Old Compaq Armada internal PSU repair

[yuuki47]

Hi all,

I have a broken Compaq Armada 1510, and of course, the internal PSU *appears* to be shot.

The laptop does nothing when I try to power it on. When I disassembled it to have a look at the PSU, I found that it was connected to the motherboard via two black and red wires.

The first thing I checked was whether the red wires were common to each other, and whether the black ones were also commoned. They were.

The PSU appeared to be just a regular DC PSU that was just inside, there were just black and red wires, which means that its output isn't controlled by an extra pin like it is on ATX PSUs.

It had a label on the side that told me the voltage (18v 2a) so I hooked it to a multimeter and checked the output. It was just 1 volt.

Should I attempt to re-cap it? Is there any resources I can look into?

But further, as a test, am I alright to hook a PSU with a similar voltage to the connector and see if the laptop turns on? The thing I'm stuck about is whether the voltage needs to be exact. Obviously, the engineers of this expect only that specific PSU to be used, so maybe the input isn't regulated.

Any thoughts?

[stj]

Re: Old Compaq Armada internal PSU repair

test without the battery - incase the battery is shorted and pulling the supply down.
those old machines use nicad batteries.

[yuuki47]

Re: Old Compaq Armada internal PSU repair

test without the battery - incase the battery is shorted and pulling the supply down.
those old machines use nicad batteries.

I did. I even pulled the PSU completely out of the machine but still nothing.

[stj]

Re: Old Compaq Armada internal PSU repair

then feed it with 15v and show pictures of the original psu

[yuuki47]

Re: Old Compaq Armada internal PSU repair

then feed it with 15v and show pictures of the original psu

With 15v? The original PSU is 18.5v. Is there a reason for that? I have an old Toshiba laptop (from the same era) power brick that does exactly 15v so I guess I could.

Here is the original PSU:



This thing is super light and super small, yet it does 18v 2a? No wonder it failed...

[stj]

Re: Old Compaq Armada internal PSU repair

15v will use more current but it's more available.
the laptop will probably run at 12v but it needs the higher voltage to charge the battery.

when i asked for psu pictures i meant the board btw

[yuuki47]

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. I could buy some third-party 18v PSU module and use it as a drop-in replacement with some gluing, but I hate the idea of gluing and internal PSUs. I think I'll solder a DC barrel jack and loosely glue it at the hole where the old Mickey-Mouse plug from the internal PSU was. Will be ugly but its an ok solution for now, can be reversed later.

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?

I wonder if I can wire an 18v regulator after the barrel jack? Will that work?

[yuuki47]

Re: Old Compaq Armada internal PSU repair

15v will use more current but it's more available.
the laptop will probably run at 12v but it needs the higher voltage to charge the battery.

when i asked for psu pictures i meant the board btw

Oh, sorry, you replied as I was typing the update above...

Anyway, here:



It also has a daughter-board like module thats covered in a thick layer of paint or something. I think that's a controller of sorts?

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

[yuuki47]

Re: Old Compaq Armada internal PSU repair

BTW, here's the laptop, with an awkward wire at the top...

And here is where the PSU used to be:


I'm thinking of gluing a DC barrel jack to the side there, awkward but will be fine.

The question is whether I should regulate the supply after the barrel jack somehow. Or will the laptop be fine with something less than 18.5v as you said?

[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

[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.

[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!!!

[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?

[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

[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.

[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...

[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

[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

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


Isn't that super high?

[yuuki47]

Re: Old Compaq Armada internal PSU repair

The output cap, in contrast, seems fine