Repairing two VIC-20 motherboards

#repair #deoxitthatsocket #commodore

On today's video, I'm going to repair a couple VIC-20 motherboards that aren't working. Both show a black screen as I found in a recent SMMC video. Let's figure out what's wrong with these and get them working again!

--- Video Links

SMMC episode where these VIC-20 motherboards were first looked at:

Hantek 2C42 $125 2-channel portable oscilloscope:

Hantek 6022BE $60 2-channel USB oscilloscope:

Adrian's Digital Basement Merch store:

Adrian's Digital Basement ][ (Second Channel)

Support the channel on Patreon:

-- Tools

Deoxit D5:

O-Ring Pick Set: (I use these to lift chips off boards)

Elenco Electronics LP-560 Logic Probe:

Hakko FR301 Desoldering Iron:

Rigol DS1054Z Four Channel Oscilloscope:

Head Worn Magnifying Goggles / Dual Lens Flip-In Head Magnifier:

TL866II Plus Chip Tester and EPROM programmer: (The MiniPro)

TS100 Soldering Iron:

EEVBlog 121GW Multimeter:

DSLogic Basic Logic Analyzer:

Magnetic Screw Holder:

Universal ZIP sockets: (clones, used on my ZIF-64 test machine)

RetroTink 2X Upconverter: (to hook up something like a C64 to HDMI)

Plato (Clone) Side Cutters: (order five)

Heat Sinks:

Little squeezy bottles: (available elsewhere too)

--- Links

My GitHub repository:

Commodore Computer Club / Vancouver, WA – Portland, OR – PDX Commodore Users Group

--- Instructional videos

My video on damage-free chip removal:

--- Music

Intro music and other tracks by:
Nathan Divino
@itsnathandivino

[AceStrife]

Hearing "Deoxit that socket" made the old "don't copy that floppy" thing flash into my mind.

[tarzankom]

Since it was my first computer, the VIC-20 has a special place in my heart. It's always good to see systems that are able to be saved.

[labnine]

As a huge Vic 20 fan, I appreciate that you were able to save a couple of these machines. It was a good watch. Thank you.

[Lukeno]

The sad answer is that yes, this probably is the future of many old computers one day. It's why it is so cool to see people coming up with modern replacement parts that can be retrofitted.

[shmoostead]

I do like this channel. You explain everything and you make mistakes that everyone makes and most of all you are clear and concise.

[cheater]

I'm so touched by Adrian telling us about his bad memories 😢😢😢

[raybarker]

Starting to look like you might have a use for a ZIF-20 as well as a ZIF-64!

[MrRepeters]

The VICS are working. A repair is a repair, regardless. Thumbs up.

[tonypitsacota]

Thank you for the cool video. I just got my first VIC a few weeks ago with 8 games, 6 cassettes, and a C2N that I cannot wait to get booted up.

[IanSlothieRolfe]

I'm inclined to beleive someone had a number of boards, got as many working as possible by swapping chips around, and these 2 boards are the ones that ended up with all the "suspect" chips, hence the blue spots.

[baremetaltechtv]

I love your videos! Great content almost every single day, im literally in love with retro computers but I can't afford one for myself so I have to live vicariously through your adventures.

[Mikelp]

First computer I ever touched was a Vic 20 on math class, 6th grade. First computer I owned was a Vic 20. My uncle gave it to me with a tape drive and books and all sorts of goodies. I couldn’t sleep for days just tinkering and typing in “kamakaze Klingon “ line by line in basic: and playing lunar lander forever. Man I miss my Vic.

[ntsecrets]

I built a very crude cable descrambler as a kid with a black screen c64 and injecting composite video into the video circuit which provided sync and there was an adjustment to manually sync it. Mostly worked except for the colors of course.

[joelstyer]

Interesting. I had visited Commodore just as the C64 was beginning development and saw talked with some of the VIC20 and C64 designers. Quite interesting. You mentioned a "Signetics" 6502 but I believe that would be a Synertek 6502 as Synertek was the second source for 6502 chips. I also don't recall Signetics making a 6402. Synertek also developed some of the 6502 peripheral chips such as the 6545 CRTC (similar to the Motorola 6845 CRT Controller chip). At the time I visited, MOS Technology was considering producing the 6545 but I don't believe they ever did. Great video, thank you.

[stephenwhite]

I am working on a 6526 replacement. A have a version that can replace an individual chip or can replace both chips on an older 64 where the two chips are next to one another. Will have to wait until the current chip shortage is resolved before I can release to the public. I am hoping that it should cost less than a real 6526 goes for on ebay.

[more.power.]

Great show Adrian I have a non working VIC20 so I can now make a move on getting it to go properly .

[amerikalast]

I just picked up a Vic 20 yesterday - along with Radar Ratrace (go figure). No video output (with or without cart) and no sound with cart. Additionally pretty much no chips are socketed. Only 3 sockets in fact: UE8, UD8 and UF8 (the 3 bus transceivers) The Kernal ROM gets very warm, basic ROM gets warm, I think everything else is very cool to the touch. No logic testing equipment at the moment and no vacuum desoldering station (lost in the mail months ago - ugh). Time to follow Ray Carlsen's best advice on Commodore repairs: "if you have a major problem with your VIC20, it's probably best to start looking for another one"

[UpLateGeek]

Wow, anyone playing the drinking game is really going to be hammered after this one!

It would be really good if you could find a way to test the individual chips on the faulty RAM SIMMs, at least any 4M*4 chips that could be reused on my Let's Make Some Memories SIMMs. I'm wondering if there's a SOJ ZIF socket adapter that could be used with the Retro Chip Tester Pro to test them? I don't think they ever made an adapter for the RAMCHECK that works with the larger capacity chips, but even if they did getting a hold of one would be next to impossible.

I have been working on porting my SIMM design to KiCad which will make them fully open-source. But it might be some time since I've been working on other projects, and I want to get a batch made up so I can fully test them before releasing the new version anyway. Then depending if I can find some 16M chips, I might start working on a new board for them.

[monchiabbad]

Let's hope some day the designs of the chips will be found and replacements can be made.

[fortheloveofcommodores]

Love your troubleshooting work. I'm learning. I have this Canadian vic20. Missing a the f7 key. Otherwise good shape. When powered on garbled screen and blind commands work. The two apparently new vic chips, won't do anything. Not even black screen. Could be anything apparently. Lol. I'll I have is a multimeter. Your input if possible would be much appreciated. No. Rush. Happy. Agee, let's keep em going as long as we can