1930s Ekco battery eliminator.

[FERNSEH]

Arrived today this bakelite cased Ekco battery eliminator. It has slight damage to the case which can be easily fixed but the innards are bit rough.
Total rebuild required.

[Cobaltblue]

I think that's about the worst example I have seen!

At least when they are like that I tend to worry less about the originality just make it functional.

Cheers

Mike T

[FERNSEH]

Hi Mike,
The capacitors are dated 1959 and there is a BY100 silicon diode in there. I fully agree, with wrecks like this one can eschew originality and build in modern components.
It's retaining the outer appearance that matters.

DFWB.

[bobhowe]

Hi David i agree with you as you want a regulated supply on the LT side kind regards Bob

[FERNSEH]

Hi Bob,
also 9volt grid bias if the unit is to used with the Ekco B37 TRF receiver.

DFWB.

[bobhowe]

Hi David what circuit will you use ? & will there be a VCR transformer used with an adaptor plate kind regards Bob

[FERNSEH]

Hi Bob,
If it is still serviceable the original mains transformer can be used for the high tension. A separate transformer for the grid bias and filament supplies.

DFWB.

[FERNSEH]

The attachment shows the modified metal case Ekco battery eliminator installed in the Ekco B37 TRF receiver.
The trickle charge winding on the mains transformer is used to supply the 2 volt valve filaments. Current must not exceed one amp.

DFWB.

[Cobaltblue]

I recently rebuilt an EKCO AC12 which forum Member Bob Moss let me have for my Cossor 481B and will be the subject of a thread at a later date.

Over the years I have rebuilt a few eliminators and have found the capacitors leaky but serviceable since they are not in a high impedance circuit but in this case 2 capacitors were low ohms and one read dead short which I have not come across before. I rebuilt the whole block using electrolytic's which look lost in the case.

A picture of the dead short cap, the oblong mark is from the paxolin spacer that separated it from it's neighbour.

These caps were sealed in Wax and Bitumen.

Cheers

Mike T

[FERNSEH]

The mains transformer is OK. Off load the HT winding is delivering 165volts and the trickle charge winding 9volts.

DFWB.

[Ed_Dinning]

Hi David, probably wise to put that transformer in an airing cupboard for a week and the impreg with wax. A megger test might show quite a bit of leakage in its present state.

I suspect that the trickle charge winding will cause the set to hum mightily, they were mainly designed to trickle charge the accumulator with the set off

Ed

[Glowing Bits!]

Originally Posted by Ed_Dinning

A megger test might show quite a bit of leakage in its present state.
Ed

Megger's are useful for all sorts of things, especially suspect transformers and spark coils.

[bobhowe]

Originally Posted by FERNSEH

The attachment shows the modified metal case Ekco battery eliminator installed in the Ekco B37 TRF receiver.
The trickle charge winding on the mains transformer is used to supply the 2 volt valve filaments. Current must not exceed one amp.

DFWB.

Hi David was surprised how loud this set is would have been a great performer in is day with more MW stations kind regards Bob

[FERNSEH]

Except for the mains transformer and HT smoothing choke all other components have been removed from the chassis.
Found this compact video recorder mains transformer. It was removed from a Gold Star machine. Will find out today what the the secondary voltages are.

DFWB.

[Heatercathodeshort]

A bit rough! A bit rough! It was obviously propping up the Middlesbrough Transporter Bridge David. It appears to have self welded itself together.
Save this project for something to amuse yourself with when you have to enter the 'Happy Flyback Home' for X television engineers.. I have some lovely little torch bulbs here you can add to your list. John.

[FERNSEH]

Hi John,
It'll clean up and with high temperature paint sprayed on it'll look good as new.
The Gold Star video transformer has three secondary windings. A centre tapped high current winding delivering 8 - 0 - 8volts. The other two must have been used for the fluorescent display, a centre tapped 2 - 0 - 2volt filament winding and the other gives out 43volts.
This transformer is of no use in the Ekco battery eliminator but can be used for the construction of a power supply for all-dry battery receivers.
What is needed is a separate filament transformer.

DFWB.

[Heatercathodeshort]

This is always the way it goes with building a battery eliminator. You end up with a can full of transformers. Not so easy to find these days but a mains transformer removed from an old Band 3 converter works well. 6.3V + 150v or 200V.
I have a couple of these Ekco units but just taking the lid off and seeing the mess just put me off! I must be getting and I am of course old! Good luck with your experiments. John.
[PS That EKCO unit must have been the cause of the jammed mechanism on the MTB in 1964..]

[FERNSEH]

The base plate and mains transformer have been cleaned and painted and look a lot better now.

DFWB.