How to connect 2 Pioneer SA-8500 II

jheu02 said:
Yes. CAREFULLY reread my last post #77 (especially the section I quoted from you) and then look at the SM for that board and its transistors. Your next hint is this problem was not due to the legs being reversed (though that will still be a factor for new transistors). Also, reread post #62 as it also offers a clue.
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I was mistaken about what was used. I actually used an 1845 and not a ksa992 as previously mentioned. Im still searching. I did replace the original 1845 because the legs were gold close to the bottom of the transistor. I replaced it and the aux side is back to working. still the same with the phone 1/2. only one side is passing audio.
 
OK, thought I had it, but glad you found where I was going with the post about putting a PNP where an NPN should have gone. So, to recap:

Q1-4 are now KSA992
Q5-8 are KSC1845
Q9,10 are KSA992

These are all correctly oriented and you've ensured that the actual legs are in the correct spot, not just the body "looking" reversed from the original, correct?

What did you replace C9,10 (470uF/6V) with? If you used 6.3 V caps and there was some voltage spike when you powered up, these could have been damaged. Based on some research ConradH has undertaken on low voltage caps and failure rates, I no longer use any caps below 16V if possible. So, if the original was <= 10V, I use a 16V or 25V cap depending on what I have on hand and what will physically fit in the space.

You have also checked the wiring for breaks visually, but did you use the continuity function of your meter?

Did you also check continuity "point to point" along the signal path? There are sometimes solder joints that appear fine to the eye, yet are still not conducting. Reflow all the original joints (those pf parts you didn't replace) and recheck the new joints you made. When reflowing the original ones, a slight touch of new solder at the joint may help. But be aware of large solder blob joints... You may want to wick away some solder from those when reflowing. The joint should have a nice slightly-concave cone shape when properly formed.

Have you taken any voltage measurements and compared them between the working L channel and non-working R channel? This will need to be your next step assuming you have the correct replacement parts properly oriented in the correct locations.
 
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Q1-4 are now KSA992
Q5-8 are KSC1845
Q9,10 are KSA992

Thats correct thats what I used. Legs are oriented correctly.

On C9,10 I used :
647-UPW1A471MPD
Aluminum Electrolytic Capacitors - Leaded 10volts 470uF 8x11.5 20% 3.5LS

The battery was dead on the Voltmeter last night so I did not get a chance to take any reading with it. That's the plan tonight.

On another note isn't odd that when the balance is faded to the non working side and the volume is cranked up 3/4 of the way that you can hear the audio. Its low but it's there.
 
if you have a test CD which you know that there's a certain part that's ONLY present in the Right channel, you could check to see if it's present under the above conditions, or whether what you're getting is bleedthrough from the L channel.

Check the C10 cap for any bulging, leakage, etc. and if able, check its capacitance and ESR.

Other than that and the reflowing of joints as mentioned earlier, you're going to have to take voltage readings to see where the difference lies between channels and / or where the chain is breaking down.
 
I wish i had a test CD.

Ill check the C10 as you mentioned

I'll have a working voltmeter tonight so I'll either have it fixed or some readings for you to help me decipher.
 
Just a music track that you know a specific instrument, voice, etc is only in the R channel will suffice. I shouldn't have used the term "test". Reference p. 43 of the SM for the board layout and where to reference the voltages. Again, black probe to chassis bare metal and red probe touching the various points. Make sure there's very little metal exposed on the red probe in case it slips...less likelihood of shorting something.

Since you have a good working channel, it should be easy to compare each point, L (good) first, then R and see where things diverge. And though the SM only gives you voltages at transistor junctions, you can also check the voltages at resistor and cap junctions if the transistor voltages look good.
 
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jheu02 said:
Just a music track that you know a specific instrument, voice, etc is only in the R channel will suffice. I shouldn't have used the term "test". Reference p. 43 of the SM for the board layout and where to reference the voltages. Again, black probe to chassis bare metal and red probe touching the various points. Make sure there's very little metal exposed on the red probe in case it slips...less likelihood of shorting something.

Since you have a good working channel, it should be easy to compare each point, L (good) first, then R and see where things diverge. And though the SM only gives you voltages at transistor junctions, you can also check the voltages at resistor and cap junctions if the transistor voltages look good.
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Checked c9,10. Both visually look fine. Also checked q1-10 all check out almost dead on to what SM says they should be.

When checking voltage at junctions what should I be looking for as far as values?
 
jheu02 said:
Just a music track that you know a specific instrument, voice, etc is only in the R channel will suffice. I shouldn't have used the term "test". Reference p. 43 of the SM for the board layout and where to reference the voltages. Again, black probe to chassis bare metal and red probe touching the various points. Make sure there's very little metal exposed on the red probe in case it slips...less likelihood of shorting something.

Since you have a good working channel, it should be easy to compare each point, L (good) first, then R and see where things diverge. And though the SM only gives you voltages at transistor junctions, you can also check the voltages at resistor and cap junctions if the transistor voltages look good.
Click to expand...

Checked c9,10. Both visually look fine. Also checked q1-10 all check out almost dead on to what SM says they should be.

