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Hints, Tips and Solutions (Do NOT post requests for help here) If you have any useful general hints and tips for vintage technology repair and restoration, please share them here. PLEASE DO NOT POST REQUESTS FOR HELP HERE!

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Old 23rd May 2007, 6:03 pm   #1
Ghostuser
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Default Coronation twin wavechange

I was given an Ultra Coronation Twin and after doing the usual stuff with electrolytics and wax caps, it burst into life on medium wave. A set of new valves brought the sensitivity and volume up to scratch, but there was no response on Long wave. Jiggling the wavechange switch back and forth produced loud crunching noises and a check with a resistance meter showed no contact on the LW part of the switch. Generous application of Maplin switch cleaner changed nothing. A squirt with WD40 however got the switch working perfectly with no scrunching noises at all. I would not normally use WD40 as a switch cleaner as it leaves a film of oil which I would have thought harmful. Just shows how wrong you can be.
Cheers to all our readers.
Nigel
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Old 24th May 2007, 5:58 pm   #2
igranic
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Default Re: Coronation twin wavechange

Now that the wavechange switch is working again, it may be worthwhile rinsing off the WD40 with switch cleaner before it does any damage. I once had a set that had been liberally dosed with WD40 or something similar, causing significant and seemingly irreversible leakage on the switch wafers and paxolin valve holders.

If you do need it, I may have a switch from a scrap Coronation Twin.
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Old 24th May 2007, 8:51 pm   #3
paulsherwin
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Default Re: Coronation twin wavechange

Nigel, you are right to avoid the routine use of WD40, but as you have demonstrated it can sometimes shift crud that normal contact cleaner won't touch, especially waxy deposits.

The main problem with WD40 is that it leaves an oily mess around. This doesn't cause problems in itself but attracts crud which can be conductive. I don't think this will cause difficulties here, especially if you clean off the surplus with a rag. Most of the problems seem to happen when there is HT around. You should certainly never, ever spray valveholders with the stuff

Paul
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Old 24th May 2007, 9:19 pm   #4
Nickthedentist
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Default Re: Coronation twin wavechange

I'd agree with Igranic... Now the WD40s done its magic, rinse it off with IPA spray, and follow up with a little Servisol to keep things working nicely
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Old 25th May 2007, 10:27 am   #5
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Default Re: Coronation twin wavechange

Hi Paul and Nick
Thanks for the observations. I got nervous about WD40 when I attended a lecture on corrosion damage to electronic components when stored in the tropics. Such components were in sealed plastic bags, with a dose of WD40 or similar inside. We were told that parts literally fell to pieces because of vapour phase corrosion.
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