Stella ST239U - UK Vintage Radio Repair and Restoration Discussion Forum

Manx Nick · 31st Oct 2016, 2:49 pm

Hi I have a Stella ST239U in good aesthetic condition however the FM signal is not receiving anything - no sounds at all.

MW/AM is really good and loud.

I have "jerry rigged" the tuner cord so that it works but other than poking around inside a potentially live set again I am not sure.

Any ideas?

Nick

Station X · 31st Oct 2016, 2:55 pm

Based on personal experience, the first thing to do is to replace the UCC85 valve. On AM it's deprived of HT voltage which leads to cathode poisoning.

Before replacing the UCC85 check that, when switched to FM, there is voltage on both its anodes, if there isn't it would point to a problem with the wave change switch.

Manx Nick · 31st Oct 2016, 4:42 pm

Thanks will check that

Manx Nick · 31st Oct 2016, 11:41 pm

Well tonight I looked again at the FM issue and managed to produce wisps of smoke and a slight burning smell. Looking at the chassis underneath, there are a few wires coming from the AC in that look a bit burnt. I won't turn on the FM again until I know what to do. If you leave it on medium wave the set can be left on for at least a half hour before it even gets warm. So there is a short somewhere I think. Who can you recommend to fix this radio so it won't kill me? ��

Station X · 1st Nov 2016, 1:15 am

Sorry, but I've managed to confuse things here. The ST239U has a UF80, not a UCC85.

If the smoke only appears on FM the fault is likely to be around the UF80. Can you see where it's coming from?

You could try posting in the Repair and Restoration Services Wanted section to see if there's a repairer close to you.

31st Oct 2016, 2:49 pm	#1
Manx Nick Pentode Join Date: Jul 2014 Location: Isle of Man, UK. Posts: 102	Stella ST239U Hi I have a Stella ST239U in good aesthetic condition however the FM signal is not receiving anything - no sounds at all. MW/AM is really good and loud. I have "jerry rigged" the tuner cord so that it works but other than poking around inside a potentially live set again I am not sure. Any ideas? Nick

31st Oct 2016, 2:55 pm	#2
Station X Moderator Join Date: Jan 2003 Location: Ipswich, Suffolk, IP4, UK. Posts: 21,289	Re: Stella ST239U Based on personal experience, the first thing to do is to replace the UCC85 valve. On AM it's deprived of HT voltage which leads to cathode poisoning. Before replacing the UCC85 check that, when switched to FM, there is voltage on both its anodes, if there isn't it would point to a problem with the wave change switch. __________________ Graham. Forum Moderator Reach for your meter before you reach for your soldering iron.

31st Oct 2016, 4:42 pm	#3
Manx Nick Pentode Join Date: Jul 2014 Location: Isle of Man, UK. Posts: 102	Re: Stella ST239U Thanks will check that

31st Oct 2016, 11:41 pm	#4
Manx Nick Pentode Join Date: Jul 2014 Location: Isle of Man, UK. Posts: 102	Re: Stella ST239U Well tonight I looked again at the FM issue and managed to produce wisps of smoke and a slight burning smell. Looking at the chassis underneath, there are a few wires coming from the AC in that look a bit burnt. I won't turn on the FM again until I know what to do. If you leave it on medium wave the set can be left on for at least a half hour before it even gets warm. So there is a short somewhere I think. Who can you recommend to fix this radio so it won't kill me? ��

1st Nov 2016, 1:15 am	#5
Station X Moderator Join Date: Jan 2003 Location: Ipswich, Suffolk, IP4, UK. Posts: 21,289	Re: Stella ST239U Sorry, but I've managed to confuse things here. The ST239U has a UF80, not a UCC85. If the smoke only appears on FM the fault is likely to be around the UF80. Can you see where it's coming from? You could try posting in the Repair and Restoration Services Wanted section to see if there's a repairer close to you. __________________ Graham. Forum Moderator Reach for your meter before you reach for your soldering iron.