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Vintage Radio (domestic) Domestic vintage radio (wireless) receivers only. |
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1st Jul 2021, 11:02 pm | #41 | ||
Pentode
Join Date: Feb 2016
Location: Tauranga, New Zealand
Posts: 132
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Re: Winding a new output transformer for a Philips B5G64A Radio
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It was just a dirty valve socket (the one of the EABC80) I did the usual tapping around the chassis and found that the sound would come and go, i then moved the valve opposite around and found it would come right. So i removed the tube and sprayed some contact cleaner in the socket and its been fine ever since! I was a bit worried that there was still some other fault (other than the "that' capacitors) that could have been the issue, and still potentially cause the newly wound OT to fail. As far as these capacitros go, they appear to be an early polyester type, I may unwind one and dissolve all the pitch coating to see whats inside. Before I do that, I have a mate with a leakage tester who can test them to see if they were indeed the cause of the OT failure. Yes it will be a good idea to replace all the caps anyway, although if these test fine and turn out to be polyester, they are likely not an issue. Paper caps on the other hand..... I dont appear to see any silver mica caps in this set, they all appear to be tubular ceramic caps. I will grab some photos for your reference anyway. the radio seems to be working very well, just need to sort out those dammed dial cords now! Quote:
Yes sorry, I did have the radio working before the transformer failed, i had even started a thread some time back about it which you should be able to find under my profile, i had intended to add to that thread, but its since expired and has been locked. basically the radio started loosing volume while it ran and i kept turning it up until no more sound could be heard. It turned out the OT had failed on me. Anyway, its definitely got the original tapped philips double gang pot which would be an impossible part to find a replacement for. You likely have already read above what the issue was, but as you say, its still a good idea to replace all the caps. Im unsure if the dirty contacts on that tube socket could have played a part in higher current draw happening on the OT primary or not. Last edited by nzoomed; 1st Jul 2021 at 11:09 pm. |
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3rd Jul 2021, 6:07 pm | #42 |
Heptode
Join Date: Oct 2019
Location: Täby, Sweden
Posts: 708
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Re: Winding a new output transformer for a Philips B5G64A Radio
The failure of the OT was more than likely the sympton of another problem, and replacing all the caps (except ceramic, mica and polyester) will eliminate a lot of uncertainty in the fault finding, and will reward you with a better sounding and more reliable radio. It's about the same bother to measure them for leakage as it is to swap them out.
I've replaced caps a few times, and lessons hard learnt are to use axial caps, and fit them so the values are easily readable afterwards. |
3rd Jul 2021, 11:03 pm | #43 | |
Pentode
Join Date: Feb 2016
Location: Tauranga, New Zealand
Posts: 132
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Re: Winding a new output transformer for a Philips B5G64A Radio
Quote:
I typically just get standard high voltage polyester caps from my hobby store. The axial type are a bit harder to get and have to buy those from the likes of RS. Those yellow mallory ones are usually quite suitable, i have quite a good stock of mustard caps here too |
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5th Jul 2021, 10:52 pm | #44 |
Triode
Join Date: Oct 2009
Location: Masterton New Zealand
Posts: 17
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Re: Winding a new output transformer for a Philips B5G64A Radio
Great job on the OPT. Make sure to test new capacitors - recently had a new one that was shorted out of the box.
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6th Jul 2021, 7:05 am | #45 |
Pentode
Join Date: Feb 2016
Location: Tauranga, New Zealand
Posts: 132
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Re: Winding a new output transformer for a Philips B5G64A Radio
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