My First/Last SX-1010

craxx6969

Well-Known Member
FYI,

I am glad everyone on the forum helped me out on the prior 1010 rebuild. That I am truly grateful for that help.

This 1010 was my FIRST pioneer purchase about 2 years ago from a fellow just 45 minutes south of me. It ran great but the stereo FM went out. All I had was mono on FM. So me being a newb I tried to recap this beast. Well I did something stupid by not reading the prior 1010 rebuilds and charged ahead and worked on the 054 board. I installed the transistors incorrectly (didn't download the data sheets) in order to determine what was E, C or B. So after installing the trans wrong, Q2 and Q3, I powered up the unit and was met with loud music and then magic smoke.:tears:

So started again by reading the 1010 threads and recapped all the boards this time using mattsd's and mtf's cap list/bom. So I get all the parts installed and go for the offset/idle. Somewhere along the line the wire from pin 13 on the 054 board to pin 11 on the protect board broke. So I recapped and installed new transistors in the protection board (all but Q7) the equalizer board, the tone and control board.

The diodes on the 054 were also checked after pulling one leg. All test good. I also replaced R11, R12, R20 and the rest were tested again by pulling one leg of the resistor.

Fast forward....

I just got done checking the resistors on the right 032 board, all are within 10% of spec and replaced most of the transistors except I have not done Q1, Q2, Q9, Q11, 12, or 3 but those were replaced once before right after the short appeared.

I pulled the output trans and checked them using EW's 6-way test and all are good.

So I am again looking for help in getting my First/Last 1010 up and running again with the experts on the forum. FYI, this my hobby not a business. I just got crazy buying the Pioneer receivers. As my title indicates First/Last one. Way too many (3 1010's)

When I fire the unit up on the dbt, Q1 on the 054 board starts to wisp smoke and the heatsink gets hot very quickly. So I shut the unit down to prevent any further damage. I tried to get some readings from the 054 board but with the wisps of smoke and the heatsink issue it is hard to keep it running to get the pin readings on any of the boards.

Where would I begin on this beast.

Thanks again to all who will guide me once more.
 
I'd begin by double and triple checking that the transistors are installed correctly. I say triple check because it took me that many times to find the one I installed wrong. If you removed diodes (more than lifting one leg), make sure they are not installed backwards, and check that the electrolytic caps are installed with correct polarity.
 
I will follow up on that. I know I have looked at the boards at least 3 times checking the correct pin outs but another look may find the culprit. Seems it should be a transistor or cap OR a bare wire touching some where.

More work....

Did your incorrectly installed transistor cause a short or ?
 
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You are headed into this one after what you been through on the last 1010? I like your drive! :scratch2:

That section (Regular) of the Power supply provides the (+) side power for the Protection board, Muting Assy. and the Amplifier.
This is were Molex connectors would be nice.

It looks like you are in for another ride with Mr. Short! :D
I learned a few tricks with the last set. I hope that's the case with this one.
Good luck. :thmbsp:
 
Lift one end of R11 and R21 (both 10 ohms 1/4 watt - they SHOULD pop) to isolate the loads. New Q1 if it really smoked. Q2 is suspect too. Hope you had extras hanging around. New 10 ohm 1/4 watt series resistors should be metal film, to fail open rather than possibly carbonize and still conduct. Check q3 and the D8 zener diode if q1 or q2 failed as well, it could have taken it with them down the drain.

Try to identify which resistors were smoking.

then fire it up again.

If it still smokes, lift R18 and REALLY check Q8.

excluding a pattern short, those three resistors are the only ones that can allow ruinous currents to be drawn through q1. Follow the q1 emitter trace with a magnifier if you have to. It IS hard to put q1 in backwards, I'm not sure what happens with the 5 bad combinations of q2 in a darlington.
 
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Lift one end of R11 and R21 (both 10 ohms 1/4 watt - they SHOULD pop) to isolate the loads. New Q1 if it really smoked. Q2 is suspect too. Hope you had extras hanging around. New 10 ohm 1/4 watt series resistors should be metal film, to fail open rather than possibly carbonize and still conduct. Check q3 and the D8 zener diode if q1 or q2 failed as well, it could have taken it with them down the drain.

Try to identify which resistors were smoking.

then fire it up again.

If it still smokes, lift R18 and REALLY check Q8.

excluding a pattern short, those three resistors are the only ones that can allow ruinous currents to be drawn through q1. Follow the q1 emitter trace with a magnifier if you have to. It IS hard to put q1 in backwards, I'm not sure what happens with the 5 bad combinations of q2 in a darlington.


Mark,

There were no resistors smoking on the 054 board from what I could tell, just the transistor. I do have extras of all the components on the 054 board and the rest of the other boards which are leftovers from other recaps and I have one completely new set of components that I ordered just for this unit (I feared there was more damage to other boards).

