UK Vintage Radio Repair and Restoration Discussion Forum - View Single Post - Radiometer SMG40 basic testing and calibration.

djsbriscoe · 11th Nov 2018, 9:40 pm

Just bought myself a Radiometer SMG40 stereo generator.

I have fixed the Composite level meter which was reading full scale deflection at switch on and was unresponsive.The LM311 comparator chip in the peak detector was defective so I replaced it and added an 8 pin socket as well. I guess someone put a signal INTO the output socket and it destroyed the chip.

I am beginning to work my way through the service manual. It has a comprehensive series of checks and adjustment procedures. I can carry out most of the DVM and scope tests apart from the distortion ones as I don't have a distortion meter.
It also mentions a wave analyser. I'm guessing this is the same as a spectrum analyser which I have access to to at work (HP E4402B 9K - 3G) but I don't know how to use it yet. So here is a chance to learn I suppose.

Has anyone done a full test and calibration of one of these generators? Can I get away with not using a distortion meter or is there a workaround for this?
Thanks.

PS I have read Mark Hennessey's info about his SMG40. Very interesting.

11th Nov 2018, 9:40 pm	#1
djsbriscoe Pentode Join Date: May 2015 Location: Hemel Hempstead, Hertfordshire, UK. Posts: 133	Radiometer SMG40 basic testing and calibration. Just bought myself a Radiometer SMG40 stereo generator. I have fixed the Composite level meter which was reading full scale deflection at switch on and was unresponsive.The LM311 comparator chip in the peak detector was defective so I replaced it and added an 8 pin socket as well. I guess someone put a signal INTO the output socket and it destroyed the chip. I am beginning to work my way through the service manual. It has a comprehensive series of checks and adjustment procedures. I can carry out most of the DVM and scope tests apart from the distortion ones as I don't have a distortion meter. It also mentions a wave analyser. I'm guessing this is the same as a spectrum analyser which I have access to to at work (HP E4402B 9K - 3G) but I don't know how to use it yet. So here is a chance to learn I suppose. Has anyone done a full test and calibration of one of these generators? Can I get away with not using a distortion meter or is there a workaround for this? Thanks. PS I have read Mark Hennessey's info about his SMG40. Very interesting. Last edited by djsbriscoe; 11th Nov 2018 at 9:56 pm.