G 7000 in protect

I have the receiver on a DBT and the light is dim but as I said the second relay will not engage.
 
It could be any number of things holding the protection circuit on.
it could be a power supply issue.
blown output transistors
and within those two things there are a number of subset issues too.

Get the service manual and start measuring your power supply voltages.

Is it a 48V relay? Might be I can't remember, check against the service manual voltages?

Takes all the guesswork out of it right?
 
Which voltages on which board specifically I have the service manual and needed some direction.
 
DC offset is very close to 0dcv on right and left channels does anyone have any ideas why the speaker relay will not engage. Thoughts appreciated.
 
IIRC the relay will not engage if the offset is too far out of tolerance, if this is happening then you cannot measure offset at the terminals. There should be two wires feeding back from the relay to the F2856 board. You are looking for the ones that attach to that board on pins 15 and 18. Once found measure from each of those to ground and see what you get. Doing this without a unit in front of me so a pic will help.
-Lee
 
Work backwards from Tr609,Tr610,Tr611 checking DCV
Tr609 is on to engage the relay, if Tr610 is on the this indicates a fault condition, depriving Tr609 of drive, thus it is off.
 
Lee thanks I was able to check DC offset between output emitter resistors and have .5 mv and 1.2 mv right and left channel. Trying to evaluate the protect circuit mentioned above. tr 609 has no voltage going to base. Working back what voltages should I have on the transistors working back, tr 610 etc
 
There are a few possibilities.
1) SCR601 is turned on if there is a over current situation. It gets its gate drive from Tr03,04. need to check or remove SCR601 to see if it is that the cause. If so have to check scr or the ckt driving its gate.
2)Is Tr610 turned on? need to check if it is being driven. Normally, Tr610 is off and Tr611 is on depriving Tr610 of drive. Need to check out all the components in this circuit. Could remove Tr610 and verify that the relay engages. Do this with the speakers disconnected.
3) Is there +30V supply to the ckt? check junction of R620,R622,R623
4) C617 is the power on delay. It charges and always drive for relay drive Tr609

Good luck
Rick
 
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