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pioneer sx-737

68.55.12.145
Posted on October 25, 2009 at 07:37:39
dhebden80
Audiophile

Posts: 4
Location: Northeast
Joined: October 25, 2009
 Hi. I'm new to the site and I really hate to start off with a question but here it goes. I have an sx-737 pioneer receiver which I bought for $5 about 5 years ago. Recently the right channel became weak. At low volume it seems clear but lacking the power that the other channel has. When I turn the volume up it starts to fade out and then clicks off at high volume. (High volume setting that is, it never gets audibly loud)It almost sounds like when you would switch a receiver off while it's still playing music and you hear that sort of fade out. I went in and switched what I think are transistors(they mount to the heatsink, are round, and there are four of them, two different values per channel). I don't think it's a pot problem because there isn't any static when adjusting balance or volume. I've done some research and a lot of people talk about replacing the "caps" I'm guessing they mean capacitors. What caps are they talking about? The small capacitors on the boards or the two big capacitors that stand alone. Anyway thanks for sticking with me, any info on this type of problem is greatly appreciated. Thanks, Dave

RE: pioneer sx-737, posted on October 26, 2009 at 10:43:32
satellite65
Audiophile

Posts: 308
Location: Illinois, NE
Joined: December 13, 2004
 Other than a DMM, the next most valuable tool for troubleshooting early SS equipment is an ESR meter. Electrolytic cap's dry out with age. Whenever I work on old SS equipment, I run thru it with the ESR meter and check every 'lytic that is reasonable to access. I usually find at least one or two with high ESR, sometimes several.

If you switched the output transistors around, you will need to adjust the bias and offset on both channels.

Paul

RE: pioneer sx-737, posted on October 26, 2009 at 12:36:48
dhebden80
Audiophile

Posts: 4
Location: Northeast
Joined: October 25, 2009
 Are the capacitors the small ones on the amp board or the two big ones that are off to the side or should I just check them all? How would I check that with a DMM? Thanks.

RE: pioneer sx-737, posted on October 27, 2009 at 11:00:38
satellite65
Audiophile

Posts: 308
Location: Illinois, NE
Joined: December 13, 2004
 I would check them all, but you really can't do it without an ESR meter.

RE: pioneer sx-737, posted on October 25, 2009 at 14:25:53
Uncle Mike
Audiophile

Posts: 1308
Location: Eastern Pa.
Joined: June 20, 2003
 Take a look at the link below. Sounds like you know a bit and this may get you in the right direction. A few bucks and a few hours may be all you need.
Get a service manual, post over there with questions you have, they are real geeks when it comes to these 80's receivers.
I have an SX838 that took all of 30 minutes, after reading ECHOWARS sticky, to get back into fighting trim!

RE: pioneer sx-737, posted on October 25, 2009 at 13:36:11
mpw
Audiophile

Posts: 39
Joined: November 30, 2000
 i have the 737 as well. it is a great receiver. sounds good and
all functions work well. i also use with a high-end audio card and
AR-4xa speakers. it is worth fixing. it is just luck to find a nice
full functioning piece that needs no work. i paid 30 dollars for mine at
a thrift store about 5 years ago. i have the sx-636 (tuner dial completely dimmed out), sx-990 which has separate amp and pre-amp connections. i am
using at as an amp (FM not functioning) with a PAS-3x tube pre-amp,
rogers ls/2 speakers and rotel turner.

michael
RE: pioneer sx-737, posted on October 25, 2009 at 09:46:09
dhebden80
Audiophile

Posts: 4
Location: Northeast
Joined: October 25, 2009
 You're probably right about not getting too bent out of shape about it. I do plan on upgrading eventually. It's a really sweet sounding unit and as I have it set right now ,A+B on the left channel in mono, it will still crank. I would like to find my next receiver as a diamond in the rough for another couple bucks at a yard sale or something. Or if too much time passes I may just buy one. Thanks for the suggestions.

RE: pioneer sx-737, posted on October 25, 2009 at 10:38:54
Neff
 Some prefer the hobby of paying next to nothing for a good sounding receiver. Kind of like seeking different women before marriage. Have fun hunting.

RE: pioneer sx-737, posted on October 25, 2009 at 08:13:15
Neff
 Mabby I am dollar foolish, but if in your situation & being that the Pioneer is not highly collectable or rare, I would toss it. Your out $5 vs experimenting with say $20 of capacitors that may not fix your Pioneer. After some archive searching myself lately for better sounding vintage SS, I find the following recommended a lot in the same power range as the SX-737.

I would consider Marantz 2230 (not 2230B that has less tube warmth sonics, but good never the less). These 2230's go for $100 less a lot on eBay. If I read the AA archives correctly, the power supply capacitirs should be upgraded to 50 VDC specs. About $10-15 for capacitors.

Some here consider the Onkyo TX-4000 or TX-5000 a bargain for $50-$80.

Others like the Harman Kardon HK 430 and state it is a sweet receiver. About $50-$75. The higher power HK 630 is likely sells for $100-130.

Another worthy of consideration is is the Yamaha Natural Sound C-1020. Perhaps $120 or so.

Finally, Luxman R-1040. Sells around $150. These are high quality receivers.
RE: pioneer sx-737, posted on November 1, 2009 at 05:25:20
EchoWars
Audiophile

Posts: 305
Location: Left of the Dial
Joined: December 2, 2002
 Hate to see it get tossed...even if not worth fixing, there's a ton of parts that other models used that would be great for guys like me to have to bring other units back to life.

RE: pioneer sx-737, posted on October 25, 2009 at 13:02:46
dhebden80
Audiophile

Posts: 4
Location: Northeast
Joined: October 25, 2009
 Kinda goes along with "if too much time passes i'll buy one" HA!

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