ADRET 470A Generator - UK Vintage Radio Repair and Restoration Discussion Forum

Wendymott · 29th Oct 2013, 2:41 pm

Hi peeps.
I am fortunate to have an Adret 470A Signal generator, which mostly works ok. The memory battery needs replacing, but that's no matter. The main problem is in FM Mode. The modulation has a nasty 5 Hz ripple on top of the carrier, and sounds horrendous.........Both in FM and O,M mode.... AM is Ok
I have checked every pin on the Bus on every module with a scope for any waveform that could possibly create this distortion, but nothing is found. I can however stop the nasty by disconnecting the coax connector from the "80 steps" module, "see photo"......... Internal investigation of this module shown no distressed components or anything that needs changing....The manual I downloaded is in French, but is not too difficult to understand.
Pity is I don't have a module extender to work on the module out of its case.
I wonder if any of you have any better ideas ?? It is a pity as this generator, although big and heavy, is ideal for Vintage radio work.
Thanks

29th Oct 2013, 2:41 pm	#1
Wendymott Octode Join Date: Jun 2013 Location: Huddersfield, West Yorkshire, UK. Posts: 1,793	ADRET 470A Generator Hi peeps. I am fortunate to have an Adret 470A Signal generator, which mostly works ok. The memory battery needs replacing, but that's no matter. The main problem is in FM Mode. The modulation has a nasty 5 Hz ripple on top of the carrier, and sounds horrendous.........Both in FM and O,M mode.... AM is Ok I have checked every pin on the Bus on every module with a scope for any waveform that could possibly create this distortion, but nothing is found. I can however stop the nasty by disconnecting the coax connector from the "80 steps" module, "see photo"......... Internal investigation of this module shown no distressed components or anything that needs changing....The manual I downloaded is in French, but is not too difficult to understand. Pity is I don't have a module extender to work on the module out of its case. I wonder if any of you have any better ideas ?? It is a pity as this generator, although big and heavy, is ideal for Vintage radio work. Thanks Attached Thumbnails