UK Vintage Radio Repair and Restoration Discussion Forum - View Single Post - Help needed with

frsimen · 17th Mar 2023, 8:36 pm

Hello Mark,

All seems as it should be with the resistors

TC2 was a good spot by Peter, I'd missed that.

TC2 feeds in on terminal 24, feeds to IC10 pins 12 and 13. The output (pin 11) should be at the opposite state, (that is input 12V, output 0V or input 0V, output 12V. The level at IC15 pins 1, 8 and 13 should be the same as IC10 pin 11.

TC2 is the tune control switch. It's the one to the left of the tuning spin wheel, marked hold, slow,fast.

While in the area you might as well check the TC1 line. You can monitor on terminal 28 and you should find an inverted version on pin 6 of IC10. TC1 is also controlled by the tune control switch.

Paula

17th Mar 2023, 8:36 pm	#249
frsimen Heptode Join Date: Jan 2011 Location: Croydon, London, UK. Posts: 772	Re: Help needed with - Racal Dana 9081 Hello Mark, All seems as it should be with the resistors TC2 was a good spot by Peter, I'd missed that. TC2 feeds in on terminal 24, feeds to IC10 pins 12 and 13. The output (pin 11) should be at the opposite state, (that is input 12V, output 0V or input 0V, output 12V. The level at IC15 pins 1, 8 and 13 should be the same as IC10 pin 11. TC2 is the tune control switch. It's the one to the left of the tuning spin wheel, marked hold, slow,fast. While in the area you might as well check the TC1 line. You can monitor on terminal 28 and you should find an inverted version on pin 6 of IC10. TC1 is also controlled by the tune control switch. Paula