Commodore 1942 monitor reassembly

I took apart a 1942 monitor to check for bulging capacitors, etc. When reassembling it, of course there is one cable I can't find a connector for on the circuit board (see cable.jpg). The cable is two wires in a clear plastic tube that ends in a white 3-wire connector. The two wires are then wrapped in black plastic and go around the CRT tube just behind the front of the monitor (see monitor.jpg).


Any help finding where that cable connects is appreciated.

[shaf]

i don't have a PCB layout only a circuit schematic, but its for the Power LED it should plug into the main board close to the 3pin socket near R413. You should be able to use the monitor without it just the LED won't light.

Thanks, but that one I've got connected. It's a pair of black and white wires in clear tubing that goes directly from the board to the light.


The one I need to find the connector for is a pair of green and red wires, thicker than the ones that connect by R413. They are initially in a clear tube, but when they wrap around the front of the CRT, they are in black tubing. It's hard to see where they end, but they go at least 7/8 of the way around the front of the CRT.

Since it wraps around the front of the CRT, it makes me think it might have some sort of degauss function?

[shaf]

Let me recheck the schematics and see what i can find. I doubt it would be a degauss function because none of the other Commodore monitors have this feature. And it usually requires a manual reallignment.

[shaf]

The 1940 and 1942 Monitor used the same electronics the only difference is the dot pitch of the CRT. with the 1942 having the finer dot pitch, it was manufactured by Daewoo between 1992 and 1993 and was a Bi-sync monitor supporting 15.75KHz and 27 -31.5 KHz.
The only 2 position connectors in can find on the schematics are for the Front LED and Headphone Connector.

[TjLaZer]

Anyone have a cap list avail for this monitor?

Better late than never?


I went to https://elektrotanya.com/commodore_1.../download.html and after waiting a while, the "...processing..." text after "This file is downloadable free of charge:" turned to a Download link. On the 43rd page of the PDF (page 40 as the document numbers them), the capacitor list starts.

[whaka]

don't know if the solution was found since... but better late than never, isn't it ?
the connector you looked for, is somewere near the power cord plug.

[Shadowfire]

Originally Posted by shaf

Let me recheck the schematics and see what i can find. I doubt it would be a degauss function because none of the other Commodore monitors have this feature. And it usually requires a manual reallignment.

Every single color CRT ever made has a degauss function and degaussing coil.

In most cases, they were simply a loop of wire around the front of the tube, connected in series with a PTC resistor, powered by the incoming AC power.

When you turn on the CRT and the PTC is cold, it allows a LOT of current to pass through the degaussing coil. This heats up the PTC, which raises its resistance and reduces the current through the degaussing coil, until the current almost completely dies off - this degausses the tube.

If you turn the unit off, then immediately back on, the PTC doesn't have any time to cool down, so it doesn't degauss the tube again. The PTC must cool down before another degaussing cycle will occur.

If you leave the unit on for months at a time, you will see the colors slowly start to get corrupted as the tube gets magnetized by the earth's magnetic field. This is why every tube has the degaussing circuit.