Eddystone 730/4's HT - UK Vintage Radio Repair and Restoration Discussion Forum

David Simpson · 23rd Jul 2018, 8:18 pm

Any Eddystone buffs out there, please ? Anyone know of V13's (5Z4G) Choke (CH1) being prone to going open circuit ? Mine has ! (Yes - I've checked the HT Switch).
V13 has been tested OK, and its Cathode & C117 floats at approx. 360V DC instead of the Manual's listing of 275V ((TP F.-). No S/C's found on the 242VHT, and the stabilised 148V . Looks a sod to remove.

Regards, David

ms660 · 23rd Jul 2018, 8:43 pm

The voltage at the reservoir looks about right if the choke is open circuit.

Lawrence.

turretslug · 23rd Jul 2018, 10:24 pm

I'm sure I recall a Gerry O'Hara article on an Eddystone restoration where an open-circuit HT choke was found to be one end of the winding being corroded through at the base connection- perhaps acidic flux and humid conditions over time? I think it was a 750 but the HT volts and current are of the same order and Eddystone seemed to like component commonality with this sort of thing. It did mean opening up the solder seam on the brass can in order to get to it, unfortunately.

"Looks a sod to remove" is apparently a common complaint with more sophisticated Eddystones!

23rd Jul 2018, 8:43 pm	#2
ms660 Dekatron Join Date: Apr 2011 Location: Cornwall, UK. Posts: 13,454	Re: Eddystone 730/4's HT The voltage at the reservoir looks about right if the choke is open circuit. Lawrence.

23rd Jul 2018, 10:24 pm	#3
turretslug Dekatron Join Date: Nov 2011 Location: Surrey, UK. Posts: 4,397	Re: Eddystone 730/4's HT I'm sure I recall a Gerry O'Hara article on an Eddystone restoration where an open-circuit HT choke was found to be one end of the winding being corroded through at the base connection- perhaps acidic flux and humid conditions over time? I think it was a 750 but the HT volts and current are of the same order and Eddystone seemed to like component commonality with this sort of thing. It did mean opening up the solder seam on the brass can in order to get to it, unfortunately. "Looks a sod to remove" is apparently a common complaint with more sophisticated Eddystones!