EuroCB EA50 alignment

A forum for the discussion of matters of a technical nature. All such activities are undertaken at the readers discretion and own risk. If you don't know what you are doing, don't blame us if it all goes wrong!
Post Reply
Posts: 34
Joined: 18 Sep 2018, 14:03
Call Sign: 329TM001

EuroCB EA50 alignment

Post by andrew30 » 04 Nov 2018, 06:32

I purchased cheap used EA50, it's working, but only drawing about 2A from 12V supply (4W input).
I took it apart and tested the C1969 transistors with my DMM and both appears to be working, so it might be a problem with biasing.
Quick glimpse at the schematic reveals variable capacitor C9, which I believe is responsible for biasing - but being a young player in PCB, I'd rather have that confirmed. :D
Specs list 7A draw to be standard, but in on the schematic there's 5A.

Schematic: ... schema.pdf
Specs: ... 0/info.pdf

Or is the problem somewhere else?

User avatar
Top Poster
Top Poster
Posts: 1157
Joined: 05 Sep 2014, 16:15
Call Sign: 163dt307

Re: EuroCB EA50 alignment

Post by dt307 » 07 Nov 2018, 21:09

this is a class c design and the bias is controlled by r2

c11 for output matching tune for max output ....... connect a power meter and a dummy load to amp

c9 is for input matching tune for lowest swr .....a swr meter between the amp and radio and a dummy load to amp

“I fear the day that technology will surpass our human interaction. The world will have a generation of idiots.”
― Albert Einstein

Post Reply