Bush VHF70. - UK Vintage Radio Repair and Restoration Discussion Forum

Roger Henderson · 8th Sep 2019, 9:08 pm

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

Beardyman · 18th Sep 2019, 2:11 pm

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.

Roger Henderson · 29th Oct 2019, 3:28 pm

Many thanks for your reply especially for the role of the capacitor.

Beardyman · 30th Oct 2019, 8:38 am

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.

8th Sep 2019, 9:08 pm	#1
Roger Henderson Diode Join Date: May 2018 Location: Swansea, Wales, UK. Posts: 4	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
Beardyman Hexode Join Date: Jan 2018 Location: Portsmouth, Hampshire, UK. Posts: 428	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. __________________ The difference between stupidity and genius is that genius has its limits. (Einstein)

29th Oct 2019, 3:28 pm	#3
Roger Henderson 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.

30th Oct 2019, 8:38 am	#4
Beardyman Hexode Join Date: Jan 2018 Location: Portsmouth, Hampshire, UK. Posts: 428	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. __________________ The difference between stupidity and genius is that genius has its limits. (Einstein)