Hi,
A good example of why not to turn old radios on with out inspection.
Can anyone help me with a model number for this transformerless set ,the valve line-up is ECH35, 6SK7,6SQ7,EL33A,6X5 and the barretter. I would guess circa 1950. Thanks.

So, you let the smoke out?

That was a popular line-up for many Kriesler sets, however limiting the list to console types I get these models:

1948 11-9 amended
1949 11-9 issue 2
1948 MAS1101/A
1948 MAS1101/B
1948 104
1948 104A

I don't have schematics for any of those.


Radiomuseum shows this list:

1948 Grand Combinette 11-10 [Versions K, L & M]
1948 11-11 [Amended]
1948 11-22 [Versions A to G]
1948 11-23 [Version C and above.]
1949 11-26

I have schematics for 11-10 and 11-22/23 but they have transformers.

I can't find any transformerless Krieslers for that era, apart from the battery sets.

Bob Yorston of the HRSA (NSW) is a Kriesler guru.

All those tubes have 6.3V heaters, and differing currents, so there must be at least a power transformer that provides the heaters with 6.3V Maybe someone replaced a bad power transformer (that used to provide power for the B+) with just a heater transformer and made the set a hot chassis by feeding the mains into the rectifier tube and to the chassis to get B+? Maybe using the ground pin of the mains plug as the return to the 230VAC (you're not supposed to do that, but it might be safer than hoping the power point was wired correctly, but if the ground is bad, it becomes hot).

Be careful.

I agree that using the earth wire as a return for the circuit is dangerous. It's also illegal and if your house has RCD's fitted they will trip due to the current imbalance. I doubt someone would receive a shock if wired contrary to this advise though, the MEN earthing system used in Australia, the United States and several other countries protects against this type of fault. The feature of this system is that the earth wiring in each house is bonded to the neutral wire at the main switchboard to the premises it is installed in. In Australia there is additional protection where roof guttering, copper water pipes, steel framing and the reo (reinforcement mesh) in concrete swimming pools are also bonded to the earthing system.

It is possible that the receiver in question has been modified by a previous owner. I've not enough knowledge of Kriesler models to be certain. Some Australian manufacturers did make AC/DC receivers and these were transformerless as a transformer will not work on a DC supply - it'll just glow red hot for a few seconds before melting down. Once example of a transformerless set is the Airzone Radiostar of 1937, made in AC-only, battery and AC/DC configurations.

Hi,
Thanks for your comments, the radio appears to be an 11.09 which has had the transformer removed and the filament circuits rewired in series with resistors added to balance the current . I have a scrap Kriesler mantel radio here with a similar chassis and will use the transformer from that.
I uploaded a couple of photos to be included in the original post they showed the amount of rat damage ,they have consumed almost all of the caps and destroyed the filter choke , fortunately they did not appear to be interested in the RF circuits.