I have already replaced Q1 and checked the one it replaced, it checked okay using the 6-way test but if you smell it you can tell it was warm/hot.

I'll pull the resistors, etc. per your instructions and post back.

thanks Mark,

Zeb, I am a glutton for punishment..:D
 
THAT component's magic smoke has been let out - do not use it again - mung it...

Mash Until No Good.
 
Sometimes the process CAN relieve stress, a sort of "revenge".

But exercise caution, use eye protection when using an anvil and sledgehammer. Shroud exposed glass, sensitive areas. :yikes:

I found that a large vise very satisfactorily crushed components without unnecessary shrapnel.
 
Sometimes the process CAN relieve stress, a sort of "revenge".

But exercise caution, use eye protection when using an anvil and sledgehammer. Shroud exposed glass, sensitive areas. :yikes:

I found that a large vise very satisfactorily crushed components without unnecessary shrapnel.

I will use caution. Funny that the wisps of smoke appear to come out between the transistor and the heat sink. But the transistors still check out okay using the 6-way diode test. Weird. I wonder if there could be a back feed into the 054 board?
 
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Check that there isn't a short to the heat sink, and that your thermal grease is both non-conductive and CLEAN. You DID use a mica insulator, right?

The big heat sink has three different voltage level collectors mounted on it, with special insulated screw sockets and mica insulators.
The + and - 470uf 80v capacitors and the 1000uf 35v capacitor hot sides go DIRECTLY to those three collectors.
 
Check that there isn't a short to the heat sink, and that your thermal grease is both non-conductive and CLEAN. You DID use a mica insulator, right?

The big heat sink has three different voltage level collectors mounted on it, with special insulated screw sockets and mica insulators.
The + and - 470uf 80v capacitors and the 1000uf 35v capacitor hot sides go DIRECTLY to those three collectors.


I use fresh Thermal silicone grease that is clean every time I replace a transistor on the heatsink, mica insulators are used. Will check for short at the heat sink.

Thanks
 
I use fresh Thermal silicone grease that is clean every time I replace a transistor on the heatsink, mica insulators are used. Will check for short at the heat sink.

Thanks

Replaced Q1, Q4, C20, C19 and C3 (2200, 1000 and 470 uf respectively. New diode at D9, Pulled R11 and R21, Still have instant hot on the heat slink and wisps of smoke from between the heat sink and Q1. Q1 had new silicone thermal grease and mica, same for Q4.

I am going to redo both 032 boards with new caps and trans.
 
Hey, I think you should isolate the short on the power supply (054). I see what you guys are doing and lifting the resistors from the regulator is cutting off the supply to the other boards. If you still have smoke you have a short in the 054 board.

The above post components you reference are not listed on the 054 board from what I can tell.

Maybe I am lost!
 
and EXACTLY WHAT were your ohmmeter readings from Q1, Q4, Q7 to the heat sink and to chassis ground? Was there any resistance from the heat sink to the chassis ground.

NOT just the collectors, but the emitters and bases of all three as well.

Do not start on another board with a bad one unfinished.

With the resistors pulled, (and you DID pull them?) there is no load that can cause problems. Especially smoke level problems.
 
I take and cut a 1/4" to 3/8" piece of heatshrink and put them on the pins of my output transistors to cutdown on possible shorts to the heatsink from the pins due to offset's from the mount or a bent pin. Might be something to look at.

Larry
 
and EXACTLY WHAT were your ohmmeter readings from Q1, Q4, Q7 to the heat sink and to chassis ground? Was there any resistance from the heat sink to the chassis ground.

NOT just the collectors, but the emitters and bases of all three as well.

Do not start on another board with a bad one unfinished.

With the resistors pulled, (and you DID pull them?) there is no load that can cause problems. Especially smoke level problems.

Readings to follow.
 
Q1 ,
E 5.52k ohms to chassis and 232.8k and falling to heatsink. I am unable to obtain a clear, specific value for the E to heatsink as the values go up, then go down.
Q1 C to chassis is at 8.90m and falling so i don't know how long to keep the meter up and running as it has an auto off function.
C to heatsink started at 155 ohms, falling to 151.6
B to heatsink 6.57m and rising
B to chassis 26.2m and falling

Q4 E to chassis 9.26k ohm
E to heatsink 215k ohm and rising
C to chassis 179 ohms
C to heatsink 2.5k ohms and falling
B to heatsink 16.69m
B to chassis 0.F

Q7 E to chassis 9.22k ohms
E to heatsink 165.8k ohms and rising
C to chassis 0.F
C to heatsink 0.F
B to chassis 14.3k and rising
B to heatsink 4.2m and falling


heatsink to chassis 192.6k ohm and falling and now it's rising.. bewildered..:scratch2:

Since I've never measured these values before I have no idea what they mean. So lay it on me. Either my readings are suspect or I don't know how to
use a dmm...
 
