Zenith 23XC36 Blue G2 pot wiring

[Carmine]

Originally Posted by ctc17

Sounds like the boost voltage is missing. Check the parts on the flyback board. Maybe the boost diode or resistor popped.

I did as you said, found a 27K resistor linked to the 1200v boost per the schematic. Tested it and it measured 32.2K, so not opened. The other resistors on the board were again higher than anything my meter could read (I'm beginning to suspect my auto troubleshooting meter isn't up to this work.)

Then I measured the two things that looked like diodes in both polarity directions, using the diode scale on my meter. Both showed open in each direction, so could this be the fault of my meter? The smaller one is wired right to the 27K resistor, so I suppose it's suspect. It is labeled X4 on the schematic, but there is no electrical specification in the diode chart, just a part number. How would I replace this if it is bad?

Photo below:

[ctc17]

First, GET THAT SOLID STATE TUBE OUT OF THERE!! and put the right regular tube in there.

You cant test those two diodes with a multimeter. You need to use something that applys in excess of 200volts like an eye type tube tester in the leakage test mode.
The smaller of the two diodes is the boost diode. Check with you meter to verify you have boost voltage coming out of it.

The long one is focus.

BUT, those solid state tubes can cause all kinds of issues like super high voltage.

[lnx64]

Solid state tube? That's...........not.............right.

I have never heard of such a thing but I can't imagine characteristics being right.

[Carmine]

Originally Posted by ctc17

First, GET THAT SOLID STATE TUBE OUT OF THERE!! and put the right regular tube in there.

You cant test those two diodes with a multimeter. You need to use something that applys in excess of 200volts like an eye type tube tester in the leakage test mode.
The smaller of the two diodes is the boost diode. Check with you meter to verify you have boost voltage coming out of it.

The long one is focus.

BUT, those solid state tubes can cause all kinds of issues like super high voltage.

Until I get some more time for troubleshootin', can you tell me (us) more about these solid-state tubes? I've never seen something like this, and it seems especially odd since the LAST thing to become solid-state was typically the HV rectifier.

Was this some kind of aftermarket part? Who made them? Why?

As for measuring voltage after the boost diode, that requires the cage to be open... Is that allowed by the TV safety gods? I'd hate to have "always seeking better gray scale" on my tombstone.

[ctc17]

This video explains my experience with one of those. They are way more efficient and the hv goes way up to the point it causes all kinds of problems.
http://youtu.be/DJ_uX8XZMQE

There is a part one somewhere too

[Carmine]

Ok, I connected the aligator end of my HV probe to both sides of the boost diode and the probe to the chassis (two separate tests). The meter didn't budge either time. The end of the diode connected to the orange wire heads for the yoke assembly.