Sony ICF-SW7600 FM problem - UK Vintage Radio Repair and Restoration Discussion Forum

msf1344 · 22nd Feb 2020, 12:22 pm

Hi folks
I have one of this Sony radio which is not good on FM band. When i search for any station its just skip. But it is perfect on AM. Anyone had similar problem. Thanks

orbanp1 · 22nd Feb 2020, 1:33 pm

The 7600 has several generations/versions.
Which one is your radio?
Best to post a picture!

Regards, Peter

msf1344 · 22nd Feb 2020, 5:36 pm

Hi. Its just a ICF-SW7600 which is the first product back to 80s. I will upload some pictures and also I took it apart and there is one picture of the main board.

orbanp1 · 23rd Feb 2020, 2:13 pm

It looks like the 7600G, at least the "matching" service manual has that title.
(Mine is called a 7600D, it is earlier than yours, and it looks like the ICF-2002.)

Here is the service manual for the 7600G:
https://www.manualslib.com/manual/59...f-Sw7600g.html

Based on the schematics, pg. 13 in the manual, you need to follow the FM signal path and see where does the signal "disappear".

Regards, Peter

Goldieoldie · 24th Feb 2020, 1:31 pm

Hi
Along with other Sony radios of this era they suffer from failure of the Ali can capacitors .
They leak their electrolyte which as well as affecting their capacitance etc can spread onto the PC tracks causing corrosion and electrical leakage where it's not wanted !
It can also get into coils causing them to go o/c .
If you look carefully at the bases of the caps your might see some leakage or corrosion of the solder lugs on the caps.
Also there might be a smell ,all tale tale signs of cap failure .
Check under the buttons on the PC for signs of leakage or liquid spill
Can be cleaned off with IPA
Cheers
Pete

msf1344 · 28th Feb 2020, 2:17 pm

Hi, please look at the attached photo. What is that yellow stuff around the transistor? Is it factory default?

Ken Taylor · 29th Feb 2020, 6:14 pm

I had a problem with FM on my 7600D, turned out the wire to the telescopic aerial had come off.

Ken

Goldieoldie · 29th Feb 2020, 9:42 pm

That gunk is a glue that Sony used. It can cause problems in some circuits as it sometimes becomes conductive with age!

msf1344 · 5th Mar 2020, 10:57 am

How to remove it and is it safe to clean it ?

Goldieoldie · 5th Mar 2020, 10:48 pm

Use a wooden toothpick and some IPA
Be careful around coils and transformers as it's easy to damage the very thin coils
I don't think this is your problem though, far more likely the caps need changing.

22nd Feb 2020, 12:22 pm	#1
msf1344 Diode Join Date: Feb 2020 Location: London, UK. Posts: 8	Sony ICF-SW7600 FM problem Hi folks I have one of this Sony radio which is not good on FM band. When i search for any station its just skip. But it is perfect on AM. Anyone had similar problem. Thanks

22nd Feb 2020, 1:33 pm	#2
orbanp1 Heptode Join Date: Nov 2009 Location: London, Ontario, Canada Posts: 675	Re: Sony icf-sw7600 fm problem The 7600 has several generations/versions. Which one is your radio? Best to post a picture! Regards, Peter

22nd Feb 2020, 5:36 pm	#3
msf1344 Diode Join Date: Feb 2020 Location: London, UK. Posts: 8	Re: Sony ICF-SW7600 FM problem Hi. Its just a ICF-SW7600 which is the first product back to 80s. I will upload some pictures and also I took it apart and there is one picture of the main board. Attached Thumbnails

23rd Feb 2020, 2:13 pm	#4
orbanp1 Heptode Join Date: Nov 2009 Location: London, Ontario, Canada Posts: 675	Re: Sony ICF-SW7600 FM problem It looks like the 7600G, at least the "matching" service manual has that title. (Mine is called a 7600D, it is earlier than yours, and it looks like the ICF-2002.) Here is the service manual for the 7600G: https://www.manualslib.com/manual/59...f-Sw7600g.html Based on the schematics, pg. 13 in the manual, you need to follow the FM signal path and see where does the signal "disappear". Regards, Peter

24th Feb 2020, 1:31 pm	#5
Goldieoldie Octode Join Date: Jul 2014 Location: Petersfield, Hampshire, UK. Posts: 1,043	Re: Sony ICF-SW7600 FM problem Hi Along with other Sony radios of this era they suffer from failure of the Ali can capacitors . They leak their electrolyte which as well as affecting their capacitance etc can spread onto the PC tracks causing corrosion and electrical leakage where it's not wanted ! It can also get into coils causing them to go o/c . If you look carefully at the bases of the caps your might see some leakage or corrosion of the solder lugs on the caps. Also there might be a smell ,all tale tale signs of cap failure . Check under the buttons on the PC for signs of leakage or liquid spill Can be cleaned off with IPA Cheers Pete

28th Feb 2020, 2:17 pm	#6
msf1344 Diode Join Date: Feb 2020 Location: London, UK. Posts: 8	Re: Sony ICF-SW7600 FM problem Hi, please look at the attached photo. What is that yellow stuff around the transistor? Is it factory default? Attached Thumbnails

29th Feb 2020, 6:14 pm	#7
Ken Taylor Pentode Join Date: Dec 2015 Location: Abingdon on Thames, Oxon, UK. Posts: 116	Re: Sony ICF-SW7600 FM problem I had a problem with FM on my 7600D, turned out the wire to the telescopic aerial had come off. Ken

29th Feb 2020, 9:42 pm	#8
Goldieoldie Octode Join Date: Jul 2014 Location: Petersfield, Hampshire, UK. Posts: 1,043	Re: Sony ICF-SW7600 FM problem That gunk is a glue that Sony used. It can cause problems in some circuits as it sometimes becomes conductive with age!

5th Mar 2020, 10:57 am	#9
msf1344 Diode Join Date: Feb 2020 Location: London, UK. Posts: 8	Re: Sony ICF-SW7600 FM problem How to remove it and is it safe to clean it ?

5th Mar 2020, 10:48 pm	#10
Goldieoldie Octode Join Date: Jul 2014 Location: Petersfield, Hampshire, UK. Posts: 1,043	Re: Sony ICF-SW7600 FM problem Use a wooden toothpick and some IPA Be careful around coils and transformers as it's easy to damage the very thin coils I don't think this is your problem though, far more likely the caps need changing.