1976 Zenith CCII

[radioguy13]

Good evening ! I am having a problem with a with a CCII with a 19HC48 chassis,
I picked this set up from a ewaste run a high school was doing due to the fact that it was in perfect condition and when I brought it home it worked like a champ !! with great sound and vivid color allthough the focus could use a touch up but here is the problem that just showed its ugly head the other night.
When the set is running it looks great but after about 2 to 3 hours of running it will trip the breaker and shut off, did this last night so today I reset the breaker and all was good again for a few hours, did not notice any smell there is no hum in the picture or sound indicating a bad filter and when touching the filter cap its cool to the touch BUT the power trans after an hour or so is cooking HOT !! measured with IR thermometer and after an hour was at 152 F is this normal or do I have a primary winding short ?? what do you guys think ?? if so is this worth saving or parting out ??
thanks Kenny

[Electronic M]

Zenith did tend to run their power transformers hot...However I think you may have a problem creating extra load. First thing is that you should look for white tubular ceramic cased caps (the bad type of "safety caps") by the flyback (above and below chassis) if present change them.
I'd also check bias voltages on the horizontal and vertical stage transistors especially the outputs...If there is a drive problem causing their bias current to rise that could trip the breaker...You might want to time your measurements out to be close to the trip time in case it is a part that likes to fail as it heats up.

[RCAZenith]

What kind of line voltage are you getting? It would be interesting to see if you are getting a good bit less than 120 causing it to run hot.


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[zeno]

Measure the draw on a power right . Be sure its 3/4 to 1 A
IIRC. ( see label)
May be a weak breaker.
Next would be the big oval cap across the p xfrmer.
Check the low ohm, usually 1.5 at the horz out base.
Too much beam current can also cause this but never seen
it on a Zenith.
If it is something dead shorting normally before tripping
you will get a very loud 60cy hum.

BTW is this an EFL set ? if so it will have a PCB on the CRT
socket ( 9-120-## ) and some other changes.

73 Zeno

[TUD1]

I have this exact set. IIRC, there were three versions of it. The latest version had the Sprague orange cap, but the earlier versions had the disaster white caps. It's a very common set. My set is also having a problem where the picture is very dark on actual programming, but overly bright on some stuff like the TV Guide.

[MRX37]

I also have a CCII, and yes my cap is orange.

TUD1 you could try pulling the luma module and spraying all the contacts with deoxit. Might want to pull the modules and do this anyway if you haven't already. Solved a lot of "touchiness" on mine.

By touchiness I mean the brightness flickering or changing by itself, tapping the set causing the picture to jump, that sort of thing.

[TUD1]

Originally Posted by MRX37

I also have a CCII, and yes my cap is orange.

TUD1 you could try pulling the luma module and spraying all the contacts with deoxit. Might want to pull the modules and do this anyway if you haven't already. Solved a lot of "touchiness" on mine.

By touchiness I mean the brightness flickering or changing by itself, tapping the set causing the picture to jump, that sort of thing.

Yeah, my 13" CCII also from '76 has a lot of that jumpiness going on. Some resistor on the luma module, and the vertical won't lock when it's cold. The 19" is just dead dark or bright. No jumpiness or anything lime that.

[Electronic M]

Originally Posted by MRX37

I also have a CCII, and yes my cap is orange.

TUD1 you could try pulling the luma module and spraying all the contacts with deoxit. Might want to pull the modules and do this anyway if you haven't already. Solved a lot of "touchiness" on mine.

By touchiness I mean the brightness flickering or changing by itself, tapping the set causing the picture to jump, that sort of thing.

I've got the same CCII model as TUD1 has as my bench set. It's never been serviced, and I'm too lazy to pull the back....I just slap it or kick the bench when it is misbehaving. Something fun(ny) about percussive maintenance.

[TUD1]

I think I'll do some experiments with putting the chassis and modules in the dishwasher. I've seen people do that, and the results were very good. My set is very dirty still.

[radioguy13]

Thanks for the quick reply !! I have checked a few things mentioned here as for the line voltage I have a steady 120v then checked the caps and it looks as if some work has been done to this set and from the looks of it not too long ago ?? maybe? have posted pictures, after posting this thread last night I didnt notice the cap that is covered with cardboard on the bottom of the chassis that looks like a small motor start cap, I ran this set for a while last night and did notice that this cap also gets a bit hot as well could this be the problem ?? also noticed that with the back off the set and chassis lowered that it seemed to play a little bit longer than it did before but I did have the AC cranked up and ceiling fans running (it was 101 here ) so that may have had something to do with it also have noticed that the power transformer seems to have a bit of an audible hum to it that you can hear even a few feet away ?? I have a 1988 zenith advanced system 3 (SE2033Y) that has literally a loud buzz that it makes all the time on or off due to a lose remote receiver transformer coil.
sorry to be so long winded
Kenny

[Eric H]

I seem to remember these sets using a sola constant voltage transformer, that motor start type cap would be part of the circuit so if it is bad then maybe it could be the problem.

[Electronic M]

Caps should not get hot if nothing external is heating them....If they are getting hot on their own they are leaking current.

[N2IXK]

That cap forms part of a resonant circuit with a winding on the power transformer. If you replace it, the capacitance value is critical to proper operation of the power supply.

[zeno]

Cap with cardboard is the one that goes. If it opens the
pix will pulsate, if it shorts will give a loud hum then
pop breaker. The cap is probably the same on all Zeniths
from abt E through K model sets. Milllions were built.

Cap in hoz out is the right one. That only applies to E & F
models anyhows.

Easy test is put a 4A slow blow in place of breaker & see
if it blows.

73 Zeno

[radioguy13]

thanks for the help I will replace that cap due to the fact that it does get pretty warm when the set is running and there is nothing near it to make it that warm, will let you know how that turns out