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Looking for help with SX-1250 repair!

M

MJLamp

New Member
Reaching out as I'm wondering if you could help me or refer me to someone. My Pioneer SX-1250 is having some major problems. I have a local guy here in Charleston, SC who works on vintage receivers and did some recapping and soldering for me a few months ago. Since the last repairs, my receiver is no longer putting out sound. He thinks it's one of the very large capacitors but not sure if he can fix it and/or source replacement parts. I'm losing confidence in him unfortunately and since I'm very fond of my receiver, I'm looking for someone who is highly qualified to look at it and repair it.

Does anyone have any suggestions?
 
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I think we need some more detail. Did the receiver work for a while after the aforementioned repair? Have you seen smoke? Do you here the speaker relays kick in? Do all the front panel lights all work?
 
So he replaced a couple caps but now I'm still having a persistent issue where the right speaker is barely putting out any sound and it sounds terrible. I've switched speakers, cables etc. and it's definitely the receiver. All of the lights work, I hear relays click in after turning it on, I've never seen smoke. The problem seems to be more of a progressive issue. Everything was working great for a while, then started glitching out here and there. Then started glitching more consistently. Now the right speaker is just not working.

Channel A - Does not work at all
Channel B - Left speaker works, Right is very low volume and grainy and sounds staticy
Channel C - Does not work at all

The tech who worked on it the past couple times is thinking that the problem might be with the larger capacitors. I believe he's referring to the 4 capacitors that are about the size of a soda can.

Would love any help on figuring out what the issue really is here. The tech is getting a bit frustrated as well and doesn't particularly enjoy working on this receiver cause of its size, weight and difficulty in accessing internal components. I'd also be grateful for any recommendations on technicians in the Charleston SC area or central East coast who are particularly knowledgeable on vintage Pioneer receivers.
 
MJLamp said:
So he replaced a couple caps but now I'm still having a persistent issue where the right speaker is barely putting out any sound and it sounds terrible. I've switched speakers, cables etc. and it's definitely the receiver. All of the lights work, I hear relays click in after turning it on, I've never seen smoke. The problem seems to be more of a progressive issue. Everything was working great for a while, then started glitching out here and there. Then started glitching more consistently. Now the right speaker is just not working.

Channel A - Does not work at all
Channel B - Left speaker works, Right is very low volume and grainy and sounds staticy
Channel C - Does not work at all

The tech who worked on it the past couple times is thinking that the problem might be with the larger capacitors. I believe he's referring to the 4 capacitors that are about the size of a soda can.

Would love any help on figuring out what the issue really is here. The tech is getting a bit frustrated as well and doesn't particularly enjoy working on this receiver cause of its size, weight and difficulty in accessing internal components. I'd also be grateful for any recommendations on technicians in the Charleston SC area or central East coast who are particularly knowledgeable on vintage Pioneer receivers.
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Definitely don't send it back to him.
 
I'll say he's a nice guy, I think this just might be a little outside of his expertise. I think that is more the source of his frustration. It is ~50 years old with a ton of components. I moved from San Francisco early 2020 and had a local guy there attempt to fix this same issue. He wasn't able to fully fix it either but it wasn't as much of a problem then so I just sucked it up and stuck it out. Now it's progressed to a point where my receiver is almost unusable.

I'm seeing two paths forward here as there is no way I'm giving up on this receiver.

1st. Lean on the help of the AudioKarma community, narrow down the potential issues, cross reference those with the local tech, confirm his ability to execute the repair and move forward with that.

2nd. Lean on the help of the AudioKarma community and find a true expert who I'm confident can diagnose and execute on a prognosis, who won't work me over like a Jiffy Lube.
 
MJLamp said:
So he replaced a couple caps but now I'm still having a persistent issue where the right speaker is barely putting out any sound and it sounds terrible. I've switched speakers, cables etc. and it's definitely the receiver. All of the lights work, I hear relays click in after turning it on, I've never seen smoke. The problem seems to be more of a progressive issue. Everything was working great for a while, then started glitching out here and there. Then started glitching more consistently. Now the right speaker is just not working.

