As i told you some weeks ago, i recently bought an RCA AR-88D from an HAM flea market.
The cosmetic was in good shape, no parts missing but the set was not working , it powered up but very fleble rx on with generator at maximum output.
The audio was distorded the s-meter not working, the audio tone control ineffective.
I asked i0mzr to help me ... he is not an ham with the hobby of technician he is a technician with the hobby of ham radio.
Now he is retired but in the past he worked for Rhode & Shwartz and in his lab he has very good instruments.
After some days, the receiver was fully restored (i changed many capacitors but without success) this is what he has done on the receivers as he wrote me all the storyboard of restoration...
Substitution of R43 and R44
Substitution of final af tube (with 6v6)
disconnected and replaced the old audio trasformer
restored phone jack
restored tone control (c117)
replaced R6 (open) this was the main issue for poor reception
replaced preaplifier tube 6sj7 (microphonic)
replaced second if tube 6sg7 (marginal)
replaced resistor of s-meter
checked all tubes with professional tube checker
replaced several condensers
total alignment of IF, RF , OSC RF, BFO
after this work he wrote me some notes about the rx performance:
"The total distortion at 1 khz with ccitt filter is about 3.5%
very good for a receiver of this class.
The linearity of the tuning scale is very good on all the bands, and
also the frequency reading and stability is very good.
The sensibility (sinad + ccitt) is 0,5 - 0,8 microvolt for 10db and
it fully respect the specifications of this receiver even after 70 year.
The selectivity is not very sharp, but is anyway very good for a receiver
of it's age.
The noise limiter is one of the best i have seen and also the tone control
is very effective.
In my opinion this is a very good receiver.."
in my blog
http://boatanchors.tumblr.com/i will put soon a video of the rx in action
