RCA K60 Console - Videokarma.org TV - Video

Jonathan · #1 07-09-2007, 01:37 PM

Well, I'm taking a break from the 630TS. I recently got an RCA K60 console from here. During shipping the dial glass broke, but I can easily glue it back together. The chassis is an RS-415B, and it has one of those strange dial systems it seems like the chassis needs to be in the cabinet to string the dial. The presets were those buttons with set screws that would move the rotor of the tuning condenser a certain amount. I removed those and really don't want to put them back in. Any harm by not putting those back in?

Also, it has 3 antennas for the 3 bands it receives. The one antenna that plugs in the top of the chassis is nothing but some wire strung around the perimeter of large piece of cardboard. The two other antenna connections had broken wires, and am not sure where they were connected. The magic antenna was in bad shape and one of the terminals broke off their post. Will the RCA service manual of the K60 (I'll order the caps and the service manual from justradios) contain info on how to string the dial and assemble the dial plate? I can't really figure all this out completely.

Thanks.

Jonathan

Tom Bavis · #2 07-11-2007, 08:47 PM

Riders pages for this radio are here - it shows the dial cord too. http://www.nostalgiaair.org/PagesByM...8/M0015508.pdf

Jonathan · #3 07-12-2007, 06:31 PM

Thanks Tom. I did have the Riders schematic for the RC-415B, the one you posted is the RC-415A which has the tuning eye but the dial cord stringing is the same. It helped a lot. Thanks.

Jonathan

Jonathan · #4 07-18-2007, 02:20 AM

Well, I got the capacitors today (from Justradios) and replaced all paper and electrolytic. I figured out how to string the dial cord and strung it. When I powered it up, I first tested the television input. It seems to work but the whole thing sounds like crap. Secondly, I tested the radio section without connecting the loop antennas. Nothing but a quiet 60Hz hum. The RCA magic antenna I got was kind of destroyed, I need to clean it off and hot glue everything. The C band loop antenna was in decent shape, and I can pick up some SW AM stations, though they fade in and out, but that is because they are sky waves and not ground waves. It seems to work well. Do the loop antennas for bands A and B need to be connected to get anything even though the antenna link is open so a closed loop antenna isn't needed?

Thanks.

Jonathan

sean · #5 07-18-2007, 07:37 AM

The loop is used for the antenna tuning circuit on bands A & B. To get a good signal it really needs to be connected. If your magic antenna is in pretty bad shape, someone over on ARF is parting out a K130 which is from the same model year. You might contact them about the loop to see if it will work for your set. http://antiqueradios.com/forums/viewtopic.php?t=73510

Jonathan · #6 07-18-2007, 12:55 PM

Hello Sean,

The loop antenna is fixable. The outer loop is out of it's notches and one terminal is ripped off the cardboard of the inner loop. I can repair both with solder and hot glue. Unfortunately, C36, the trimmer for the A band (AM Broadcast) is cracked it the corner of the ceramic where the one terminal connects to ground. I can't really tell if it uses a mica sheet or something and not really sure if the cracked piece is causing any issues. Also is there any difference in gain between the victrola and television audio inputs?

Thanks.

Jonathan

sean · #7 07-18-2007, 04:19 PM

It's hard to tell from the schematic on Nostalgia Air but it doesn't appear that there would be any difference in the gain between the two inputs. It looks like they would both be fed into the grid of the 6SF5 through switch S3. The TV input was really just a sales gimmick to make it appear as though the new radio you are buying in 1940 will be compatible with the TV set you might buy in a year or two.

Jonathan · #8 07-19-2007, 01:38 PM

Well, I fixed the magic antenna and connected it up. I get poor sensitivity as I can only pick up one or two stations on broadcast AM that are the strongest. Also, in the schematic, C3, which is 6.8pF, I mistakenly replaced it with a 68pF, so I'm going to put the 6.8pF capacitor back. When I tested band C (SW) it seemed to work really well, so there must be problems with the switches or the bandwidth of the tank circuits.

Thanks.

Jonathan

Jonathan · #9 07-21-2007, 01:47 AM

One think I missed was measuring the resistors for drift. % resistors are drifted more than 20% of their nominal value. Going from the schematic at http://www.nostalgiaair.org/PagesByM...9/M0015509.pdf R1 which is 4.7M is drifted to around 7M and R2 which is 33k is drifted to around 50k. R10, R9, and R19 are all 470k. R10 drifted to around 560k (within 20% tolerance but I changed it anyway), R9 was around 700k and well out of tolerance. R19 was around 650k and made up one of the filters connected to the tone switch. In my opinion, this resistor really never affected anything because it just made up one of the tone switch filters, but I figured I'd change it anyway. R8 is 390 ohm and measured 465 ohm, This is just within 20% tolerance, but I think I saw silver on it so it must be 10% tolerance, so it's somewhat drifted. I never changed it yet because I only have a 0.5W 390 ohm resistor, the RCA parts list says it's 1W. The rest of the resistors are within spec and the voltages I measured are pretty much spot on with the service manual.

Also, what can I do with C36? The ceramic is cracked and I think it needs to be replaced. Can I just find a modern replacement of the same capacitance and that should work fine?

Thanks.

Jonathan