Well, the old gal is starting to look pretty good. I did remember messing with the ram chips back in the day because there was a bad character in the video ram. That's probably how those pins got bent. 😀 Thanks for making my old junk look so good!
I am amazed that washing the motherboard didn’t cause problems. Years ago, I was a mainframe computer tech. I had a water cooled mainframe that several motherboards had gotten wet. There were many signals that had shorted to ground. Took about a week to get everything working.
So long as there's no power, water generally doesn't cause a problem. IPA rinse afterwards works to help ensure there's not much for mineral deposits and as alcohol is miscible, will help guarantee everything is dry before power is applied. 12v is even generally fine fully submerged, so long as their aren't close tracks. Unfortunately most PCB's do have close tracks which allows the shorts that destroy things
My school computers were 3032 PET's in the late 80s. They were stolen and dumped in a river. My teacher recovered them and kept them in a warm dry cuppboard while the school wait for the insurance guys to call. About 6 weeks after their "swim", my friend and I decided to fire one up to see if it worked, and despite having been upto its monitor in river water and sludge, it fired right up like it was new. They don't make stuff like that anymore!!
That is the most thorough clean for a computer I have ever seen... All I did to my PET's guts when I got it was wipe the motherboard with a damp towel to get rid of most of the visible dust... Didn't even take the CRT apart at all.
"I don't know if its on, so I'm going to check if the CRT filament is glowing". Hehehe, most people would just flip the switch. Fun video. The PET is the first computer I ever used as a child.
I shudder to think about how many of these great old machines are rotting in landfills, possibly still working if they were recovered. People like you, me, and other enthusiasts on and off youtube spend so much time cleaning, repairing, and restoring them with so much care, while so many others just discard vintage computers because they see no value in them.
One thing you can do with old analog supplies to be more cautious: If what you are worried about is a regulator putting out more voltage than it should, if you use a Variac on the line cord, and monitor the outputs of the regulators as you slowly bring up the mains voltage, if you see one of the regulators start to exceed it's rated output, stop increasing the line voltage and investigate. Better than simply applying full line voltage and hoping for the best, especially when rare chips are involved.
In the early 80's, I worked as a PCB assembler for a manufacturer of thermoforming machines part of the process was to wash the water based flux of in the sink with warm water and an old toothbrush. In the mid 90's, I worked in a heat treating shop that cracked natural gas to use the carbon in the carburising furnace. This meant there was a ton of free carbon in the air and it collected in crt monitors like crazy. A few minutes in the sink with hot water and soap then a week under my bench and they were good as new.
I use to wash circuit boards the same way at work. My Biomedical Clinical students could not believe I did this. Would always use some compressed air the next day to make sure boards are dry.
When I first started in computers in 92. Air compressor and water among other things. Just keep on eye on the coils and stuff. But chips, diodes, transistors and stuff is okay. Before the internet. This was sort of a secret. I talked to enough board level electronic repair people as I call them that told me tons of stuff you could get away with. But it does not go without warning. I once cleaned up colecovision that looked new once done. But I did the power up test before the clean up. Worked fine. After the clean up. It did not work. But looked brand new. At the time I checked the voltages and a few areas. Since I did not want to destroy it. I sold it on e-bay for a nice profit. I hope the person who purchased it enjoyed my honestly. I explained in detail what I did and checked. So no issues. I was surprised about how much I got for it too. But it also included games, controllers, and such.
I've gone as far as using the dishwasher to clean boards before now but most often I'll use foam cleanser, a stiff natural fibre brush to scrub the presistent bits and followed by a rinse down with clean water then a good rinse off with isopropyl alcohol which takes way the water, it's immensely satisfying to do and see the 'as new' condition reappear. Handy hint to avoid personal injury, make sure your significant other is out for the day and isn't likely to discover a stack of circuit boards in the dishwasher. And hell. *NEVER* lift a CRT like that, always support it from underneath
The production quality of your channel has gotten really good. I really enjoy your coverage of arguably some of the most boring topics on earth. Love it.
