in a different way and kill my laptop...

Well, it's a relatively safe alternative.
After all, the original PSU came with Nichicon capacitors and not some ultra-cheap low-end junk. Granted back in those days, many PSUs still used good caps, even from lower-tier manufacturers (though not always, of course.) So there's a really good chance this is a well-designed PSU and won't kill anything if it goes bad. Judging by the one picture you posted, it seems to be constructed pretty well. At least I would trust it way more than any new cheap "Replace" adapter from China with junk caps, questionable semiconductors, and who knows what other cut corners.

Of course, if you don't want to fiddle with the old PSU, then using a genuine name-brand OEM adapter (like from Dell, HP, Lenovo, and etc.) would be the safest and easiest route.

Ohhhh, I pulled out the startup cap and measured its ESR.
https://cdn.discordapp.com/attachmen...127_185357.jpg

Isn't that super high?

Capacitance is still in spec, though getting close to the upper end of +20%, suggesting high-ish internal leakage.
ESR is not high for such old general purpose series cap. In fact, KME series production was discontinued a very long time ago (early-mid 90's, IIRC) and was replaced by KMG. So at such an old age, it just doesn't hurt to replace it anyways. The Panny FR cap will have a fraction of that ESR.

The output cap, in contrast, seems fine
https://cdn.discordapp.com/attachmen...127_184723.jpg

Are the output caps rated at 680 uF? If so, the capacitance is still in spec... though getting a little low (but that's normal, given their age.)
On the other hand, if the output caps are 470 uF, they are definitely reading too high and need to be replaced. If they are 560 uF caps (weird cap size, yes), then they are bang-on.
ESR seems a little high-ish too, but probably OK for their age. I don't think the PSU is not starting because of them.
These being Nichicon PL series, the main thing to check is for any green corrosion on their leads on the bottom, right near the rubber plug. If you see any, replace them and don't re-use them. If not, they might be OK to put back, at least for now to see if the PSU starts up with the new startup cap.
If the PSU doesn't start up, check the usual stuff: output rectifying diode for short-circuit, primary-side auxiliary winding rectifying diode, and finally the 431 shunt on the secondary and opto-coupler.

BTW, since the PSU is not powering ON, MAKE SURE TO DISCHARGE THE PRIMARY CAPACITOR(S) BEFORE starting work on the PSU. With faults like this, sometimes the primary caps can remain charged for a long time with over 300V DC. It won't kill you, but can hurt and definitely scare you. So just beware and check the primary cap(s)'s voltage before doing any work. If they are charged, discharge them with something like a plug-in soldering iron or glue gun (connect the plug across the cap terminals - this will discharge the cap in a matter of a second or less.)

Yikes! What the hell? I commend you, I can't handle roaches. I'd throw up as soon as I pulled the outlet.

I can handle them, as in literally I don't mind picking them up with my hand... but otherwise to "handle them" in my home - NOPE.
I've been collecting & fixing junk discarded and used electronics for over 10 years now. I do absolutely everything I can to make sure my house does not get infested. Some of the things I picked up did have a few dead ones... and recently a microwave that had hatched eggs (but the egg shells were crumbly and old, so I lucked out.) Of course, anything I pick up or buy goes outside for a thorough inspection first. One thing I've learned from this "trade" (refurbishing and fixing old electronics) is that roaches have a very particular smell. I also tend to prefer to pickup things only in the winter when its really cold (below freezing) or summer (really hot.) In case of the former, the roaches will try to run away to a warmer place when the temperatures drop. So if I pickup a TV or something similar and leave it outside in the cold for a few days, chances are the roaches will run away to somewhere else to avoid the cold (their eggs can still be a problem, though, which is why I try to inspect every nook and cranny on everything I bring in... and it really sucks doing that in the freezing cold, but I just DO IT. ) In contrast, when it's hot in the summer, my hands are not freezing so I can take my time to open and inspect any item I pickup for as long as I like. And with the day being long, I don't have to worry about it getting too dark too early. So summer and winter are the seasons where I don't mind picking up stuff more often.
Also, both roaches and bed bugs cannot stand temperatures above 50C. So one easy trick to get rid of them is to build a big box and put a heater inside, then run it till everything reaches a nice toasty 50-55C. This will kill both the roaches and their eggs. No toxic chemicals or sprays needed.

[stj]

Re: Old Compaq Armada internal PSU repair

the 33uf startup cap has bad internal leakage between the contacts.
the higher uf reading is the givaway.

the psu will be good-as-new if the caps are good.
psu's dont age, just the caps because they are liquid-filled.

on that subject, at some point you should inspect the laptop board and the backlight invertor circuit for leaking caps

[yuuki47]

Re: Old Compaq Armada internal PSU repair

The output cap, in contrast, seems fine

[yuuki47]

Re: Old Compaq Armada internal PSU repair

Ohhhh, I pulled out the startup cap and measured its ESR.


Isn't that super high?

[Th3_uN1Qu3]

Re: Old Compaq Armada internal PSU repair

Forget the roaches.

