Dynatron SRX26 low radio volume. - UK Vintage Radio Repair and Restoration Discussion Forum

reeltoreelrob · 2nd Feb 2017, 10:36 pm

Hi all,
Just wondered if anyone had any ideas about this, AM does not work, that does not bother me too much and have read the threads about this.
The FM works and pulls in all the stations I would expect and the tuning indicator goes up to the high quarter on most channels, the thing is I have to have the volume up to about half way the get decent volume, the record deck with the sonotone cartridge only needs to be about a quarter turn on the volume control to get decent level of sound. Both channels are equal and the selector switches seem smooth and crackle free.
Does anyone have any pointers before I go inside it.
Thanks in advance
Rob.

Grubhead · 3rd Feb 2017, 1:30 am

The RF section could be to blame, check any coils for bad soldering. If there is an IC that works both AM and FM then I think you will have the culprit.

Nuvistor · 3rd Feb 2017, 9:31 am

I think this unit uses the Mullard module for AM, that could well be the problem on AM.
On FM it appears that the RF/IF section is working with the signal strength showing good. Check the AF coupling caps from the detector onwards.

You may well be lucky and all the set requires is the switches cleaning, I would try that first.
Frank

Edward Huggins · 3rd Feb 2017, 11:14 am

There was poor quality control on these chassis. Check for cracked PC board/s or dry joints in the RF/IF sections. A X12 glass can help. The AF stages seem to be as they should.

reeltoreelrob · 4th Feb 2017, 10:35 pm

Hi all,
Thanks for the comments, it will give me a starting point.
It is a shame the quality control was poor on these as I think they are a great set for the time giving a decent sound.

2nd Feb 2017, 10:36 pm	#1
reeltoreelrob Pentode Join Date: Nov 2010 Location: Birmingham, West Midlands, UK. Posts: 202	Dynatron SRX26 low radio volume. Hi all, Just wondered if anyone had any ideas about this, AM does not work, that does not bother me too much and have read the threads about this. The FM works and pulls in all the stations I would expect and the tuning indicator goes up to the high quarter on most channels, the thing is I have to have the volume up to about half way the get decent volume, the record deck with the sonotone cartridge only needs to be about a quarter turn on the volume control to get decent level of sound. Both channels are equal and the selector switches seem smooth and crackle free. Does anyone have any pointers before I go inside it. Thanks in advance Rob.

3rd Feb 2017, 1:30 am	#2
Grubhead Heptode Join Date: Dec 2016 Location: Sheffield, South Yorkshire, UK. Posts: 539	Re: Dynatron SRX26 low radio volume. The RF section could be to blame, check any coils for bad soldering. If there is an IC that works both AM and FM then I think you will have the culprit.

3rd Feb 2017, 9:31 am	#3
Nuvistor Dekatron Join Date: Aug 2013 Location: Wigan, Greater Manchester, UK. Posts: 9,433	Re: Dynatron SRX26 low radio volume. I think this unit uses the Mullard module for AM, that could well be the problem on AM. On FM it appears that the RF/IF section is working with the signal strength showing good. Check the AF coupling caps from the detector onwards. You may well be lucky and all the set requires is the switches cleaning, I would try that first. Frank

3rd Feb 2017, 11:14 am	#4
Edward Huggins Dekatron Join Date: Sep 2015 Location: Southwold, Suffolk, UK. Posts: 8,338	Re: Dynatron SRX26 low radio volume. There was poor quality control on these chassis. Check for cracked PC board/s or dry joints in the RF/IF sections. A X12 glass can help. The AF stages seem to be as they should. __________________ Edward.

4th Feb 2017, 10:35 pm	#5
reeltoreelrob Pentode Join Date: Nov 2010 Location: Birmingham, West Midlands, UK. Posts: 202	Re: Dynatron SRX26 low radio volume. Hi all, Thanks for the comments, it will give me a starting point. It is a shame the quality control was poor on these as I think they are a great set for the time giving a decent sound.