Pioneer SX-650 Woes

[goat67]

I installed the new 560 ohm resistors on pin 1 to 4 and pin 6 to 4. On the GWH-101 board I installed new capacitors 1, 2, 7, 8, 9, 10, 13, 14. Also new transistors Q1 and Q2 which came as 2 SA992 that I soldered the 2 emitter leads together which gave me a 5 pin hook up as per the kit instructions. Also replaced Q3 and 4. I had screwed up the Q1 and 2 install and redid them and checked everything. As far as I know or can tell every new component is correctly installed. I went ahead and gave you the pin readings for Q1 even though not requested.

Board Pins Readings
1. 31.7v
3. -32v
5. 32v
7. -32v
12. -35.5v
14. 34v
28. -35.5v
29. 34v

Q4
E -35.3v
B -35.3v
C 9.0v

Q2
E -34.4v
B -34.3v
B -34.4v
C -35.0v
C -34.4v
Q1
E -34.5v
B -33.8v
B -34.5v
C -34.4v
C -35.3v

Pins with resistors
Pin 2 12.0v
Pin 4 9.9v
Pin 6 8.7v
All 3 are positive readings.
Thanks for all your time and help.

Is that a typo on how you installed the resistor I hope so.

Why did you install all these new parts?
When did you install them?

You say you screwed up Q1 and Q2 did you get new transistors to replace these? It looks like these are shorted or installed incorrectly. How did you screw up.
There should be no need to solder the pins together the circuit board has been made to allow each emitter lead to be soldered in individually look at the image above

I would like images of this board component side to verify installation I need to see clearly how the transistors have been installed and the capacitors.

What are the part numbers of the transistors you installed? Where did you get them?

Is there anything else you have done and not mentioned.

I would like you to get readings of the power pack pins 1 thru 7 to ground both channels dcv

and the voltages for Q1 and Q2 like this so I can identify each of the transistors
Q2 is a transistor pair in one package two transistors with a common emitter

Q2a
E
B
C
Q2b
B
C

 

[49hawkeye]

I had installed the new parts before I had started this thread and had mentioned that in my first post. Probably shouldn't have but, like Yogi Berra said, hindsight is 50/50.
The Pin 1 to 4 was a fat finger mistake. It was 2 to 4. I went ahead and replaced Q1 and 2 with the original ones and then checked everything again:
New Board Pins Readings
1. 30.1v
3. -30v
5. 30v
7. -30.3v
12. -35v
14. 33.8v
28. -35.v
29. 33.8v

Q4
E -34.2v
B -34.6v
C 25.3v

Q2a
E -10.7v
B -11.3v
C -35.0v

Q2b
B 0.00v
C -35.5v

E .5v
B 0.0v
C -35.1v

Q1b
B 0.0v
C -33.9v

Left Channel SP-40W
Pin 1 30.1v
Pin 2 1.2V
Pin 3 40.8mV
Pin 4 17.3V
Pin 5 -30.2
Pin 6 -1.2V
Pin 7 -4.8mV
Q1a

Pins with resistors
Pin 2 -15.2v
Pin 4 -20v
Pin 6 -25.2v
I also reinstalled the SP-40W I had removed to do the resistor check and when I turned on the DBT it dimmed a bit and then got brighter so I shut it off.
Attached are 2 pictures I hope will suffice, if not let me know and I'll shoot some more.
Thanks for the help.

 

[Watthour]

View attachment 2472281

It is going to requre a meter with much better resolution than 100mV (±1 digit) to perform diagnosis and eventual adjustment.

 

[49hawkeye]

This meter will read down to 1/10 mV. Is that not low enough or do I need one that can read .00 mV or lower?
Thanks.

 

[goat67]

I want you to only do as I tell you Why did you reinstall the power pack?

I asked
What are the part numbers of the transistors you installed? Where did you get them?

I would like images of this board component side to verify installation I need to see clearly how the transistors have been installed and the capacitors.

Left Channel SP-40W
Pin 1 30.1v
Pin 2 1.2V
Pin 3 40.8mV
Pin 4 17.3V
Pin 5 -30.2
Pin 6 -1.2V
Pin 7 -4.8mV

Remove both Power packs and install the resistors as stated.

