Page 1 of 1

EuroCB EA50 alignment

Posted: 04 Nov 2018, 06:32
by andrew30
Hi,
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: http://www.cbradio.cz/doc/_Other/Zesilo ... schema.pdf
Specs: http://www.cbradio.cz/doc/_Other/Zesilo ... 0/info.pdf

Or is the problem somewhere else?

Re: EuroCB EA50 alignment

Posted: 07 Nov 2018, 21:09
by dt307
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