Commodore 1701 tarnished RCA connectors

[luRaichu]

Bought this one on eBay and had it shipped. It’s very dirty.
There is also corrosion on some of the metal parts inside, including shields on the main board.
Like the title says, the RCA connectors are tarnished. What’s the best way to make them shine again?

[Alex KL-1]

Depending on the level of tarnishing, sometimes I simply polish it with car polishing wax. This brings back even some shine if connectors are fair.
The inner contacts are more tricky; normally I spray all contact cleaner I know and use some used male RCA connector to work/clean it.

[vol.2]

there's a product called Caig Deoxit. put a little bit of that on a magic eraser and shine them up

i would go through all the pots in the set as well. with that level of dirt inside, the pots are bound to be filthy and cleaning them all thoroughly with Deoxit will eliminate inevitable glitchy issues

that way if a symptom appears you'll know it not dirty pots. assuming you penetrate the pots correctly and twiddle them a sufficient number of times (I once was told 50 times by a old tech many years ago).

[luRaichu]

I haven't gotten to the pots or RCA plugs yet. But I was wondering, what should I do about the corrosion inside? I'll grab a better picture someday.
Also, one of the screws holding the back shell on was so rusted that I'd left it out. How do I get a replacement?
Plus, I need a special cable to use S-Video on this monitor. I was about to buy a Blackmagic cable that looked right on Evil-Bay but someone snagged it before me. So now I will have to order some more shit to build a cable proper. What's worse is that it looks like imgbb dropped one of the pictures on this thread

[vol.2]

You can just use a simple passive S-video to Luma Chroma adapter like this https://www.8bitclassics.com/product...a-rca-adapter/

But you can find them all over the place like on ebay or whatever.

The corrosion inside? If it's from electrolyte, it needs to be neutralized. If it's just rust, then there's nothing much you can do other than take everything apart and treat it, but that risks messing up other stuff and I would just leave it.

IIRC, the voltages the 1701/1702 were expecting are a little bit higher than what the eventual s-video spec became, so you will probably have to adjust the image a little to compensate.

"How do I get a replacement?"

You can try just taking it to a hardware store and see if they can find one, and if they can't ask for help figuring out what size you need. Then you can order it from McMaster Carr. https://www.mcmaster.com/products/screws/

Go to a smaller HW store where they will actually talk to you.

[luRaichu]

Maybe I used the wrong search terms or something cause I can't find those cables on eBay..

As for the rust it's easily accessible on the chassis which can slide out (I think). I would rather not let it spread and ruin more metal parts inside. It's triggering my OCD.

[Electronic M]

Originally Posted by luRaichu

Maybe I used the wrong search terms or something cause I can't find those cables on eBay..

As for the rust it's easily accessible on the chassis which can slide out (I think). I would rather not let it spread and ruin more metal parts inside. It's triggering my OCD.

Rust typically doesn't hurt anything. I've had 50s sets where the chassis had spots that were almost rusted through from mouse pee, and a 1970s Sylvania metal cabinet set the looked like it had been in a field since the first Regan administration that came back to life and worked great without rust treatment. Unless you live near the Ocean or plan to keep it outdoors or in your shower room the rust won't grow further... granted on SS sets loose rust flakes could go places and do bad things where they end up so rust fix primer isn't a bad idea.

[zeno]

Many 60's Hi Fi's had this happen. Iy was a fine white powder on
the RCA plugs / sockets. Never caused any problems but we would
clean it up with WD40 on a Q-tip.

Zeno

[vol.2]

Originally Posted by luRaichu

It's triggering my OCD.

Best to just let it go. If you want to dust things that you need access to on the inside, my go-to method is a long, soft paintbrush and a mini shopvac. Just use the brush to gently disturb the loose dust and have the vac hose next to it to suck up the remnants.

You don't want to go ham on old, brittle PCBs if you can at all help it as you can end up cracking things like solder joints, etc and make more trouble for yourself

[luRaichu]

Originally Posted by Electronic M

Unless you live near the Ocean or plan to keep it outdoors or in your shower room the rust won't grow further...

I store this set outside on the patio in a plastic bag. Away from direct sunlight of course.

[luRaichu]

This is the S-Video adapter I just made for the Commodore monitor. First time using heat shrink tubing as well, overall a satisfying build. I'm getting better at soldering tiny wires.
When using the Commodore's separate Y/C input with my DTV converter box, dot crawl is gone of course but the picture is slightly darker. That is okay since I'd always turn down the brightness a bit when using American NTSC to get those deeper blacks. With S-Video the black is dark enough on the default brightness. Does it lack a pedestal?

[ARC Tech-109]

Pedestal should be the same between composite and split Y/C. I too had a problem with a Commodore CM-141 having a lower black level but I just tweaked the screen up slightly and adjusted the brightness as needed.

[vol.2]

Originally Posted by luRaichu

When using the Commodore's separate Y/C input with my DTV converter box, dot crawl is gone of course but the picture is slightly darker. That is okay since I'd always turn down the brightness a bit when using American NTSC to get those deeper blacks. With S-Video the black is dark enough on the default brightness. Does it lack a pedestal?

Remember when I said:

IIRC, the voltages the 1701/1702 were expecting are a little bit higher than what the eventual s-video spec became, so you will probably have to adjust the image a little to compensate.

Commercial S-Video spec has a lower voltage level than what the Commodore YC monitors are expecting, and will therefore display slightly darker. The issue is that S-video did not exist yet Commodore made those monitors, so they just chose a pedestal and went with it. When S-video was invented, they didn't care about what Commodore chose and made it in line with NTSC levels.

It's nbd, just turn up the brightness a little bit. Do it in a dark room and turn up a black raster until you just barely can see it glow and then back it off a tiny bit until the glow fades to edge of glowing or off.

[luRaichu]

Somewhat off topic, but it would be nice to have a box that would comb filter Composite into the separate Y/C components since this set has the usual notch filter for Composite in.
Especially for use with Raspberry Pi analog out since their chipsets don't allow split Y/C, only Composite.
I'm not sure if this kind of device already exists but there's gotta plenty of comb filter chips out there for newer set designs. Would be an easy and interesting project that's for sure

[old_tv_nut]

Originally Posted by luRaichu

Somewhat off topic, but it would be nice to have a box that would comb filter Composite into the separate Y/C components since this set has the usual notch filter for Composite in.
Especially for use with Raspberry Pi analog out since their chipsets don't allow split Y/C, only Composite.
I'm not sure if this kind of device already exists but there's gotta plenty of comb filter chips out there for newer set designs. Would be an easy and interesting project that's for sure

A comb filter requires at least a one-line video memory.
For an analog comb filter, that would require finding a glass delay line from an old TV, not just a chip. For a digital comb filter, you would need the chip(s) that do(es) A/D and D/A and memory management plus whatever memory chips are required.