• The move to the new server is done. There are some software and database maintenance updates in process. This has us passing the hat around to help out. We appreciate any donations. Seriously, even a dollar helps. The payment page may be found here - https://www.audiokarma.org/support.html

Pioneer SA-9100 Problems

zeppoleon

zeppoleon

New Member
Hello!

I recently just purchased a Pioneer SA-9100 off ebay. I have them hooked up to a pair of B&W DM602 S2 speakers (120W max, 8ohm). I have to say, the amp sounds amazing! Very clear and warm.

But after a few hours or so of listening to music, the pops and cracks started to appear. At first it was very subtle. My right speaker would make a small pop noise, and I wouldn't notice it was the speaker. But soon, the whole right speaker would crackle and pop audibly, causing the protection light to go on. When this happens I switch it off immediately. I re-re-checked all the connections, and everything looks fine. (FYI: I am using the A+B speaker settings. I have the left terminals on the A and B outputs going to the left speaker for bi-wiring, and vice versa for the right. I'm not sure if this is okay to do.) Anyway, I did something and it worked for another 3 hours until it all of a sudden crackled and pop'd and shut off. I wanted to make sure it wasn't my speakers, so I plugged in my headphones, and soon enough my headphones started to crackle and pop randomly. It's not exactly static, the music can be very clear up until this point.

Although the problem is mostly affecting the right speaker, the left speaker sometimes also crackles at the same time as the left one.

It seems the problem is getting worse, as when I turn on the amp today, the speaker sometimes immediately starts to crackle and make popping noises. The very sound makes me cringe. I switch it on and off again, and it stabilizes itself sometimes for a few minutes. It's just very fickle.

I have been lurking around, and have found threads that are related to my problem, but I want to get a personal opinion from you guys. I'm not very skilled at the electrician standpoint, but I'm sure I could do a few things my self to fix up this wonderful amplifier.

Help is much appreciated, thanks!
 
Register to hide this ad
Are you able to replace two transistors per channel on the amplifier cards? If not, (even, if) update your profile so that we can see if there's someone nearby you that can do this work.

That involves buying or downloading the service manual, having soldering and desoldering equipment (and skills) as well as a Digital MultiMeter, buying a few transistors (online ordering at mouser.com) and then, under direction, installing them.

The description you posted does indicate a known problem, with the 2sc1451 transistors in the power amplifier section.

And YES, leave it OFF to minimize damage. This can be a trivial, inexpensive fix, or a real mess if you don't. The transistors are precisely positioned to do major damage to your output transistors - which up to this point, seem ok.
 
Thanks for the replies.

markthefixer said:
Are you able to replace two transistors per channel on the amplifier cards? If not, (even, if) update your profile so that we can see if there's someone nearby you that can do this work.

That involves buying or downloading the service manual, having soldering and desoldering equipment (and skills) as well as a Digital MultiMeter, buying a few transistors (online ordering at mouser.com) and then, under direction, installing them.

The description you posted does indicate a known problem, with the 2sc1451 transistors in the power amplifier section.

And YES, leave it OFF to minimize damage. This can be a trivial, inexpensive fix, or a real mess if you don't. The transistors are precisely positioned to do major damage to your output transistors - which up to this point, seem ok.
Click to expand...

I will probably need to get someone to do that for me, as I have no soldering experience. I have actually downloaded the service manual already. I decided to open the unit up to see if I can identify anything unusual, and to my surprise I found the relay (behind the power switch) totally melted the plastic cover off, also melting the covers of a few wires around it. As seen in this picture:

DSC_6520.jpg


Nothing looks like it was damaged from what ever happened, just melted the plastic. Other than that, the unit was pretty clean inside. The seller said that he got a technician to check the capacitors, and they are supposedly fine.

What should I do about the relay?
 
THAT was deliberate, but really it's only cosmetic. It could be replaced, but it is a pita to do, as the original variation of the case is no longer available with the mounting ears down by the bottom, the versions nowadays have the ears by the top, so additional hardware (standoffs) is needed to mount it.

A new relay IS a good idea, and it's a shame the original case is damaged, because a two pole version of this relay, that I have used, can snap fit a NEW relay core into the old case, but the wires on the bottom of the case still have to be removed from the old relay's core and installed on the new one.
 
markthefixer said:
THAT was deliberate, but really it's only cosmetic. It could be replaced, but it is a pita to do, as the original variation of the case is no longer available with the mounting ears down by the bottom, the versions nowadays have the ears by the top, so additional hardware (standoffs) is needed to mount it.

A new relay IS a good idea, and it's a shame the original case is damaged, because a two pole version of this relay, that I have used, can snap fit a NEW relay core into the old case, but the wires on the bottom of the case still have to be removed from the old relay's core and installed on the new one.
Click to expand...

So I don't really need to change the relay out? I'm fine keeping it like that if it causes no problems.

And about those transistors...
is this what you are talking about?