Just like the owner said and a friend of mine who works pest control confirmed, the whole place was sprayed for both roaches and bed bugs last summer, any roaches that showed up (they only did once there was food left around for them to eat, which took over 1 month), died within 2 days tops. It's another 2-3 months at least until a professional pest control company is needed again, this kind of job is done once a year. Pay for spraying once, get a repeat for free 1 month later, good for 6 months to 1 year. This building is good for 1 year certainly as the janitor does a great job, she's an awesome lady, and most inhabitants do take their trash where it belongs, every day.

But holy crap, I have NEVER seen anything close to this electrical wiring ever, in my whole LIFE, not only career as a licensed electrician (that's my actual diploma, I made a living off complex electronics repair and still do but it started as a hobby because I don't like being covered in dust and cement and climbing ladders every goddamn workday). Wow. Fucking idiot. I'm sure other people got shocked too - just surprised this installation never killed anyone. It was only luck and our culture of generally NOT plugging shit in the bathroom even if there is a properly installed outlet, because we are used to improvised installations (especially heating) and exposed live wiring, that prevented a fatal electrocution from happening.

Oh, before you ask - yes, there is an automatic washing machine. It's in the kitchen. It used to be plugged into... wait for it.... an UNGROUNDED outlet. I'll let you guess why.

[yuuki47]

Re: Old Compaq Armada internal PSU repair

Years, years and years of 240V HOT ALL OVER THE WALLS, ESPECIALLY AND INCLUDING THE BATHROOM.

Yikes! What the hell? I commend you, I can't handle roaches. I'd throw up as soon as I pulled the outlet.

But that's off-topic

[yuuki47]

Re: Old Compaq Armada internal PSU repair

for the startup i would raise it to 47uf
longer life and cheaper and more common than 33uf.

i wouldnt use a barrel plug - there is no real standard for the size on laptops and the sockets arent cheap either.
you cant use regular barrel plugs from stuff like radio's because they can only handle one or two amps

I have a barrel plug that's rated for 3A 12v. For 20v, the current would be even less, and the laptop draws 2A max at 18.5v judging from the old PSU spec, so it should be fine I think. And its brand new, not harvested from anywhere.

There is the option of repairing the PSU. I'll order the cap you suggested and see if that makes it output more than 1 volt.

But is that REALLY a good idea? Is it really safe to use a 20+ year old PSU, even if I re-cap it and it outputs a stable 18v? I'm nervous it'll fail in a different way and kill my laptop...

[Th3_uN1Qu3]

Re: Old Compaq Armada internal PSU repair

I took a gamble and hooked a 19v supply directly. IT WORKED!!!!!!!!

Passes RAM test and everything. I did a quick boot test with a Windows 98 startup diskette and it seemed fine.

Now this is a question of what I do about the dead PSU. Obviously, I cant use it with a hot wire hanging from the top. That's dumb.

Great job. Now, about "dumb", you should have seen the place I rented almost 5 months ago, completely oblivious until the winter celebrations and New Year's, and it's been like that for a long long time as when I pulled the socket in the bathroom there were plenty of dead roaches, some already turned to dust. So years.

Years, years and years of 240V HOT ALL OVER THE WALLS, ESPECIALLY AND INCLUDING THE BATHROOM. Good thing I never plugged more than my hair trimmer in the bathroom, and that's 1) got a 2-prong plug, no earth and 2) a battery, and I only plug it in to charge it, leave it overnight, unplug, then use it, as the mains wire is too short and nonstandard. It was a China special, bought it from an actual China Mall bout 3 or 4y ago - yes, we actually have stores called China Mall here in Romania. They've kinda gone out of style in the big cities but still see plenty of business in poorer or rural areas.

ALL THE WALLS WERE HOT. All but two of the outlets had earth ground wired - this is in theory, a good thing, right? Only mr. Electrical Tech had done a dumb, dumb, dumb mistake IN THE MAIN PANEL which sits above the entrance door and wired the earth ground indeed... TO PHASE. 240 VOLT. And outside, on the 3-phase distribution panel, this particular inhabitance has an upgraded electrical meter - 60 AMP SHUNT.

Sure, it has an RCD too, so it was somewhat safe, at least it won't kill you, right? Think again. Where were the two wires coming from the smaller shunt of the RCD? In the panel inside the inhabitance, sure, behind the fuses... IN AIR. Because when the guy hooked them up (I did), all the lights started flickering then seconds later the power goes out and STAYS out due to the enormous ground fault created by this awesome installer. Poor RCD was just doing its job. Dumb fuck thinks it's broken, leaves it disconnected. Wow. I'm speechless.

I had already rewired the whole place and used the extra phases to add more sockets (I finally have enough wall sockets with room to spare and I HAVE plugged in all my toys, yay!) when I discovered that the whole shebang could have been fixed by correcting ONE SINGLE WIRING MISTAKE in the house panel, but it was behind the rack of fuses and had the right color for earth ground so I didn't pay it any mind.

