Pionner SX-1010 Trips Relay Once After Sitting for 2 Days.

Ben Rothman

Ben Rothman

Active Member
Hi everyone, I have a mostly restored pioneer SX-1010. All the caps have been replaced and about 80% of the transistors have been replaced. My guess is that my issue stems from an old transistor. When I use my pioneer consistently it is completely fine and sounds fantastic. If I let the unit sit for about two days or so, and I decide to use it, about 10 minutes into playing something (this issue occurs on all inputs) the protection relay will trip quickly. After that the unit works perfectly. I can play for hours on end with zero issue. Makes me think that maybe it's a cold solder joint? I cannot get it to repeat this issue unless I let it sit for 2 days. I know the output transistors our original, and a couple others on the amp boards.
 
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The SX-1010 uses the typical Pioneer protection circuit. C1/2 and Q1/2 on the protection board are the usual culprits, those have been replaced? The easiest way to troubleshoot it would be to check the voltages on the cathodes of D5/6/7, the odd one out will the one that put in protection. You'll have to check these while it is protect mode. If D5 you have an over current detection, D6 or D7 will be DC on the output. Also make sure the voltages on Pins 10/11 and 12 are OK while it is in protect mode. Pins 10/11 should be +35 which is a regulated voltage and given the fact that regulator board runs on the hot side in these receivers it could be power supply problem also.

Craig
 
llwhtt said:
The SX-1010 uses the typical Pioneer protection circuit. C1/2 and Q1/2 on the protection board are the usual culprits, those have been replaced? The easiest way to troubleshoot it would be to check the voltages on the cathodes of D5/6/7, the odd one out will the one that put in protection. You'll have to check these while it is protect mode. If D5 you have an over current detection, D6 or D7 will be DC on the output. Also make sure the voltages on Pins 10/11 and 12 are OK while it is in protect mode. Pins 10/11 should be +35 which is a regulated voltage and given the fact that regulator board runs on the hot side in these receivers it could be power supply problem also.

Craig
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Hi Craig, happy new year! I’m not able to check any voltages while the unit is in protection mode. The unit quickly goes into protection mode and then comes out. What I don’t understand, is the circumstances that cause the unit to go into protect mode. If I don’t use it for about 2 days and then use it, after about 10 minutes it will quickly go in and out of protection. After that the unit is completely fine and I can play it for hours if not days without a single issue. The problem only occurs when I haven’t been using the unit for 2 days.
 
Sounds like a cold Solder joint in the Protection board. Check and or reflow every joint you worked. Also did you put in a 1n4007 between pins 9 &10 (Cathode to 10). Helps keep Relay field collapse at shutoff from affecting Q7. It was incorporated by pioneer in later series.
 
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larryderouin said:
Sounds like a cold Solder joint in the Protection board. Check and or reflow every joint you worked. Also did you put in a 1n4007 between pins 9 &10 (Cathode to 10). Helps keep Relay field collapse at shutoff from affecting Q7. It was incorporated by pioneer in later series.
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That definitely sounds like it could be the issue. I just reflowed all the solder joints on the entire protection board. I booted up the unit to make sure it was still operational, and everything seems good. I’m going to let the unit sit for 2-3 days before I turn it on and use it again. Hopefully this solves my problem.
 
larryderouin said:
Sounds like a cold Solder joint in the Protection board. Check and or reflow every joint you worked. Also did you put in a 1n4007 between pins 9 &10 (Cathode to 10). Helps keep Relay field collapse at shutoff from affecting Q7. It was incorporated by pioneer in later series.
Click to expand...
Sorry I forgot to reply to this part! Yes, I did add a fly back diode.
 
larryderouin said:
Sounds like a cold Solder joint in the Protection board. Check and or reflow every joint you worked. Also did you put in a 1n4007 between pins 9 &10 (Cathode to 10). Helps keep Relay field collapse at shutoff from affecting Q7. It was incorporated by pioneer in later series.
Click to expand...
I reflowed all of the solder on the protection board and the issue still persists. Upon further inspection, I noticed that all of the transistors on the protection board are original. Do you think any of those could be my culprit?
 
Ben Rothman said:
I reflowed all of the solder on the protection board and the issue still persists. Upon further inspection, I noticed that all of the transistors on the protection board are original. Do you think any of those could be my culprit?
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about 80% of the transistors have been replaced.
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yes.....
 
markthefixer said:
yes.....
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Hi Mark, happy new year! I plan to replace all of the transistors on the protection board. I do have a quick question, why do you think the 1010 only goes into protection after 10 minutes of playing, after the unit has not been used for two days. After it goes in and out of protection that one time, it plays perfectly for hours and hours.
 
False triggers are a leakage phenomenon, and as the old transistors age, who knows exactly what chemical processes are crawling along due to residuals of processing reactions, incomplete passivation and a host of other things learned over the years. Throw in temperature variations, and you've got a mind twisting -who dunnit- as to the EXACT cause.

These are PROBABLY the longest serving transistors from their manufacturing batches.