Where are those located? Is it those metal domes on the side of the black heatsinks? There are 4 of them (2 on each):

DSC_6536.jpg


I'll have to see where I can get it repaired. I have a friend that can solder things, I might ask him.

I'm glad there doesn't seem to be many problems with this one! Extra pic for sexyness.

DSC_6546.jpg
 
Those big-uns are the output transistors we want to keep healthy, even though GOOD replacements are slightly less than 4 bucks each.

The culprits are little silver top hat/can looking things with a c-shaped hunk of metal wrapped around them on the amplifier cards that are mounted to the heat sinks that have the output transistors on them. They are an assembly. Remind your pal to be very careful with the little fragile bias diodes also mounted on the heat sink, with wires that LOVE to break off right at the body of the component, so don't bend the wires anywhere near it's body.
 
markthefixer said:
Those big-uns are the output transistors we want to keep healthy, even though GOOD replacements are slightly less than 4 bucks each.

The culprits are little silver top hat/can looking things with a c-shaped hunk of metal wrapped around them on the amplifier cards that are mounted to the heat sinks that have the output transistors on them. They are an assembly. Remind your pal to be very careful with the little fragile bias diodes also mounted on the heat sink, with wires that LOVE to break off right at the body of the component, so don't bend the wires anywhere near it's body.
Click to expand...

Ahh, okay. So this is what you mean?:

DSC_6583.jpg


Well, I noticed on mouser that the transistor has 3 prongs, while the one on the amp has 2, if I am not mistaken.

I'll have to order at least 4 then, right?

Thanks so much for your help! Merry Christmas to everyone btw.
 
Gotta get us on the same page....

The big silver oval power transistors (called a TO-3 case) on the big heatsinks have 2 prongs and the CASE makes the third connection, the "collector". These TO-3 cased power transistors on the big heatsinks also have 2 polarities: A,B are pnp while C,D are npn.

This means that the TO-3's cases are at +50v( or so) volts on one half of them and -50v(or so) on the other half. IF they contact that heat sink (grounded) directly, sparks will fly.... Thus they are mounted on electrically insulating sheets of clear mica, and a white goop applied that's called thermal transfer compound - so that while we keep the electrons insulated, we allow the heat to escape.

Now what you show in the picture is ANOTHER power transistor (lower power) called a TO-220 and this one has a B528 on it. They are used in THIS amplifier as "drivers" for the TO-3 power output transistors. (in some lower powered amps - THEY are used as the power output transistors. The heat sink that is attached is bent into a "U" shape with 90 degree corners with a sharper radius of bending.

tranlead.gif


The 2sc1451;s that need replacing are the ROUND ones that look like this:
011_goapower_002.gif


while these are repaired (top) and original (bottom) stv-3h or stv-4h diodes (h=horseshoe):
attachment.php
 
Last edited:
markthefixer said:
Gotta get us on the same page....

The big silver oval power transistors (called a TO-3 case) on the big heatsinks have 2 prongs and the CASE makes the third connection, the "collector". These TO-3 cased power transistors on the big heatsinks also have 2 polarities: A,B are pnp while C,D are npn.

This means that the TO-3's cases are at +50v( or so) volts on one half of them and -50v(or so) on the other half. IF they contact that heat sink (grounded) directly, sparks will fly.... Thus they are mounted on electrically insulating sheets of clear mica, and a white goop applied that's called thermal transfer compound - so that while we keep the electrons insulated, we allow the heat to escape.

Now what you show in the picture is ANOTHER power transistor (lower power) called a TO-220 and this one has a B528 on it. They are used in THIS amplifier as "drivers" for the TO-3 power output transistors. (in some lower powered amps - THEY are used as the power output transistors. The heat sink that is attached is bent into a "U" shape with 90 degree corners with a sharper radius of bending.

tranlead.gif


The 2sc1451;s that need replacing are the ROUND ones that look like this:
011_goapower_002.gif


while these are repaired (top) and original (bottom) stv-3h or stv-4h diodes (h=horseshoe):
attachment.php
Click to expand...

Ohhhh, I think I found what you're talking about now:

DSC_6602.jpg


I'm sure that is the 2sc1451 transistor.

I think someone already replaced one of the TO-3s as it is a different brand from the rest. The rest are, I think, original because they have the old Toshiba logo on them (Coca-Cola style). If you don't mind, I seem to be having trouble finding the 2sc1451 transistors on mouser, could you spare me a link?

Thanks a lot Mark, your help has been invaluable.
 
zeppoleon said:
I see. What replacement transistor can I use then?
Click to expand...

My apologies, I usually include the replacement parts numbers straight off, I held off because the replacement process will take a bit of posting, because the lead arrangements are different between these transistors, and I didn't want you (edit: or somebody else) "jumping off into the deep end" without having your eyes open...



from mouser.com:
2sc1451 ???case ebc 150v .05a 0.7w 150hfe 130mhz
512-KSC3503estu to-126 ecb 300v .1a 1.2/7w 150mhz 40-320hfe $0.28 ea


The original has an ebc arrangement in a triangular pattern, the new one has ecb in a linear pattern.

