[murf]

Hello fella's,
Have not visited for a while as summer is now here.
Have a nice RCA 811k that I re-capped and it has an issue that is driving me nuts.
Plays well except on the lower half of the band. There I get backround noise and static in between the stations as well as a smaller amount while tuned in to the station.
Higher end of the scale is fine.
Seems like an alignment problem, but I get no response from any of the upper adjusters or the lower adjustments under the chassis.
Have re-capped etc. and checked and  swapped the tubes for others.
Found that if I connect a ground wire, it gets a little better on the lower end of the scale. Makes no difference on the upper end of the scale.
Otherwise works great. Very good reception on am and shortwave bands.
Any RCA experts out there that would have a clue?
May be picking up a couple more of these tomorrow as well as an 813k, so I need to get educated on these.
Thanks in advance,
murf

[Radioroslyn]

Check the outside plates on the tuning cap to be sure they are not bent/shorting.

[Chas]

If the lozenge shaped mica caps were replaced. Then a complete alignment is required. Any piston cap. adjuster that has no effect, that L/C circuit associated with it has a problem. Any IF can that the slug tuning is very broad, has broken wires in the litz windings and/or leaking/drifted tuning cap. The values posted for the Lozenge caps are not necessarily the ones used. RCA tuned the radio by using cap values that worked for the radio. If any of the wiring was disturbed in the RF/OSC sections including that in/out of the band switch could seriously miss align the radio. FWIR this radio has rubber wiring.

Was the band switch sprayed with "sooper-gloopo Tuner cleaner", WD-40 or similar? Saturated band switch wafers will have a serious effect on sensitivity. Some radios have B+ on contacts, could easily arc and burn out the band switch. De-gook with 91% propanol alcohol, stuff from Walmart, pack clean cotton rag carefully under band switch to catch excess, use an acid brush to scrub the wafers and the center blades. Blow dry with gentile compressed air. Do not tun o power until completely dry and any bristles from brush removed...

If any tube sockets got the same treatment do the same cleaning.

Do check the Antenna coils on all bands, an open coil can be a problem.

If this chassis uses any chassis grounds via a rivet, solder this rivet to the chassis or drill out use fresh hardware with toothed washers. FWIR RCA uses a punched tang from the chassis for grounds but that may not be so in the RF/OSC sections.

GL

Chas

[murf]

Seems it is mostly due to interference coming from within the 4 walls of my house.
Have found similar problems with other radios.
Time to run an outdoor long wire I guess.
murf

[EdHolland]

Do try a good aerial/antenna first. This will help, as the efficiency of short antennas is very much compromised on broadcast band, and this gets worse as you go towards the 520 kHz end.

Does your set have a loop antenna/wave magnet in the console, or just the connection for a wire?


Caps can cause trouble. On my 110K, I did had to track down a bad mica cap in the RF section for one of the shortwave bands. I could not get the required adjustment with the trimmer during alignment. This band was created with several fixed caps, leaving the main tuning cap only making very small changes to the overall combined capacitance. Drift in the fixed caps did not have to be much to cause a big effect. That shouldn't be such a problem on the regular "broadcast" band.