Q1 ,
E 5.52k ohms to chassis and 232.8k and falling to heatsink. I am unable to obtain a clear, specific value for the E to heatsink as the values go up, then go down.

Q1 C to chassis is at 8.90m and falling so i don't know how long to keep the meter up and running as it has an auto off function.
C to heatsink started at 155 ohms, falling to 151.6
B to heatsink 6.57m and rising
B to chassis 26.2m and falling

Q4 E to chassis 9.26k ohm
E to heatsink 215k ohm and rising
C to chassis 179 ohms
C to heatsink 2.5k ohms and falling
B to heatsink 16.69m
B to chassis 0.F

Q7 E to chassis 9.22k ohms
E to heatsink 165.8k ohms and rising
C to chassis 0.F
C to heatsink 0.F
B to chassis 14.3k and rising
B to heatsink 4.2m and falling


heatsink to chassis 192.6k ohm and falling and now it's rising.. bewildered..:scratch2:

Since I've never measured these values before I have no idea what they mean. So lay it on me. Either my readings are suspect or I don't know how to
use a dmm...

EVERY one of the readings to the heat sink should have come back as OL.

desolder and isolate q1, q4, q7 to-220 transistor leads from the PC board, perhaps unscrew the heat sink from the board, too. THEN measure from c,b,e on all three to a KNOWN PROVED bare metal heat sink connection, watch out the paint can act as an insulator (but we cannot rely upon it), that's why when I do heat sink readings I periodically return to prove that the one lead on the heat sink remains conductive to the heat sink. Perhaps somebody fooled with or defeated the transistor's electrically insulated mountings on the heat sink.

Also look at the two screws mounting the heat sink to the board, they are CLEAR of any traces on the board.

The transistor leads to the heat sink resistance readings ALL should be OL. period. ALL nine. .PERIOD.
A single exception is a potential problem since the heat sink is no longer floating ("electrically isolated"), two exceptions IS a problem, usually accompanied by smoke and thunder.

When doing the heat sink dismount examine the heat sink MINUTELY for any shorts to the heat sink. Above or below the board, including components leaning on it.

I especially got out a SX-1010 power supply (busted board but..) and examined it CAREFULLY, and there should be NO conduction (OL) from the heat sink to any of the transistors, OR the ground OR ANYTHING ELSE!!

I expected to see one short, but these results are way off the pale.

The heat sink is electrically FLOATING, connected to nothing.

There are three mounting points for the transistors, each is a plastic assembly with a brass threaded piece in it that the mounting screw mates with. The assembly is used specifically to isolate the heat sink from the electrically live screw that mounts the TO-220 transistors by their collector tab.
ANYTHING but OL is >BAD<. period.
 
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EVERY one of the readings to the heat sink should have come back as OL.

desolder and isolate q1, q4, q7 to-220 transistor leads from the PC board, perhaps unscrew the heat sink from the board, too. THEN measure from c,b,e on all three to a KNOWN PROVED bare metal heat sink connection, watch out the paint can act as an insulator (but we cannot rely upon it), that's why when I do heat sink readings I periodically return to prove that the one lead on the heat sink remains conductive to the heat sink. Perhaps somebody fooled with or defeated the transistor's electrically insulated mountings on the heat sink.

Also look at the two screws mounting the heat sink to the board, they are CLEAR of any traces on the board.

The transistor leads to the heat sink resistance readings ALL should be OL. period. ALL nine. .PERIOD.
A single exception is a potential problem since the heat sink is no longer floating ("electrically isolated"), two exceptions IS a problem, usually accompanied by smoke and thunder.

When doing the heat sink dismount examine the heat sink MINUTELY for any shorts to the heat sink. Above or below the board, including components leaning on it.

I especially got out a SX-1010 power supply (busted board but..) and examined it CAREFULLY, and there should be NO conduction (OL) from the heat sink to any of the transistors, OR the ground OR ANYTHING ELSE!!

I expected to see one short, but these results are way off the pale.

The heat sink is electrically FLOATING, connected to nothing.

There are three mounting points for the transistors, each is a plastic assembly with a brass threaded piece in it that the mounting screw mates with. The assembly is used specifically to isolate the heat sink from the electrically live screw that mounts the TO-220 transistors by their collector tab.
ANYTHING but OL is >BAD<. period.

mtf,

I kind of figured that was a huge issue since the readings were all over the place.

Interesting that before I took the readings I insulated the 2 screws that hold the heatsink to the pcb with nylon washers hoping that would resolve any issues. And I did notice that the paint/coating on the heatsink was interfering with the readings.

Is it possible to use a different type of heatlsink on the transistors (single mount one screw similar to those used on other SX models or even a glue on heatsink (jb weld).

I will take the heatsink off the pcb and then measure from each pin on the transistors to chassis ground and report those readings. If I desolder the transistors from the pcb then wouldn't that defeat the procedure to find that short (or am I off on this)?

Will further my research on this perplexing issue...

Thanks again for your help
 
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