Yes!!!!!!!
I got my newly acquired Pioneer SX-850 up and running again.

I replaced three regulator transistors in the main power supply board and a charred resistor. That was it!

The relay sound clicked in and I was hearing wonderful sounds from her!

Even though, NTE is not well regarded in these circles, I could not resist the convenience and picked up the NTE equivalents for the repair job. I certainly hope the unit will sing for many more years.

Total cost was around $7 for the parts, so I got a gorgeous working SX-850 for less than 20 bucks. Not bad!!


Regards,

crooner

Feel the transistors by finger and see how warm or hot it is after 5, 15, and 30 minutes. If too hot you may have to heat sink them. Just a suggestion for long life.

I thought about that too. But the heatsink shared by two of the newly replaced transistors is not small. My guess is that the unit was used in an enclosed area with poor ventilation.

Also, considering the unit is more than 25 years old, a failure of the original parts after many many hours of use is not a bad reliability record.

I'll keep an eye on the heat dissipation tho.

Regards,

crooner

Yes, you guys were right! this is a damn good receiver.

Doing some late night FM listening right now to check out this baby. So far so good!

FM section rivals that of my McIntosh MR67 tube tuner, which I judge extremely good, and it's my reference.

A tad noisier than the '67 in stereo, but the MPX filter works wonders here. It detracts very little from the original source, and gives a clean, smooth sound. Cleverly implemented.

I first listened to my own FM broadcasts via my flea size transmitter. Excellent portrayal of the female voice. Good bass performance but never heavy or boomy. A tad rolled off on top, which is nice. I like that sound...

Performance on regular FM stations, like the NPR outlet that I am listening to as I type this, is outstanding. The center tune meter is very accurate and the signal strength meter is a bonus compared to the SX-780 that does not have it.

The amplifier section is not overpowering, which I prefer to the blasting sound of some rival receivers. The volume control has a nice usable range.

That's one of the things I like best about vintage Pioneer receivers, they blend very well with the B&W DM110 speakers I am using.

I've listened to quite a few 70s Marantzes (including a 2240B and a 4400 quad) and the sound was always bass heavy (trying to give an impression of power, perhaps?)
even with tone controls on flat and no loudness compensation.

It has ran cool so far. I can barely feel it warm with my hand on the top grille.

Like B3Nut said, this one is a keeper.

Regards,

crooner

I think the SX-850 is in itself what vintage audio is all about. . . One of the last really good ones, enough power to drive most speakers to wickedly loud levels, real walnut veneer, big but not to big, heavy but not too heavy, a presence that commands attention and one of the more pleasant daily drivers that you can find.

Originally posted by gyusher
I think the SX-850 is in itself what vintage audio is all about. . . One of the last really good ones, enough power to drive most speakers to wickedly loud levels, real walnut veneer, big but not to big, heavy but not too heavy, a presence that commands attention and one of the more pleasant daily drivers that you can find.


Sssssshhhhhhhhhh man I just heard the price go up another $20 with all the people lurking out there sucking up all your knowledge ! Watch it man they're out there :p:

:lmao:
Army

Congrats on getting that 850 up and running! That one was the successor to my 838, another 50wpc beaut. If the tuna in that 850 is anything like my 838's, you've got an excellent one. An 850 is one of the ones I want in my stable....got an old TOTL 828 coming in a bit, bad channel but that shouldn't be hard to sort out.

Great score, and good work! Don't ever let that puppy get away from ya...

TP

Sssssshhhhhhhhhh man I just heard the price go up another $20 with all the people lurking out

In the last two years I have sold 43 SX-850s most of them mint, all near mint. . . I think the word is out. . . I averaged over 300 bucks each with a high of 650.00 plus shipping. . . That one I bought for 450.00 from Retro_stereo and I doubt that will ever happen again in my lifetime anyway. . .

Most were sold off eBay to repeat buyers or buyers that were recomended to me by other buyers. Now sorry to say they are getting just too hard to find in that condition. . .