Ekco PB189

[jmedley]

I bought the radio about 6 months ago, it had been stored in an attic for many years and looked dry and sound with no woodworm. The cabinet cosmetics were only fairish having areas around the control knobs where the original finish was worn away to the bare wood and there were quite a few scratches.
With the rear panel removed a good sign was that is was full of dust and with the chassis out, only a few lifetime repairs were visible.
This model has some interesting features, it has motorised tuning with AFC.
not bad specification for 1938, the year I was born.
The capacitors were of a contruction that I had not come across before, mostly being wax or tar filled carboard tubes. I tested the coupling capacitor to the audio output valve and was suprised to find it checked out OK, knowing the damage that may result if it became leaky I restuffed the cardboard tube with a modern "yellow" tubular cap. Mostly the other caps tested OK and have been left in situ.The wiring and general condition looked OK, so I fired it up and the valves lit up and the total current drawn was fine, there was quite a lot of hum which went away when the main reservoir and smoothing cap was bridged. Then some stations could be tuned but the performance was terrible.
The IF frequency should be 126kHz but then using the siggy gen tuning the IF stages to 126kHz proved to be no better and the tuning didn't peak.
Swinging the generator output freq. it was better at 136kHz but of course this pointed to problems within the IF stages. Removing every screening can
I saw more caps of an unknown variety, flat white disc- like, value 140pf. They were all totally duff and replaced with silver mica types. There were a few more caps in the cans that I also changed. Back with the generator and it all aligned nicely to the specified 126kHz. with plenty of output.
What a differnce, VERY powerfull output and many many stations available using my long wire aerial. The station preset tuning is robustly made but needed the switch contacts cleaning. The AFC was not working!
The discriminator coil wouldnt set up at the test point and I found that only one diode was working in V4 (2D41) I pulled out the valve and temporally fitted 2 IN4148 diodes on the vave base. The discriminator coil L19 then set up OK
The disc. output is then amplified by triode V2 which changes the inductance
in th osc. tuning coils to effect slight re-tuning. AFC still wouldnt work, a simple case that V2 heater was O/C. Luckily I had a replacement which solved the problem. I can understand that this AFC fault may have been present from long ago without detection, since the radio works quite accurately without the AFC operating at all.
A fault then appeared being a very loud hum and crackle, which turned out to be the EverReay output valve OP42 shorting heater to cathode, my good friend Phil G4SPZ kindly gave me a NOS equivalent a KT41 for which I was very gratefull, thanks Phil.
I was so pleased with the repair outcome I decided to re-finish the cabinet too. All in all I now have a very good radio in better nick than me from 1938 Picture attached Jim

[Phil G4SPZ]

Lovely job, Jim, that set looks magnificent! Well done. Interesting write-up too. Glad the output valve did the trick. The 2D41 was a special Ekco type number, but there's an equivalent that's more readily obtainable. Cheers,

[Heatercathodeshort]

That sounds and looks like a nice receiver. The white 'pajama buttons' connected across the IF transformer windings are notorious trouble spots in pre war Ekco receivers. John.

[Andrewausfa]

Good job. I love the large dials on these. I think mine's missing one of the connectors for one position on the motor tuning but otherwise works very well.

Andrew

[mark pirate]

You have done a great job on the cabinet, it looks like new!
I would love to get one of these motor tune sets, they look fascinating.

Mark