LEAK Trough Line Stereo light bulb problem - UK Vintage Radio Repair and Restoration Discussion Forum

uk_snowman · 23rd Jul 2018, 9:31 pm

The tuner light bulb is not working in the Leak unit.
The bulb works fine when connected to my bench power supply at 6v DC
when I test the voltage to the bulb connector i get 6v AC but zero DC

Any thoughts would be appreciated

buggies · 23rd Jul 2018, 10:19 pm

I don't know the circuit so my suggestions are of general nature...

Assuming the 6 volts (of any variety) is on the socket with the bulb in situ and it is not illuminating, then it cannot be making connection properly.
If volts on the socket with the bulb out then it could be just a high impedance feed which will be slugged when bulb fitted.
You could try bulb temporarily wired across the dvm when testing at the socket.

turretslug · 23rd Jul 2018, 10:37 pm

I recall contact problems between bulb end-caps and holder being a pain in the head here- I'd painstakingly clean both caps and holder leaves to apparently good effect, only for it to go flickery again later. In the end, I soldered a small jumper between cap and contact leaf at each end- kinda defeats the point of a holder, but stopped the contact problem.

The bulb runs from the general 6.3V heater distribution with one side to chassis, so AC only at the holder is expected.

23rd Jul 2018, 9:31 pm	#1
uk_snowman Hexode Join Date: Jun 2013 Location: Norwich, Norfolk, UK. Posts: 281	LEAK Trough Line Stereo light bulb problem The tuner light bulb is not working in the Leak unit. The bulb works fine when connected to my bench power supply at 6v DC when I test the voltage to the bulb connector i get 6v AC but zero DC Any thoughts would be appreciated __________________ Now where did I put that part again!!!

23rd Jul 2018, 10:19 pm	#2
buggies Heptode Join Date: Jan 2009 Location: West Lothian, UK. Posts: 762	Re: LEAK Trough Line Stereo light bulb problem I don't know the circuit so my suggestions are of general nature... Assuming the 6 volts (of any variety) is on the socket with the bulb in situ and it is not illuminating, then it cannot be making connection properly. If volts on the socket with the bulb out then it could be just a high impedance feed which will be slugged when bulb fitted. You could try bulb temporarily wired across the dvm when testing at the socket. __________________ George

23rd Jul 2018, 10:37 pm	#3
turretslug Dekatron Join Date: Nov 2011 Location: Surrey, UK. Posts: 4,400	Re: LEAK Trough Line Stereo light bulb problem I recall contact problems between bulb end-caps and holder being a pain in the head here- I'd painstakingly clean both caps and holder leaves to apparently good effect, only for it to go flickery again later. In the end, I soldered a small jumper between cap and contact leaf at each end- kinda defeats the point of a holder, but stopped the contact problem. The bulb runs from the general 6.3V heater distribution with one side to chassis, so AC only at the holder is expected.