1971 Philco color Tube Hybrid

[Lain94]

Here are some photos of the schematic, I have used my oscilloscope to check various points, so far I have concluded the burst amp transistor is ok as well as the 3.58mhz oscillator IC based on the waveforms I got. I am suspecting a bad or out of tolerance crystal at this point and already ordered a replacement one of the appropriate case size and power rating. We will see if that resolves this color being out of sync.

https://imgur.com/a/ZgjkHZm

[old_tv_nut]

If the oscillator is running but won't sync, I suspect the crystal is OK and something else is wrong. It appears that D98 (or D96, hard to read) (between R124 and the IC) is a varactor diode used to control the oscillator frequency. I would check it out.

[old_tv_nut]

Have you checked the diode? I'd like to know if my guess was wrong or not.

[Lain94]

Diode will be checked next, crystal replaced and issue persists albeit not as severe. I am thinking this could be simply a matter of adjusting the 3.58mhz oscillator inductor.

[old_tv_nut]

Originally Posted by Lain94

Diode will be checked next, crystal replaced and issue persists albeit not as severe. I am thinking this could be simply a matter of adjusting the 3.58mhz oscillator inductor.

You mean you haven't tried adjusting it yet?

[old_tv_nut]

Does the service info give an adjustment procedure? It looks to me like there is a tuned output transformer that may or may not have much effect on the oscillator frequency depending on wha the internal IC output circuit is. Is that coil mentioned in the procedure?

[Lain94]

Originally Posted by old_tv_nut

You mean you haven't tried adjusting it yet?

I later ended up trying to adjust it but to no avail, all it seems to change is whether or not the rainbow barber polls pattern is in motion or not. I will be revisiting this project soon as I had to put a lot of things on hiatus last year but will be going on a marathon of sorts later this summer and I am aiming to get the Ford Philco color sync issue resolved hopefully soon.

[Lain94]

Originally Posted by old_tv_nut

Does the service info give an adjustment procedure? It looks to me like there is a tuned output transformer that may or may not have much effect on the oscillator frequency depending on wha the internal IC output circuit is. Is that coil mentioned in the procedure?

From what I have been able to deduce there is a varactor that is controlling and automatically adjusting the oscillator frequency in parallel with the oscillator itself.

[Lain94]

Well... I am pretty confused. I tried powering on the tv and for some reason the crt won't show a raster...sound works, tuning works, but no static or snow on screen no signs of life on screen. all tube filaments light up including crt filament, no sounds of flyback coil whine anymore....no sounds of HV even going to crt anode either...checked all tubes ...tubes are a ok including HV rect. Checked G2 controls, crt bias, birghtness contrast ect...nothing.. last powered on last winter before i had to move all my tvs a thousand miles via uhaul due to moving and tv sat in storage in climate controlled facility up until being moved into my home a month ago. So now instead of being sooo close and only having the color sync issue...now the CRT is not seeming to get ANY HV as far as i can see through anode and no coil whine from flyback despite flyback being a NOS one that i installed myself and worked just fine before....what happened? grrr

[Alex KL-1]

Check if H osc are working, and ASAP, since the HOTube don't resist if are not receiving the waveform. Or, the flyback opened, or fuses in series with HOT.

[Lain94]

Originally Posted by Alex KL-1

Check if H osc are working, and ASAP, since the HOTube don't resist if are not receiving the waveform. Or, the flyback opened, or fuses in series with HOT.

6LB8 is in charge of being the Horiz. osc. and horiz afc in this set. Emissions were fine as far as i could tell no leaks or shorts either. I will check the flyback next. No burning smells, arcing sounds, sparks, or flames apparent.

[ARC Tech-109]

Check the G2 resistor for the horiz output tube itself?

[zeno]

The set got moved. Dont remember on yours but the hoz hold
is usually on the back. Be sure it didnt get smashed in. Common
to happen.

Zeno

[Electronic M]

Originally Posted by Lain94

6LB8 is in charge of being the Horiz. osc. and horiz afc in this set. Emissions were fine as far as i could tell no leaks or shorts either. I will check the flyback next. No burning smells, arcing sounds, sparks, or flames apparent.

Don't just check the horizontal oscillator tube, check the horizontal oscillator circuit with an oscilloscope or DMM. If you have a scope verify waveform/amplitude, if you don't have a scope check the grid voltage on the horizontal output tube and compare it to the voltage listed in the Sam's. You should have significant negative voltage there normally, but if the osc isn't oscillating then the voltage will get close to Zero or even go positive both of which are bad.