Icom R71a repair

[Brian Lyons]

I have an Icom R71a which I bought new in 1990.

Its performance is degraded and I wish to restore it back to service,
so that I may once again use it on a daily basis.

Here is what I have done for repairs to date

a) correct cold / open solder joint on bridge rectifier in power
supply to correct intermittent loss of power and noise problems

b) replace electrolytic capacitors with tantalum caps in dc to dc
converter stage of display board (replaced on spec to help reduce
noise)

c) replace C1, C7, C11 on RF board to regain lost sensitivity (must
have had high RF power hit at some point)


I still experience noise in medium wave band. The noise will build to
a point that there is complete loss of signal below about 2.5khz with
the radio going silent. At times, the signal returns after brief
interruption. Tuning up to higher frequency and then back down
sometimes restores signal.

Also, years ago, local AM stations would cause full deflection of S
meter. This no longer occurs and there is poor DX reception in MW
band.

Any suggestions what to look at next for cause of fault?

I have read posts that some owners have replaced capacitors on PLL
board. Which ones? What problems does this correct?


Thanks!