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Sansui G-5700 no sound

yes the wire off the diode would explain it . it should just solder back on .you might need to remove some insulation from the lead . post a picture.
get the correct fuse . 125v rating will be fine but has to be 2amps see what other markings on the fuse .it will determine whether slow or fast blow . i am thinking it will be fast blow . if it has a T it is slow blow . T being time delay .
you say continuity between transistor pins ? are you testing 3 pins to each other on one transistor then 3 pins on the other one ?
 
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im sorry I did not get continuity between the pins of one transistor at a time, so I only tested them one at a time, I soldered and I posted a pic of the diode soldered on their. I will be get a new fuse tonight and will post back on tonight.
 

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ok near on 1.30am here plus had a few beers . try with new fuse in . using instructions from earlier post again .
good luck .
 
I put the new fuse in and the same thing is happening... no lights on the receiver just a bright bulb in the dbt.
 
ok I found two pieces touching each other I fixed it and now it turns on, I tried doing the bias adjustment and I put it at zero and when I barely move the adjustment it turns off and the dbt lights up bright, and I tried to just keep turning it and it only went up to .7mv. but I didn't even get it up to .1 before it turned off.
 
did you turn it past the original setting ?
are you reading the meter correctly ?
try turning it back down to see if amp powers up ok .if so check the other channel at the same points on the other output transistor board . don't adjust it though
 
ok the other side was all over between .1-.40 but after about a minute it was at .9mv, the other side is still at .0mv
 
i have a feeling it might be the wattage of the dim bulb tester isn't high enough . do you have a 80w bulb ?
 
I will try a 75, I have a bigger one also if you think I should try that...it does the same thing
 
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i am suspecting now a resistor or 2 may be blown . 2 ways we could go about this .one is check all resistors side for side whilst still soldered in and unsolder if reading high or low in bad channel and test again
next way to make sure its not just the current being limited too much by the lamp is turning the bias down on the good side and trying to adjust the bias on the bad side . this i feel would be the easiest next move .mark where the bias pot is set before moving it . it is vr3 by the way .
 
I tried turning down the bias on the good side and adjusting the bad side and the same thing happens...i will try to check each resistor by the one i replaced but i don't know what they are suppose to be about
 
ok good side resistors are odd numbers ..bad side are even numbers and one digit higher ..so for examples r53 is in good channel same placement and expected value in bad side is r54 . .all the values are on the schematic plus they are colour coded . here is an online colour code calculator .http://www.dannyg.com/examples/res2/resistor.htm
power off and unplugged .
 
ok so the new one (R58) is not the same as the original on the good side, also the one all the way to the right (R70) on the bad side is not the same as the good side.
 
r70 is a fuse resistor 220 ohms and would affect the bias circuit unsolder one side and test again .
if its open or high it would also affect the reading on r58 whilst in circuit .
while r70 is unsoldered check r58 again in circuit it should read 1.2k ohms or pretty close
 
if that's how i see it then 0.22k = 220 so ok
r58 should be 1.2k . so tr20 needs testing . its is PNP .ECB looking at the flat side pins down .
 
TR20 detects DC and activates the protection, you can pull this transistor out if you think its a problem, it does not need to be installed for the amplifier to run, but I have never seen one of these fail in all the G5700/6700/7700 I have repaired, which is quite a few..........
 
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