UK Vintage Radio Repair and Restoration Discussion Forum - View Single Post - Nordmende Globetrotter 808 output stage problem.

MotorBikeLes · 16th May 2022, 5:48 pm

I temporarily wired in a good 470 pot and quickly set the quiescent current to 10mA with 9v input, and in fact it was just under 5mA when run from mains only. I checked the two resistances of the pot, getting 202 and 249 ohms respectively. I decided to try a 220 and a 270 to replace the pot with as a first try, but the QC was 7.3mA, so not suitable. Thinking further, I dug out a 7.5K pot of correct size to fit, set it mid point, and put the 220 and 270 resistors back in position Set exactly at 10mA with a minimum of 5mA and max of 20mA. I will leave it at that, as there is no chance of O/C pot causing havoc now.
I had fastened it up before seeing Leon's last reply, so will not proceed further with his suggestion. That way, at least, I won't make things worse.
Thanks for replies, Les.

16th May 2022, 5:48 pm	#10
MotorBikeLes Nonode Join Date: Dec 2012 Location: Kirk Michael, Isle of Man Posts: 2,350	Re: Nordmende Globetrotter 808 output stage problem. I temporarily wired in a good 470 pot and quickly set the quiescent current to 10mA with 9v input, and in fact it was just under 5mA when run from mains only. I checked the two resistances of the pot, getting 202 and 249 ohms respectively. I decided to try a 220 and a 270 to replace the pot with as a first try, but the QC was 7.3mA, so not suitable. Thinking further, I dug out a 7.5K pot of correct size to fit, set it mid point, and put the 220 and 270 resistors back in position Set exactly at 10mA with a minimum of 5mA and max of 20mA. I will leave it at that, as there is no chance of O/C pot causing havoc now. I had fastened it up before seeing Leon's last reply, so will not proceed further with his suggestion. That way, at least, I won't make things worse. Thanks for replies, Les.