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Pioneer sx 939 sound disappointing

Again, this is a sx-1010 control board but will give you an idea of what to look for. The four tantalum's are light blue tear drop looking things, two on each side of the center line of the board. They are labeled 2.2 35v, replaced with 2.2uf 50v electrolytics observing the silk screen polarity marked on the board as seen in the second picture.

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Thank you, your replies have been a great source of information for me, l will keep an eye out for these tantalums just in case when l get to recapping her. I have ordered capacitors and transistors but will take couple of weeks to arrive, as am in Australia.
 
Hi guys, just to update l finished recapping the Pioneer (control amp, main amp, mute and tuner) have not done equalizer yet. I also replaced suspect transistors as described by you all, the main amp actually contained two 2sa809's but l sourced some local replacements. The control amp DID have those four tantalums as pointed out also.
The sound improvement is unexpectedly VERY noticable, the bass is so much more controlled and the mids are back, it also has none of the flatness or "laziness" it had before, it has COMPLETELY transformed the sound and l am not imagining this as l used my other receiver as a before and after reference, they are now very closely matched which is strange as they couldn't be more different in every other way. Thank you to ALL of you for your help, much appreciated. I now know which side of the fence l will be on when it comes to the original vs recapping debate from now on. Now l just have to figure out why the fm tuner lacks sensitivity, works well with a good indoor powered antenna though, the fm didn't work when l bought it so l recapped the board, replaced HA1137 and spent hours re-aligning just using the signal meter, far from ideal l know but l got it all aligned on dial and picking up stations but like l say has to have a good antenna.
 
Yes, it sounds like the tuner needs an alignment, esp if you were adj the disc coil slugs. You should be able to zero the discriminator for the ~7.5V bias per the sm. the thd adjustment, you really need a RF SG and a thd meter to do that properly.
 
Thank you for your reply, at what point do l measure the 7.5vac bias, l can't find a reference to this in the SM? Yes l thought that might be the case, l will prob take it in to local repairer for alignment soon.
 
correction, 5.6VDC step 4,5 tuning meter center, in the sm, the best is to measure/adj for 0 dcv or lowest you can get, across the tuning meter pins 6/8 on awe-041
 
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