rca 45x11 tube radio

[timmy]

hi all, would it make much difference if i changed all the caps in this rca 45x11 am radio to get better reception, it works and the electrolytic was changed but not the others.

[Bill Cahill]

Hi. I've found it improves both the quality of the sound, and, to a degree, the reception.
I'd change them along with mica caps.
Bill Cahill

[timmy]

besides the 2 section electrolytic the other caps would be mylar, i think based on the values because they are paper type and one on the antenna. and there is 2 caps off of the on- off switch and dont know what they are unless they are the line caps, .01 400.

[Reece]

Change the wax paper caps. They'll be leaky and can short and spit out their waxy guts. Inexpensive to do.

[DavGoodlin]

Originally Posted by timmy

besides the 2 section electrolytic the other caps would be mylar, i think based on the values because they are paper type and one on the antenna. and there is 2 caps off of the on- off switch and dont know what they are unless they are the line caps, .01 400.

Timmy, the schemo on Nostalgia Air shows a .05 mf cap from pin 5 of 35Z5 to ground (load side of on/off switch) functioning as a line noise arrester.
This particular application requires a Y2 safety cap because it is AC, not DC(.047@250 VAC) $1.89 [email protected]

I need to get in the habit of using Y2 caps in this function myself. I have a Zenith J615 I just finished that had a shorted (and visually bloated) .05 @ 400V connected across the line, it was shorted and destroyed the 35W4 and #47 pilot light, which had functioned as a fuse in this case.

[timmy]

so what your saying is not to put back the .05 400v but rather a .047 250v instead. i have that schematic from that site but its rather grainy and cannot make out some of the values. the radio works but if all the other caps are changed i wonder how much better the reception will be on pulling in stations.

[DavGoodlin]

Maybe the .05 is not important but do make sure its 250 Volts AC, those caps are usually found in a computer monitor across the incoming line filter. I have transplanted a few of those inductor-capacitor filters into old AM radios. the result is usually better reception and less crackle if you're in a noisy area like near a road.

[timmy]

whats the difference with 250v or the usual 400v. because i think i have used .05@400v for the ac in tvs.

[DavGoodlin]

Originally Posted by timmy

whats the difference with 250v or the usual 400v. because i think i have used .05@400v for the ac in tvs.

A 400V maybe OK, since 120 volts AC x 2.828 is 340 volts peak-to-peak. I have done it but according to Just Radios, you should use ones bearing an AC rating on them. I used to test all and replace only the bad caps years ago. After reading how serious some are about replacing ALL the caps, I decided to buy and use the right stuff first.h

[Reece]

For line noise caps, you should use the safety caps. Reason: if they fail, they fail open and won't start a fire with a short the way ordinary yellows or orange drops or the equivalent can. Go on JustRadios website and there's a tutorial on the use of these caps.