Icom R71 Repair
 

Hello.I'm new here and thought I'd throw this out there to see if anyone else has encountered this problem with the R71 radio.I recently took one of my R71s out of storage and the signal meter pegs to the right even when no antenn is hooked up.If I turn the preamp off it settles do about the middle of the scale.Someone told me it had to do with the voltage inverter going bad.This circuit is on the matrix board inside a metal can labled PS2.From what I understand a transistor gois bad inside this and has to be replaced.I opened the metal housing up and removed the small pcb inside.Supposedly the replacement transistor is a 2SD400.I went to the local electronics store(not-rip-me-off Shack) and they sold me a NTE382 transistor.Is this a proper replacement for it?I'm going to replace the electrolytic caps.in the circuit which may have caused the problem in the first placd.I'm going to recap the rest of the radio too once I get this straightened out.When I recap the radio,will this nessitate a realignment?Does anyone have a suggestion on where to send it for alignment?Thanks

Icom R71 Repair
 

In article ,
Blackhawks1 wrote:

Hello.I'm new here and thought I'd throw this out there to see if anyone
else has encountered this problem with the R71 radio.I recently took one
of my R71s out of storage and the signal meter pegs to the right even
when no antenn is hooked up.If I turn the preamp off it settles do about
the middle of the scale.Someone told me it had to do with the voltage
inverter going bad.This circuit is on the matrix board inside a metal
can labled PS2.From what I understand a transistor gois bad inside this
and has to be replaced.I opened the metal housing up and removed the
small pcb inside.Supposedly the replacement transistor is a 2SD400.I
went to the local electronics store(not-rip-me-off Shack) and they sold
me a NTE382 transistor.Is this a proper replacement for it?I'm going to
replace the electrolytic caps.in the circuit which may have caused the
problem in the first placd.I'm going to recap the rest of the radio too
once I get this straightened out.When I recap the radio,will this
nessitate a realignment?Does anyone have a suggestion on where to send
it for alignment?Thanks

Blackhawks1-

I'm not familiar with that particular radio. I know that other similar
receiver S-Meters will go upscale if the RF Gain Control is turned down.
You might check to see if turning that control fully clockwise will
correct the S-Meter problem.

Before replacing the transistor, I'd check the existing one with an Ohm
meter. Many digital multimeters have a diode scale. The meter will
measure conduction of a diode in one direction but not the other. A
transistor acts like two diodes connected together at the Base. You
would check the Base-Collector junction and the Base-Emitter junction to
see if either is shorted or open in both directions.

Fred
K4DII