Sansui tuner t-550sw upgradation

[Roushon]

Hi All,
I purchased this tuner Sansui t-550sw some
months back and it is working fine except the low output in
MW. FM is perfect. It is about 35 years old. So far I had
replaced the electrolytic capacitor in the main power
supply section.

I believe the low output will improve once I change all the
electrolytic caps in the tuner.

But unfortunately, there is no service manual available on
the net.

I need some help regarding the choice of caps I should
make for different sections of the tuner. Or/and if I should
make some other changes/replacments for improvement
of the sound output?

Some clean pictures are in this site.

160Ôª·Å£ºÈÕ±¾É½Ë®4²¨¶ÎÊÕÒôÍ·¡££¨´øam£¬ fmÌìÏߣ©¶àͼ_¶þÊÖÔÓ»õÆÌÂÛ̳_̫ƽÑóµçÄÔÍø²úÆ·ÂÛ̳

http://itbbs.pconline.com.cn/photo.do?tid=9170799&pid=64925104&seq=11

The piece I have, had `tracon' brand caps in PS. There are
too much dust to make any sense to take picture. Some
PCBs are vertically installed, that makes things harder.

Thanks in advance.

Roushon.

 

[DF96]

When there is a fault the best option is to find the fault, then fix it. Randomly changing components is more likely to introduce new faults.

 

[raindog]

Doing a complete re-cap is a big job but usually worth the trouble ( especially in such old equipment ) but the low MW output can be also due to misaligned RF circuits.

 

[Roushon]

Thanks DF96 and Raindog for your precautionary advices.
I plan to change the electrolytic caps, but need some
suggestions regarding it. Can I just use any good quality
general purpose capacitors of the correct values or are
there some choices to be made with respect to
brand/series for best result?

Regards
Roushon.

 

[DF96]

Any normal commercial quality caps will do. Check the voltage rating. Avoid suppliers who look too cheap, as they may stock 'Chinese copies' instead of the real thing.

Unless you are very lucky, changing caps is unlikely to fix the AM fault.

 

[Roushon]

OK, thanks!
Will post here the result after I am done with it.

Regards
Roushon.

 

[Roushon]

FM dead

Happy new year to all. It is been a very long time since I am away from the forum. Too busy on family and work. But nature tells me to come back.

The FM in the radio is dead suddenly. Any guess where should I look at. MW and SW are working perfect.

Thanks and regards
Roushon.

 

[DF96]

I would guess you need to look at the FM section. Check DC voltages. If you are lucky it will be a power supply issue. If it is an RF issue then you need to find someone who understands RF circuits.