Clansman RT351

[ribbonmicsrus]

I have just acquired a 351, basically working OK, power o/p, frequency and plenty of modulation.
However there is a distinct crackle both on TX audio and RX audio, anyone experienced a similar problem, it appears the same on headset and telephone handset so I assume no problem there.
Also, is the RX audio level normally lower on SKT1 than SKT2.
73
Andy

[ex seismic]

Skt 1 and 2 are in parallel.
If you take it apart be careful of the flexible printed circuit attaching the sockets to the main chassis, they are not as flexible now as when they were made and can crack easily.

[ribbonmicsrus]

Thanks, yes, it does seem like a dry joint as if inserting handset into SKT1 and wriggling it gently, the audio level returns to normal.
Also have been informed noise problem might be the VCO pots getting dirty.

Andy

[Jon_G4MDC]

This seems like a pointer to the flexible circuit being cracked before you have taken it apart? Might be an idea to check it.

[ribbonmicsrus]

Hi Jon

After taking it apart, I found the film wire in excellent condition. Further examination showed that a pin on SKT1 had never been soldered, after correction this, I now have full audio on both sockets. The Racal inspector must have had an off day!!

73
Andy G3UEQ

[Jon_G4MDC]

Well done and what a nice find!

I have an RA117 which had the same on the trimmers in the bandpass filters.
Silver tag wrapped with silver wire but no solder. Worked well for 30years but then...
Persons unknown "realigned around the problem" but it was never any good.

I cleaned and soldered the connections and set all the trimmers back to match their tarnish marks.
It didn't need test gear.

[ribbonmicsrus]

Yes Jon
How the hell it got through final inspection with MOD gear I don't know!

BTW, just found thread on AR88 loss factor in slugs of HF oscillator that you were involved in. Fascinating, luckily my AR88 (early model, engraved FP) was OK in that respect.

73
Andy

[Jon_G4MDC]

Now you have fixed it you can enjoy the rig.

I need to get back to my RA117. It was good after that fix 20years ago but now I think it has gone off the boil again. I reckon there is something not right with the 1MHz oscillator and harmonic generator.

Before that on the bench is the 10m FM Pye Cambridge mentioned in another thread and 10m conditions have been good of late.

[ribbonmicsrus]

Jon
Not quite ready to enjoy, still has the crackle on receive and transmit!
Best of luck with the 117, I sold a nice RA17 and RA121D couple of years ago, getting too heavy for me!

I saw you thread re the Cambridge, best of luck with that. I am sure you will be "spurred" on!
73
Andy

[ex seismic]

As has been suggested I think, try waggling the two squelch pots a bit, sorted one of mine out.

[ribbonmicsrus]

Thanks Seismic

Will do when I open it again, just going to do basic voltage checks as suggested by Simon on another forum and if no luck will do that. Want to tread carefully, just hope don't need to get a donor unit!
Andy

[Oldcodger]

Originally Posted by ribbonmicsrus

Hi Jon

After taking it apart, I found the film wire in excellent condition. Further examination showed that a pin on SKT1 had never been soldered, after correction this, I now have full audio on both sockets. The Racal inspector must have had an off day!!

73
Andy G3UEQ

Andy- even 353 inspection teams had similar myopic problems. We ( in MSDS) often joked that we kept on falling over the white sticks.

[ribbonmicsrus]

I like your thinking