8th Sep 2019, 9:08 pm | #1 |
Diode
Join Date: May 2018
Location: Swansea, Wales, UK.
Posts: 4
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Bush VHF70.
With reference to this thread:-
https://www.vintage-radio.net/forum/...d.php?t=157650 Thank you for your very informative article. It is very welcome and timely too. I am working on a VHF70 restoration which has gone quite well but the dial lamps and a 30 Ohm resistor (R36) underneath keeps blowing. When you refer to "a 30R WW in the return circuit had been blown to bits, this was caused by a 0.05uF cap across the mains that had gone short circuit", I presume the Cap you refer to is C65 on the auxiliary upright panel. Best wishes, Roger Last edited by Station X; 9th Sep 2019 at 10:13 am. Reason: Thread split. |
18th Sep 2019, 2:11 pm | #2 |
Hexode
Join Date: Jan 2018
Location: Portsmouth, Hampshire, UK.
Posts: 430
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Re: Bush VHF70.
Apologies for the late (very!) response!
Yes, C65 had developed an internal short & blown the 30R WW. As C65 is for RF filtering of the mains its value isn't that critical BUT if you do replace it ensure the replacement is the correct X rated capacitor suitable for mains voltages or higher. I replaced mine with a 0.1uF as it was all I had to hand. Hope that helps.
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29th Oct 2019, 3:28 pm | #3 |
Diode
Join Date: May 2018
Location: Swansea, Wales, UK.
Posts: 4
|
Re: Bush VHF70.
Many thanks for your reply especially for the role of the capacitor.
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30th Oct 2019, 8:38 am | #4 |
Hexode
Join Date: Jan 2018
Location: Portsmouth, Hampshire, UK.
Posts: 430
|
Re: Bush VHF70.
You are most welcome. I replaced the blown resistor with a 33R wire wound as it was the nearest I could find. A few ohms either way isn't going to make that much difference. Hope your set is coming along well.
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The difference between stupidity and genius is that genius has its limits. (Einstein) |