When checking voltage at junctions what should I be looking for as far as values?
 
They're printed on that page of the SM I referenced, with arrows pointing to where the voltage should be read.
 
Sorry for the confusion. I checked at each leg of the transistors where the arrows are pointing. ( Q1,2,3,4,5,6,7,8,9,10) they all were almost exact to what the SM says they should be.

You mentioned "you can also check the voltages at resistor and cap junctions if the transistor voltages look good." I just didn't know if there was going to be a value that i should look for when i test the caps and resistors.

So the search continues for the problem.....Is it possible that another area on a different board is causing the issue?

One mistake i made when i started this process was not reinstalling each board and then powering the amp up to see if all is good before moving to the next board. I did work on 1 board at a time, but after i put it back in i did not power it up and test that everything was installed correctly.

As I mentioned when i started this post I purchased a used SA-8500 II from the auction site. I am on the verge of starting to recap it and see if i duplicate the problem. By replacing one component at a time.

What do you think? (you've got to be tired of trying to diagnose over the internet at this point)
 
personally im not a big fan of blowing 2 units apart at the same time. i would finish the first before starting the second. cant you use the working unit as a refrence?
 
moewillis said:
personally im not a big fan of blowing 2 units apart at the same time. i would finish the first before starting the second. cant you use the working unit as a refrence?
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Im with you it seems like a bad idea at first, but i can't seem to locate the problem on the first unit. My thinking is if i followed the same recapping I might have the same issue, and i would be able to see the board that is causing the issue. Then I can go back to the original amp that is causing problems and go back through that board.

I just can't find the problem. I totally get why companies charge what they charge for doing recaps on these amps.
 
do you get any audio out of the bad channel on any setting (phono, tape, aux etc.)? not the bleed through but actual sound?

i skimmed through this thread but havent intently followed it from the start. have the outputs been checked? emitter resistors?
 
moewillis said:
do you get any audio out of the bad channel on any setting (phono, tape, aux etc.)? not the bleed through but actual sound?

i skimmed through this thread but havent intently followed it from the start. have the outputs been checked? emitter resistors?
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I was able to get audio out of the Tuner and Aux on both channels (L & R) the problem is in the Phone1 and Phone 2 I just cant locate where. jheu02 (john) has been walking me through mistakes. Im sure im about to wear him out with questions and problems :idea:
 
scratch what i said about emitters and outputs if you are getting some audio. i cant help but think this may have been caused by the backwards caps and the improper transistors. surely it is in your phono board (if thats the only input causing you problems). have you ohm'd out the resistors on the board? i would check every single component on that board if you havent already
 
moewillis said:
scratch what i said about emitters and outputs if you are getting some audio. i cant help but think this may have been caused by the backwards caps and the improper transistors. surely it is in your phono board (if thats the only input causing you problems). have you ohm'd out the resistors on the board? i would check every single component on that board if you havent already
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Well i started with all the transistors last night and then stopped because i wasn't sure how to check the rest of the components. Im new to this for the most part, and working in a live amp makes me a bit nevous, so I'm really waiting for exact instructions before I start probing. Ohming the the resistors seems easy enough. ( the amp doesn't need to be hot to do this correct?)
 
at this point i would not put any power to it at all. ohming resistors you do NOT want any power involved at all. the meter sends a small current and then reads the drop to give you an ohm reading. introducing volts in that circumstance is bad.

let me go download a manual and take a look at the thing so im not speaking so generally and can be more specific.ive not worked on an 8500.
 
moewillis said:
at this point i would not put any power to it at all. ohming resistors you do NOT want any power involved at all. the meter sends a small current and then reads the drop to give you an ohm reading. introducing volts in that circumstance is bad.

let me go download a manual and take a look at the thing so im not speaking so generally and can be more specific.ive not worked on an 8100.
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Cool thanks! Just to be sure we are talking about the same amp. Its the SA-8500 II not just the SA-8500.
 
okay, i read through your thread and looked over a service manual. you guys have dug into it pretty good. i find it interesting that all the transistor voltages checked out okay. i am a little suspect with them having been installed incorrectly. did you actually test them when you pulled them to swap the leads back? i would also be curious if the signal for the right channel at pin 16 on awf-023 is passing on to pin 3 on aws-110.

i dont want to jump in and mess up anything someone else has started with you. again if it were me and i was stumped i would test each component on that board to confirm there is no problem. but dont go off on a tear if someone else is in the middle of working with you.
 
moewillis said:
okay, i read through your thread and looked over a service manual. you guys have dug into it pretty good. i find it interesting that all the transistor voltages checked out okay. i am a little suspect with them having been installed incorrectly. did you actually test them when you pulled them to swap the leads back? i would also be curious if the signal for the right channel at pin 16 on awf-023 is passing on to pin 3 on aws-110.

i dont want to jump in and mess up anything someone else has started with you. again if it were me and i was stumped i would test each component on that board to confirm there is no problem. but dont go off on a tear if someone else is in the middle of working with you.
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I'm still checking things. When i checked the transistors last night it was with them still in the board and the power on the amp on. That poor board is begging for mercy i have soldered and unsoldered and resoldered so many times.
 
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