07-05-2022, 10:53 AM
(This post was last modified: 07-05-2022, 10:55 AM by Mike Watterson.)
I turned it on on LW and was greeted by typical interference buzz. Nothing when switched to ferrite rod. Connected up sig gen and the LW, MW, & SW is close enough correct. Perhaps the ferrite/external switch above chassis was jammed in ferrite position. See below.
Nothing on VHF.
However no surprise it doesn't get RTE R1 252 kHz (is it even on today?) or BBC R4 198 kHz as it's very deaf.
Replaced the 4uF 80V electrolytic with 2x 2.2uF 100V in parallel (you'd want maybe at least 35V here) taking care that + ends to chassis.
Now there is very weak VHF.
So at least some progress. No difference between my spare EL84, EF89 and ECH81 and the originals. Cleaned and oiled jamming mechanics on AD switch. Reason for pilot ls that the switch above the chassis is a push-on/push-off type and thus the piano key button isn't meant to stay down, so lamp is only indication of external or internal ferrite aerial. Also off on PU, SW and VHF.
A poor ECC85 usually means no reception at all? Stops oscillating.
Perhaps there is an open circuit IFT connection? That sometimes still works but with very poor sensitivity. That will be the next thing to check?
Nothing on VHF.
However no surprise it doesn't get RTE R1 252 kHz (is it even on today?) or BBC R4 198 kHz as it's very deaf.
Replaced the 4uF 80V electrolytic with 2x 2.2uF 100V in parallel (you'd want maybe at least 35V here) taking care that + ends to chassis.
Now there is very weak VHF.
So at least some progress. No difference between my spare EL84, EF89 and ECH81 and the originals. Cleaned and oiled jamming mechanics on AD switch. Reason for pilot ls that the switch above the chassis is a push-on/push-off type and thus the piano key button isn't meant to stay down, so lamp is only indication of external or internal ferrite aerial. Also off on PU, SW and VHF.
A poor ECC85 usually means no reception at all? Stops oscillating.
Perhaps there is an open circuit IFT connection? That sometimes still works but with very poor sensitivity. That will be the next thing to check?