Great video! That PET turned out great! I liked the music too by the way. I think the CRT comes out through the front, along with the bezel. I don't remember how the bezel is attached though, I never had to remove a PET CRT myself but I seem to remember a RU-vid video of someone doing it. The cassette recorder is a Sanyo if I recall correctly. They cut the corner off so that it doesn't get in the way of the heat sink. I think your cassette recorder is the first one they put in, but there are at least two other models that were used on the PET-2001. Commodore was known for just grabbing what was on hand and using it in production; that's also why there are several different versions of the bezel and the sticker. There's a video on RU-vid at ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-xzMdKCOOvKI.html with a comparison of one of the other recorders: the Sanyo M1540A (I think Commodore named the floppy drive for the VIC-20 for that). The LED on the motherboard is not for power but for diagnostics. You have to short a pin on one of the ports to make it run a diagnostic program that tests everything and turns the LED on. Sorry I don't remember details. There's a lot of information online, e.g. at www.6502.org/users/andre/petindex/repairs.html Commodore used single-wipe sockets that were pretty bad. Looks like at least those sockets for the RAM chips were already replaced with dual-wipe sockets. Good deal! And as I said in the comments on your last video: Tynemouth makes a board that allows you to expand the memory to 32KB and switch between various versions of the Kernal and BASIC ROMs.
BTW, broken chip pins are an incredibly easy fix. Just take some old dead chip and break the legs off it for a nice collection of spares, just at or below the bend/shoulder. Then with a tiny bit of solder on the pin to be repaired, use a soldering iron and tweezers to hold the replacement leg in place while melting the solder and pressing the leg flat onto the broken pin. I’ve found that works great to fix broken pins. If the pin to be fixed is broken off right at the body of the chip, that does require a little dremel work to grind the plastic or ceramic away to expose some of the old pin. Then use the same method with a replacement pin that was also broken off right at the body of the donor chip so it has that bend and a little bit of horizontal flat surface to solder with.
You take a lot of time and care when restoring vintage equipment, and it definitely shows with your results. Glad to see computing history being preserved as it should.
Oh man that was such a satisfying watch. Really glad the old behemoth has ended up in caring hands. Very early, rare and sought after version with the white CRT phosphor and blue bezel / commodore symbol, too. 23,000 mfd capacitor!? I wonder how much it holds now? Boy did I wince (as I'm sure many others did too) while you were trying to remove the CRT but thankfully everything worked out wonderfully. It's amazing how cobbled together this was. Let's use our calculator and cash register keypad tooling for the keyboard, who needs full size? Oh, tape drive? Let's just buy some cassette recorders from Sears and chop them up. Case for the thing? Well we do make filing cabinets. Let's use filing cabinet sheet steel and tooling. Sure. And lo, a new era of computing was born. Great job. Thank you for preserving and documenting this :)
I would love having a Commodore with basic loaded. I wrote many programs in basic during the late 1980's. A friend and i created a learning program. My first child used it and was able to skip kindergarten. And she did not struggle in first grade as well. Only when she started the second grade it she was very smart and passed with top grade!. Unfortunately I do not have that program any longer. It would still be effective to kindergarten kids.
I would have also checked the big capacitor to see if it's still up to the job and there is no leaks because electrolyte tends to leak out of electrolytic capacitors
I am never quite sure computers are completely inanimate objects...I am sure the soul of your PET is giving a huge sigh as it gets cleaned and feels the touch of human hands once more.... :)
So satisfying to watch that thing become clean again and look like new. And that number 7167, even after all these years, that's just etched in my brain. 😀
I've got a 4016 per which I bought new way back when. Its been under the stairs untouched since about 2001 when we moved in. Have the cassette drive and a single floppy disk drive. I think its about time I pulled the old girl out and fed her some 240V juice. I did remove the 16k ram and installed 32k at some point. I remember buying it and having to remove the passenger seat from the car to get it to fit in. Its bringing back a shed load of memories, thanks a great article.
Back then I owned a "Challenger 1P" computer from tiny Ohio Scientific. It's not surprising to see that it was very much like this Commodore Pet: 6502 processor, character generator video, and static RAM (I bet these were 2114s too). Even the motorboard layout looks very similar.
