[Boatanchors] Racal 17L - missing tuning hiss on Mc dial

[McDonald, J Douglas]

That's almost certainly the problem. If you replaced any fix cap in the bandpass filter, it needs realignment.
If you just replaced one, you could try just adjusting that one stage.

If you did not replace any fixed cap, one or more are likely bad. Then you need
a full alignment. There's plenty of advice on that on the British forums.

Did you check all the electronics feeding it and amplifying the output?
My RA17 had problems with those, including a really bizarre one:
the two tubes involved were not getting enough filament voltage due to being
at the end of the filament chain. That was not enough to prevent some reception.


Note that there's an RA17 forum at
RacalRA17forum at groups.io

its quite active.

Doug McDonald

________________________________
From: boatanchors-bounces at mailman.qth.net <boatanchors-bounces at mailman.qth.net> on behalf of francesco sartorello via Boatanchors <boatanchors at mailman.qth.net>
Sent: Saturday, March 14, 2020 3:44 PM
To: milsurplus at mailman.qth.net <milsurplus at mailman.qth.net>; boatanchors at mailman.qth.net <boatanchors at mailman.qth.net>
Subject: [Boatanchors] Racal 17L - missing tuning hiss on Mc dial

Hello guys,

I am spending a lot of time in restoring a really nice RA17L, which worked
very well something like twenty years ago.

I took all the obvious steps, checked  and replaced tubes, checked all
voltages and resistance, replaced all paper caps and most of micas, and I
have now a radio which works perfectly on bands 0 and 1, with a dramatic
loss of sensitivity higher up.

I think problem lies in the 37.5 Mc  amplifier chain and mostly in the BP
Filter, because at TP3, while doing test in accordance to the manual, I
measure mVolts, not 3-5 V as expected.

Is this the reason why I miss the tuning hiss on Mc dial?