[Premium-Rx] East German Receivers EKD 1000/300/500

[Heinz Breuer]

Hello,

I don't know how many of you have these receivers. They are available 
quite cheap if you compare them with Rohde & Schwarz equipment from the 
same era.
If you don't know these receivers here are a few pictures:
http://www.seefunknetz.de/ekd100.htm
http://www.seefunknetz.de/ekd300.htm
http://www.seefunknetz.de/ekd500.htm

I had a couple of these receivers from my collection on the bench 
recently and would like to give a few hints.

All these receivers suffer severly from corrosion. I had a fuse holder 
so badly corroded that it didn't pass the current to the 5V regulator. 
The fuse got so hot that it virtually unsoldered the fuse holder 
brackets from the circuit board.

I had the selector switch for the af output corroded so that audio was 
erratic. Same symptoms for the bandswidth selector. Thanks to Deoxid it 
is working fine now.

Audio was erratic, only worked when pulling the af gain knob. A shot of 
CaiLube saved the af gain pot.

One receiver didn't work due to small electrolytic capacitors in a 
rectangular plastic case (green colored) split open and shorted. Almost 
all capacitors housed like this are split open and need replacement.

Two power supplies were dead on mains power due to the relays in the 
power supply found open. Power supplies for the EKD 300 and 500 are 
prone to this. I found a very good website having a workaround to 
prevent these defects. http://funktechnikelemente.de/Reparatur%20NT_00.pdf

The owner of this website http://funktechnikelemente.de has NOS spare 
parts for these receivers including the relays.

Hope this helps to keep these receivers alive.

vy 73
Heinz DH2FA, KM5VT