DOG: Intermittent Click click, clickclick! RCA ITC008 (27F650TYX1)

[Jason D.]

Got one here that is a stumper:

RCA 27F650TYX1, no pic or sometimes pic but goes out when relay
intermittently clicks and heater dims and brightens, sometimes dims
out and back on every time relay clicks. Let TV batter the relay with
time, now no picture. Relay clicking is very erratic in pattern.

Did voltages checks: 5V stable for the micro/jungle, 7V good, 22V
good and never above specs, 126V never above but when it unloads
becaue of horizontal drive cutting out voltage drops to appox 106V
then relay clicks voltage comes back up and horizontal cuts in at all
once.

Did troubleshooting tips:

Pulled crt board & vertical plug. Click click click still unaffected.
Pulled BL001 plug to disable pincushion. Still clicking.
Checked EHT (aka X-ray protect), never above 2.3V.
Checked beam sense, within specs.
Checked vertical & horizontal waveforms, all GOOD.
Scoped the cathodes for emissions, kine bia sensing come up and get
into operation when heaters is hot enough.
Checked SMPS with scope, good there too.

Flexed & smacked the chassis with no effect on that fault.

Oh YES, did cut off both plugs and solder both ends of pincushion 3
wires (two brown and one blue wires, wire order in correct positions),
have done this modifications 20 times before with success.

Sigh! Looks like either big IC (IV001?) is the blame or data bus
"dirty". Seen this before?

Cheers, Wizard

 

[William R. Walsh]

Hi!

Got one here that is a stumper:

Okay, forgive me if you've done this and if it sounds obvious:

Did you check the offending relay? Perhaps it has burned contacts or is
otherwise not functional.

William

 

[Jason D.]

Hi!


Okay, forgive me if you've done this and if it sounds obvious:

Did you check the offending relay? Perhaps it has burned contacts or is
otherwise not functional.

William

If you're famillar with this ITC008, this relay is used for degaussing
only. This relay clacking is syptom of a problem.

Cheers, Wizard

 

[Asimov]

"Jason D." bravely wrote to "All" (28 Oct 05 02:12:02)
--- on the heady topic of "DOG: Intermittent Click click, clickclick! RCA
ITC008 (27F650TYX1)"

You didn't mention the audio output anywhere...
I have read of this behaviour in RCA's caused by the audio output.
If the relay is good then it's a shot in the dark...

A*s*i*m*o*v


JD> From: [email protected] (Jason D.)
JD> Xref: core-easynews sci.electronics.repair:346535

JD> Got one here that is a stumper:

JD> RCA 27F650TYX1, no pic or sometimes pic but goes out when relay
JD> intermittently clicks and heater dims and brightens, sometimes dims
JD> out and back on every time relay clicks. Let TV batter the relay with
JD> time, now no picture. Relay clicking is very erratic in pattern.

JD> Did voltages checks: 5V stable for the micro/jungle, 7V good, 22V
JD> good and never above specs, 126V never above but when it unloads
JD> becaue of horizontal drive cutting out voltage drops to appox 106V
JD> then relay clicks voltage comes back up and horizontal cuts in at all
JD> once.

JD> Did troubleshooting tips:

JD> Pulled crt board & vertical plug. Click click click still unaffected.
JD> Pulled BL001 plug to disable pincushion. Still clicking.
JD> Checked EHT (aka X-ray protect), never above 2.3V.
JD> Checked beam sense, within specs.
JD> Checked vertical & horizontal waveforms, all GOOD.
JD> Scoped the cathodes for emissions, kine bia sensing come up and get
JD> into operation when heaters is hot enough.
JD> Checked SMPS with scope, good there too.

JD> Flexed & smacked the chassis with no effect on that fault.

JD> Oh YES, did cut off both plugs and solder both ends of pincushion 3
JD> wires (two brown and one blue wires, wire order in correct positions),
JD> have done this modifications 20 times before with success.

JD> Sigh! Looks like either big IC (IV001?) is the blame or data bus
JD> "dirty". Seen this before?

JD> Cheers, Wizard

.... If all else fails, hurl it across the room a few times!