I have a RCA CTC-148/148 chassis, Model 26100AK, May 1988 with a sound
problem. The +24.9V feed to the audio output IC is at +24V or so at
very low volume but falls to as low as 3V as the volume is turned up.
Obviously very distorted sound at all but the lowest volume levels. It
is fed from a solid +24.9V source through resistor R1905U. I cannot
read the value or the markings on the resistor as they are too faint.
The resistor reads approximately 550 ohms out of the circuit. My guess
is that it should be down in the tens of ohms at most since it feeds
the entire audio output circuit. Does anyone have a schematic of the
CTC-148/149 with the resistor value? I hate to shell out the cost of a
whole photofact for a set that old.

TIA,

H, R, (Bob) Hofmann

From a quick look at my old "Profax" schematics, courtesy of a long -
expired ES&T subscription, R1905 in this set (CTC 148/149 chassis) is a 10
ohm, 2W resistor connected between the + side of C4701 (+26V source) to the
+ side of C1915 (+26v audio source). Hope this helps.

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I have a RCA CTC-148/148 chassis, Model 26100AK, May 1988 with a sound
problem. The +24.9V feed to the audio output IC is at +24V or so at
very low volume but falls to as low as 3V as the volume is turned up.
Obviously very distorted sound at all but the lowest volume levels. It
is fed from a solid +24.9V source through resistor R1905U. I cannot
read the value or the markings on the resistor as they are too faint.
The resistor reads approximately 550 ohms out of the circuit. My guess
is that it should be down in the tens of ohms at most since it feeds
the entire audio output circuit. Does anyone have a schematic of the
CTC-148/149 with the resistor value? I hate to shell out the cost of a
whole photofact for a set that old.

TIA,

H, R, (Bob) Hofmann

Phil - Thanx very much. I tried a 8.2 ohm resistor I had handy and it
worked great, will put in a 10 ohm when I get a chance tomorrow. The
film (I think) resistor that was in there didn't look close to a 2-watt
unit, the 8.2 ohm I put in was a 4W wirewound.Thanx again.
H. R. (Bob) Hofmann