Philips 'Superinductance' model 274A

[AlanBeckett]

There's this - http://www.ebay.co.uk/itm/U10-DW2-CV1443...SwT5tWKg0C
A bit cheaper.

Alan

[Murphyv310]

Hi.
I am sure I would have a suitable rectifier valve in my stock that you could have for a nominal sum, assuming your customer is "tight". Let me know if that is of any help.

[Old Sparky]

Is the DW2/CV1443 a direct equivalent to the 1821, in particular with regard to theheater voltage & current? I tried to find 1821 data yesterday, but couldn't. Maybe I'll try again today. Point taken aboutthe silicon diodes, Trevor. I don't know what the owner paid for his 274A, and haven't been able to find one for sale on eBay or elsewhere, to establish it's value. Whilst on this topic I've never gone in for restuffing capacitors, approaching any job with my service engineer's 'hat' on - i.e., if a a later component was available than that already fitted, we just fitted the new part. No-one thought of restuffing the original part, or otherwise disguising the new one where I worked, and I don't suppose they did anywherre else either. In this particular case, AFAIK, I was only asked to repair the radio, but, before going any further, maybe I'll check with the owner.

I've just seen your latest post. Trevor. I don't think my customer is 'tight', but I may get back to you after contacting him.
Having found brief data for the CV1443, it seems that this would be a good substitute, although Cres. max is given as 8uf, and the originals are 16uf. BTW I see they have 3 small holes in the top, so maybe putting in some dewmineralised water and reforming them will mean they can still be used.

[Murphyv310]

Hi.
I'd replace the 4 pin base with an IO and fit an AZ31.
Have you confirmed the other valves are OK or not? The detector is now just about impossible to find and it's not got any direct equivalent, others do work but with less performance.

[Old Sparky]

Since my last posting, I have found several British 4pin Rectifiers on ebay, including a CV1443 @£30, an untested 1821 @ £15, and several tested/NOS 1821s @ prices from £50 to £228 (that last one if a definite no-no!), so hopefully I won't need to swap the valvehoder for an octal one. I don't have a valve tester, nor a known working radio which uses similar valves, Trevor, so have no way of knowing the condition of the other valves, except that all their heaters (filaments) test OK on a meter. I'll contact the owner and explain the situation to him, then await his reply before proceeding further.

[boater sam]

Lash in silicon diodes and a 500 ohm 10w dropper resistor and see what the rest of the valves are like. Once you can get it working, you could hide the diodes in the valve base if they are required not to show.
Getting it going first could save a lot of anguish and cash, all those valves will be pricy.

[pwdrive]

As Alan pointed out in an earlier post, the DW2 is a substitute for the 1821, same heater voltage and heater current:

http://www.r-type.org/pdfs/dw2.pdf

Second hand ones sometimes turn up on Ebay.

Lawrence.

[Murphyv310]

A temporary test with silicon is the quickest way. Would save the cost of other valves if it's going to be too expensive.

[Old Sparky]

Thanks, all for your helpgful advice. I've emailed the owner explaining the current position, but haven't yet had a reply from him. I may well try fitting a couple of silicon diodes and a series resistor, at least as a temporary measure, but before so doing, I need to replace several waxed paper caps. The radio is currently in a partially dismantled state pending doing this work, so I can't just tack in diodes, etc., refit the other valves and test it.

[Murphyv310]

Hi.
Why not feed the filaments from the sets mains transformer, leave the rectifier out and feed the HT from an external variable source? This would give you some idea what state the set is in, it would be a pity to replace caps if there are other problems elsewhere, Those beautiful cans can hide corroded coils and the possibility of faulty or low emission valves is quite high. If you don't have a variable HT supply your variac can be made into a simple variable HT supply with a bridge reccy and a 10uf cap (not critical) I do this on many sets that are dubious, a quick and easy lash up.