View Full Version : Kalok octagon kl-320 and compaq portable issues

January 30th, 2016, 11:57 AM
Hello forum. I got a boxed pc 5150 and a original compaq portable. They both have issues. The compaq portable seems to have a power supply issue or something is shorting inside it. The 5150 had a kalok octagon kl-320 hdd in it with some st11 controller. The hdd was giving me a dead short, and when I pulled it out, the machine booted just fine to BASIC. When I tried to power upp the hdd with another psu, a capacitor on the board exploded and let out its magic smoke. Does anyone know any information on that drive? is it even worth fixing? Does anyone know common problems with compaq portables? When I plugged it in it turned on for a second and illunintated the led but after that it was just dead. Any help is greatly appreciated. Attached are some pictures of the hard drive.293212932229323

January 30th, 2016, 12:05 PM
I would just toss the kl-320 and consider yourself lucky. :-)

January 30th, 2016, 12:07 PM
Do you know about the compaq portable? I would love to get it up and running too.

January 30th, 2016, 10:02 PM

Even if i agree with Stone ("toss this thing"), if i were you i'd try to replace the capacitor, because tantallum are cheap and it shouldn't be too difficult to unsolder and solder the new one.
With a bit of luck, it MIGHT work again. If "it's dead Jim", then apply Stone's solution...

But i have to add that i don't like at all the little black spot onto the top of the other tantallum, near the dead one: paint or burnt ?

January 31st, 2016, 12:38 AM
Shame about the HDD since 20MB MFM HDDs don't grow on trees. I have seen working 80MB MFM HDDs fetch ridiculous prices like 250 Dollar on ebay. Unfortunately the Kalok isn't really among the casual ones, so even if you get a bunch of MFM drives it's unlikely that you get the same type (For parts).

January 31st, 2016, 05:14 AM
That is paint, all the caps have paint spots on them. Does anyone know the values of those caps?

January 31st, 2016, 05:22 AM
They're usually marked.

January 31st, 2016, 06:34 AM
It should be on the side facing the PCB, be careful when you straighten it. You should read something like "475", "106" or "226" and a letter. If you're lucky, you'll find 4,7uf, 10uf, or 22uf :D

January 31st, 2016, 07:15 AM
Can't tell for sure, but that sort of looks like just a filtering cap. It that is the case I would sort of expect the drive to power up and work without it. But if this one went bad, there is a possibility that one of the others is also bad and does not have enough voltage across it to go boom. That would also jive with how it briefly powered up and then would not.

I'd also check around with volt meter to see if that exploded capacitor connected through any other component rather than directly between ground an power. In which case that component may also be damaged.

January 31st, 2016, 07:58 AM
Can't tell for sure, but that sort of looks like just a filtering cap. It that is the case I would sort of expect the drive to power up and work without it.Really? Even if it's short? I wouldn't think so.

January 31st, 2016, 10:42 AM
I had to replace all of the tantalum caps on the 12V rails (including those on the video and floppy drive cards) on my Portable before it would do anything close to showing signs of life.

Does the red light on the motherboard come on? Mine would blink briefly then the PSU would trip out.

Pull all the expansion cards and floppy drives power, and give it a try.

I replaced the 12V rail smoothing tantalums with regular electrolytic caps, 25V 10uF. C83 is the motherboard one. 16V limit is a bit close on power-up to the 12V.. most of mine went up in smoke like the one below.

https://farm9.staticflickr.com/8108/8657945919_571cc57857.jpg (https://flic.kr/p/ec5eFD)
Pop! (https://flic.kr/p/ec5eFD) by Phil Andrews (https://www.flickr.com/photos/philandrews/), on Flickr


January 31st, 2016, 12:26 PM
on my portable the red light just blinks for a split second and then it just does nothing and the psu fan just spins. I pulled all the cards and drives and still nothing, then put the cards back in 1 by 1 and still nothing.

January 31st, 2016, 12:27 PM
ill pull the board and look at all the caps next.

January 31st, 2016, 02:57 PM
You have a short circuit somewhere and it's forcing the PSU into overload shutdown. Pull the power connector off the motherboard (in the image above) and then power up- either look at the CRT neck and see if it begins to glow- or if you have a meter check the voltages, what you should expect at each pin is printed on the motherboard next to the connector. The fan will always spin, it's an AC one connected to the switch. The CRT is run from the DC side of the PSU.

I'd say your most likely cause will be a shorted tantalum somewhere. Probably on the 12V rail because the tolerances are a bit close. You can pull C83 off the board temporarily to check for operation.


January 31st, 2016, 05:57 PM
Well, with the board removed the neck of the crt lights up for a split second when power is first turned off but then goes dark. I dont have my multimeter on hand to check the voltages on the psu though.

January 31st, 2016, 06:54 PM
Then you may have a shorted component in the video circuit or in the psu. It's definitely going into protect if it comes on for about half a second or so.

Possibly putting a meter or light bulbs on each rail might show (briefly) which one is failing.

If not, pull the power to the VDU and check the supply again, nil load.


January 31st, 2016, 07:17 PM
I may be completely done for with this project if the crt or parts of the crt assembly have failed. These machines seem to be very rare and finding such a component may be impossible.

January 31st, 2016, 08:10 PM
Much more likely just a shorted capacitor causing the psu to shut down on overload.


February 2nd, 2016, 01:00 PM
well, thankfully I unplugged the crt and the same issue is still persisting. I will recap the whole psu and figure this out. should I recap the rest of this machine or just try recapping the psu?

February 2nd, 2016, 03:47 PM
Personally I'd start there. Most of the caps on the boards are tantalum.. inspect them carefully for cracks and staining. If they look suspect, change them. You may still have a few firecrackers.

However, get the voltages right on the PSU first. It's a hard-worked thing for the size it is, redoing it will only serve to improve matters. Once you've got that, everything else should fall into place more easily.


February 3rd, 2016, 04:42 PM
Well, Great news! the kl320 is back up and running again. I recapped the whole board and got it back to life. Hopefully this means good things for the portable's power supply. I found this29375while figuring out the values of the caps. it seems that this is my problem. However the electrolytics were nasty too, so I bought all new caps. Here are some pictures of the kl320 back up and running.

February 3rd, 2016, 05:11 PM
That would be a shorted tantalum capacitor. It's normal for that to happen when they get this old. I typically clip it off and call it good until another one fails.

February 3rd, 2016, 07:45 PM
Good deal. Nice to see things come back to life after a simple fault is enough to render them "dead".


February 6th, 2016, 11:49 AM
Well I recapped most of the power supply, and it still goes into protect mode. my local store has the rest of the caps on order for me. Hopefully the other caps will do it, but If not I may be stuck. Does anyone have a spare Compaq Portable Power supply? I doubt it.

February 7th, 2016, 03:13 PM
Not offhand, but I can take some volts measurements on mine if it'd help to see if anything's badly wrong.

What do you get, voltage-wise, on each rail before it goes into protect?