Marconi T11DA

[kestrelmusic]

This nice little set was given to me by a kind member of this Forum. It was, shall we say, in a challenging condition. It’s an exercise in getting a five (octal!) valve superhet into a very small case. It’s medium wave only, provoking my usual grouse about the lack of any decent AM broadcasting nowadays.

The case was grimy but not, thank goodness, chipped or cracked, so I was able to clean it up with polishing paste. It’s come up a treat, and where the original overpainting was flaking I rubbed it down and used a spray paint which was a pretty good match for the original.

The set originally had a linecord dropper, which was beyond repair, so I used a capacitor in its place with the pilot lamp and its bypass resistor as part of the heater chain (originally it was in the HT line). The detector valve heater was open circuit, so that had to be replaced. In addition, the rectifier seemed to be slightly gassy as there were intermittent sparks inside it, so that was also replaced.

The whole thing needed a good clean and some corrosion sanded down. The usual capacitors needed to be replaced, including the reservoir/smoothing unit. It now produced a good signal with an IF input, but not a peep at any other frequency. This proved to be the oscillator padder open circuit due to a fracture in the lead; fortunately it was a mica cap with ring connectors so I was able to solder in a replacement lead. All well. Alignment was pretty good; the IF was spot on, the oscillator close and the frame aerial circuit only needed a tweak.

The original speaker was an energized one. The field coil was open circuit, probably due to the intermittent shorts in the rectifier. In addition, the tinsel leads to the speech coil were damaged. In the end I obtained a replacement speaker and mounted the original output transformer on the chassis.
The dial cord needed to be replaced – this was less of a faff than most of them! Some lubrication needed on the tuning gang bearings and the sliding cursor.

But I think this is a pretty little set and well worth the effort to restore.

[vinrads]

I call that a success, well done I enjoyed the step by step of the repair. I wonder why they decided not to include long wave?

Mick.

[medge799]

Nice job Gerry! As the donor of this radio I did not expect for one moment that it would ever have been back in commission. I think it had been out in the previous owner's garden for decades. Do you have a picture of the innards too? I'd love to see it if so...

Well done!
Mark