Commodore 1701 tarnished RCA connectors
 

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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?

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.

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).

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 :wtf:

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.

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.

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:smoke:

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

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

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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?

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.

Remember when I said:

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.

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.

Here's a comb filter card for computer video capture, but it doesn't have analog output.
https://www.youtube.com/watch?app=desktop&v=xSb_-Y_vn5E

I found the Phillips/NXP TDA9183 chip which seems to have everything you need on the same IC. Example circuit looks simple enough + there is a DIP version available so you can probably breadboard it.

A switched capacitor delay line - trying to think if I ever saw that implementation, but yes, it has everything needed.

You could look for an S-VHS VCR or one of the VCR/DVD recorder combos with S-video output....The transport need not work if you're just using it as a comb filter.

It seems to be that an ordinary home VCR with a comb filter only passes the input right thru to the output (EE mode) without going thru the comb filter at all regardless if its composite or S-Video. I'd actually be inclined to pull the 1-H delay line out and use it with the Pi making my own Y/C separator.

Fudoh weighed in on comb filters in 2012 on AVS, you might find this interesting
https://www.avsforum.com/posts/22243853/

So if you can find an Entech SVSI or CVSI-1 for cheap you're in business, or get a Pioneer DVD recorder and run things through it.

1701 can only be RBG modded via the neck board, and I'm not aware of any examples for such a project on that set on the webs.

There's some cheap Aliexpress neck board kits, but idk if they are trustworthy or what.

I don't wanna bother with RGB mods. I watched an Adrian's Digital Basement video on YouTube about the 1701/1702 and I remember him saying that the RGB levels used are over 0.7Vpp. So you'd need to get some transistors and amplify your RGB to what the neckboard uses.

The neck board mod kits are made to do that; they are essentially simple RGB input stages that give you a wide range of control over the tube grids, but rely on the existing electronics for sync and deflection. Like I said, I've never used one, but they should work in theory.

I don't know off the top of my head what the RGB voltages are for a 1701, but they are always higher than NTSC levels at the neck board. Just glancing at a random schematic for one of my sets, the drives take 5.8V and the outputs take 7V. After they leave the outputs, the RGB signals get boosted up to some level of roughly ~200V.

Don't get me wrong, I'm not advocating for it. I would probably just keep it Luma Chroma as that is sufficient IMHO. The leap from composite video to s-video is far, far greater than the leap from s-video to RGB. As far as I'm concerned, most people can't tell the difference between the two when the TV is viewed from a normal viewing distance; you have to take close-up pics to see the difference.

I think the main reason to do RGB in most cases is that it's convenient if you have a whole ecosystem of stuff that's already wired up that way. And it is a little bit better, so (all other things being equal) there's no reason to not have it.