I've just had the misfortune of having my output transformer burn out. I had replaced all caps except the two big electrolytics which had seemed to be ok and have been listening to the radio all weekend with it sounding great, merely went outside to help my wife strt the whipper snipper and the dog started barking inside, my wife popped in and came out saying the house was full of smoke, so I raced in and found the radio lifeless with a horrible acrid smell in the air. I unplugged it and pulled the back off to find the power transformer hot as hell and block stuff dripping out... Not good.
It was fine all weekend and no warning, if only I hadn't popped outside for 20 odd minutes!
Question.... Is there an off the shelf replacement for one of these, or can I get the cooked one re-wound?

HI Jamie,

There is a Radiola version of this unit on ebay ending at 2131 tonight. Bids start at $20.

Dont let the pickup only stop you as there a number of members who live locally and could help you out.

http://www.ebay.com.au/itm/282181784558

Cheers, Graham...

Thanks for the suggestion Graham and the link, something fishy about Ebay, I was trawling around looking for one to no avail, but pasted in your link and boom boom! Lo and behold... So thank you for that, I've bid on it, hopefully if I win the auction, somebody can pick it up and post it to me, if the guy is cranky about posting it, I did message him, but can't really afford to let it get away either... Cheers!

I had replaced all caps except the two big electrolytics

Those would be the very first ones to replace as they are infamous for taking out power transformers in exactly the way you describe.

And even with restored valve equipment, I NEVER leave it operating when I'm not present.

Yes well, I don't think I'll be trusting any electrolytic caps again anytime soon... Or later. There was no hum or anything to make me suspect them, but your point has been very well illustrated by my latest experience! It had been performing fine for hours and hours over two days and within 20mins flat... Paf... Gone! Bit of a bugger!

How do you know the transformer has burnt out? Despite the smell and smoke, it might still work.

Unplug all the valves and any lamps, measure the windings for continuity. If they measure ok, turn the radio on (still with the valves and lamps unplugged) and see if smoke or smell starts again. If after an hour nothing happens, and the transformer is mostly cool, it could be ok.

Measure the outputs, (heater winding is most likely ok), and the HT voltages are reasonable and within 20% of each other.

After that plug in the lamp(s), should light up normally. Then all valves EXCEPT THE RECTIFIER, they should also light up.

If all these tests pass, the transformer is most likely ok despite the beating it received. Just fix the power supply (including a new rectifier as the old one is most likely short circuit or at least damaged) and you'll be ok.


Even so, the biggest issue will be the horrible smell which will hang around for ages.

Worth a try I suppose, but when I got to the radio, it was still plugged in, switched on, but no signs of life, dial lamp and valves all gone out, I'll be surprised if there's continuity...

Ah, so it had already fused.

You're quite unlucky, never had that happen, and I often run radios for long periods unattended. Whenever one dies I've been there to witness it.

The only smoking power transformer I've had was on a radio I purchased at the Wagga Wagga Salvation Army, and it smoked the first time it was plugged in. The transformer was defective internally, a replacement restored things to normal.

Yes I need to find a replacement, according to Kevin Chant, this particular specimen is a fairly usual run of the mill transformer and I should be able to substitute it for one out of a wrecked radio, I found this link too searching on the net:

http://livinginthepast-audioweb.co.uk/index.php?p=xfrmrvt1419es

It's a simple 250v-0-250v output with two 120v primaries, which can be wired in series for 240v or parallel for the 120v US power supply. The only concern is the 3.15v-0-3.15 heater, filament tap, totals 6.3v whereas the schematic says the original actually has 8v, but I doubt if the difference would matter that much, so it seems a worthwhile option.

At 55 quid plus shipping, that's a very expensive option. I wouldn't rate that radio worth anything like that expenditure.

If you won that item on eBay for $20, and assuming its tranny is okay, then that's more like the budget.

£55.44 would be at least $120 plus shipping, plus the cost of the other parts. That's extremely expensive for such a common radio.

I've got at least 4 B15's, and I wasn't even trying.

Just pick up a cheapie from eBay, and transfer the bits over. All you need is new electros.
The eBay radio will get you the replacement rectifier, the proper speaker, and the transformer.

There is something seriously not right here: Careful of the nomenclature we are talking power transformer not OP that's the one on the 6AQ5.

AWA B15 is featured in July 2013 Silicon Chip. The power transformer is not as you described. Valves, 6BE6; 6BA6; 6AV6; 6AQ5; 6X4. B+ at 6X4 cathode 250V and it's back biased (R15) to help get C28 wrong and the bias if you mess it up (6AQ5 will not like having no grid 1 bias)

Transformer is a conventional Primary 230-260; 200-230 Volt a fairly standard primary. That valve lineup is also similar to HMV 64 chassis & earlier, only they used 6M5 out. The power transformer is likely similar and common as. Heater winding is not centre tapped.

I do wonder if yours is an original transformer. However, do make sure that you know which winding fried. The HMV chassis is 50's and ran through several models for ages. I have repaired more than a dozen, so that is a source, as they were extremely popular, even I have a green one.

If you intend to try the transformer again to make sure its cooked I would insulation test between windings & earth leakage test as well. Do not over look that a short in a heater, or dial lamp socket, can also wipe out a transformer. Initial checks .... rectifier on the bench.

I've bid on it, hopefully if I win the auction

It ended with one bid, so logically that would be yours.

Maybe you just recap the one from ebay and thats all you need to do .

Yes I won the auction! Yay, yes I think that's the best idea, re-cap the new one and junk the old for spares unless another transformer turns up at some stage, the one from ebay looks a bity sad and grotty, but should tidy up well with some work! Thank's for your help! Cheers!!!