Remove both Q1 Q2 Q3 and Q4 and test them using the info I posted earlier.

Q1 looks like it is good. Do not mix these up when you test them same goes for that you remove keep track of where they cam from.
Q2 looks like it is bad test it verify
I can not say for sure but Q4 looks like it is installed wrong I need a better image verify

Post your results.

Test the transistors and remove the power packs and install the test resistors. no more or less


Yes you need a meter that can measure in the mv range
so it should be able to read in the mv range ie .001 to .999 volts

 

[49hawkeye]

In your earlier post I read to remove the power pack, not packs, so I left the other power pack installed. I reinstalled the right one to check the dcv as that is the only way I have to do it. I will now pull both power packs, Q1, Q2, Q3 and Q4 and test them.I will hook up resistors to pins 2, 4 & 6 on both power pack pins. Will get a better picture of Q4. Q1 and
Q2 are the original transistors (2SA798) which I reinstalled. I take it my meter is not sufficient to test this with. Suggestions on a meter I should get?
Thanks

 

[goat67]

You can do the transistor tests with any ohm meter

I want the power packs pulled until we get the circuits working before them.

When we get to powering on again we will verify the voltages using the resistors instead of the actual power packs.

Remove both Power packs and install the resistors as stated.

Remove Q1 Q2 Q3 and Q4 and test them using the info I posted earlier.
post results remember Q1 and Q2 will be like testing 2 transistors post results using Q1A and Q1B

This is a decent meter it is auto ranging and can measure hfe
https://www.amazon.com/HOLDPEAK-Multimeter-Automatic-Resistance-Protection/dp/B07RFGGH1K/ref=sr_1_7?crid=145KXE67A5367&keywords=holdpeak+multimeter+hfe&qid=1644411862&sprefix=holdpeak+multimeter+hfe,aps,66&sr=8-7&th=1

 

[Watthour]

This meter will read down to 1/10 mV. Is that not low enough or do I need one that can read .00 mV or lower?
Thanks.

The photo confused me, since the range is evidently set to V, and not mV. All the while we were discussing the measurements in terms of mV.

 

[49hawkeye]

Sorry about that, I should have set it to dcmV . So, I ordered the meter today, thanks for the link . I removed the power packs and attached the 4 resistors on pins 2, 4 & 6 on both left and right channels. Attached is a, hopefully, better picture of Q4. Tomorrow I will pull and test the transistors and post my results. Thanks guys for being so patient with me. Learning this from scratch is a bit of a learning curve. Plus side I am getting much better at soldering, written communication and using a meter!

 

[goat67]

The main thing is to take it slow pay attention to what you are asked to do. For example I asked what transistors you replaced and what are the part numbers of them.
I see you have the original Q1 and Q2 installed but what about Q3 and Q4?

Do you understand what the markings on the board mean regarding the transistors? Do you know how to identify what pins are what on a transistor?

 

[49hawkeye]

Hi Guys. I have to take a few days away from this. I hurt my back working at my daughters house and since I have to put the amp away every day I will not be picking it up and moving it for a bit.
Thanks for all the help so far and talk to you in a few.

 

[goat67]

Get better we will be here when you get back

 

[49hawkeye]

OK I'm finally back. Pulled the transistors today. I labeled the pin layouts and trans type as I believe this to be correct as facing the flat side of the transistor. Please correct me if I am mistaken. I worked Q1 and Q2 from left to right.
Here are my results :

Q1A PNP: Layout of pins B, C, E
- to base, + to collector, result = 835
- lead to base, + to emitter, result = 875
+ to base, - to collector, result = OL
+ to base, - to emitter, result = OL
- to emitter, + to collector, result = OL
+ to emitter, - to collector, result = OL

Q1B PNP: E, C, B
- to base, + to collector, result = 824
- lead to base, + to emitter, result = 867
+ to base, - to collector, result = OL
+ to base, - to emitter, result = OL
- to emitter, + to collector, result = OL
+ to emitter, - to collector, result = OL

