Completely new to this, have kind of a lot of questions

[RoadWarrior]

Hi so I recently obtained a Compaq Portable computer dated 1985. The previous owner received it but never powered it on, though the owner before him said it worked. I powered it on but only the fan turns on and nothing else(I was thinking at least something would show on the screen or a noise from the speaker). It has two floppy drives and no hard drive so would it only actually start working when a disk is inserted? I opened it and I'd say the capacitors on the left in the picture were slightly warm, but a little LED on the motherboard was not lit up when powered on.

I am asking this because the previous owner has just found an MS-DOS for it and has lots of blank disks for it he will pretty much give me. But I don't want to already be accumulating all this stuff if the computer does not work. Also, he has a few IBM 5160's for parts, would the hard drives from them work on this Compaq? Thanks!

 

[Ole Juul]

Welcome to the forums!

Nice machine. I recommend you keep it with two floppies. For one, it is historically correct. For another, once you get used to it it's very functional and a lot of fun to work off two diskettes. Thirdly, the PSU may not be adequate to run a HDD. I don't have this exact machine so I'll wait for others to weigh in on the HDD/PSU info.

You might start by checking the seating of all the cards and chips. If that doesn't go anywhere, then take out all cards except the video. If that works, add the rest in one by one. Remember that nothing is hot-pluggable, so turn power off when plugging. You might also check the voltages on the PSU if you have a meter.

It should show something without the disk, but you'll want one anyway. When working, it should check for a boot disk and then complain that there isn't one. I'm sure you can get this going. There's a lot of expertise in this forum. Hang in there!

- Ole

 

[Pcmx]

Nice machine and welcome! I just got an Apple 2e, I think also from '85 that had been sitting for over ten years and didn't beep or do anything until I removed and reset connectors and cards using only the ones needed, which on the Apple 2 is none, then adding the rest like Ole Juul suggests. Hope it's something simple like that for you and you are able to get it working as good as you'd like it to.

 

[per]

Nice machine. Seems like it got a SixPackPlus card and a modem card in addition to the graphics and Floppy-controller cards.

How long have you been running it when you have tested it? The Compaq Portable doesn't show the actual RAM count on startup, and since your machine got the full 640KB, counting it may take a minute or so. I would suggest just having it on for five minutes and see if anything happens. If not, then you may try to remove anything but the graphics card and retry.

 

[DOS lives on!!]

Very nice maching you've got there.

The machine will still turn on and check for a disk wheather or not a disk is inserted into the floppy drive. It will not however, boot unless a boot disk is inserted. Like mentioned, remove all the unneeded cards except the floppy drive controller card and the video card, and disconnecting the floppy drives to see if anything eventually shows on the screen. Then, plug back in the floppy drives, turn the computer on, and wait to see if the drives are accessed at all.

 

[RoadWarrior]

Ok just to make sure I highlighted what I believe your instructions are telling me. So I just remove one thing at a time then turn on to see if there is any difference? I will probably have to buy a volt meter as I don't have one.

 

[DOS lives on!!]

Yep, remove what looks like the AST SixPak card, and any other cards besides the video and floppy controller card. You don't need to disconnect the data cables from the floppy drives, just the power cables.

 

[Stone]

Ok just to make sure I highlighted what I believe your instructions are telling me. So I just remove one thing at a time then turn on to see if there is any difference?

No, that's back asswards. Just do what Ole Juul (and two others) said above and that was...'take out all cards except the video. If that works, add the rest in one by one.' How could you misinterpret that? Maybe you should practice your reading comprehension before you even attempt to touch that computer.

 

[RoadWarrior]

Well unless you tell me otherwise I thing I broke it. I bought a multimeter, got the MS-DOS and blank disks. Opened it up to start working on it and powered it on. I think a resistor went up in smoke, or at least something did. It was right behind the vent you see on the left, tried getting a picture but I think it is sort of useless as I can't see anything wrong.

 

[Chuck(G)]

Who thinks it's yet another Rifa line filter capacitor?

 

[RoadWarrior]

Here's the picture, all I know it came from this area. It happened the instant I flipped the switch.

 

[Chuck(G)]

Well, a little magic smoke is to be expected on these older systems. Stuff ages and goes kablooie.

Not fatal, but rather a chance to brush up on your soldering skills. These old systems are very repairable, not like your latest (or not so late) bit of Apple kit.

First thing: get yourself a multimeter and a decent soldering iron.

 

[MikeS]

Here's the picture, all I know it came from this area. It happened the instant I flipped the switch.
View attachment 9494

Can't really tell much except that it's the power supply, which is to be expected; smoke or explosions are often the best problems to have since sometimes they actually remove a problem and they're usually easy to find visually. Have a close look in that area for anything charred, discolored, blown apart, etc.

I take it that with all the unneeded cards removed as suggested there's still no light or activity on the disk drive(s)?

 

[Bungo Pony]

It's most likely a capacitor that exploded. Had that happen in an Apple II floppy drive. Do a Google image search for "Blown capacitor" to see what a blown up one looks like. You'll likely be able to find the culprit if you know what you're looking for.

a lot of fun to work off two diskettes.

...and that's precisely why I don't collect PCs. I always found it a chore to use floppies on the PC, but using two floppies on a Commodore 64 was heavenly :D

 

[RoadWarrior]

Are the power sources the same as the IBM PCs? There is some people in the Computer Science side who do vintage computing, but the clubs don't really get going until the fall, so though I'll see about working on it, hopefully I'll definitely get it working then.

 

[liudr]

Best of luck fixing it. I just rescued one like yours. What y described as no beep happened to me several times. But after I took apart the keyboard and cleaned it, of course the foam pads degraded, and left the keypad as a circuit board, I was able to boot every time since then. My keyboard is dirty inside. Does yours have DS HD floppies? Mine is DS DD. Glad that someone traded with me a while back and I got an unopened box of Verbatum 360K disks. Worked like a charm and now I am running DOS 1.10 on the backup disc.