Ever since I watched this series when it first came out, I've been lusting after a PET 2001 like no other computer. Just a few days ago, I was finally able to fulfill that dream. I found a 2001 missing its C2N style datasette and 6550 memory chips but otherwise in great shape for only 50€. Since the 6550 RAM has gotten stupidly expensive, I bought a Tynemouth adapter until I can afford a more elegant solution. I also found a datasette for it and am currently in the process of making my dream computer nice again!
Hi, the memory chips with the clipped pins, you can mount the IC into a new socket and solder the short pins, then plug the new socket into the PCB socket.
He was on the right track with the tube when he started angling it so that the screen was parallel to the bottom -- he just gave up too soon. I went through the same thing when I first tried replacing a PET crt. Which reminds me -- the later 2001-Ns aren't any better.
Thanks so much for this video; saves me the anxiety of deciding what the best way to clean motherboards is. Keep up the great work, it's helping us out here.
My roommate had a full pint of rum and coke spill into his old NES (don't ask how). I washed the whole thing out in the sink and let it sit for a week. Runs like new (plus a new 72 pin connector).
My buddy in college had a soda explode in his backpack with his i7 laptop. Soda just poured out of his disc drive when he took it out of the bag. We ended up taking the whole thing apart and washed/dried everything. The only problem was that the LCD was damaged from the soda (splotches), but it still turned on and worked.
The rubber ends of the keyboard plungers originally had a carbon conductive layer on the tips which deteriorates over time. Watch The 8-Bit Guy video also repairing a Commodore Pet. He debunks the use of pencil lead to replace the carbon layer. But conductive silver paint works a charm. You may want to try a "conductive paint pen/marker". Cut small circles of foil tape may also work.
I've actually had a lot of luck with this kind of conductive pad by just rubbing it on fresh printer paper until the pad stops looking shiny. It worked on my MSX, Amigas, Sega Genesis pads, etc.
What a funny power supply, but that's the era for eccentricities. Thumbs up for not being afraid of water, things dry people, especially in a controlled application. I'd be shocked if the tape deck didn't need a new belt. ^_^ It would have to be bezel end how the tube got in there, it's wider. Kudos on your cleaning thoroughness. ;)
Logan Jorgensen I still think of the old standard linear power supplies like this as normal. Easy to build, easy to repair, very reliable. I remember making a linear power supply for a Commodore 128 when it's power supply toasted. Worked great for many years till the computer was retired.
On the old discrete transistor PDP-8s it was actually specified in the manual to use mild soap and water to clean the logic boards. I doubt that transformer gets even slightly warm when the computer is running. Most of the heat will come off of the 7805s.
Back in the Apollo era, the TTL modules that the flight computers used were bathed in some solution (can't remember what it was). If the module weighed heaver after dunking than it did before, that means that it wasn't properly sealed, and the module was tossed.
I am 100% down to see more "Computer picking" like finding retro PCs at barns act and bringing them back to life like you t do here (even though I know most are found on Ebay)
What I usually do on chips that have broken legs (assuming they at least have stubs left) is take one of those male breadboard wires (the ones that have a plastic square bit at the end of the wire with the pin that goes into a breadboard) and just solder the pin of the wire onto the leg, then cut off the rest of the cable along with the plastic bit because I only need the pin obviously (cutting it after soldering it is easier because you can hold onto the wire while soldering it in place). It has fixed a couple of ROM chips for me, I'm sure you could use something else but it's just what I had in my drawer that seemed like a suitable replacement, not too soft and also thin enough to push into a socket easily
Fond memories of this model indeed!! Went to Secondary School ( ages 11 - 16 ) here in the UK from 1978-1983. For most of that time we had a single Pet 2001-8 , in a school of over 1200 kids!!! In fact most of my o-level course work was done on this solitary Pet ( or by sending a hand written listing to the local University where they transferred it onto Punch cards to be used on the Main Frame !!! ) Used to bribe the caretaker to let us stay after hours so we could use it. Hours & hours in typing in programs from various magazines & books when I was supposed to be doing Computer Science coursework . Even more hours spent playing - 2 games stand out in my middle aged memory - Star Trek & Nightmare Park Would really love to be able to find one & give it a good home
A gallon jug of distilled water from the grocery store is cheap. Poke some holes in the lid to make like a shower nozzle. Almosnt needs a second set of hands... or jerry rig a contraption to hold it up. Tap water is probably fine... but distilled for peace of mind.
