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Hello and advice where to start?

M

mattw2121

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Dec 5, 2023
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I started my passion and career in technology with a TI-99/4A and then moved through the Apple ecosystem with an Apple IIe and Apple IIc. From there I headed into the world of IBM and clones (and have been there ever since). I've enjoyed watching retro computing videos over the past few years and have always wanted to learn how to do some basic repairs myself.

This past weekend, I stumbled across a Kaypro 16 at a local estate sale. I picked it up for 20 dollars thinking it would be something interesting to cut my teeth on. When I got it home, I blew out all the dust and attempted to fire it up. It did start up and displayed an error and (from memory) gave an option for S (to skip/disable) or R (restart). Unfortunately I can't remember the exact error or options, because moments later there was a loud pop and smoke. I pulled power at that point. I'm guessing a capacitor blew.

Now, that bring me to this forum. Can someone recommend a good path for me to learn how to fix this myself? I'm not expecting to be able to fix this machine up in the next couple of weeks. I'd like to learn the basics of electronic repair with this machine and willing to put in whatever work it takes, but could really use some advise on where/how to start.
 
Hello Matt and welcome to the forum. Be sure to modify your avatar to display where in the world you are located.

Nice find on the kaypro. There are plenty of folks here who can help you with repairing that machine. Sounds like the supression capacitor blew in the power supply. Dont worry its pretty common with its age. Do you have a soldering iron and do you know how to use it? Plenty of videos on youtube cover the basics of soldering. Best to LEARN on something other than the kaypro,, like a cheap kit you can buy and build. You will also need a decent multimeter at the mininum.. not one of those 8 dollar harbor freight ones but something half way decent. Used ones on ebay dont cost much.

My advice is learn basics on your own not on that machine and then when familiar with soldering and your multimeter, attempt to repair the kaypro.. Althought it doesnt sound broken. Sounds like its trying to read a floppy disk or its internal hard drive (which may be dead). Ie. you have a mostly working machine.

Mick
 
My path was to actually go to the local technical college (LWTC, Lake Washington Technical) and take the Electronics Technician certification course. It teaches you a ton of the basics and quite a bit of hands-on.

But it does require time.
 
Thanks for the replies! Learning to solder on something other than the Kaypro sound like a good idea :)

As a new hobby, I don't want to sink a ton of money into it until I've determined that I will really enjoy it. Would this be a good basic learning iron?


Would these be good kits to learn soldering with?



Thanks again!
 
mattw2121 said:
Thanks for the replies! Learning to solder on something other than the Kaypro sound like a good idea :)

As a new hobby, I don't want to sink a ton of money into it until I've determined that I will really enjoy it. Would this be a good basic learning iron?


Would these be good kits to learn soldering with?



Thanks again!
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No, start with this one. I can attest its decent. I use it myself. https://www.amazon.com/gp/product/B00M1O9ZSG/ref=ppx_yo_dt_b_asin_title_o00_s00?ie=UTF8&th=1

Kits like that are fine. The SMD one might be a bit much for a beginner, stick to through hole stuff in the beginning.

Remember to have lots of 91% Rubbing alcohol on hand to wash the pcbs when you are done to get the flux off as it will be corrosive and cause issues afterwards. Scrub with a toothbrush and rubbing alcohol until it dries clean with no flux residue.. If its sticky or blotchy you didnt clean enough.
 
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Yes, to do SMD well requires a microscope. At least for my old eyes.

Next you're going to want a hot air rework station (some of which come with soldering irons, so that might be a path)

I also ended up getting one of those cheap reflow ovens, which are actually quite nice, but not so much for rework.
 
DougM said:
Yes, to do SMD well requires a microscope. At least for my old eyes.

Next you're going to want a hot air rework station (some of which come with soldering irons, so that might be a path)

I also ended up getting one of those cheap reflow ovens, which are actually quite nice, but not so much for rework.
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I use magnification goggles.. Too many tools costs too much. ID rather spend that money on more vintage gear.
 
