Rigonda Bolshoi help. - UK Vintage Radio Repair and Restoration Discussion Forum

soldier101983 · 27th Nov 2019, 3:44 am

I have a Rigonda Bolshoi with a power supply fault. When the power supply is turned on the transformer starts buzzing very loud and starts getting very hot. Hot to point starts smoking. This is not a loose core problem the core is fine. Any idea what could be causing this?

paulsherwin · 27th Nov 2019, 12:05 pm

It could be lots of things. What is your level of expertise? Do you have a test meter, soldering iron etc.?

theredhouseinn · 28th Nov 2019, 12:19 pm

Unplug the multiway connector from the main chassis. Does the tx still buzz with this disconnected?
If it dosn't, then you have a short cct on the main chassis.
If it does then there are two bridge rectifiers on the psu which could be faulty.
I found that the rec and caps on this unit to be very reliable, but you never know.
If the tx has smoked then it is likely that a winding has burnt out and may not useable.
There are two primary windings for mains, and six secondaries for ht, bias, and heater supplies.
Never switch on a vintage valve unit until all major components have been tested, and then run it up on a variac very slowly.

John.

27th Nov 2019, 3:44 am	#1
soldier101983 Diode Join Date: Nov 2019 Location: Manchester, UK. Posts: 2	Rigonda Bolshoi help. I have a Rigonda Bolshoi with a power supply fault. When the power supply is turned on the transformer starts buzzing very loud and starts getting very hot. Hot to point starts smoking. This is not a loose core problem the core is fine. Any idea what could be causing this?

27th Nov 2019, 12:05 pm	#2
paulsherwin Moderator Join Date: Jun 2003 Location: Oxford, UK Posts: 27,967	Re: rigonda bolshoi help It could be lots of things. What is your level of expertise? Do you have a test meter, soldering iron etc.?

28th Nov 2019, 12:19 pm	#3
theredhouseinn Hexode Join Date: Jan 2013 Location: Kelvedon, Essex, UK. Posts: 273	Re: Rigonda Bolshoi help. Unplug the multiway connector from the main chassis. Does the tx still buzz with this disconnected? If it dosn't, then you have a short cct on the main chassis. If it does then there are two bridge rectifiers on the psu which could be faulty. I found that the rec and caps on this unit to be very reliable, but you never know. If the tx has smoked then it is likely that a winding has burnt out and may not useable. There are two primary windings for mains, and six secondaries for ht, bias, and heater supplies. Never switch on a vintage valve unit until all major components have been tested, and then run it up on a variac very slowly. John.