Sony ICF-SW1 problem - UK Vintage Radio Repair and Restoration Discussion Forum

beepilot · 24th Oct 2019, 12:40 pm

I recently purchased a Sony SW1 with the usual problem i.e. motorboating indicating faulty electrolytic capacitors. The sound through headphones was absolutely fine being clear and with good volume. I therefore decided to replace all sick capacitors, using tantalum equivalent, which I have now done. It was not easy due to the small, closely packed PCB. I think that I did it reasonably well using a 25W Antex iron with a pointed tip going down to less than 1.0mm.
Now for the problem. The radio works but not very well in as much as there is reasonable volume when switched on but it quickly fades away. Also I have notced that the red tuning indicator does not always show and if it does initially this also fades away. It seems that in AM mode the volume only fades to a usable level but in FM it can fade to nothing.
I would like to think that I could fix this however I took on the cap replacement because I was able to follow a clear set of instructions. I do not have any test equipment other than a mutimeter and my radio knowledge is very limited so any help would be appreciated.

henrymarpla · 25th Oct 2019, 9:00 pm

And capacitors of DC-DC CONVERTER...?

TrevorG3VLF · 25th Oct 2019, 9:25 pm

What is a Sony SW1?
If it is a battery set, I would look at the set taking excessive current and dropping the supply voltage.
Perhaps a tantalum capacitor has been connected the wrong way round.

AC/HL · 26th Oct 2019, 2:09 pm

https://www.cryptomuseum.com/spy/sony/icfsw1/index.htm
http://www.radiomanual.info/schemi/R...F-SW1_serv.pdf

24th Oct 2019, 12:40 pm	#1
beepilot Retired Dormant Member Join Date: Oct 2019 Location: Bovingdon, Hertfordshire, UK. Posts: 1	Sony ICF-SW1 problem I recently purchased a Sony SW1 with the usual problem i.e. motorboating indicating faulty electrolytic capacitors. The sound through headphones was absolutely fine being clear and with good volume. I therefore decided to replace all sick capacitors, using tantalum equivalent, which I have now done. It was not easy due to the small, closely packed PCB. I think that I did it reasonably well using a 25W Antex iron with a pointed tip going down to less than 1.0mm. Now for the problem. The radio works but not very well in as much as there is reasonable volume when switched on but it quickly fades away. Also I have notced that the red tuning indicator does not always show and if it does initially this also fades away. It seems that in AM mode the volume only fades to a usable level but in FM it can fade to nothing. I would like to think that I could fix this however I took on the cap replacement because I was able to follow a clear set of instructions. I do not have any test equipment other than a mutimeter and my radio knowledge is very limited so any help would be appreciated.

25th Oct 2019, 9:00 pm	#2
henrymarpla Triode Join Date: Jan 2013 Location: Mar del Plata, Argentina Posts: 47	Re: Sony ICF-SW1 problem And capacitors of DC-DC CONVERTER...? Last edited by henrymarpla; 25th Oct 2019 at 9:06 pm.

25th Oct 2019, 9:25 pm	#3
TrevorG3VLF Rest in Peace Join Date: Apr 2011 Location: Matlock, Derbyshire, UK. Posts: 1,378	Re: Sony ICF-SW1 problem What is a Sony SW1? If it is a battery set, I would look at the set taking excessive current and dropping the supply voltage. Perhaps a tantalum capacitor has been connected the wrong way round.

26th Oct 2019, 2:09 pm	#4
AC/HL Dekatron Join Date: Nov 2003 Location: Heckmondwike, West Yorkshire, UK. Posts: 9,642	Re: Sony ICF-SW1 problem https://www.cryptomuseum.com/spy/sony/icfsw1/index.htm http://www.radiomanual.info/schemi/R...F-SW1_serv.pdf