Sometimes we get to see it sooner, like with the 2sc1451transistor, or the old Sanyo solid aluminum caps (think tantalum cap type, but using aluminum) that get so leaky they turn into short circuits.
 
markthefixer said:
False triggers are a leakage phenomenon, and as the old transistors age, who knows exactly what chemical processes are crawling along due to residuals of processing reactions, incomplete passivation and a host of other things learned over the years. Throw in temperature variations, and you've got a mind twisting -who dunnit- as to the EXACT cause.

These are PROBABLY the longest serving transistors from their manufacturing batches.

Sometimes we get to see it sooner, like with the 2sc1451transistor, or the old Sanyo solid aluminum caps (think tantalum cap type, but using aluminum) that get so leaky they turn into short circuits.
Click to expand...
Hi Mark, I think that settles it. I’m gonna replace all of the transistors on the protection board, as well as the remaining transistors on the amp board. I have one more question for you, do you think it’s the transistors on the protection board? Or elsewhere? The issue I’m having happens no matter what input I’m on and or what volume level. It only happens if the 1010 has been sitting for a day or two. Then on the first use after about 10 minutes It will very quickly go into protection then out of protection. After that one time, the 1010 plays perfectly for hours and hours.
 
it goes into protection and waits a turn-on timeout interval before clicking back in? That's a false trigger.
If it's shorter (or longer - heat related) it could be the relay driver.

it could be a dc spike from an amp, when the protect is reliable we'll know.

it could be a tired relay driver transistor -that's covered in the list (c2690), a worn out discharge transistor (c2383) or noisy overcurrent sense transistor or dc sense transistor.

this could go on and on with pages and pages of typing.

do the full protect retransistor - it doesn't alter the sound coming out... , THEN we'll see if the amp has a quirk...
 
markthefixer said:
it goes into protection and waits a turn-on timeout interval before clicking back in? That's a false trigger.
If it's shorter (or longer - heat related) it could be the relay driver.

it could be a dc spike from an amp, when the protect is reliable we'll know.

it could be a tired relay driver transistor -that's covered in the list (c2690), a worn out discharge transistor (c2383) or noisy overcurrent sense transistor or dc sense transistor.

this could go on and on with pages and pages of typing.

do the full protect retransistor - it doesn't alter the sound coming out... , THEN we'll see if the amp has a quirk...
Click to expand...
Hi Mark, I believe when the unit goes in and out of protect it’s about the same amount of time it takes the unit to come out of protection when first started. I plan on finishing up the rebuild by replacing all the transistors on the protection circuit as well as the two amplifier boards. Besides that everything else has been been rebuilt and is working great.
 
markthefixer said:
:thumbsup::lurk:
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Hey Mark, I have couple of questions regarding my 1010. Two of the big components I never replaced are the two filter caps, as well as the output transistors. Do you think it’s work it for me to replace these parts? They both work. I was thinking if I don’t replace the outputs that its still a good idea to remove them and apply new thermal compound?
 
Replace the big caps, redo the thermal compound on the outputs, but you should be fine with the original outputs.
 
They're almost fifty years old at this point. Sure, you can run a car on 50-year-old tires, but should you? No. They will *work*, but will not perform as well as new caps. You can still buy replacements that are the proper size, but in ten or twenty years that may not be the case.
 
EastPoint said:
They're almost fifty years old at this point. Sure, you can run a car on 50-year-old tires, but should you? No. They will *work*, but will not perform as well as new caps. You can still buy replacements that are the proper size, but in ten or twenty years that may not be the case.
Click to expand...
You make a good point. Do you happen to have the link to where I can buy the main filter caps?
 
markthefixer said:
it goes into protection and waits a turn-on timeout interval before clicking back in? That's a false trigger.
If it's shorter (or longer - heat related) it could be the relay driver.

it could be a dc spike from an amp, when the protect is reliable we'll know.

it could be a tired relay driver transistor -that's covered in the list (c2690), a worn out discharge transistor (c2383) or noisy overcurrent sense transistor or dc sense transistor.

this could go on and on with pages and pages of typing.

do the full protect retransistor - it doesn't alter the sound coming out... , THEN we'll see if the amp has a quirk...
Click to expand...
Mark, I have some interesting news to share. So my entire system is the SX1010, a Dual 1229Q, and a pair of original altec Lansing 508 (4ohm) tower speakers. From what I've read the 1010 can handle a 4ohm load. just to make sure nothing else in my system was causing the issue, I removed my 1010 and in its place put my unrestored 1250. It's fully original and has never been touched. So far I've been listening to the 1250 on my main system for about 4 hours without issue. I then plugged my 1010 into a pair of 8ohm Klipsch bookshelf speakers. I have not gotten the 1010 to go into protection while being hooked up to the Klipsch. Could this be because the 1010 is not being pushed as hard? I still plan on finishing off the restoration of the 1010 like we discussed. I am just curious what your thoughts on why the 1010 only acts up a bit with 4ohm speakers.
 
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