(this is for the folks reading this and saying "HUH, what about the 2310??")
I am making a different recommendation for this part for this model of amplifier than I usually do ("c2310") because the amplifier could be running these transistors hotter (6.7 mA with ~40v c to e) than most, and the 3503 is a to-126 case more suited to dissipating heat, and I also have successfully used it in similar circuit situations in higher power amplifiers that turned out to be surprisingly quiet. The only fly in the ointment may be the hole size of the 9100, it might be a tight fit for the to-126 lead size.... or not....
 
Last edited:
markthefixer said:
My apologies, I usually include the replacement parts numbers straight off, I held off because the replacement process will take a bit of posting, because the lead arrangements are different between these transistors, and I didn't want you (edit: or somebody else) "jumping off into the deep end" without having your eyes open...



from mouser.com:
2sc1451 ???case ebc 150v .05a 0.7w 150hfe 130mhz
512-KSC3503estu to-126 ecb 300v .1a 1.2/7w 150mhz 40-320hfe $0.28 ea


The original has an ebc arrangement in a triangular pattern, the new one has ecb in a linear pattern.

(this is for the folks reading this and saying "HUH, what about the 2310??")
I am making a different recommendation for this part for this model of amplifier than I usually do ("c2310") because the amplifier could be running these transistors hotter (6.7 mA with ~40v c to e) than most, and the 3503 is a to-126 case more suited to dissipating heat, and I also have successfully used it in similar circuit situations in higher power amplifiers that turned out to be surprisingly quiet. The only fly in the ointment may be the hole size of the 9100, it might be a tight fit for the to-126 lead size.... or not....
Click to expand...

Pssh, you don't have to apologize! I should apologize for being so inept.

I'll definitely keep the different lead arrangements in mind. I just want to make sure I have the arrangements right. I've labeled the ebc leads in this picture:

circ.jpg


What kind of solder is best for this? And what are your suggestions on actually putting on the new transistors? Thanks again!
 
The labeling of Q6 & Q7 ARE CORRECT.

Tin / lead 60 / 40 solder is fine, that is what was used, and if it turns out to be 63 / 37 or some variation is fine.

That last question is quite deceptive, if your buddy has experience replacing parts, the answer is short - depending upon his experience. Otherwise chapters could be written.

Lining up the leads to the holes is interesting, align the OUTER two leads with their corresponding holes, then bend the center lead out to the last hole. You could "split the difference" and not have the transistor exactly on the line with the holes, but rather to bend the two end leads to one direction, and the center lead in the other direction.

attachment.php
 
Last edited:
markthefixer said:
The labeling of Q6 & Q7 ARE CORRECT.

Tin / lead 60 / 40 solder is fine, that is what was used, and if it turns out to be 63 / 37 or some variation is fine.

That last question is quite deceptive, if your buddy has experience replacing parts, the answer is short - depending upon his experience. Otherwise chapters could be written.

Lining up the leads to the holes is interesting, align the OUTER two leads with their corresponding holes, then bend the center lead out to the last hole. You could "split the difference" and not have the transistor exactly on the line with the holes, but rather to bend the two end leads to one direction, and the center lead in the other direction.

attachment.php
Click to expand...

Alright! I'll make sure the knowledge you gave me will be put to good use. Thanks a lot - I think you have answered all my questions. Hopefully everything goes as planned! I'll update this thread if anything happens.
 
You are in good hands. The amp is going to be quiet and wonderful once you are done restoring it!

That relay is a total PITA to replace in the 9100. Like you said Mark, I just re-use the old shell and snap a new relay in.
 
markthefixer said:
My apologies, I usually include the replacement parts numbers straight off, I held off because the replacement process will take a bit of posting, because the lead arrangements are different between these transistors, and I didn't want you (edit: or somebody else) "jumping off into the deep end" without having your eyes open...



from mouser.com:
2sc1451 ???case ebc 150v .05a 0.7w 150hfe 130mhz
512-KSC3503estu to-126 ecb 300v .1a 1.2/7w 150mhz 40-320hfe $0.28 ea


The original has an ebc arrangement in a triangular pattern, the new one has ecb in a linear pattern.

(this is for the folks reading this and saying "HUH, what about the 2310??")
I am making a different recommendation for this part for this model of amplifier than I usually do ("c2310") because the amplifier could be running these transistors hotter (6.7 mA with ~40v c to e) than most, and the 3503 is a to-126 case more suited to dissipating heat, and I also have successfully used it in similar circuit situations in higher power amplifiers that turned out to be surprisingly quiet. The only fly in the ointment may be the hole size of the 9100, it might be a tight fit for the to-126 lead size.... or not....
Click to expand...

The ksc3503estu is no longer available - are any from the current series dstu/d/cs appropriate substitutes? Thanks.
 
You must log in or register to reply here.
Back
Top Bottom