Rare find! A Magnavox Brittany tv!

[bandersen]

What's wrong with soaking

[Yamamaya42]

Brightness parts fixed, mew tubes in

Get a faint image on screen now, very faint, Det diode may be weak.

Cant get horz lock hod pot does little horz lock tune cap does not help.

suspect that it's off freq.

http://suzaku.live-evil.org/0413250136.jpg
I could never do the math for this to convert to HZ, but I think it's too high
like 17-18hz MORE bad resistors perhaps?

[bandersen]

Yes, looks like around 17kHz. It will be an LC tank circuit that sets the frequency. Could be a mica cap is off.

[Yamamaya42]

Checked the resistors on the osc coil they seemed OK did not check ALL others on the area.
There is no instructions on how to set this horizontal oscillator circuit, several paper caps have been replaced that were leaky so I suspect the circuit was adjusted to work with them as they went bad, and thus it is running too fast now.

There is a variable cap ( horizontal lock) on the grid of the horizontal AFC that seemed to do something but not enough, and a ferrite ( horizontal speed) on the back of the osc coil that I did not try to adjust yet, also an UN-named adjustment in front of the osc under the chassis.

It looks like its trying to lock, but the frequency is too far off

[Yamamaya42]

Originally Posted by bandersen

Yes, looks like around 17kHz. It will be an LC tank circuit that sets the frequency. Could be a mica cap is off.

yes, there is mica domino capacitors in the circuit that have not been replaced.

guess i will order them with the new focus parts

[bandersen]

Adjust horizontal speed - that sets the frequency

[Yamamaya42]

Originally Posted by bandersen

Adjust horizontal speed - that sets the frequency

That's what I thought i might be, but was not sure, no idea why they picked Horizontal Speed over Horizontal freq, I guess that they decided that frequency was not vague enough, and decided to make it a bit more confusing!

http://suzaku.live-evil.org/maggie-horz.jpg
It looked like that adjustment was turned all the way, or almost, all the way out, have not tried turning it in yet.

Focus parts are ordered, as is 2 mica caps, 5pf and 330pf, may end up not needing them, if i can tune this in, but since I was spending the money for shipping, I got them anyway.

Still not sure about the old det diode, it SORT of tests like a diode with a digital meter, but the fancy all in one digital tester can't ID it as anything (cap/resistor/diode/transistor/ETC) checker. where it has no problem testing the new 1n60, so I suspect the old diode may be leaking/ breaking down.

[bandersen]

Good ahead and adjust it. You're not going to hurt anything. Looks like a class synchro-guide oscillator.
BTW don't mess with the 100K temp comp resistor if you don't need to. It is designed to change value with temperature to keep the oscillator from drifting.

[Yamamaya42]

Originally Posted by bandersen

Good ahead and adjust it. You're not going to hurt anything. Looks like a class synchro-guide oscillator.
BTW don't mess with the 100K temp comp resistor if you don't need to. It is designed to change value with temperature to keep the oscillator from drifting.

yeah, I left it alone, it was easy to ID, it was that strange part stuck in there wrapped in 50+ year old shrink wrap tubing, there was a 3rd domino mica cap in there that I did not order, that was not shown on the schematic, hooked in direct parallel with the variable cap for horz lock, it's ALMOST, but not quite too discolored to read the value dots on it!
But this one did not seem as critical as the 2 that were ordered.

[Yamamaya42]

another problem found!

!st video amp is dead!

i got a signal in. almost nothing out.
IF is mostly working , sync is trying to lock but has little to grab on to.

http://suzaku.live-evil.org/maggie-1st-amp.jpg
found another bum resistor.
R145 = 9.2k it has to go!

[Yamamaya42]

no wonder the 1st amp id dead, ANOTHER bad resistor...
R141 = 9.5k
but 143 is fine.

looks like each stage will be a fight.

[timmy]

Originally Posted by Yamamaya42

no wonder the 1st amp id dead, ANOTHER bad resistor...
R141 = 9.5k
but 143 is fine.

looks like each stage will be a fight.

Boy that set has a lot going on sounds like something I would get into 😂

[bandersen]

I hope you're right, but usually unless a resistor is open or shorted it can be way off and a circuit will still pass a signal.

[Yamamaya42]

I GOT IT! I GOT IT!

http://suzaku.live-evil.org/0417251400.mp4

seems there was also a voltage problem -100 was down to -13, something shorted, 50 ohms to ground, was not there before.
did not take long to find, something on the audio amp sub chassis, unplugged it, and -100 came right back up, and 1st amp came to life.

just have to find what failed on the amp later.

the sound heard is as always is the fans of my servers.

[Yamamaya42]

BTW, that rusty focus coil and the new pot and power resistor is working very well, creating a good strong field, it grabbed that little screwdriver very well when on, and let go when I shut it off!