UK Vintage Radio Repair and Restoration Discussion Forum - View Single Post - ITT VC51/1 Gremlin Hunting

Studio263 · 18th May 2007, 8:44 am

It used to be a popular bodge to run a big resisitor (usually 4K7 I think) from the mains input to the tube heater. This picked up the volts a little at that point and livened up the emission a bit. The set I remember is most clearly on was the Philips 210A, the last few in use seemed to have all had it done!
Obviously it is not a nice thing to do and not recommended, the real answer is another tube. An idea would be to remove the non-standard parts and repair the set as best you can with the pootube you have. Then when a good one comes along you can just drop it in.
Modifications like this to the heater circuit could affect the functioning of the bulbs, do they work normally once the resistor is removed?
I noticed another resistor across the dropper (the vertical white one). This looks as if it has been fitted to bridge out a defective section. Doing this is OK but it used to be considered wise to remove the wire completely from the original failled section just in case it joined up again when things get warm. Unlikely I know!

18th May 2007, 8:44 am	#28
Studio263 Octode Join Date: Apr 2007 Location: Hampshire, UK. Posts: 1,576	Re: ITT VC51/1 Gremlin Hunting - Stage 1. It used to be a popular bodge to run a big resisitor (usually 4K7 I think) from the mains input to the tube heater. This picked up the volts a little at that point and livened up the emission a bit. The set I remember is most clearly on was the Philips 210A, the last few in use seemed to have all had it done! Obviously it is not a nice thing to do and not recommended, the real answer is another tube. An idea would be to remove the non-standard parts and repair the set as best you can with the pootube you have. Then when a good one comes along you can just drop it in. Modifications like this to the heater circuit could affect the functioning of the bulbs, do they work normally once the resistor is removed? I noticed another resistor across the dropper (the vertical white one). This looks as if it has been fitted to bridge out a defective section. Doing this is OK but it used to be considered wise to remove the wire completely from the original failled section just in case it joined up again when things get warm. Unlikely I know!