KayPro 4 WIP

Performa

Active member
In 2019, I responded to an advertisement for a KayPro 4 computer way out on the eastern edge of Wisconsin, not too far from Manitowoc. Thankfully the machine was in good cosmetic shape, so I bought it and hauled it back to Point. A couple weeks later my life got kinda crazy and remained so until earlier this year. The KayPro had languished in storage until the summer of 2021, when it finally came home.

I knew that it powered on, but lacked a boot disk for it. Likewise, I knew it had RIFA caps on board that were bound to explode if left unchecked, so I never ran it for long. My last effort to work on it was before the last show, but I came up short on that one so it was cut from the roster, as I didn't want to bring anything to the show that "might" set off the smoke alarms.

So, here it is!



...and inside!



 

Performa

Active member
The machine does power up, and the monochrome monitor is still very sharp and bright. One disk drive spins, the other doesn't- but that could just be a dead belt or a seized-up slider assembly. The big issue is the RIFA caps- I've not found a guide on how to do this, so I'm shooting a little blind on this one. They're in there, somewhere- so the goal then is to get them out.

 

Performa

Active member
If you need any reference I can snap a few photos of my power supply.
That would be awesome! I've got mine pulled apart now, and I have a feeling the RIFAs on this one are long gone. Here, let me grab some photos...
 

Performa

Active member
According to the no-contact voltage tester, something in here still has a readable charge. I guess I'll know what soon enough. 😬

 

PS2it

Member
Here ya go! Hopefully this will help somewhat. I recapped mine a couple of years ago, but it never worked. The power supply checked out, so I'm sure it's got a board issue. I should probably take some time and go through it again.

28
 

Performa

Active member
Here ya go! Hopefully this will help somewhat. I recapped mine a couple of years ago, but it never worked. The power supply checked out, so I'm sure it's got a board issue. I should probably take some time and go through it again.
Many thanks for the photo! Odd thing though, my power supply is different than yours, and indeed all the other Kaypro PSU's I've seen online so far. It's weird!



It was a nightmare to get this out, and I imagine it's going to be just as much fun getting it back in there. 🙃
 

Performa

Active member
Here are the floppy drives pulled out. The power connectors were very stiff and I didn't want to damage them by forcing the plugs out, so I just pulled the whole assembly put to work on it as there was enough cord to do it.

 

Jasper

Well-known member
Many thanks for the photo! Odd thing though, my power supply is different than yours, and indeed all the other Kaypro PSU's I've seen online so far. It's weird!



It was a nightmare to get this out, and I imagine it's going to be just as much fun getting it back in there. 🙃
Good luck!
 

Performa

Active member
So, the caps I need to fix the power supply properly will arrive sometime before Christmas, but they haven't been able to narrow down the delivery date any closer. I'll keep everyone posted when they arrive!
 

Performa

Active member
Update, the caps (as well as most other parts I had on order) will arrive "sometime in Q1 of 2022" per the carrier. Yikes.
 

Performa

Active member
Alright, so a few days before Christmas, another box came in. Inside were a slew of parts- all no-name (or weird name) off brands... but they were available and so I had bought them to replace the parts I may yet, someday, still receive. While these cost a lot more, and are probably junk, they'll be a good stopgap until the "real deal" gets here... eventually.

The kit I got to replace the RIFA's in the KayPro were "Bojack" branded "Film Cupacitors" (not a typo on my end). As I know the KayPro can run even after the caps blow, I figured these smaller caps were worth a shot. If they did blow up or catch fire, the KayPro's PSU is fairly well isolated from any delicate components, so of all the machines to have something "pop" inside, the KayPro is actually one of the safer bets, at least to my thinking. So, I got the old caps out (only burned myself once!) and the new ones in. The new ones have no indicators for polarity, so I guessed, and hoped that things would work out okay.

Flipped the power on today, and I'm pleased to say the PSU is still working, the screen powers up, and the board kicks on asking for a disk. The floppy drives are still messed up as one spins up and remains so, while the other never budges, but for the moment at least I'm happy- I didn't kill the computer trying to fix it, which is a win in my book.

As for the disk drives, I'm going to try to fix them. Failing that, I do know that there's a way to configure a cheap GoTek floppy emulator to load the KayPro software. If I can't get the disk drives working by April 1st, I'll look into it so we can have the KayPro at the big show.

Photos to follow!
 
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