Halisson
Member
Hello everyone,
I'm having trouble with a Sansui 9001.
The equipment is in very good aesthetic condition and little or no technical intervention. I did preventive maintenance replacing the resistors and transistors to92 of the F2624, overhauling the output transistors, replacing the capacitors of the F2624, F2638, F2639, F2689, F2636. In these boards, I replaced the transistors for TO92, among other components that aesthetically had some alteration (resistors, diodes) relays cleaning with DeoXit or ultrasonic bath.
It turns out that when using 2x mode, the equipment when coupling the relay makes a POP, releasing a certain voltage to the point of audibly disturbing the speakers, and also occurs when turning off the equipment. In 4ch mode, it's perfect, no POP on power on or PowerOff system. I stopped the exchange of components and validation of the other points because I want to resolve this issue before further procedures.
This problem already occurred before replacing the above components. I inverted the F2624 boards for testing, unsuccessful.
It is working perfect with quality response and testing 2x or 4ch mode the device, just this problem after power on ( POP on coupling speakers) , or power off immediately ( POP, again );
The timeline follows the flow:
00 sec - Turns on the device;
01: 10s - 1st strong VU peak;
04: 20s - Release the sound ( POP speakers mode 2x ); ( No POP on 4ch mode )
Relays flow, in order of activation
1 ° F2634 4ch function switch & REC Relay 02 docks 1 ° I can't hear the action of Relay 01;
2 ° F2636 (volume and filter Circuit Board) Relay 03
3 ° F2689 (Circuit Board Protector) Relay RL601
In F2636, I already put the bipolar capacitors;
The measurement after coupling the relay, offset is at 0.00vdc.
If I increase the R601 relay activation time to 15 or more seconds, when docking the relay, there is still the POP. I read this article (https://www.qrxrestore.com/restoration-tips/ I had a customer who's unit developed a giant pop when switching to 2X. And then a unit on the bench that we had just recapped, did the same thing I had to use the scope, pour over the schematics and actually think, to figure it out Turns out that a cap that feeds the relay that switches to 2X mode has the cap marked backwards on the board This cap only comes into play in 2X mode, but audio passes to the right channel, and is reverse biased by 8v (installed backwards) It's a 50v cap, and I guess most caps could handle the reverse bias We just got a new bag of 2.2uf @ 50v caps in, and I guess they couldn't handle the reverse bias.) but that's not the case.
What may be happening?
My sincere apologies for the English translated by Google Translate
appreciate any help.
Regards,
Halisson
I'm having trouble with a Sansui 9001.
The equipment is in very good aesthetic condition and little or no technical intervention. I did preventive maintenance replacing the resistors and transistors to92 of the F2624, overhauling the output transistors, replacing the capacitors of the F2624, F2638, F2639, F2689, F2636. In these boards, I replaced the transistors for TO92, among other components that aesthetically had some alteration (resistors, diodes) relays cleaning with DeoXit or ultrasonic bath.
It turns out that when using 2x mode, the equipment when coupling the relay makes a POP, releasing a certain voltage to the point of audibly disturbing the speakers, and also occurs when turning off the equipment. In 4ch mode, it's perfect, no POP on power on or PowerOff system. I stopped the exchange of components and validation of the other points because I want to resolve this issue before further procedures.
This problem already occurred before replacing the above components. I inverted the F2624 boards for testing, unsuccessful.
It is working perfect with quality response and testing 2x or 4ch mode the device, just this problem after power on ( POP on coupling speakers) , or power off immediately ( POP, again );
The timeline follows the flow:
00 sec - Turns on the device;
01: 10s - 1st strong VU peak;
04: 20s - Release the sound ( POP speakers mode 2x ); ( No POP on 4ch mode )
Relays flow, in order of activation
1 ° F2634 4ch function switch & REC Relay 02 docks 1 ° I can't hear the action of Relay 01;
2 ° F2636 (volume and filter Circuit Board) Relay 03
3 ° F2689 (Circuit Board Protector) Relay RL601
In F2636, I already put the bipolar capacitors;
The measurement after coupling the relay, offset is at 0.00vdc.
If I increase the R601 relay activation time to 15 or more seconds, when docking the relay, there is still the POP. I read this article (https://www.qrxrestore.com/restoration-tips/ I had a customer who's unit developed a giant pop when switching to 2X. And then a unit on the bench that we had just recapped, did the same thing I had to use the scope, pour over the schematics and actually think, to figure it out Turns out that a cap that feeds the relay that switches to 2X mode has the cap marked backwards on the board This cap only comes into play in 2X mode, but audio passes to the right channel, and is reverse biased by 8v (installed backwards) It's a 50v cap, and I guess most caps could handle the reverse bias We just got a new bag of 2.2uf @ 50v caps in, and I guess they couldn't handle the reverse bias.) but that's not the case.
What may be happening?
My sincere apologies for the English translated by Google Translate
appreciate any help.
Regards,
Halisson
Last edited:
I suggest looking for bad solder joints, and possibly a grounding issue.