Cossor 1324 FM generator. - UK Vintage Radio Repair and Restoration Discussion Forum

Riccampbell · 20th Dec 2013, 6:47 pm

Perhaps this is a bit of a long shot, but does anyone know where I could find a manual for the above? I just missed one on ebay. I would be most grateful for anything at all concerning this very nice bit of kit. Ric.

Freya · 20th Dec 2013, 6:53 pm

Attached is circuit if that helps

WME_bill · 20th Dec 2013, 7:53 pm

Cossor 1324. Well it is nice to see that that circuit + other data which I posted in January 2011 is proving of use to someone.
The manual for the 1320 (from Jon's Valvepage) is sufficiently close that it will be helpful in working on your 1324.
The MoD CT202 appears identical electrically to the 1320, though in a different style of case. Does anyone have that manual ref BR1771 (14).
When you have got your machine working, please let us know what you found.
I have the 1320 TV alignment version. Virtually identical circuit, but with square wave amplitude modulation, rather than audio, and External FM/Sweep only. It needs some attention , and so joins the pile under my bench. wme_bill

ukcol · 21st Dec 2013, 11:26 am

This thread may be of interest if you haven't already seen it.

https://www.vintage-radio.net/forum/...ad.php?t=98376

Riccampbell · 23rd Dec 2013, 4:21 pm

Many thanks for the schematic and comments. As a beginner I am still at the head scratch stage, I have connected my trusty electrolytic reformer and so on, it runs alright, no nasty smells and the valve voltages are all in order. Nothing much happened when connected to my (cossor) scope. I noticed in a comment from Bill a number of caps were replaced, I shall carefully delve further. Cheers, Ric.

maninashed · 23rd Dec 2013, 4:51 pm

Hi Ric, I had a particular problem with mine in that there was no audio out and no rf modulation. You may not have that problem. There were a number of brown Hunts capacitors inside, which you should change. Once powered up at normal mains voltage, there should be a detectable rf output, just use a length of wire as an aerial, and a radio nearby tuned to a quiet area of the fm band, and you should get some results.
One thing that I would check if I were you is the mains filter network which is inside the back behind a panel, replace the capacitors fitted across the mains with modern X rated components, or there may well be a dramatic end to the originals!
Bill

Riccampbell · 22nd Jan 2014, 3:05 pm

Hello Bill, thanks for the reply. I haven't updated the mains filter yet but certainly will do so. I have tried allsorts whilst trying to detect an output, using my little Philips set (which I have got working) but all to no avail. I will check again for hunts capacitors and replace those I find. Cheers, Ric.

maninashed · 22nd Jan 2014, 6:58 pm

Ric, if its anything like the one I have, you will need to do several things to get this to work reliably. Firstly, ensure the mains cable is fit for purpose.
Check that the power supply is working properly with correct voltages at the output ie at the +ve end of C4 you should have about 180v. Unless the psu is working properly, nothing else will.
You need to check all the paper capacitors in the range 1n and above. Even if they look ok, they will be leaky so its best to replace with modern components.
Clean the rotary switches with Deoxit or Servisol and work them to and fro.
There are a number of pre-set pots on the rear panel, these ,I have found, can suffer from 'tin whiskers' and short internally, so you may need to remove them and clean them, use servisol and a very small brush / can of air blaster.
If you pm me with your email address, I have the full manual and will send it to you (if you haven't already got one).
Bill

Riccampbell · 23rd Jan 2014, 6:40 pm

Thanks again Bill, I did replace the mains cable, I used 3 core rather than the 2 core it came with so it now has an earth connection. I have made a note of your "things to check" and will go through it as per the list. I'll let you know what happens! Thanks for the offer of the manual but I do have one. Cheers, Ric.

20th Dec 2013, 6:47 pm	#1
Riccampbell Tetrode Join Date: Nov 2012 Location: Huntingdon, UK. Posts: 98	Cossor 1324 FM generator. Perhaps this is a bit of a long shot, but does anyone know where I could find a manual for the above? I just missed one on ebay. I would be most grateful for anything at all concerning this very nice bit of kit. Ric.

