G7000 With NO Driver Board F-2856

sansuilove

Active Member
Hello everybody.
I recently acquired a nice looking G7000.
But the heart of it was taken away : F-2856.
Searched for it on the web but nothing..
I assume the only alternative I have in front of me is ordering a PCB? anyone has any experience with this kind of work?
Thank you .
 

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I think you may need to look for a parts unit or use that one as a parts unit. Ordering a new card would be impossible I believe; as the Sansui of today has little or nothing to do with the Sansui of the past. The 7000 is a great receiver and well worth the effort to get it working.
 
I thought about ordering a custom made (China) pcb.
Had a look at the parts and nothing special there . Was happy when I saw no coils/thermistors or any hard to replace components.
Maybe 2sk109 is the toughest.
 
thought about ordering a custom made (China) pcb.
Eek!!
Why was the pcb yanked = probably because the pcb was smoked beyond repair.
To be honest, I'd suggest to forget about the F-2856 and use a different amp.
Suggest to use a LME498xx based design as it is the simplest!!
Good luck ever getting a real 2sk109, unless it is pulled from an old unit.
You could look at the Elektor Q-watt design, it is a good design

I have a old G-7500 that smoked the transformer primary, I plan on putting in a transf/PS from a parted-out Pioneer SX-1050 and use a LME49830 with Semelab lateral MOSFETs.
 
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Hi rcs16,thank you for the answer.
I read on another forum that 2sk109 can be replaced with 2n3819 (I believe 2 of them)
About the LME498 etc - I have no idea what is that.
 
Unit stays in protection , discovered that ZD602 was shorted + R612 out of specs (0.3K instead of 10ohm)
What I would like to ask is - should ZD602 anode get the same voltage as the base of TR606?
ZD602 Anode = (-58V) . Cathode = (0.0V)

TR606 - 2sb507
 

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I'm having an issue with ZD602 - RD33E (33V 500mA Zener)
Measured voltage at the Anode and I get -59.6V .

Pulled out TR606 - nothing changed.
Voltages of TR606 :
E = -41.5
C = -59.6
B = -59.6

Is this normal?
Thank you
 
You mean the voltage goes first to ZD602 and then to TR606? I took all measures when both ZD602 & TR606 are OUT of circuit.
 
zd602 being a zener and one end tied to ground holds the voltage down to its preset value .. 33v in this case .
 
check continuity to ground at its other end ..i bet if you check other side voltage it will read about 800mv different and positive .
 
Doing right now .. don't go please :)

Edit :
Holy cow! both sides have continuity to ground!
and the cathode side gives 0.003v
Anode side gives -59.6
 
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it should measure 33V right across it in circuit but isn't so .turn the power off first .
diode test zd602 and see what it measures . in theory its open circuit and will need replacing
 
I tried replacing it with 35V zener diode and it blew right away. the voltage at the TRACE of the anode is as I said -59.6V so any diode will blow. am I correct?
 
what is the current rating for the replacement ?
what value is r611 reading ? it should be 5.6k and limiting current somewhat .
is tr606 correct and right way round ? make sure its not shorted base to collector .if it is then there is only 10 ohms between the zener and power supply .
there will be -58v without the diode installed or if open .
 
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I'm using EQA01-35R diode (35v) . 500mA .
R611 reads 5.64K one leg pulled for test.
Tr606 tested out of circuit not shorting anywayz

Voltages at R611 is -52/-38
At the EQA01-35R diode it measure -38 anode side and 0.002 at cathode side.
 
have you got a pnp transistor with high enough ratings to try in tr606 place ?
just another idea ..unsolder tr606 emitter and be sure its not connecting .power up and get voltages for B C and E
 
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