Ekco Radio.

[Murphyv310]

Hi.
I have been given a Pre War Ekco TRF Radio to repair. I think its an AD65? Perhaps someone can confirm its model.
It already has had some work done but I intend to re-cap and re-stuff the remaining caps.
There is some rust around the chassis, the speaker cloth is long gone as its original speaker.
The cabinet is very dull but overall its by far not the worst set I've repaired.

                   

[pwdrive]

Looks like an M23.

Lawrence.

[pwdrive]

M23 Schematic:

http://31.201.170.111/nvhr/Ekco_M23AC.pdf

Lawrence.

[Murphyv310]

M23 Schematic:

http://31.201.170.111/nvhr/Ekco_M23AC.pdf

Lawrence.

Thanks Lawrence.
Indeed it is an M23.
I remember Radio Dave on the UKVRR restoring one of these about five years ago.
It was an amazing restore and from memory the set looked brand new

[Murphyv310]

Well the speaker cloth arrived early this morning.
I’ve glued it to the baffle board and attacked the cabinet with my electric polisher and WOW what a difference.
Next the radio itself.

   

[radioman]

As you say Trevor - WOW
what a transformation !
With that polish and the new cloth it looks like new.
I can't believe that's the same set I saw a few weeks ago.

Andy

[Yorkie]

Looks splendid Trev - information is sparse  beyond the 'Broadcaster' data sheet, but electrically, it only has eleven caps and five resistors so hopefully won't pose too many problems, provided that all the transformer/inductor windings are intact. I guess the smoothing choke and half wave metal rectifier could possibly be suspect, but fingers crossed that the OPT, inter-valve transformer and mains transformer are all intact, and the speaker speech coil.

Good luck with the restoration!

[Murphyv310]

Hi.
Well the interstage transformer has an O/C secondary so I'm thinking of going down the R C coupling method, I'm hoping to hide the components as best as possible.
The original selenium rectifier has been disconnected and a single IN4007 has been fitted with no ballast resistor. The HT rises to 375v quickly then falls to 280v which way too high. I’ve actually got a new selenium rectifier and am actually contemplating fitting it just to see how the HT behaves. Failing that I'll select a suitable resistor for the IN4007 to give me around 180v HT which is close to what it should be.

[pamphonica]

Trevor, have you considered using the original Selenium rectifier in series with the 1N4007? I use this trick in Avo valve testers where I want the series resistance to be maintained but with a new rectifier. Hopefully no chance of the selenium rectifier being upset. It just contributes resistance.
regards
Jeremy

[Brianc]

Will an R/C coupling give you enough gain, Trevor? It's a fairly simple TRF with no special Hi Q coils or similar gimmicks and those AF transformers were often 1:5 step up - that's quite a lot of gain!