20th Dec 2013, 7:53 pm	#3
WME_bill Octode Join Date: Oct 2007 Location: Exeter, Devon, UK. Posts: 1,554	Re: cossor 1324 FM generator Cossor 1324. Well it is nice to see that that circuit + other data which I posted in January 2011 is proving of use to someone. The manual for the 1320 (from Jon's Valvepage) is sufficiently close that it will be helpful in working on your 1324. The MoD CT202 appears identical electrically to the 1320, though in a different style of case. Does anyone have that manual ref BR1771 (14). When you have got your machine working, please let us know what you found. I have the 1320 TV alignment version. Virtually identical circuit, but with square wave amplitude modulation, rather than audio, and External FM/Sweep only. It needs some attention , and so joins the pile under my bench. wme_bill Last edited by WME_bill; 20th Dec 2013 at 8:03 pm.

21st Dec 2013, 11:26 am	#4
ukcol Rest in Peace Join Date: May 2003 Location: Harlaxton, Lincolnshire, UK. Posts: 3,944	Re: Cossor 1324 FM generator. This thread may be of interest if you haven't already seen it. https://www.vintage-radio.net/forum/...ad.php?t=98376

23rd Dec 2013, 4:21 pm	#5
Riccampbell Tetrode Join Date: Nov 2012 Location: Huntingdon, UK. Posts: 98	Re: Cossor 1324 FM generator. Many thanks for the schematic and comments. As a beginner I am still at the head scratch stage, I have connected my trusty electrolytic reformer and so on, it runs alright, no nasty smells and the valve voltages are all in order. Nothing much happened when connected to my (cossor) scope. I noticed in a comment from Bill a number of caps were replaced, I shall carefully delve further. Cheers, Ric.

23rd Dec 2013, 4:51 pm	#6
maninashed Rest in Peace Join Date: May 2011 Location: Preston, Lancashire UK Posts: 955	Re: Cossor 1324 FM generator. Hi Ric, I had a particular problem with mine in that there was no audio out and no rf modulation. You may not have that problem. There were a number of brown Hunts capacitors inside, which you should change. Once powered up at normal mains voltage, there should be a detectable rf output, just use a length of wire as an aerial, and a radio nearby tuned to a quiet area of the fm band, and you should get some results. One thing that I would check if I were you is the mains filter network which is inside the back behind a panel, replace the capacitors fitted across the mains with modern X rated components, or there may well be a dramatic end to the originals! Bill

22nd Jan 2014, 3:05 pm	#7
Riccampbell Tetrode Join Date: Nov 2012 Location: Huntingdon, UK. Posts: 98	Re: Cossor 1324 FM generator. Hello Bill, thanks for the reply. I haven't updated the mains filter yet but certainly will do so. I have tried allsorts whilst trying to detect an output, using my little Philips set (which I have got working) but all to no avail. I will check again for hunts capacitors and replace those I find. Cheers, Ric.

22nd Jan 2014, 6:58 pm	#8
maninashed Rest in Peace Join Date: May 2011 Location: Preston, Lancashire UK Posts: 955	Re: Cossor 1324 FM generator. Ric, if its anything like the one I have, you will need to do several things to get this to work reliably. Firstly, ensure the mains cable is fit for purpose. Check that the power supply is working properly with correct voltages at the output ie at the +ve end of C4 you should have about 180v. Unless the psu is working properly, nothing else will. You need to check all the paper capacitors in the range 1n and above. Even if they look ok, they will be leaky so its best to replace with modern components. Clean the rotary switches with Deoxit or Servisol and work them to and fro. There are a number of pre-set pots on the rear panel, these ,I have found, can suffer from 'tin whiskers' and short internally, so you may need to remove them and clean them, use servisol and a very small brush / can of air blaster. If you pm me with your email address, I have the full manual and will send it to you (if you haven't already got one). Bill

23rd Jan 2014, 6:40 pm	#9
Riccampbell Tetrode Join Date: Nov 2012 Location: Huntingdon, UK. Posts: 98	Re: Cossor 1324 FM generator. Thanks again Bill, I did replace the mains cable, I used 3 core rather than the 2 core it came with so it now has an earth connection. I have made a note of your "things to check" and will go through it as per the list. I'll let you know what happens! Thanks for the offer of the manual but I do have one. Cheers, Ric.