UK Vintage Radio Repair and Restoration Discussion Forum - View Single Post - Cossor 494AC. My first proper restoration

Sideband · 8th May 2009, 10:56 pm

If there is no cathode voltage, the valve isn't drawing any current. Have you got voltage anywhere else? It seems unlikely that you would have two faulty valves giving exactly the same results. Check that you have anode and screen-grid volts. If there is a cathode bypass capacitor, make sure it's not short-circuit.

Let us have a list of voltages that you have and it should help in locating the fault.

The 7C5 is basically a 6V6 with a different base. You could change the valve socket to octal and rewire for a 6V6 but why?

Rich.

8th May 2009, 10:56 pm	#2
Sideband Dekatron Join Date: Oct 2003 Location: Croydon, Surrey, UK. Posts: 7,571	Re: Cossor 494AC. My first proper restoration If there is no cathode voltage, the valve isn't drawing any current. Have you got voltage anywhere else? It seems unlikely that you would have two faulty valves giving exactly the same results. Check that you have anode and screen-grid volts. If there is a cathode bypass capacitor, make sure it's not short-circuit. Let us have a list of voltages that you have and it should help in locating the fault. The 7C5 is basically a 6V6 with a different base. You could change the valve socket to octal and rewire for a 6V6 but why? Rich. __________________ There are lots of brilliant keyboard players and then there is Rick Wakeman.....