RCA F27351WN CTC177BE Has no color. Black and white picture only

[Radford]

The display will only show in Black and White. No color! The user said that
the unit would not turn on but when we got the unit it did turn on. The
only schematic that we have is for the CTC176 which came from the
Electronic Servicing & Technology magazine. (PROFAX 3108 CTC176) Do not
know how close the schematic is with this unit. We check the Color kill
pin on the T-chip and is was at 3.6V. We do not want to invest in the
repair manual because this is the only unit that the University has. Have
not check yet for the 3.58 MHz reference osc. Any thoughts on what could
cause this problem would be greatly appreciated.

 

[Tom MacIntyre]

The display will only show in Black and White. No color! The user said that
the unit would not turn on but when we got the unit it did turn on. The
only schematic that we have is for the CTC176 which came from the
Electronic Servicing & Technology magazine. (PROFAX 3108 CTC176) Do not
know how close the schematic is with this unit. We check the Color kill
pin on the T-chip and is was at 3.6V. We do not want to invest in the
repair manual because this is the only unit that the University has. Have
not check yet for the 3.58 MHz reference osc. Any thoughts on what could
cause this problem would be greatly appreciated.

I think the schematic will be pretty close overall, but who knows if
it is close with the circuitry in question. Did you check the
crystal's solder connections? What about the capacitor in the crystal
circuit? Freeze the T-Chip? Do you have a crystal tester, or one to
swap in?

Tom

 

[RonKZ650]

176 and 177 circuits are identical. Have you tried an eprom IC? If not that,
then LA7610 is bad.
Ron

 

[ezwizzard]

The display will only show in Black and White. No color! The user said that
the unit would not turn on but when we got the unit it did turn on. The
only schematic that we have is for the CTC176 which came from the
Electronic Servicing & Technology magazine. (PROFAX 3108 CTC176) Do not
know how close the schematic is with this unit. We check the Color kill
pin on the T-chip and is was at 3.6V. We do not want to invest in the
repair manual because this is the only unit that the University has. Have
not check yet for the 3.58 MHz reference osc. Any thoughts on what could
cause this problem would be greatly appreciated.

check for open inductor in the burst keyer circuit.

 

[Radford]

I looked at the 3.58 MHz crystal which did not have a signal on it. The
voltage seemed fine at 3.6V Forgot to mention that the display seemed to
be washed out. Not a good Black and white image. Had the user bring me the
remote to the set and access the menu. There was color in the menu! At
this time I hit reset in the menu and now the set has color. The picture
is fine!!! I am at a total lose as to what happen to this set to cause
this kind of problem. The user said that the set made a POP sound when he
turn it on and would not turn on after that. Let me thank everybody for
there help and suggestion. Has anybody seen this type of problem resolve
by resetting the settings?