Hello..my first TV

[Donj]

Well, Fired it up after a day attempting to restore continuity in the 12 prong plug attaching the low voltage supply to the main chassis. The prongs, as well as the mating receptacles are coated with a grey substance, almost looks like it is plated on. Problem is it appears to be a damn good insulator. Got it scuffed off the prongs, however, the receptacles are pretty much inaccessible to all bit the finest dental pick. Hard to scrape with the Bakelite casing allowing such a tiny access hole. Got the set fired up by constantly fidgeting with the plug until all circuits came to life. I think I'll try putting my smallest drill bit in the Dremel to abrade the contacts from within.
Anyhow the set finally came to life with an incredibly bright raster so all the HV must be functioning properly. Cannot go any further till I remedy the multiple bad connections. Had it on for about 10 minutes and in that short time had to readjust the plug about 4 times to restore operation.

[JohnCT]

Originally Posted by Donj

The prongs, as well as the mating receptacles are coated with a grey substance, almost looks like it is plated on. Problem is it appears to be a damn good insulator.

I wonder if that coating wasn't some sort of contact lubricant that decided to morph into something else after a few decades.

Before running a drill into the contacts, I'd experiment and see if the coating can't be dissolved with a cleaner first.

John

[old_coot88]

I would certainly try contact cleaner first, like Deoxit or similar.

[Donj]

OK, finally got the problem taken care of. No amount of deoxit,alcohol,acetone, brake cleaner, oxalic acid or just plain water would touch it. Not wanting to overdo things with the Dremel tool, I found a diamond Dremel abrasive wheel that I managed to cut into a strip the width of the plug pins. In and out of the socket holes a few times seems to have removed the deposit to the point of reliable contact.
Once powered up I found that the speaker was dead. Took a look at the connector pins on the leads that plugged into the speaker and found the same thing. Cleaned them up with abrasive and now have a working speaker. Leading to the next question...
I presently have no input source for the set .. Wifey tossed the vcr a while back and I have to order a modulator for the dvd player..
Should I not be hearing something from the speaker even with no signal input?
Static, a hiss, something? All I hear is a slight hum controlled with the volume and a short static click when I change between channels.

[old_tv_nut]

Originally Posted by Donj

...
Should I not be hearing something from the speaker even with no signal input?
Static, a hiss, something? All I hear is a slight hum controlled with the volume and a short static click when I change between channels.

You posted a pic with a blank raster (no "snow"). I'm guessing without any RF noise getting through, your audio may be quiet also.

Is this chassis one of those where the "contrast" control is really an IF gain control?

[Donj]

Just did a bit more reading and found this.." A potentiometer (contrast) control, permits this voltage to be changed on v2, v3, and v4 so as to vary the gain of the video i-f amplifier"

[old_tv_nut]

Originally Posted by Donj

I'm not thinking so..... OOPS. Just did a bit more reading and found this.." A potentiometer (contrast) control, permits this voltage to be changed on v2, v3, and v4 so as to vary thegain of the video 1-f amplifier"

So, I presume you're going to turn it and see (or hear) what happens