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Old 26th Nov 2019, 12:45 pm   #23
theredhouseinn
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Join Date: Jan 2013
Location: Kelvedon, Essex, UK.
Posts: 272
Default Re: RCA AR88D Comms Receiver.

Next phase.
I have disconnected the var cap, tried various caps to tune, still have the fault.
I put the var cap on the bridge and it varies from 20pf to 140pf, the cct says 8pf to 128 pf, no problem here then.
I have cured one intermittent fault on range 5, the padder was intermittent when flexing the lead at one end, the capacitence changed from 3000pf to 300 pf.
The only common factor that is left is the coil former material that is killing the Q at LF.
the 3 high band formers are different to the 3 lower band formers.
Does anyone have any more theories?
John.
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