Transformer Sizzling and Wax Melting - UK Vintage Radio Repair and Restoration Discussion Forum

SeamuSct · 27th Dec 2021, 4:47 pm

Hi all, and greetings from South Africa.

I received an early 60s pilot radiogram with gararrd 209 record player. Was used as a table in someone's house until now.

Filthy dirty and will need a LOT of woodwork, but after a wipe down I examined the electronics. Valve radio/receiver not working. The transformer (220v 250v) sizzles once you plug it in and press ON. Strangest thing Ive seen.

Im still fairly new to the radios scene but I know my way around tape recorders.

I got the record player to sort of work through an external power source but will need a new needle and lubricant seems to be wearing off.

But please can someone tell me the next actions I need to take on the radio/receiver tranformer scenario.

See link below for reference to the transformer problem.

https://youtu.be/VCh62d5GnMI

paulsherwin · 27th Dec 2021, 5:00 pm

Nice stereogram.

The transformer either has shorted turns, or is being grossly overloaded. The first thing to do is check for short circuits across and between the windings.

If this has been out of use for a long time and is completely unrestored, it is likely to need a fair bit of work before it can be used reliably and safely.

Skywave · 27th Dec 2021, 9:26 pm

Tackling faults like this is best done using the 'cause & effect' method of analysis. Disconnect all the wiring from the transformer except for its mains input, then switch the set on. The transformer will either continue to show signs of distress - as before - or it won't. If the former, the transformer will have short-circuit turns on its primary and will be U/S. If the latter, then the transformer is being overloaded. In that case, look for short-circuits in the heater wiring or in the rectification & filtering circuit.

Al.

Richardgr · 28th Dec 2021, 2:36 pm

You might be able to do the above just by temporarily removing fuses.

I have one of those devices that sits between the plug and wall socket, giving a real time indication of power being consumed, and that can be a good guide if the power consumption is non-typical.

SeamuSct · 30th Dec 2021, 11:40 pm

Thank you all very much. I am currently in a good mood. I got my old valve tape recorder and connected it up to the speakers and along the way have discovered various scaly wiring jobs that need rectifying. Makeshift mic inputs, old school aux inputs and a strange wire crossover that makes the aux input play only through the left speaker. Strange.

I haven't yet continued with the radio. I will need to fix these wire jobs after testing out the sole transformer idea. Our house is from the 1800s so testing the earth leakage and breakers first will be a good idea, and with new years this process will take a while longer.

The speaker they have taken out of the AUX system seems to be coming back to life. After a few muffled noises, the speaker is starting to sound well again. These speakers are built to last compared to even some 80s top range stuff.

Anyways, I will continue my adventure and keep the thread rolling... Everyone's comments are greatly appreciated.

27th Dec 2021, 4:47 pm	#1
SeamuSct Diode Join Date: Dec 2021 Location: Cape Town, Cape Province, South Africa. Posts: 2	Transformer Sizzling and Wax Melting Hi all, and greetings from South Africa. I received an early 60s pilot radiogram with gararrd 209 record player. Was used as a table in someone's house until now. Filthy dirty and will need a LOT of woodwork, but after a wipe down I examined the electronics. Valve radio/receiver not working. The transformer (220v 250v) sizzles once you plug it in and press ON. Strangest thing Ive seen. Im still fairly new to the radios scene but I know my way around tape recorders. I got the record player to sort of work through an external power source but will need a new needle and lubricant seems to be wearing off. But please can someone tell me the next actions I need to take on the radio/receiver tranformer scenario. See link below for reference to the transformer problem. https://youtu.be/VCh62d5GnMI Attached Thumbnails

27th Dec 2021, 5:00 pm	#2
paulsherwin Moderator Join Date: Jun 2003 Location: Oxford, UK Posts: 27,932	Re: Transformer Sizzling and Wax Melting Nice stereogram. The transformer either has shorted turns, or is being grossly overloaded. The first thing to do is check for short circuits across and between the windings. If this has been out of use for a long time and is completely unrestored, it is likely to need a fair bit of work before it can be used reliably and safely.

27th Dec 2021, 9:26 pm	#3
Skywave Rest in Peace Join Date: Jun 2006 Location: Chard, South Somerset, UK. Posts: 7,457	Re: Transformer Sizzling and Wax Melting Tackling faults like this is best done using the 'cause & effect' method of analysis. Disconnect all the wiring from the transformer except for its mains input, then switch the set on. The transformer will either continue to show signs of distress - as before - or it won't. If the former, the transformer will have short-circuit turns on its primary and will be U/S. If the latter, then the transformer is being overloaded. In that case, look for short-circuits in the heater wiring or in the rectification & filtering circuit. Al.

28th Dec 2021, 2:36 pm	#4
Richardgr Heptode Join Date: Oct 2019 Location: Täby, Sweden Posts: 702	Re: Transformer Sizzling and Wax Melting You might be able to do the above just by temporarily removing fuses. I have one of those devices that sits between the plug and wall socket, giving a real time indication of power being consumed, and that can be a good guide if the power consumption is non-typical.

30th Dec 2021, 11:40 pm	#5
SeamuSct Diode Join Date: Dec 2021 Location: Cape Town, Cape Province, South Africa. Posts: 2	Re: Transformer Sizzling and Wax Melting Thank you all very much. I am currently in a good mood. I got my old valve tape recorder and connected it up to the speakers and along the way have discovered various scaly wiring jobs that need rectifying. Makeshift mic inputs, old school aux inputs and a strange wire crossover that makes the aux input play only through the left speaker. Strange. I haven't yet continued with the radio. I will need to fix these wire jobs after testing out the sole transformer idea. Our house is from the 1800s so testing the earth leakage and breakers first will be a good idea, and with new years this process will take a while longer. The speaker they have taken out of the AUX system seems to be coming back to life. After a few muffled noises, the speaker is starting to sound well again. These speakers are built to last compared to even some 80s top range stuff. Anyways, I will continue my adventure and keep the thread rolling... Everyone's comments are greatly appreciated.