Q2A PNP: B, C, E
- to base, + to collector, result = 735
- lead to base, + to emitter, result = 830
+ to base, - to collector, result = OL
+ to base, - to emitter, result = OL
- to emitter, + to collector, result = OL
+ to emitter, - to collector, result = OL

Q2B PNP: E, C, B
- to base, + to collector, result = 753
- lead to base, + to emitter, result = 851
+ to base, - to collector, result = OL
+ to base, - to emitter, result = OL
- to emitter, + to collector, result = OL
+ to emitter, - to collector, result = OL

Q3 NPN: E, B, C
- to base, + to collector, result = 759
- to base, + to emitter, result = OL
+ to base, - to collector, result = OL
+ to base, - to emitter, result = OL
- to emitter, + to collector, result = 800
+ to emitter, - to collector, result = OL

Q4 NPN: E, B, C
- to base, + to collector, result = 732
- to base, + to emitter, result = OL
+ to base, - to collector, result = OL
+ to base, - to emitter, result = OL
- to emitter, + to collector, result = 798
+ to emitter, - to collector, result = OL
Thanks for all the help.

 

[goat67]

Q3 And Q4 should be from left to right ECB flat facing please verify your reading look wrong for these.
Q1 and Q2 with flat side facing away left to right B1 C1 E C2 B2 these readings look good.

what are the part numbers for Q3 and Q4

 

[49hawkeye]

Well it seems I crossed the C and B leads. Q3 and Q4 are 2sc1438.
So here are the corrected readings:
Q3 NPN: Facing flat side E, C, B
- to base, + to collector, result = OL
- to base, + to emitter, result = OL
+ to base, - to collector, result = 779
+ to base, - to emitter, result = 827
- to emitter, + to collector, result = OL
r+ to emitter, - to collector, result = OL



Q4 NPN: Facing flat side E, C, B
- to base, + to collector, result = OL
- to base, + to emitter, result = OL
+ to base, - to collector, result = 747
+ to base, - to emitter, result = 822
- to emitter, + to collector, result = OL
r+ to emitter, - to collector, result = OL
Thanks for the fast reply on this.

 

[goat67]

Ok these look correct
What is the history with these transistors have you ever removed them and replaced them?
I think you said you had updated these with new parts correct?

Have you ever reinstalled these originals and powered back up?

I do not trust a transistor if it has been installed incorrectly have these ever been installed incorrectly?

You do realize the board shows the markings of the pins for the transistors right?

When we get to the point of reinstalling these transistors I am going to want to get an image for each of these so that I can see that the transistors are installed correctly.

 

[49hawkeye]

Sorry for the late reply, my back again.

To answer you Q1 and Q2 are the original transistors. I thought I had installed the new ones wrong so replaced them. Q3 and Q4 are new ones. I am sure they were installed correctly, at least the way I read the diagrams on the board. Attached are photos of them in the boards but not soldered in. The ones with the blue tape are Q2 and Q4. If the placement is incorrect in the photos then I will need to get some replacements as that is the way they were soldered in. If that is the case can you recommend a source?

Thanks for all the help.

 

[goat67]

Ok Q1 and Q2 are installed correctly. I can not see Q3 and Q4 can you get a better picture showing the pins and the board?
What is the part number of Q3 and Q4? You have old and new parts please give both part numbers
So the original Q3 and Q4 you removed them to install the new ones have they ever been reinstalled?

Looks like you changed the way Q3 has been installed right? What about Q4

 

[49hawkeye]

Q3 and 4 part numbers:
Original = 2sc1438-V as listed in repair manual
New = 2sc1438
I don’t think I installed either Q3 or Q4 incorrectly, but I could be mistaken as I paid no attention to the orientation prior to their removal and testing.
No, I have not reinstalled the original transistors.
Attached is a better picture of Q3.

 

[goat67]

Install the original Q3 and Q4 and send me images of how they are installed Q3 is installed correctly. Please get an image like you did of how Q4 is installed with the original.
Do not power up until I verify transistors have been installed correctly.