Pioneer SX-1050

[SeniorSteve]

I wasn't aware of the "pop crackle and silence" when it went out, but that shouldn't change anything. I looked at the power amplifier and there are 8 electrolytic capacitors, an incredible low number. Two of them in each side are paralleled so you actually could replace with 6 capacitors. Let's just see if it is in the power amplifier first. I know you don't have it at the moment so when you do get it we can start figuring out what's wrong.

Here is another way to test the receiver, but you will need another amp or receiver to do this. Pull the pre amp out to main amp in jumpers. In the pre amp out side, connect some RCA cables to another amps aux in. Now you can test the Pioneer to see if it is before the main power amp. The only caution I would have is to set the volume control on the amp you are using for the test to no more than a 10 o'clock position when first testing. This way you won't be blasted. You can test the SX 1010 to your heart's content and see if it's intermittent. Remember, this is to determine if it's in the power amplifier of the SX1010 and using an external amplifier will eliminate the internal amp.

I'll back off now.
Steve

[electra225]

Thanks, Steve. I really appreciate you sharing your considerable knowledge. Your suggestions certainly simplify the troubleshooting procedures. And it makes sense to try and split up the receiver to see if the trouble is ahead of the amplifier.

And, just for grins, I've never tested a transistor before. I have a transistor tester. What can you tell me about this procedure?

[electra225]

I dug this receiver out this afternoon. It works! It sounds pretty good, even with cheap little speakers. I have no idea why I lost the left channel. I have to assume it was a faulty connection of some kind. It pulls 53 watts on the line, per my KAW. That doesn't sound like a lot to me. I don't know what to think now. I don't have the little doodads you use for the "main in, pre out" connections, so I use short patch cords. I'm sure I didn't use the same ones as before. Maybe one of them was bad somehow? None of the controls are scratchy. The lights are out for the speaker indicators, but everything else seems to work.

[SeniorSteve]

That is very good news Greg. I'm curious if it was stored in a climate controlled setting. That does sound like a nice Pioneer unit and I hope it stays working for a long time.
Steve

[Firedome]

Sounds like well worth the trouble. One of my first SS receivers that replaced an old mono H-K tube unit was a low-ish power Pioneer SX-626 bought from Stereo Discounters in 1972, a big mail-order outfit that sold all over the US but had their warehouse near us in Baltimore. It served well and excellently for a number of years, finally replaced by a Sansui AU-717, a really nice amp. That served me for 20 years but the protection circuit acted up and it wouldn't "boot up". I took one look at the schematic and sold it to a tech who could fix it. Big Japanese SS amps are way over my head. A SX-1050 might be worth persevering with though.

[electra225]

I want to use it for my music "repurposing" project. Putting records and tape on CD. I like the SX-1050 due to it's versatile switching. I'm going to run it for a few hours more before I hook it up to the computer. I dug it out getting ready to send it to electronics recycling. I don't trust anybody around here to fix it, and I don't want to do it myself. I can't imagine it really being broke, then setting for five years or so unused fixed it.

[TC Chris]

Sounds like well worth the trouble. One of my first SS receivers that replaced an old mono H-K tube unit was a low-ish power Pioneer SX-626 bought from Stereo Discounters in 1972, a big mail-order outfit that sold all over the US but had their warehouse near us in Baltimore. It served well and excellently for a number of years, finally replaced by a Sansui AU-717, a really nice amp. That served me for 20 years but the protection circuit acted up and it wouldn't "boot up". I took one look at the schematic and sold it to a tech who could fix it. Big Japanese SS amps are way over my head. A SX-1050 might be worth persevering with though.

I've got a Sansui AU-717 on the disabled list also, suffering from the same malady. I was wondering whether (1) the protection circuit was working to protect against a real defect, like DC offset, or (2) the protection circuit was the problem. if the latter, just throwing new parts at it (like new caps) might solve the problem.

And I've go my Dad's Pioneer SX-626 waiting for work also. A handsome device..... It developed some notable audio distortion and I was suspecting caps again. And it was getting unreliable on the FM stereo switching.

Chris Campbell

[electra225]

The wife has been listening to "The Ride" this morning on the old SX-1050. Fairly drifty FM since there is no antenna. But both channels have worked fine. The speakers I'm using are like 5-watters, so we have to keep the volume low lest we smoke them. So far, so good. I have no idea why the left channel quit. I was using an RCA equalizer on it to process music. Wonder if it went wonky?

[electra225]

I brought this receiver into the house and connected it to my computer. Kind of a waste for such a big amplifier, but it has very flexible switching to go between components. It says it draws 490 watts on the nameplate. It pulls around 55 watts in operation. There are three power terminals on the rear of the cabinet so you can connect other components for power. Those are rated for a total of 300 watts, so that is part of the rating. I need to find a better pair of speakers that will give me more bass.

[electra225]

I need to discover a better way to clean the push-in controls on this receiver. Every one of them seems to give trouble at a different time. I can't seem to get them all 100% clean. Any ideas what to use and how to use it for greatest effect?

[TC Chris]

The usual answer is DeOxit. For wafer switches I have a little short-bristle artist's brush to allow applying it in small quantities in the right location. But my Denon integrated amplifier has developed wonky pushbuttons now and will need some treatment. So far I have been too lazy to unplug all the cables and extract it for attention. I just jiggle the button(s) until it's behaving itself. Aaargh!!!! My plan was to position it so the switch mechanism was vertical, assuming the device is in one of those sheet metal tunnels that most pushbutton PCB switches are, and then dribble DeOxit down from the top while working the buttons.

DeOxit's company also makes "fader lube" for potentioeters and such, but the plain ol' stuff is probably best for sliding contacts.

Chris Campbell

[electra225]

I don't have any De-Oxit. Would regular contact cleaner work?

[TC Chris]

Yeah, but DeOxit has a good reputation.

Chris Campbell

[Conelrad]

Just no WD-40, please.

[electra225]

I've decided to pull this receiver and go thru it. The switches are so dirty, I can't depend upon it. It will be down on the list considerably, but I need to take the time and do it the best I can. When it messes up, it ruins my music production and I have to start over. I put the Marantz 2245 in its place. The switching is not as versatile, but I have a little Radio Shack tape monitor box I can use that I've used before. I just need to remember how to hook everything up......

[TC Chris]

I've got one of those Radio Shack switch boxes for tape recorders (or any other sources, for that matter). They let you switch the inputs and outputs of tape decks and connect one to the other as well. Very useful when the amp has limited input choices.

Chris Campbell

[electra225]

The SX-1050 has two phono inputs, two tape inputs, an "aux" input which is still line level. So I can have three tape decks connected at once. It also has tape monitor controls and some other features I really like in my music production. The Marantz sounds almost as good, but it only has one phono input and one tape input. The Radio Shack doodad helps take up the slack.