Zenith Tv Help
 

Hi,

My own workshop Zenith tv, a nice old 19EC45, shorted its trippler
divider because of cracks in the housing. This was a 270Meg divider but
I had a 450Meg type salvaged from a newer Zenith who's CRT went weak. I
tried it but couldn't manage to control the high voltage enough for a
good focus.

However, I had a 200Meg trippler from an old 70's Panasonic (h/k short)
and this gives a good focus with a 10 Meg resistor in series with the
CTL line. I replaced the 50uF 16WV electro (pos to gnd) behind the 9-90
horizontal driver module because of leakage. The arcing must have
damaged this.

However there was a kink in the center of the pix after I was done. I
found the 14 ohm resistor beside the replaced electro was cracked. Maybe
I did it when changing the electro, maybe it already was cracked. Anyway
the kink remained, so I checked the damper diode at the C-E of the HOT.
It measured far higher than expected with the low ohms range and wildly
intermittent when moved. Replaced the damper diode and now the image is
just shy of perfect.

The problem that stymies me is a dim jagged feathering along the right
edge about 1/8" wide. It is made up of only red and blue. When I turn
down the colour control it fades away and the BW image is perfect. I'm
guessing it has something to do with the colour blanking but can't
imagine why just red and blue. I checked the video driver module but all
seems okay.

Any ideas where I might look?

(BTW the 9-90 module had a tan colour power resistor R821 along the
bottom edge which I had previously written on the PCB with an arrow as
being 220 ohms but it measured about 2K ohms, guessing also damaged by
the arcing, so replaced it with 2W 220 ohms and it's ok.)

TIA

Asimov
******


.... # --- electrocuted tribble

Zenith Tv Help
 

Check the electrolytic and resistor that are in parallel in the horizontal
driver circuit. They are located near the driver transformer.


"Asimov" wrote in
message ...
Hi,

My own workshop Zenith tv, a nice old 19EC45, shorted its trippler
divider because of cracks in the housing. This was a 270Meg divider but
I had a 450Meg type salvaged from a newer Zenith who's CRT went weak. I
tried it but couldn't manage to control the high voltage enough for a
good focus.

However, I had a 200Meg trippler from an old 70's Panasonic (h/k short)
and this gives a good focus with a 10 Meg resistor in series with the
CTL line. I replaced the 50uF 16WV electro (pos to gnd) behind the 9-90
horizontal driver module because of leakage. The arcing must have
damaged this.

However there was a kink in the center of the pix after I was done. I
found the 14 ohm resistor beside the replaced electro was cracked. Maybe
I did it when changing the electro, maybe it already was cracked. Anyway
the kink remained, so I checked the damper diode at the C-E of the HOT.
It measured far higher than expected with the low ohms range and wildly
intermittent when moved. Replaced the damper diode and now the image is
just shy of perfect.

The problem that stymies me is a dim jagged feathering along the right
edge about 1/8" wide. It is made up of only red and blue. When I turn
down the colour control it fades away and the BW image is perfect. I'm
guessing it has something to do with the colour blanking but can't
imagine why just red and blue. I checked the video driver module but all
seems okay.

Any ideas where I might look?

(BTW the 9-90 module had a tan colour power resistor R821 along the
bottom edge which I had previously written on the PCB with an arrow as
being 220 ohms but it measured about 2K ohms, guessing also damaged by
the arcing, so replaced it with 2W 220 ohms and it's ok.)

TIA

Asimov
******


... # --- electrocuted tribble