Channel A - Does not work at all
Channel B - Left speaker works, Right is very low volume and grainy and sounds staticy
Channel C - Does not work at all

The tech who worked on it the past couple times is thinking that the problem might be with the larger capacitors. I believe he's referring to the 4 capacitors that are about the size of a soda can.

Would love any help on figuring out what the issue really is here. The tech is getting a bit frustrated as well and doesn't particularly enjoy working on this receiver cause of its size, weight and difficulty in accessing internal components. I'd also be grateful for any recommendations on technicians in the Charleston SC area or central East coast who are particularly knowledgeable on vintage Pioneer receivers.
Click to expand...
It's a two channel receiver. A, B, and C go to the exact same place...
 
You sure it is not the volume control needing a cleaning? I had one that I eventually sold with one channel being noisy, but it was volume control that needed a cleaning. It is a big job to get to it to clean it. Right channel would cut out or become scratchy.
 
ivandezande said:
It's a two channel receiver. A, B, and C go to the exact same place...
Click to expand...

Ya, I'm aware. Not sure how to refer to speakers A, B and C. Also, the fact C works but the others don't is something the tech called out. I assume he was implying that if one works, they all should work? Either way, it's not the case here.
 
simplynuts said:
You sure it is not the volume control needing a cleaning? I had one that I eventually sold with one channel being noisy, but it was volume control that needed a cleaning. It is a big job to get to it to clean it. Right channel would cut out or become scratchy.
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Thanks for the suggestion. I'll have to look into how to diagnose that. The symptoms are certainly similar. Wonder if the other channels (A & C) would be affected from that as well. Any direction or suggestions would be welcome. Otherwise, it's on the list of possibilities pending further thoughts and feedback. Thanks again!
 
As @ivandezande mentioned, there are only two amplifiers, one for each channel, and one pair of protection relay contacts for each channel. If any of them work, all of them should work separately. All the speaker terminations are simply selected by the pushbutton switches for any two of the three speaker outputs to be active at one time. If all three switches are selected, none of the speaker outputs will get output power. The NC contacts of each of the A/B/C switches are interlocked with the opposing switches. Study the schematic for clarification, but if some of the NC contacts are failing or dirty, that could create the symptom you describe.

If there are doubts, it can always be tested with headphones.

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Watthour said:
As @ivandezande mentioned, there are only two amplifiers, one for each channel, and one pair of protection relay contacts for each channel. If any of them work, all of them should work separately. All the speaker terminations are simply selected by the pushbutton switches for any two of the three speaker outputs to be active at one time. If all three switches are selected, none of the speaker outputs will get output power. The NC contacts of each of the A/B/C switches are interlocked with the opposing switches. Study the schematic for clarification, but if some of the NC contacts are failing or dirty, that could create the symptom you describe.

If there are doubts, it can always be tested with headphones.
Click to expand...

Thank you Watthour, great suggestion and will add it to the lists of possible issues. Is this something I could easily address myself?
 
A very common issue with the 1250 is in the filter switches. With the unit off, cycle the two filter switches 50 or a hundred times. Turn on the receiver and see if the exercise helped your issue. Mine still does this even after my unit was rehabbed by one of the AK gurus. Give it a try.
 
merlynski said:
Welcome to Audiokarma, you are in the right place! Are you interested in fixing it yourself?
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Thanks Merlyn. Probably not. I already have a ton of hobbies and not sure if I have the mental bandwidth or time to get in to the nitty gritty of the technical aspects of it all. I'd have a lot to learn and cringe at the thought of breaking something out of inexperience.
 
MJLamp said:
Channel A - Does not work at all
Channel B - Left speaker works, Right is very low volume and grainy and sounds staticy
Channel C - Does not work at all
Click to expand...
How do the headphones sound ? Your speaker select switches probably need disassembly and cleaning.
 
@MJLamp

"Channel A - Does not work at all
Channel B - Left speaker works, Right is very low volume and grainy and sounds staticy
Channel C - Does not work at all"

You might already know but just making sure; when you are cycling/pressing to these channels A,B, and C, are you also moving the speaker wires or it just remains in speaker B terminals?
 
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