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Old 12th Feb 2012, 2:59 pm   #12
matspar
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Join Date: Aug 2009
Location: Portsmouth, Hampshire, UK.
Posts: 230
Default Re: Pye VT2 EHT problems

Hi Dom,
Unfortunately I've not used a scope before, but many thanks for the suggestion. Something I must learn about one day..

John,
I have tried a couple of other lopt's today by swapping over the pair of top cap connectors. I refitted the suspect one before trying this (am I right in thinking I should leave the original wired in place underneath?)

Both donor lopts behaved in exactly the same way as the original - no sparking from the top caps but a very small one present from the EHT anode connection. One was better than the other although I do know they both worked a few years ago and have been dry stored ever since. I didn't have a rectifier valve fitted when trying this.

Don't know what you think but this has cast a bit of a doubt about my duff lopt diagnosis, I may have a go at working out the connections and completely fitting the slightly better one (a 'coffin' type from a Ferguson 991T) and try again.
I feel a bit stumped with this set now, not much left to try or replace!

The can type smoothing capacitor is still the original one and looks to be in fair condition, no bulging etc. Do you think it may be worth replacing this just to draw a line under it?

Also would it help to carefully removing the pitch from the overwind on the original lopt? I've been reading the very detailed posts about the dampness acting like a shorted turn. Was wondering if this may be worth a go if I don't get any improvements from leaving it in the warm.

I won't get another chance to work on the set now until next weekend so everyone can breathe a sigh of relief!!! Thanks again & speak soon!

Matt
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