04-06-2023, 05:03 PM
A bit more progress today. made a cradle for the chassis to sit in upside down to avoid breaking the ferrite aerial off.
Electrolytic can rebuilt and refitted, the 4uf section was rewired to the EL84 screen grid as it was originally and the extra cap that had been fitted under the chassis removed. This section of the original cap must have failed some time in the past, I am surprised that the whole thing was not changed at the time.
The tone correction capacitor on the EL84 anode has split, massively leaky so it got changed for a 1500v item, don't want to risk the output valve should a lower voltage one fail.
The agc line was not what it should be so the reservoir cap was changed. The eye now works fully but strangely there is a slight delay when tuning before the eye catches up. I have never noticed this before on an FM set.
Investigated the selenium rectifier a bit more closely. It does not get too warm after a couple of hours and the HT voltage is what it should be according to the circuit diagram. I will leave it working as it is and see if it degrades. Seems a shame to replace it with silicon diodes but I can re-stuff the tube if the need arises.
Short wave is producing nothing other than mush but there is no proper aerial in the workshop, just 10 feet of wire in the ceiling so I am not expecting much.
The coil pack is very complicated and fragile so I think I will leave well alone as far as alignment but it would be nice to hear something on the short wave.
Electrolytic can rebuilt and refitted, the 4uf section was rewired to the EL84 screen grid as it was originally and the extra cap that had been fitted under the chassis removed. This section of the original cap must have failed some time in the past, I am surprised that the whole thing was not changed at the time.
The tone correction capacitor on the EL84 anode has split, massively leaky so it got changed for a 1500v item, don't want to risk the output valve should a lower voltage one fail.
The agc line was not what it should be so the reservoir cap was changed. The eye now works fully but strangely there is a slight delay when tuning before the eye catches up. I have never noticed this before on an FM set.
Investigated the selenium rectifier a bit more closely. It does not get too warm after a couple of hours and the HT voltage is what it should be according to the circuit diagram. I will leave it working as it is and see if it degrades. Seems a shame to replace it with silicon diodes but I can re-stuff the tube if the need arises.
Short wave is producing nothing other than mush but there is no proper aerial in the workshop, just 10 feet of wire in the ceiling so I am not expecting much.
The coil pack is very complicated and fragile so I think I will leave well alone as far as alignment but it would be nice to hear something on the short wave.
Boater Sam.