A safe way to start it up is connecting it to a lab-power supply. And if all is well reform or replace the big cap. If there is a problem the lab supply will limit the current. You can feed DC to the input of the rectifier bridges. (that way it also does not matter if you, by accident, connect the polarity wrong.
Windex is called Glassex in the Netherlands, it is one or two percent soapy water and a drop of ammoniac, a little bit blue colouring and at least 95 percent water. You can easy make it yourself by adding half a drop of dishwashing liquid, half a tablespoon of methylated spirits, or vodka. Actually it is rather silly to buy the stuff ready made in a spay bottle. Making a thousand litres costs a few Dollars. (consumer price, wholesale only a few nickels)
I always wash my dirty computers and eletronics, regular tap water and detergent. After this i set up a fan and let it dry for at least 12 hours. Never have a problem.
I got my first PET 2001 on Saturday, it took me 7 hours to take it apart and clean it completly, I had the same problem with the keyboard and I used aluminium tape to fix it, you just have to cut out small squares or use a leather punch and get the right size, but after 2 hours of work on the keyboard it is working, like if it was new
Oh yeah, I saw that in Davids video (The 8-Bit Guy), but that thing is expensive, at least thats what he said, of course it could be better than the tape, but thats the only thing I got right now and it is still working after 3 days :D
I'm always impressed by your videos, but I've enjoyed watching your restoration process and production quality improve. If you had a Patreon page, I'd support your work. Don't stop restoring and resurrecting our vintage tech.
@@adriansdigitalbasement I enjoy how much of your enjoyment (and tenacity) comes across in your videos--it's not just another day at the office. Keep following your heart and know that folks appreciate your efforts.
That high voltage transformer in the monitor is so very nice looking. Looks to be a bobbin wound secondary with very good potting and insulation. I bet it would handle well over what it's doing for the CRT tube.
For the motherboard wash I recommend doing it with distilled (or at least deionized) water instead of tap water. It's not really corrosion that you want to avoid here, but rather creating deposits of minerals (from the water) that can short together traces and pins even after you think it's dry. At least that's what I do with my motherboards. Distilled water is cheap.
Separately, I did a similar thing with a Sega Genesis motherboard I was working on. I had a new kitten that got up on the table I was working on and agreed it needed to be thoroughly rinsed... So I ended up washing it thoroughly then used IPA on it to flush the water, and then once it was mostly air dry, I put it in my oven at the lowest possible temperature for like 30 minutes. This thoroughly evaporated all the water that might've gotten under chips.
Great stuff. Really nice cleanup job on the PET. For straightening sheet metal a pair of crescent wrenches work really nicely if the bent area is near the edge of the panel.
With that liquid from the transformer, I suspect it's something from the insulating tape on the transformer's windings. I'd recommend doing a high voltage test on the transformer if you can. You don't want the case suddenly coming live, or live leaking to the board. though I don't think it'd actually be an issue, it's better to have piece of mind.
He did turn it on in the last part so surely there was high voltage in that CRT that needed to be discharged...unless it's been a few days since he did the last part.
Hi, at 22;20 you had a chip with two pins clipped, put the chip into a fresh IC socket with turned sockets/pins, then plug the IC socket into the PCB socket. That way if needed you can solder the clipped pins to the socket and still be able to remove it. Because the pins are missing, it may be due to corrosion, permanently putting the chip into its own socket will prevent any stress on the original pins.
Every time I see that horrendous early PET keyboard it feels like... well, in this case, like we're into a cash register refurbish. Even the color coding looks like that in an old point of sale machine!
