sansui au 2000 power supply voltage change over

[petehall347]

ok finally found it .. sorry .

 

[petehall347]

right now 24 and 25 appear to be out to lunch right now .

 

[vic]

sorry for poor resolution .. but its centre left

ok this is what I have

 

[petehall347]

sorry cant figure it out from board layout .

 

[vic]

sorry cant figure it out from board layout .

ok thanks maybe someone else will have an idea. I mean everything is working thanks to you just wondered whether this is a problem? Someone has done this for a reason I guess.

 

[petehall347]

where the plugs might go appear to be shorted together looking at the pic .can you confirm this ?

 

[vic]

where the plugs might go appear to be shorted together looking at the pic .can you confirm this ?

yes there is like a welded wire there

 

[vic]

where the plugs might go appear to be shorted together looking at the pic .can you confirm this ?

Pete I decided to removed that wire that shorted the 2 pins and plugged 24 and 25 back in and all good. Puzzles me why this was done?

 

[petehall347]

i could hazard a better guess if i knew where the wires ended up .

 

[vic]

i could hazard a better guess if i knew where the wires ended up .

Ok after the change amp worked for about 45min, Now gone in protection mode and staying there so the reason 24 and 25 were shorted was to stop it going in protection mode, I have taken a few close up pics where the wires go. I'm not sure what part No the circuit board is, If you follow the 2 grey wires No.24 and 25 you can see where they go, thanks
ps let me know if u need more pics

 

[vic]

Ok after the change amp worked for about 45min, Now gone in protection mode and staying there so the reason 24 and 25 were shorted was to stop it going in protection mode, I have taken a few close up pics where the wires go. I'm not sure what part No the circuit board is, If you follow the 2 grey wires No.24 and 25 you can see where they go, thanks
ps let me know if u need more pics

just done another clean of that circuit board and I have it going again will see what happens when it warms up. OK been on now for over 2 hours and all good, Strange!! does that mean just a good clean fixed everything?

 

[petehall347]

still not seeing what those wires connect to . need component id numbers .

 

[vic]

just done another clean of that circuit board and I have it going again will see what happens when it warms up

just done another clean of that circuit board and I have it going again will see what happens when it warms up. OK been on now for over 2 hours and all good, Strange!! does that mean just a good clean fixed everything?

still not seeing what those wires connect to . need component id numbers .

Ok got it its the F-2497 circuit board for installing emitter resistors
It went to protection again, when I unplug 24 and 25 then plug them back in it comes out of protection for around 20 min. then goes in protection again

 

[petehall347]

do the wires connect across thermistor PR01 ? if so one of them is either detecting too much heat or is faulty .

 

[vic]

still not seeing what those wires connect to . need component id numbers .

And to you too Pete

do the wires connect across thermistor PR01 ? if so one of them is either detecting too much heat or is faulty .
So the way it was shorted was to bypass this? Is it safe to leave it shorted or will it cause damage in the future?

 

[petehall347]

it is best to fix properly so it works as intended .

 

[vic]

it is best to fix properly so it works as intended .

ok, yes those wires go to the PR01 they are both numbered 10 and 10 on the circuit board this is one of 2 boards labelled F-2497 the one we are looking at is the front one.

 

[petehall347]

does the main heat-sink on that side run hot ?

 

[vic]

does the main heat-sink on that side run hot ?

no all the Output Transistors hardly heat up. Most of the heat comes from the 2507 and 2508 boards

 

[petehall347]

any markings on the pr01 thermistors ?