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A flyback question

I have a Panasonic TV that is about a decade old that has developed an intermittent loss of raster. Only once could I get it to respond to a little judicious percussive maintenance.

It has been along time since I have explored the guts of a TV. I have experience in board level repairs an want to pull the circuit board to inspect for poor connections.

The flyback looks as if the high voltage lead can be unplugged from the transformer itself and would be more convenient than doing a disconnect at the CRT. Is this feasible? Is the connection at the flyback a simple straight plug in or is there a locking feature.

The nature of the raster loss leads me to believe that it is NOT the loss of high voltage, but some other signal. The picture just blinks out sometimes making a couple of steps toward darkness. The sweeps do not change and the focus and contrast do not change.

I no longer own a voltmeter with a suitable high voltage probe.

Charlie

Reply to
Charlie Bress
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"JPM". Wonderful. I will remember that.

Reply to
William Sommerwerck

I've seen some that can be removed and some that can't. If yours looks as if it unplugs and is locked to the fly by a cap then it may be removable. This is something I can't give a yes or no answer to.

If the HV drops in many cases the picture will shrink as some voltage supplies are scan derived. (well at least they were back when I repaired tv) I doubt via your description of the symptoms that the HV is at fault.

Reply to
Meat Plow

I doubt it too. That's why the question I posted. I am looking for the simplest way to disengage the flyback and HV cable from the CRT

Charlie

Reply to
Charlie Bress

What are you hoping to accomplish by removing the HV from the CRT?

Reply to
Meat Plow

Then I can slide the circuit board out (all the other connectors are straight forward) and inspect for bad solder.

Charlie

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Reply to
Charlie Bress

Taking it out of the picture tube isn't that difficult. Usually you just have to squeeze them a little and they come out.. If you push the rubber "suction" cup up you can see how it is in there and how to get it out.. It is usually rather simple. Oh and of course be sure to discharge it first.. Those things have a nasty bite.

Mike

Reply to
Michael Kennedy

Some can be removed, it's easier to just disconnect it from the CRT though. Slip a grounded screwdriver under the anode cup until you touch metal, then lift up the edge of the rubber cup and disengage the clip from the tube.

Reply to
James Sweet

Don't over-complicate the situation. Just resolder the vertical output. Very common on these sets. You may have to replace the IC and a couple of related caps, but most likely just bad solder connections.

Leonard

Reply to
Leonard Caillouet

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