HMV 900 update. - Page 2 - UK Vintage Radio Repair and Restoration Discussion Forum

Heatercathodeshort · 27th Nov 2017, 7:00 pm

Quote:

Originally Posted by line sync

I love that huge eht smoothing capacitor next to the crt.Robin

'Built' by British Insulated Callenders [BIC Later to become British Insulators Calender Construction BICC] .1uf + .1uf 5kv. They built the National Grid so I reckon they could manage a 5kv capacitor.

They are very reliable but when compared with a Visconol, must have been very expensive. John.

Jac · 27th Nov 2017, 7:09 pm

The beautiful 0.1 + 0.1 µF - 5kV capacitor.

Jac

Heatercathodeshort · 27th Nov 2017, 7:14 pm

Interesting example JAC. I have never seen a TCC one. John.

Jac · 27th Nov 2017, 7:25 pm

John,

Both my HMV 900 and Marconiphone 702 have such a TCC one.
The 1 µF - 1500V in both sets is also TCC.

After careful submitting them to high voltage via a series resistor, they formed good. So both sets still have their original EHT capacitors.
They must have been (and still are) of good quality, performing good after 80 years!
Quite different from the EHT smoothing capacitors in the 706/707/904/905 series (in my very limited experience).

Jac

Techman · 28th Nov 2017, 7:02 pm

I'm loving the originality of this set!

I appreciate both extremes of repair/restoration. I appreciate the work that Argus25 puts into his restoration with gleaming metalwork with no dust in sight. I also love to see originality with a set as it would have been found operating in a home environment, with genuine historical repairs as would have been done by engineers of the time, with only the components replaced that would have needed to be due to fault conditions.

27th Nov 2017, 7:09 pm	#22
Jac Heptode Join Date: Jun 2006 Location: Eindhoven, Netherlands. Posts: 642	Re: HMV 900 update. The beautiful 0.1 + 0.1 µF - 5kV capacitor. Jac Attached Thumbnails

27th Nov 2017, 7:14 pm	#23
Heatercathodeshort Dekatron Join Date: Jun 2005 Location: Warnham, West Sussex. 10 miles south of DORKING. Posts: 9,147	Re: HMV 900 update. Interesting example JAC. I have never seen a TCC one. John.

27th Nov 2017, 7:25 pm	#24
Jac Heptode Join Date: Jun 2006 Location: Eindhoven, Netherlands. Posts: 642	Re: HMV 900 update. John, Both my HMV 900 and Marconiphone 702 have such a TCC one. The 1 µF - 1500V in both sets is also TCC. After careful submitting them to high voltage via a series resistor, they formed good. So both sets still have their original EHT capacitors. They must have been (and still are) of good quality, performing good after 80 years! Quite different from the EHT smoothing capacitors in the 706/707/904/905 series (in my very limited experience). Jac Attached Thumbnails

28th Nov 2017, 7:02 pm	#25
Techman Dekatron Join Date: Nov 2009 Location: Lincolnshire, UK. Posts: 5,000	Re: HMV 900 update. I'm loving the originality of this set! I appreciate both extremes of repair/restoration. I appreciate the work that Argus25 puts into his restoration with gleaming metalwork with no dust in sight. I also love to see originality with a set as it would have been found operating in a home environment, with genuine historical repairs as would have been done by engineers of the time, with only the components replaced that would have needed to be due to fault conditions.