I took the oppertunity ( while my wife was sleeping) to take my radio to the repair man this evening. He is really on top of things and is a walking encyclopedia on these things. He suspects as you do that the transformer is burnt out due to the wrong rectifier valve. There is some sign of heat around it. One of the valves he identified as out of a TV. But all is redeemable. And its now on its way to a full restoration.I indicated to him that I wanted to learn how to do this sort of work and he is going to help me.

The rectifier is possibly TV and certainly was not about in the early days. 6V6 despite being normally used as an audio output, was actually used, I think in the Horizontal output, It works both ways as 6CM5 which is a TV switching tube (Horizontal OP) & a few others were used as audio amps. 6CK6 is a video amp that looks similar electrically to 6M5 only the suppressor is not tied to cathode.

Marc

Some of the old transformers are robust, so the only way to tell if the transformer is ok is to insulation test it, check its voltages with the rectifier out & if it appears ok leave it idle (minus rectifier) for a while.

Looks can be deceiving, I have a Philips transformer (123L) that has windings glued in place & insulation added to stop them contacting the lamination's, (motor re-winders advice as to how) as they were escaping out the side. Its been going for years.

Beware: This is not the only Philips transformer of the same construction, that I have seen doing the same thing.

There is around an amp difference between the filaments of 5Y3 and 5AS4. That may have caused the transformer to get over hot. but a B+ overload will do same.

There is a Russian 5Y3 that looks more like a 6X4 internally. These appear to have a cathode sleeve & heat up like a heater valve, eliminating 5Y3's normal start up, voltage surge. I have used these.

Marc

Problem solved sorry guys for repeating my self

Actually the problem is not entirely solved, hence the comment. The normal procedure is to inspect it to gauge what it will require to fix it. If the transformer has cooked a winding, this will destroy the integrity of it and it is liable to self destruct in a cloud of smoke, if the damaged wires are shorted.

There are then choices of buying a new transformer, and they are not cheap; Getting it rewound, & there is a guy in our Radio Club that I have had do two. One of which I was not surprised at it failing: It looked underrated; or you may have to get back to us to see who has one to suit.

I have been fixing chasses for a long time & I do not have an infinite source of spares and I am sure your fixer will often be faced with the same problem. I have also given training to a few in the club and sorted out a few uncooperative sets.

Once you start dealing with burned out transformers, blown, or missing valves & other peoples paid time, it can get very expensive.

Marc

What I am going to do is rely on my tech to finish this and I will be trying to learn how to do restorations myself soon so if you can recomend any books to me that I can study in my long night shifts. I will be looking to purchase a cheapy to operate on in time. Oh and when I said problem solved I was referring to all the repeat comments that I have now deleted it was my own silly fault not realising there was a second page and when I commented my tablet would take me back
to the first page lol.i can see many extra overtime shifts needed to get this old girl to full splendour but anything worth doing is worth working for.

But having said that , I am very interested in reading the comments as I have been learning bit by bit from this forum.

If a transformer has failed that merely slows things down if the project is going ahead. Stuffed rubber wire also slows things down, but if you change Electrolytic & wax paper caps, & change the bad resistors as you go. You can knock it over in a few hours.

A lot of technical book shops have fallen by the wayside & there are a lot of the uneducated putting things on the WEB.

Perhaps email Pages of Cobram (pages.cobrambigpond.com) as a starter the owner is into Ham radio. Others like HRSA may have something & some who have such things may respond?

Marc

There are a couple of books by Marcus & Levi called Practical Radio Servicing and Elements of Radio Servicing that pop up on Ebay from time to time. Both are very good to learn the basics. There's quite a few editions of each but the ones from the 1950's are best.

I will look them up

Wow I pulled the original speaker cloth out of the old girl this week and washed it. Would you believe its still in top shape .