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Thanks again for the welcome and replies! I'm ordering up the recommended iron and will grab some through hole kits.

Is there any specific electronics 101 or vintage electronics repair videos that are recommended? I can search some stuff up on YouTube, but just checking if there are some "go to" ones that I should watch?
 
Just find a video with someone who teaches you well and isnt bad at speakingor annoying. Lots and lots of choices.
 
Welcome to VCFED.

Probably another RIFA capacitor failure...

You should be able to see the damage when you open it up!

A good idea to practice your soldering (and desoldering) skills first though...

You will also find that you may require a couple of different soldering irons and tips. Low power and very fine tips for delicate work up to much higher powers and larger tips for heavy duty work.

You will also require a multimeter (I have both an analogue and digital), and then expand in the future to a component tester and oscilloscope. You can start off "budget" and expand as your new-found hobby progresses.

Dave
 
Soldering practice is good but

If you do it on new stuff, it won't teach you about old solder.

Get something cheap of a similar age and practice on that. Hardest bit is normally desoldering. The old solder often doesnt want to flow and you end up overheating and damaging the PCB & tracks or you try to mechanically remove something that hasn't quite desoldered.

Techniques

heat the pin with your iron and with difficult stuff, its often worth wiggling it.

Suck the solder free, I keep the iron in contact while I do, and the PTFE nozzle on my sucker has 'adjusted' to fit around it, then if (when) you find its not all come out, resolder with some new flux cored lead solder (dont use the lead free stuff) and try again. If it resolutley will not desolder, some Non corrosive flux can help.

resoldering is normally simple but the pads & pins need to be clean and free of oxidisation/oil etc. Mechanically clean pins and wipe PCB pads with IPA. In the worst cases, some additional flux can help.

IC's are the hardest. Heat and suck each pin and look to having the solder pulled from the top as well as the bottom. Resolder as necessary to get the solder to flow freely (voltage supply / 0V pins are often the hardest as the tracks are thicker and pull the heat away). I set my iron on about 300C to get a quick heat & flow but if its giving grief, let the IC cool a bit.
When each hole looks clean, the IC will often need a 'wiggle'. You can do this pin by pin, sometimes I even use the iron to melt the remaining solder and a stick to push the pin into the centre of the hole. A final wiggle will probably break any little fingers then lift, but if it doesn't come easily, dont pull because thats when you lift the tracks and pads. Wiggling on the other hand rarely breaks anything.

Ultimately, if the chip is dead and you cant get it desoldered, just snip the legs then remove each pin separatley while heating with the iron :)

Tools, a good sucker is the key. I use either an old green Radio Spares one or my Engineer one (I have a blog on here about the tools I use) The powered ones are ok, but I can go faster with the hand held sucker on vintage boards.

Cant stress this enough, Take your time. Its a hobby and if something is giving gyp, walk away until your ready to have another go.
 
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Wow, thanks for the detailed info and advise! I have ordered the Engineer Solder Sucker. I'll look to purchase some older boards that I'm not concerned about to practice desoldering and soldering back on. Thank you all!
 
mattw2121 said:
Wow, thanks for the detailed info and advise! I have ordered the Engineer Solder Sucker. I'll look to purchase some older boards that I'm not concerned about to practice desoldering and soldering back on. Thank you all!
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Just go to a thrift store or good will and buy some cheap electronics. Really cheap and things noone would feel bad about ruining. radios etc.
 
Gary C said:
Soldering practice is good but...
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This is all excellent advice.


If you want to go a step further in TH rework I found the through-hole desolder stations (mine's a CSI 474A but it's pretty old) are far more effective than the hand solder sucker tool if you use it right.

The trick is to heat the solder around the lead until you see it melt, then continue to heat for another 15 seconds, then press the trigger (starting the vacuum) and move the sucker gun in a circular motion around the lead such that the lead is moving while the solder is being sucked out and the joint is cooling.

The result is a completely disconnected lead.
 
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