Old Compaq Armada internal PSU repair

[stj]

Re: Old Compaq Armada internal PSU repair

oooo......
look at the black coated hybrid circuit closely - does it have a few burns on the left side?
it looks darker in places

[yuuki47]

Re: Old Compaq Armada internal PSU repair

My camera sucks and it really can't focus up any closer than this, but here are some photos from different angles.









That M-Tester I have can test all kinds of things, let me know what you want to test and I'll take it out!

[stj]

Re: Old Compaq Armada internal PSU repair

then take some close pictures

[yuuki47]

Re: Old Compaq Armada internal PSU repair

Well, I replaced the startup capacitor today — still nothing.

I also checked the voltage across the big brown cap next to the startup cap and the voltage was 350v. Makes a pretty impressive bang when you discharge it too. Something is telling that this isn't the problem...

[stj]

Re: Old Compaq Armada internal PSU repair

one advantage over ebay is aliexpress gives you shipping options.

never use super cuano - they are slow as fuck.
use aliexpress standard or saver and to the u.k. can usuallly be about 2 weeks

[yuuki47]

Re: Old Compaq Armada internal PSU repair

But you need pins not a socket

Oh, crap. Even though I've been messing with retro tech for years this completely skipped my mind. God...

I've never bought from Aliexpress but they are cheap as hell, almost alarmingly cheap. They seem to guarantee that I'll get my items within 15 days if I buy over £9 of things.

My problem with CF is that the adapter is cheap, but the CF cards themselves are expensive as balls. £15 for 4GB of memory? You can get a 32GB SD card for £5...

Also, I did some research, and apparently CF cards aren't very reliable for storing OSes because the SWAP/PAGE file Win98 and the like use to temporarily store memory data causes constant writes that wear down CF very fast.

Well, eBay has a single SD card adapter for £22 while Ali has it for £5. I was able to get two SD card adapters plus 2 compact flash adapters for £17. That's less than eBay, and I get three extra things for future vintage projects

From my research, Aliexpress seems okay, so I'll buy and hope that all goes well...

By the time the 15 days pass, I should hopefully be able to get the PSU repaired. If not, I'll resort to the barrel plug. Thanks again!

[stj]

Re: Old Compaq Armada internal PSU repair

https://www.aliexpress.com/item/33026043666.html

or

https://www.aliexpress.com/item/1005004733494391.html

[stj]

Re: Old Compaq Armada internal PSU repair

compact-flash is ide.
but that adapter is no good - you need pins not a socket

if you want to be retro, install FreeDos
https://freedos.org/
it works really well - i use it sometimes
runs all dos software but also recognises larger drives and supports fat32

[yuuki47]

Re: Old Compaq Armada internal PSU repair

Well, for now, I will wait for the capacitor

Meanwhile, I realized that I don't have a hard disk to install an operating system into when I do get this thing booting.

I'm aware of SD card adapters but laptops use 2.5 inch IDE and not the normal size one, so I'd have to get both 2.5inch adapter and an SD card to IDE adapter. Which starts to make things really pricey...

I found this CF to 2.5 IDE adaptor but it looks kind of dodgy. The connector doesn't seem to be keyed, for one. How can I trust that I won't plug it backwards?

On top of that, it seems to directly connect the compact flash card. Is compact flash IDE in disguise and I don't know it????

I mean, this is a power supply board so I should post this elsewhere, but this is what I need to figure out now...

[stj]

Re: Old Compaq Armada internal PSU repair

just try it.
btw, if you do replace the cells and they are regular size then eneloop style will stay charged for years.
ikea sells rebranded ones pretty cheap
spot welders are also cheap if you have a car battery spare.
this guy reviews them
https://www.youtube.com/c/Luca_Techy/videos

[yuuki47]

Re: Old Compaq Armada internal PSU repair

I wonder if these are special nicad batteries and if there are 7 or 8 cells in it

There are eight. There is a green nylon cover or whatever material that is that just makes them appear as if they are three long tubes. The voltage makes sense too. 8*1.2=9.6v, which matches what's on the label.

I think they're standard cells...

But I wonder if the controller disables itself once the batteries go below a certain voltage, like lithium controllers do. I heard NiMh don't suffer from this problem though, right?

[stj]

Re: Old Compaq Armada internal PSU repair

8 nimh cells - it's on the label.

strangly the capacity isnt

[sam_sam_sam]

Re: Old Compaq Armada internal PSU repair

I wonder if these are special nicad batteries and if there are 7 or 8 cells in it

[Th3_uN1Qu3]

Re: Old Compaq Armada internal PSU repair

Should be enough iron if you use both of them at the same time and do all the prep beforehand - file it or sand it down to make it coarse and have the solder get something to grip on, gobs of slightly acidic flux, and definitely 63/37 SnPb or that hybrid bastard snpb alloy with bismuth which melts at 138C.

