UK Vintage Radio Repair and Restoration Discussion Forum - View Single Post - My first valve radio project

indigo.girl · 28th Dec 2016, 6:57 pm

I've removed R8 from the circuit and also snipped one end of R11 so I can test everything independently.

R8: Total resistance is 1M ohm (higher than 700K spec). As I move the wiper resistance changes from 0 to 1M ohm on a log scale so most of the increase in the final quarter turn. But I don't see the peak resistance at the 3/4 position like I do when its in the circuit. This still doesn't explain the 240k ohms I measure across R8 in situ (would increase expected value up to 90 K)

R11: On spec at 108 K ohms (100K)

R9: On spec at 23 ohms (22)

28th Dec 2016, 6:57 pm	#170
indigo.girl Retired Dormant Member Join Date: Apr 2016 Location: Loughborough, Leicestershire, UK. Posts: 754	Re: My first valve radio project - Philips 462A I've removed R8 from the circuit and also snipped one end of R11 so I can test everything independently. R8: Total resistance is 1M ohm (higher than 700K spec). As I move the wiper resistance changes from 0 to 1M ohm on a log scale so most of the increase in the final quarter turn. But I don't see the peak resistance at the 3/4 position like I do when its in the circuit. This still doesn't explain the 240k ohms I measure across R8 in situ (would increase expected value up to 90 K) R11: On spec at 108 K ohms (100K) R9: On spec at 23 ohms (22)