Crackle and pop on a SX-525 on right speaker only

Z

zorak2003

New Member
Hi everyone. I'm pretty new here and new to working on stereos all together. I have a Pioneer SX-525 that has a lot of popping and pour sound quality on the right speaker. After much research I found that it could be a bad transistor. I tested each one on the amp board and found that 2 were bad. They are listed below. Does anyone know of a site where I can find an equivalent replacement for them? I found this one https://english.electronica-pt.com/components-cross-reference?ref=C738 but wanted to check with some of you experts to make sure I was getting the right parts.

T C373
C738 55D
 
john stumpf said:
perhaps it would be best if you said which ones by number you want to replace
Click to expand...
The 2 numbers at the bottom are the numbers on the transistors. I think when searching for them you just need C373 and C738. I'm not sure what the T and 55D stand for. Is there some other number you were meaning?
 
What board are the bad transistors located and the "Q" reference or "Equipment list" item.
The transistors you reference might be replacements from a previous repair?
 
They are on the Tuner Unit. I don't have any experience on how to read the schematics of a circuit board. So I have no idea how to locate them on the schematic. Below is a pic of the board. I've circled where the 2 transistors are located and I included the schematics. The one on the top left has the number T C373 on it and the other has C738 55D. If you need a better pic I can take one after I get home. I hope this helps.

upload_2017-9-22_12-26-42.png

upload_2017-9-22_12-31-39.png
 
I assume you've diagnosed this and it is not related to the speakers (by swapping sides), cables (including both speaker wires and source to receiver cables), or dirty controls or switches?
 
When I tested them with the multimeter I got a reading no matter how I connected it. That's why I thought they were bad. At the time I thought I was checking the Amp Board but after looking at the service manual I realized it was the tuner board. Should I go back and check the Amp board?
 
Yes, and you'll have to remove the transistors to test properly.
Check and see if the pop and crackle are only in the Tuner and Phono. Run an AUX input and hear if it pops and cracks. This will isolate the boards to check.
 
Still would like to know that you've eliminated switches, pots and cables before going inside. 90% of problems of this nature with vintage receivers are related to those.
 
yes I have tried swapping the speakers and I still get the static on the right speaker input. It doesn't matter whether it's the A or B speakers either. Also I cleaned the knobs. When I turn any knobs the sound doesn't change so I don't think they are just dirty. I will check to see if I can hear it with the volume down and get back to you.
 
Ok I just tried going through AUX and both tape deck inputs with no change. Also there is no sound when the volume is down. It sounds more like a muffled distortion with some popping form time to time without even touching the knobs. The popping does get louder the higher I have the volume.
Anything else I should try before taking the Amp board out to test the transisitors? Also should I be testing any other parts?
 
Now we know the problem is in the preamp section. The easiest way to find this (probably a bad transistor) is to buy a can of freeze spray (sometimes called "Circuit Cooler") and spray a very small amount on each transistor in the preamp, one at a time, waiting 20 seconds or so between. The transistor you cool that makes the sound go away or get worse is the bad one. Turn the volume up just enough to hear the popping so you don't blow your speakers.
The preamp is the board that the tone controls are mounted on, AWG-011. It only has 2 transistors on it and one is probably bad. The other thing it could be is a bad capacitor.
 
Last edited:
I thought I would test the capacitors while I wait to get some freeze spray. I found 2 that didn't give me a reading so I'm pretty sure they are bad. The numbers on them both are 1/25 m sanyo. The table below shows the part numbers but I'm not sure what to search for. How do I find an equivalent?

upload_2017-9-22_21-25-43.png
 
If that is what you pulled out then replace with the same values.
Not sure what board your working?

I found this in the database:
SX-525

Head Amp Unit (AWF-003)
AWF-003: C1: 3.3uF 16v CSSA: 647-UKL1H3R3KDDANA 3.3uF 50v
AWF-003: C2: 3.3uF 16v CSSA: 647-UKL1H3R3KDDANA 3.3uF 50v
AWF-003: C7: .47uF 25v CSSA: 667-ECQ-V1H474JL .47uF 50v
AWF-003: C8: .47uF 25v CSSA: 667-ECQ-V1H474JL .47uF 50v
AWF-003: C9: 3.3uF 25v CSSA: 647-UKL1H3R3KDDANA 3.3uF 50v
AWF-003: C10: 3.3uF 25v CSSA: 647-UKL1H3R3KDDANA 3.3uF 50v
AWF-003: C15: 100uF 35v CEA: 647-UPW1V101MPD 100uF 35v
AWF-003: C16: 100uF 35v CEA: 647-UPW1V101MPD 100uF 35v

