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 Astor Devon Fringe
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 Return to top of page · Post #: 1 · Written at 12:48:27 AM on 30 July 2018.
Samt's Gravatar
 Location: Hobart, TAS
 Member since 6 May 2013
 Member #: 1337
 Postcount: 72

I have a 1965 Astor Devon Fringe in excellent condition. I would like to restore it and use with a RF modulator. I have restored vintage radios before but this is my first television. The Astor Devon Fringe is a valve set but uses x4 silicon diodes as a bridge rectifier in the power supply. Luckily the chassis uses mainly polyester and polystyrene capacitors which I find are usually still good. My concern is the Ducon electrolytics. I am debating whether to attempt to reform the Ducon Electrolytics slowly at reduced voltage or opening the cans and installing new electrolytics in the cans. My only concern about using the original electrolytics is if any short out which could overload the silicon diodes in the rectifier causing them to short and taking out the transformer. Has anyone restored a symilar set and what method seemed to work best?


 
 Return to top of page · Post #: 2 · Written at 5:20:40 PM on 31 July 2018.
Ian Robertson's Gravatar
 Location: Belrose, NSW
 Member since 31 December 2015
 Member #: 1844
 Postcount: 1291

Ducon cans of that vintage are usually reformable. But check to see if there are any signs of chemical leakage (white crusty stuff) around the insulating base of the electros..

I'd remove the 6CM5, 6AL3 and 6GV8 and bring the chassis up on a 60 watt dim bulb. (That's with a 60 watt incandescent lamp in series with the active of the power to the chassis.)

Let it run for a day then remove the other valves.
Let it run until the lamp goes out and then a few more days to reform the caps.

Put the valves back in without the dim bulb in series and you should see some activity.

You are right, you won't have to re-cap this set.

Advantage of the dim bulb is, if something fails, the lamp will protect the chassis from any damage. It is safe to run unattended.

If you do have to replace the cans, I don't agree with re-stuffing can electros in TVs.
Reason - the electros in TVs need to support fairly high ripple currents and your small axial electros are not really up to the job on a long-term basis.

You can get some excellent new electros from the Czech Republic, intended for the guitar and audiophile market, at a good price. NOS twist-lugs are also available but are VERY exy and need to be re-formed anyway.

This one is a handy replacement part for TVs.
https://tubedepot.com/products/jj-can-capacitor-50uf-x-50uf-500v


 
 Return to top of page · Post #: 3 · Written at 11:36:37 AM on 6 August 2018.
Irext's avatar
 Location: Werribee South, VIC
 Member since 30 September 2016
 Member #: 1981
 Postcount: 196

WRT restuffing can electro's. As long as you use caps rated for power supply use ie high ripple current electro's, you should be fine. I am a member of the VideoKarma forum and in the states it is common practice to restuff can electro's there and there have been no reports of failures so far and they are doing this in colour receivers dating back to the late forties as well as very early B&W sets. However you may not need to if the caps are not visibly leaking and can be reformed successfully. I have restored a PYE W101 from 1956 which still has it's original can electro's that responded well to a reform.


 
 Return to top of page · Post #: 4 · Written at 12:08:24 PM on 14 August 2018.
Ian Robertson's Gravatar
 Location: Belrose, NSW
 Member since 31 December 2015
 Member #: 1844
 Postcount: 1291

In my experience Ducon cans are frequently reformable, UCC cans almost never., they are either O/C or leaky.

I just replaced that huge (and open circuit) under chassis UCC 100μF + 200μF can in an HMV F4 with a Czech JJ 50μF + 50μF 500v can and now have about 50mV p-p ripple on HT1. These caps are obviously very good.

I also replaced the UCC 40μF + 80μF with the same 50 + 50.

The Ducon can in this F4 had reformed perfectly.


 
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