Dynatron SRX 26 Static in left channel issue - UK Vintage Radio Repair and Restoration Discussion Forum

KitesAreFun · 28th May 2020, 6:27 pm

Hi there.

I wonder if anyone can help me.

I’m trying to fix a 1973 Dynatron SRX 26. There is a radio like static sound in the left channel which responds to volume, tone controls, contour and s filter. The select buttons do nothing to stop it. The radio and record player work great, albeit slightly louder in one channel so I need to off centre the balance and it sounds fine. I’ve done all the basics such as cleaning all control pots and switches which does nothing. The 4 transistors measure at 30v and 15v which I understand is correct. I’ve had a poke around and all the caps look fine. I can solder and I have a multimeter but I’m still a relative newbie to this. Any help would be really appreciated!

David

Edward Huggins · 28th May 2020, 8:00 pm

The fault you describe is very common in these later Dynatrons, especally with one channel being low or completely dead. I don't quite understand what you mean by "static" which is not a word one uses in relation to audio frequncies. Do you mean the volume control is noisy when turned?

KitesAreFun · 28th May 2020, 8:27 pm

No. It’s white noise I suppose, or a radio that hasn’t been tuned to a station. It’s not a noisy pot that needs cleaning as far as I’m aware.

28th May 2020, 6:27 pm	#1
KitesAreFun Diode Join Date: Aug 2016 Location: Crawley, West Sussex, UK. Posts: 2	Dynatron SRX 26 Static in left channel issue Hi there. I wonder if anyone can help me. I’m trying to fix a 1973 Dynatron SRX 26. There is a radio like static sound in the left channel which responds to volume, tone controls, contour and s filter. The select buttons do nothing to stop it. The radio and record player work great, albeit slightly louder in one channel so I need to off centre the balance and it sounds fine. I’ve done all the basics such as cleaning all control pots and switches which does nothing. The 4 transistors measure at 30v and 15v which I understand is correct. I’ve had a poke around and all the caps look fine. I can solder and I have a multimeter but I’m still a relative newbie to this. Any help would be really appreciated! David

28th May 2020, 8:00 pm	#2
Edward Huggins Dekatron Join Date: Sep 2015 Location: Southwold, Suffolk, UK. Posts: 8,328	Re: Dynatron SRX 26 Static in left channel issue The fault you describe is very common in these later Dynatrons, especally with one channel being low or completely dead. I don't quite understand what you mean by "static" which is not a word one uses in relation to audio frequncies. Do you mean the volume control is noisy when turned? __________________ Edward.

28th May 2020, 8:27 pm	#3
KitesAreFun Diode Join Date: Aug 2016 Location: Crawley, West Sussex, UK. Posts: 2	Re: Dynatron SRX 26 Static in left channel issue No. It’s white noise I suppose, or a radio that hasn’t been tuned to a station. It’s not a noisy pot that needs cleaning as far as I’m aware.