Pioneer SX-737

[gkhashem]

I have just cleaned the unit and replaced the dial bulbs with some white LEDs. I left the meter bulbs for now since I was not in the mood to play with them but they do work as do all the other bulbs.

I dusted the unit out since it was slightly dirty now I had a question.

I looked at the boards on top. It appears the tuner board is on the right side. It is the only one with the sky blue caps. Are these the ones that are the Sanyo capacitors that will fail? No other board on top had any sky blue caps.

Is my observation correct. It looks like an untouched unit. But I am by no means an expert. So would I be correct and should I get the sky blue capacitors replaced?

Thanks for any input.

 

[Awesomeaudio]

I'm not familiar with the X3X models, but from what I have read is that you should never touch the tuner boards in any form. By re capping the tuner board it throws out the alignment and you need specialised equipment and certain knowledge to realign.
If the tuner still works ok, then leave it.

 

[gkhashem]

Thanks for the input. Yes it works fine and they look OK no bulges etc. Just wondering why the other boards I can see have no sky blue caps maybe it's been done already?

 

[Awesomeaudio]

Not sure why they used blue caps. Perhaps these were specific for the tuner board spec.
Post up some pics if you can.
It will give us something to check from.

 

[larryderouin]

This is from the Parts list that I used when I did my 737 back in 2013. Note the Caution at the top. Double check all boards on the 737. IIRC the Tone Control Board and the Phono EQ board DO contain a few sky blues. If you DO NOTHING ELSE, replace the following Transistors pre-emptively 2sc1541 (2) Main Amp Board, and 2sa725 and 2sa726 on all boards that carry them.


The tuner is included for completeness, but the caps that are LESS than 1 microfarad should be left alone as a few could disturb the tuner's adjustments. TALK to me if / before doing the tuner - there are pitfalls!! NOTE: The precaution is MarktheFixer's, NOT MINE.

4.7 25 c25 sx-737 awe-043 tuner-assy 647-UPW1H4R7MDD 4.7 50
10 16 c27 sx-737 awe-043 tuner-assy 647-UPW1H100MDD 10 50
0.47 50 c28 sx-737 awe-043 tuner-assy 647-UVZ1HR47MDD 0.47 50
1 50 c33 sx-737 awe-043 tuner-assy 647-UPW1H010MDD 1 50
0.33 10 c38 sx-737 awe-043 tuner-assy 647-UVZ1HR33MDD 0.33 50
1 10 c39 sx-737 awe-043 tuner-assy 647-UPW1H010MDD 1 50
0.47 10 c40 sx-737 awe-043 tuner-assy 647-UVZ1HR47MDD 0.47 50
0.47 50 c49 sx-737 awe-043 tuner-assy 647-UVZ1HR47MDD 0.47 50
0.47 50 c50 sx-737 awe-043 tuner-assy 647-UVZ1HR47MDD 0.47 50
4.7 25 c58 sx-737 awe-043 tuner-assy 647-UPW1H4R7MDD 4.7 50
47 6 c59 sx-737 awe-043 tuner-assy 647-UPW1H470MED 47 50
10 16 c64 sx-737 awe-043 tuner-assy 647-UPW1H100MDD 10 50
0.1 25 c66 sx-737 awe-043 tuner-assy 647-UVZ1H0R1MDD 0.1 50
220 16 c67 sx-737 awe-043 tuner-assy 647-UPW1E221MPD 220 25
100 16 c68 sx-737 awe-043 tuner-assy 647-UPW1E101MED 100 25

Check the Tuner section parts list for each cap in the above list (C39etc.) for a cssa type. Cssa are Solid Aluminum caps. These are the sky blue's that are known troublemakers. and are known as "capsistors", a term coined by Fred Longworth years ago to describe a cap that turns into a resistor. Also read the Tuning Fork Guide #2 on caps and how and why they are used in PIONEER Gear. The Tuning Fork guides are found in the STICKY THREAD TUNING FORK GUIDES. http://audiokarma.org/forums/index.php?threads/pioneer-tuning-fork-service-guide.249745/

I replaced all caps 1uf and above in my tuner and it ended up fine.
Larry

 

[gkhashem]

Larry I do not know how to fix these units. Anyone know someone up in my area that does this kind of work. I had a guy do a SA-9100 two years ago but he retired.

 

[gkhashem]

Anyone on a tech suggestion? I can travel to the Boston area too.

 

[larryderouin]

If it's running fine, and all you are worried about isthe blue sanyo's onthe tune,i'd leave it be, until you can find a trust worthy tech between u and boston.

 

[larryderouin]

To add a final note. I went back thru my 737 recently and replaced all the lytic caps on the tuner that were NOT done in 2015 with WIMA film caps (all < 1uf). No changes in SQ or response. YMMV!

 

[mel clifty]

Thanks Larry