Control Amp Unit (AWG-011)
AWG-011: C1: .47uF 25v CSSA: 667-ECQ-V1H474JL .47uF 50v
AWG-011: C2: .47uF 25v CSSA: 667-ECQ-V1H474JL .47uF 50v
AWG-011: C5: 100uF 6.8v CEA: 647-UPW1C101MED 100uF 16v
AWG-011: C6: 100uF 6.8v CEA: 647-UPW1C101MED 100uF 16v
AWG-011: C7: 1uF 25v CSSA: 647-UKL1H010KDDANA 1uF 50v
AWG-011: C8: 1uF 25v CSSA: 647-UKL1H010KDDANA 1uF 50v
AWG-011: C19: 47uF 50v CEA: 647-UPW1H470MED 47uF 50v
AWG-011: C20: 47uF 50v CEA: 647-UPW1H470MED 47uF 50v

Main Amp Unit (AWH-006)
AWH-006: C1: 1uF 25v CSSA: 647-UKL1H010KDDANA 1uF 50v
AWH-006: C2: 1uF 25v CSSA: 647-UKL1H010KDDANA 1uF 50v
AWH-006: C7: 220uF 35v CEA: 647-UPW1H221MPD 220uF 50v
AWH-006: C8: 220uF 35v CEA: 647-UPW1H221MPD 220uF 50v
AWH-006: C9: 47uF 50v CEA: 647-UPW1H470MED 47uF 50v
AWH-006: C10: 47uF 50v CEA: 647-UPW1H470MED 47uF 50v
AWH-006: C17: 2.2uF 50v CEA: 647-UPW1H2R2MDD 2.2uF 50v
AWH-006: C18: 2.2uF 50v CEA: 647-UPW1H2R2MDD 2.2uF 50v
AWH-006: C21: 10uF 16v CEA: 647-UPW1E100MDD 10uF 25v
AWH-006: C22: 220uF 50v CEA: 647-UPW1H221MPD 220uF 50v
AWH-006: C23: 100uF 50v CEA: 647-UPW1H101MPD 100uF 50v
AWH-006: C24: 47uF 50v CEA: 647-UPW1H470MED 47uF 50v

Power Supply Unit (AWR-007)
AWR-007: C5: 220uF 50v CEA: 647-UPW1H221MPD 220uF 50v
AWR-007: C6: 47uF 16v CEA: 647-UPW1H470MED 47uF 50v
AWR-007: C7: 330uF 35v CEA: 647-UPW1V331MPD 330uF 35v
AWR-007: C8: 470uF 25v CEA: 647-UPW1E471MPD 470uF 25v
AWR-007: C9: 220uF 25v CEA: 647-UPW1H221MPD 220uF 50v

CR Unit (AWX-012)
AWX-012: C2: 33uF 10v CEA: 647-UPW1A330MDD6 33uF 10v

BOM List
647-UKL1H3R3KDDANA | 4
667-ECQ-V1H474JL | 4
647-UPW1V101MPD | 2
647-UPW1C101MED | 2
647-UPW1H470MED | 6
647-UPW1H101MPD | 1
647-UPW1V331MPD | 1
647-UPW1E100MDD | 1
647-UPW1H2R2MDD | 2
647-UPW1H221MPD | 5
647-UKL1H010KDDANA | 4
647-UPW1E471MPD | 1
647-UPW1A330MDD6 | 1
 
You must log in or register to reply here.

Similar threads

PapaGino
Crackle and pop on a SX-525 with DIY speaker plugs
2 3 4
Replies
72
Views
7K
microchannel
M
B
Pop/crackle in right speaker
Replies
0
Views
126
Brett027
B
F
Pioneer SX 525 and SX 939
Replies
4
Views
2K
Oldsansui441
Oldsansui441
C
sx-525 LOUD pop when engaging speaker?
Replies
2
Views
441
larryderouin
larryderouin
R
Work to do on SX-525
Replies
0
Views
418
Rock&Roll
R
Back
Top Bottom