Crosley bakelite tv

[old_coot88]

There's two resistors coming off either end of the horiz.hold control, R85 (68K) and R86 (150K). If either of these has drifted in value signifigantly, it can throw the H.hold out of range. Check these for correct value before messing with the coils.

[Kevin Kuehn]

Originally Posted by Radiotronman

Ok, I'll try that, but how can you tell which are terminals 5-6. They're not numbered.

Looks like terminals 5-6 are in parallel with R89(22k).

[Radiotronman]

The 150K is pretty close and the 68k reads 61.5k. Would that being less cause it?

[old_coot88]

Originally Posted by Radiotronman

The 150K is pretty close and the 68k reads 61.5k. Would that being less cause it?

Easy enuff to find out. Bump the value up by sticking a resistor in series with it. Try say, a 8.2K and see if it improves the lock-in range, or makes it worse.
(Of course this isn't gonna address the sync issue.)

[bandersen]

No, that's plenty close enough.

[Radiotronman]

Ok, there was another cap stuffed behind a terminal board I didn't see connected to the horizontal oscillator transformer (.01). I replaced it and the horizontal us much better, but still unstable. The vertical is unstable as well. At least I have done firm of a picture. Now to get the sync stable...

[Radiotronman]

I can get the horizontal to hold for only seconds at a time.

[Kevin Kuehn]

Did you try what bandersen suggested?

Originally Posted by bandersen

One side of the coil adjusts the shape, the other side the free running frequency, That's usually the end that is accessable from outside the chassis. Set the horizontal hold control in the center and adjust that coil until you get a lock.

[old_coot88]

Originally Posted by Radiotronman

I can get the horizontal to hold for only seconds at a time.

Could you post the schematic covering the video detector and video amp chain?
I'm wondering if there's a chance the vid.detector diode* could be installed backward. There's been a couple of such cases on this forum, and it produces a display very much like what's seen in the screen shot you posted.

*That's assuming it uses a SS diode (1N34 etc.) and not a tube diode (6AL5 etc.)

[bandersen]

If tweaking the hor. oscillator coil doesn't help and vertical is touchy too, possibly an issue in the sync circuit.

[Radiotronman]

I adjusted the end in top of chassis, but it didn't really do much. The one underneath has s partially broken s www head. But I didn't out the horizontal hold in center when adjusting the top one. I can try that.

[Radiotronman]

Ok, I tried doing what Banderson suggested and I can get a picture, but it will not hold. Constantly having to readjust to keep it close. Should I look in the sync section?

[dieseljeep]

Originally Posted by Radiotronman

I adjusted the end in top of chassis, but it didn't really do much. The one underneath has s partially broken s www head. But I didn't out the horizontal hold in center when adjusting the top one. I can try that.

When the adjustment screw was damaged, I would solder a 6/32 nut to the screw and use a nutdriver to do the adjusting.
The Riders for the slightly newer 12" set has a notation on the schematic, for improving the horiz hold range. Replace the 150k resistor, r87 on the Sams to a 100k and see what happens. As others have noted, the sync circuit seems to need further trouble shooting.

[EdKozk2]

I once had a RCA KCS 68 chassis with close to the same horizontal circuit. The set had the same symptoms as your Crosley. The trouble was bad mica and paper caps in the sync circuit.
Ed

[Kevin Kuehn]

Have you tried adjusting the Horizontal Lock trimmer? Sams shows it as B2 on the back right side of the chassis? That trimmer cap sets the sync input level to the AFC portion of the horizontal oscillator. Otherwise I guess look over the sync circuit. An oscilloscope could be real handy right about now.