Yeah. Right color for earth. Wired straight to 60A 240V hot from the distribution 3-phase 380 (now 415 with the new EU 230V standard) panel which happens to be right to the left of my door for the whole floor, and it's a rather big building. 8 floors, 100 individual living spaces.

[stj]

Re: Old Compaq Armada internal PSU repair

for the startup i would raise it to 47uf
longer life and cheaper and more common than 33uf.

i wouldnt use a barrel plug - there is no real standard for the size on laptops and the sockets arent cheap either.
you cant use regular barrel plugs from stuff like radio's because they can only handle one or two amps

[yuuki47]

Re: Old Compaq Armada internal PSU repair

BTW, for the startup cap, I'm thinking getting these. They should be good right? They are Panasonic FR's

For the output caps, I can't seem to find any readily available replacements at that exact spec. Hmmm... I have one of those M-Testers. Should I pull them out and measure their ESR and capacitance? Is that a good enough test?

[yuuki47]

Re: Old Compaq Armada internal PSU repair

think about fixing it, not bodging it.

I hear ya but I still HATE the idea of internal PSUs.

But I always wanted to do component level repair, it's just that I never knew how to learn it properly. I've fixed things in the past but they were simple problems.

I think what I will do is I will take a piece of square plastic, drill a hole into it, and attach a barrel jack connector. This way, it'll cover the big PSU hole and it won't look ugly at all. Plus, I'll be able to use ANY laptop adapter with it (most are center positive, right?)

Still, for curiosity's shake, I'd love to fix the internal PSU and maybe convert it into an external one.

That being said, they are quite old at this point, and indeed may already be EOL - particularly the small 5x11 mm "startup" cap seen at the bottom-right of this picture

You mean the one besides the big long brown cap? I can try replacing that...

The output caps are Nichicon PL series from the looks of it. They have PL(M) printed on them...

The big brown cap is KMG 400v 65uf.

The startup cap is a KME 35v 33uf.

There is also a fat black cap on the top right, this is a Nichicon R7 series from the looks of it.

BTW, the capacitor legs are covered in glue. Not sure why, maybe to insulate them since they are high voltage? How do I go about removing them, desoldering alone wont work...

PS, thank you very much for the useful info!!!

[momaka]

Re: Old Compaq Armada internal PSU repair

But anyway, I don't really trust this flimsy power supply.

I wouldn't call it flimsy.
2 Amps @ 20V (OK, 18.5... whatever ) is 40W, which isn't a lot or hard to do.

Also, note this original power supply has Nichicon capacitors, which are very high quality. That being said, they are quite old at this point, and indeed may already be EOL - particularly the small 5x11 mm "startup" cap seen at the bottom-right of this picture:
https://cdn.discordapp.com/attachmen...126_220859.jpg
(BTW, please use the forum's "Manage Attachments" feature to add pictures. This way, pictures will stay with your thread indefinitely instead of disappearing after a few years, which online hosts are known for regularly.)

Also, another point worth mentioning is that while Nichicon capacitors are considered a very good and reliable brand, you might want to check the series of the ones in your PSU. If they are PR series, you should definitely replace them. The PR series are known to leak electrolyte from their bungs after many years. I think PL and PF series also had similar issues, but not as often. So worth a look there. The output caps are the ones on the left in the above picture.

I'm also concerned about input voltage, I'm not sure it's a good idea to use 19v on it. I think 18.5v exactly is best for long term health, no?

No, the exact voltage hardly matters with laptops. I doubt there is any circuit inside the laptop that needs anything this high. Probably only the battery charging circuit, as stj noted, and that too may be OK, depending on the voltage rating of the battery. Otherwise, I'm pretty sure anything down to 14-15V will work OK or anything as high as 24V. I wouldn't go past 24V, though, just in case there are any parts that are only rated for 25V (a standard voltage rating)... though I doubt it, since 18.5V is too close to 20V, meaning most parts are probably rated to withstand up to 35V.

But yeah, 14-24V will do just fine without any adverse effects on the life of components whatsoever.
Just to be on the safer side, though, use a standard 19.5V or 20V laptop adapter... and that's if you do decide to go with an external one.

My suggestion, of course, would be to try to repair the old PSU. Again, it likely needs its startup cap replaced. Just make sure you use a good quality brand like Rubycon, Panasonic, Nichicon, or United Chemicon, if you want the repair to last any reasonable amount of time. Preferably pick a low ESR series from those. Panasonic FR is one of many. Panasonic FC, FM, and FS would be just as good. From Rubycon, good choices would be YXJ, YXF, YXH, YXG, YXM, ZL, ZLH, ZLJ, and ZLQ. Nichicon: PW, PJ, PS, PM, HE, and HW. UCC (United Chemicon): LXZ, KY, KYB, KZE, KZH, KZM.

[stj]

Re: Old Compaq Armada internal PSU repair

think about fixing it, not bodging it.
replace the small electrolytic in the psu with a low impedence part like panasonic FR series
it will probably start.

next step will be to open the battery without too much damage to see what size the cells are.
or you could replace the harddrive with an adapter for an sd card or ssd