Cobra 148 GTL frequency changes when cover is put back on
 

A friend brought over a Cobra 148 GTL that was off frequency on
sideband (3 kHz or more). I put the radio back on frequency, but when
I put the case back on it goes back off frequency by as much as 1 kHz.
I have seen radios change frequency a little as the metal case gets
put back on, but this one goes nuts. It also goes nuts if I put my
hand near the circuit board. It is too big a change to be normal for
these things. It had been moded for extra channels, and Iunsoldered
all the extra wires off to see if that was behind the problem, but the
frequency instability remains. Has anyone seen a Cobra 148 GTL do
this before? This is the older model with the five pin mic plug on
the side of the radio.

Defnroc

On Sat, 09 Apr 2005 17:38:21 GMT, (Def N Roc) wrote:


A friend brought over a Cobra 148 GTL that was off frequency on
sideband (3 kHz or more). I put the radio back on frequency, but when
I put the case back on it goes back off frequency by as much as 1 kHz.
I have seen radios change frequency a little as the metal case gets
put back on, but this one goes nuts. It also goes nuts if I put my
hand near the circuit board. It is too big a change to be normal for
these things. It had been moded for extra channels, and Iunsoldered
all the extra wires off to see if that was behind the problem, but the
frequency instability remains. Has anyone seen a Cobra 148 GTL do
this before? This is the older model with the five pin mic plug on
the side of the radio.

Defnroc


Does that have the old MB8719 PLL? If it has the newer RCI8719, it could be the
cause. I read on a website that RCI8719 was designed with one pin floating, that
causes it to go haywire with a channel mod.

http://www.radiomods.co.nz/addon_mb8719manual.html

Vinnie S.