[MrFixr55]

Hi Glyphmon,

+1 on what Morzh said. For non-electrolytic capacitors, the modern mylar capacitors rated 630VDC are best. For these caps, the higher the voltage the better.

The original caps may have been rate 200V because the old paper / foil / wax caps were much larger at higher voltages. Mylar or polypropylene dielectric is much more efficient, hence, these caps are smaller.

RE C24, yes, if you can hollow out the shield that the existing cap is in, certainly do so and install the new cap in that "can". This is the audio input cap. It is possible that it was shielded because of its physical location, but this was not common.

For electrolytics, it is different, at least it used to be. These were rated in "working volts". A 20 uF 450WV electrolytic would not achieve 20uF at 150V. With modern electrolytics, this may have changed.

It is best to replace the electrolytics with capacity values close to spec. However, the electrolytics back then had a tolerance (the level of accuracy) between -20% and +50% so a little more wasn't bad. However, for the capacitor closes to the cathode of the rectifier should not be too high. 20uf is not bad. I suspect that these caps have been replaced already as electrolytic caps do fail.

When you test a resistor in circuit, devices that parallel the resistor or in series-parallel with the resistor can affect readings. However, they often cause a lower reading than the actual resistance. I suspect that the resistor in question is open (burned out), as the resistors in series with it read correctly.

R5 and R7 can be tested easily. To do so:
"Open" the link between Terminals 1 and 2 on the back of the set. This terminal board is marked "Phono"

Locate Pin 5, "P1" of the 6H6 and connect one probe there. Connect the other probe to Pin 1 of the Phono terminal board. You shoud see a reading that is a sum of the value of R5 and the resistance of the IF transformer secondary. Since the secondary is only about 15 Ohm, then the received reading accurately reflects the reading for R5, 56,000 Ohms. If open, then you need to remove, disassemble and verify coil and resistor continuity.

To check R7, check between Pins 1 and chassis ground or pin 3. The reading should about 220,000 Ohms

If you did not find C33 in the radio or on the schematic, I wouldn't worry about it. Unfortunately, you can't call their tech support department and ask about the error in the documentation. The person that designed the radio was likely dead as of 1990, and RCA itself is dead. In fact, when I work on one of the radios in my collection, I say a prayer for those who built it and used it. Thinking about the history and the lives of the people surrounding these vintage radios is for me a touching part of this hobby.


Hope this helps.