The Chinese sell it in all forms and it is cheap. I bought a tiny tub of solder paste, "Mechanic" brand, ages ago then forgot about it for years. When I gave it a whirl, it's an absolutely beautiful thing. Think Chipquik but doesn't melt at regular operational temperature of most electronics, therefore it can be a permanent solution, not just for removing large parts with small irons. Yeah, you can leave it there. It won't melt, flow elsewhere or cause cold joints, and it is just as elastic as our favorite SnPb and even easier to work with.

[yuuki47]

Re: Old Compaq Armada internal PSU repair

Will that ancient chemistry catch fire or explode in your face while you are soldering on it? Zero chance. It's safe. Worst you can do is some smoke and damaging the cells. Give it a shot.

My top priority is completing the repair on the laptop and the PSU, I may do this afterwards.

I have TS80P soldering iron and also a junky £10 one that is actually kinda ok. Was using it for years before I got the TS80P.

Anyway, I'm not that bothered about the battery as long as the laptop works.

[Th3_uN1Qu3]

Re: Old Compaq Armada internal PSU repair

no leaks - they may be good.
just need to charge and then flatten them a few times to condition the chemicals in them.

btw, surface-mount electrolytics do have the specs printed on them.

You telling me that this 20 year old battery could work? Is it safe to just try it?

I'm guessing that soldering directly on top of battery cells is a horrible, horrible idea so if it works, it works. If it doesn't work, oh well, no battery. It's not a big deal to me..

It is a horrible, horrible idea for lithium. You may be able to get away with just a tiny bit of lost capacitance on this old NiMH, even if you retrofit new cells.

But you need a BIG soldering iron - it needs to get so hot and transfer heat so fast that just 3-5 seconds on top of a cell should flow the solder completely, else you give it a few minutes break then try again, a file or some sandpaper, and RA flux (rosin active, requires cleaning after you finish the job with isopropyl alcohol or paint thinner or it'll slowly eat at whatever you put it on, or straight acid flux - not the usual RMA used for working on boards.

RA flux is usually what you would use on a 50+ year old radio or TV set for reconditioning. Those ancient solder joints will laugh at any Amtech professional BGA repair, even if they never even THOUGHT about lead-free soldering at that time, and it is most likely high grade eutectic 63/37 Sn/Pb. Same for soldering on batteries. Is it a bad idea, yes, there are much better ways, and a DIY spot welder can be made from your junk bin and needs all of four parts (the fourth is the on/off switch, you don't actually need one, you can unplug it from the mains after you are done working with it!). But is it doable? Certainly.

Will that ancient chemistry catch fire or explode in your face while you are soldering on it? Zero chance. It's safe. Worst you can do is some smoke and damaging the cells. Give it a shot.

yes try it.
nimh batteries lose capacity slowly as they get used

True, but you forgot to mention the incredibly fast self-discharge rate, can't use them in a clock or remote - they'll go flat in a couple weeks where a single use alkaline will work for 2 years - and their bad habit of becoming a solid, huge, beefy wire (yeah, a fancy way for me to say hard short circuit) if left for too long on zero volts.

But they usually don't bloat, blow up or catch fire (no, scratch that, they never do. maybe vent some hydrogen from the safety valve if you REALLY abuse them, and you won't be able to smell it and even have any idea it happened, unless you're close and hear the hiss of the escaping gas), unlike modern day lithium.

You are still going to find NiMh packs on brand new power packs for cordless tools to this day, although they are falling out of fashion, very slowly. The chemistry is old and disadvantages many, but they're reliable workhorses and you can put a series X cap for limiting the AC mains in and one single diode as the ONLY charging circuit... and it'll just charge. Every day. For years. Safely. It's the high self discharge (leakage, if you wish) they have which allows this.

[stj]

Re: Old Compaq Armada internal PSU repair

yes try it.
nimh batteries lose capacity slowly as they get used,
but unlike lithiums you cant really overcharge them or damage them by draining them too much

those tiny rectangular caps dont contain liquid - so no problem.

[yuuki47]

Re: Old Compaq Armada internal PSU repair

no leaks - they may be good.
just need to charge and then flatten them a few times to condition the chemicals in them.

btw, surface-mount electrolytics do have the specs printed on them.

You telling me that this 20 year old battery could work? Is it safe to just try it?

I'm guessing that soldering directly on top of battery cells is a horrible, horrible idea so if it works, it works. If it doesn't work, oh well, no battery. It's not a big deal to me. Though I'll still remove the cells to keep the container and charging controller, mostly because there'll be a big battery hole on the side of the laptop otherwise.

Also, I'm talking about the tiny SMD caps that are about the size of a rice grain. But maybe those don't fail as much.

[stj]

Re: Old Compaq Armada internal PSU repair

no leaks - they may be good.
just need to charge and then flatten them a few times to condition the chemicals in them.

btw, surface-mount electrolytics do have the specs printed on them.

[yuuki47]

Re: Old Compaq Armada internal PSU repair

BTW I think someone asked a picture of the battery before? Here it is... it's a NiMh... although I don't think I'm comfortable with refitting new cells. Don't you need welding tools for that?




PS, sorry for not uploading image attachements. Won't do it again!