Commodore 64 (C64) WTF Modulator Repair

A short video covering the repair of a Commodore 64C.

#commodore #c64 #modulator #repair

[spidermcgavenport]

Thank you, GadgetUK164, much appreciated Commodore 64 RF modulation repair.

[yorgle]

When I buy an "As-is for repair or parts" item on eBay, this is exactly what I don't want.
Troubleshooting a component failure is fine, but if somebody has damaged the board with inept soldering, they can keep it. I'm perturbed enough by the soldering damage I've inflicted myself on things in the past, so I really don't want to be stuck with somebody else's mess. You did a great job salvaging this but it must have been frustrating.

Fortunately I've been lucky on that. The only bad example I've run into was a Genesis that had traces deliberately scratched up inside.
Other than that, I also ran into a different Genesis that had been very expertly soldered - so expertly that I didn't even notice the work at first. On closer inspection I realized the CPU was 2 years older than the rest of the machine, there was flux residue all over one of the surface mounted ASICs, and there was a nicely installed kynar wire snaking over to it. Although that machine had been previously worked on, I couldn't complain since the work was better than I could do, and it seemed to work fine other than a weak 5V supply.

==
This has to be the first time I've seen anyone put this much effort into repairing an RF modulator. :) I've never worked on a C64 but on anything else I like to just delete those things. I guess in this case it was required to get any video output at all, which is unfortunate.

[rasberrycast]

Amazing fix! That poor board had been through the wars. All for a possible crystal bodge absolutely crazy.

[DaveCurran]

Nice save, a very neat repair considering the state it arrived in. Those are the sort of boards where someone's had a real go at bodging things that I tend to consign to the spares pile. I'd guess from the solder on the datasette port and on the diodes near the IEC port that someone has fitted (or at least tried to fit) an internal SD2IEC. Maybe the idea was to remove the modulator and fit the SD2IEC in it's place to give rear access to the SD card. Not that it will work without the modulator anyway.

[Four_X]

Awsome repair bud, it never ceases to amaze me just how dumb some people are
when it comes to attempting repairs, the guy who tried to repair that c64 nearly
butchered it, it's a good job it landed in the hands of someone like you who knows
what the hell there doing.

I've just repaired a Neo-Geo 6 Slot with a backup ram error myself, i have a repair
video on my channel if your interested.

Also if you have the time check out my channels intro video it's a mod of the C64
Loader for Operation Wolf with the classic music from Ocean loader (Jonathan
Dunn) i think you will like it, i know you like the original loader.

[JorgeCarvalho_web_dev]

Great video man! You are a true ACE.
How about do a video of fixing my Sinclair PC200 that gives an error at boot "System Serial port error" and don't goes any further?
Cheers,
Jorge

[crumplezone]

Some people should be made exempt from holding a soldering license :) great vid and neat finish Gadge :)

[TheWilldrick]

thanks for another C64 vid! I already fixed (thanks to you) a DOA C64c a family member was about to throw away!

EDIT: what do you think about the mod that consists on using a DIMM socket to replace all RAM ICs on the C64?

[jocktrucker]

Thanks for not putting us through that game again!! Sick of Navy Seals!!
Great videos, do a bit of repairs myself and refer back to you now and again!!

[Boinger]

The modulator generates the composite output as well as RF and buffers the s-video for the DIN port. VIC outputs s-video natively. You can bypass it with a few transistors as an amp/buffer and sometimes improve video quality to boot. Who needs RF anyway.

[DLiberator]

Nice repair. That modulator looked in pretty bad shape appeared to have been butchered. Well done getting it working again composite picture looked really good.

[bwack]

Nice repair! Had the same short circuit on my modulator pads after first time I removed the modulator (pads were fine though). I didn't find it at first and ordered a new VIC-II ic. Now I have a spare VIC IC because there was nothing wrong with it in the first place :) Not sure why the S-Video is worse than Composite.

[GadgetUK]

Willdrick, I cannot reply to your message - no option?!?! Glad you sorted a C64, what was wrong with it? Regards SIMM / DIMM mod for C64, personally I would just socket the DRAM and use original chips. At some point someone will produce a small tidy SRAM modern board to do the job!

[psyolent.]

did someone try to fix that with an axe? jesus mate. well done getting it back to life!!!!

[themaconeau]

Damn, looks heaps better than mine >.<

[RiotRetroGaming]

Amazing work. Just my breadbin to sort now *wink, wink, nudge, nudge* lol

[RetroMarkyRM]

Hey Mr.G. Im working on a c64c 250469. Had two hot ram chips, socketed and replaced them but same problem. Check ed all the usual suspects and voltages, power pack is fine etc. Im thinking could it be the LS chips? Any thoughts on where to start looking next?

[RETRONuts]

How did you make the s-video cable, could you make a video of how too, but if it to much trouble no worries

[larsenmats]

I got a cleaner picture from SVideo on a C64c that had a rather fuzzy picture with ghosting by recapping the motherboard (did not recap the modulator)

[MrBuckshot]

I bought a commodore 64 (bread bid style) and I am having trouble with controller port 2. it reads the directions down left right and fire but not up. all of my keys work. what needs to be done to fix this problem