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M -1000/U Main circuit board 1 help

gosmeyer said:
:)I’ll take the board off your hands if ya find it.
Manual is amazing.
Click to expand...
mine is a full assembley with amplifiers and everything else. Not sure that I want to part with it.

check out the one on the auction site where that photo came from...search for MX-1000
 
Well, that’s on the way. I got him to move some.
Much cleaner than what I have. Guess I have some spare parts now:)
 
Somebody went through a lot of trouble to label most of the components on one board as well as re-capping that board. The other board has 4 replacement emitter resistors -- So possibly has some new output transistors as well.
 
gosmeyer said:
Well, here’s the reason for the whole thing.
Get ya a gander at this:eek2:



View attachment 1950041 View attachment 1950043 View attachment 1950044 View attachment 1950045 View attachment 1950047 View attachment 1950048
Click to expand...
ouch!
the original boards can be repaired, but they won't win any beauty pagents

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as the man said, bunch of emiter resistors replaced. You probably need to replace all of them to make sure they are as close as possible
what I do nto see is any factory modes...so you would have to iplement them.
IIRC,
E01xx no modes
E02 to midE02, manual modes done by Yamaha (factory or service center, not sure which
E02 mid < revisions implemented in the amplifier boards

this is how the new boards version looks like (mid E02xx and above)
MX_Amp_Brd1.PNG
MX_Amp_Brd2.PNG

here is how the drop-in replacements for thise emiter resistors look like
MX_Amp_EmiterRes.PNG
 
Thanks,
Think ya be able to find one of your old parts list? If not it’s time to put pen to paper.
I was reading about the mods per version.
 
upload_2020-8-11_14-55-55.png

this is the product of someone's work trying to remove the amplifier boards. I do not see any other explanation for this type of damage.
 
I don’t know brother, I have never seen anything like it. I’m sure there is worse but I haven’t seen it personally.
She’ll be a champ again :music::rockon:
Thanks for staying in the loop. Appreciate your skill set on these.
 
Alright, back on this after some home remodeling-
After installing the new very nice main board from the bay and a lot of new parts on the subs I decided plug in the DBT and light it up.
As a result R316 smoked. You can see in pics that it had damage there before but labels are over the discoloring.
R310-R330-R316 were new.
This was it’s 1st power up.
Suggestions where to start tracking?
715B2764-118F-44A5-90BC-1E9588DCB41E.jpeg2973D1F1-7E4B-4918-B11E-CB690705D4C0.jpeg
Thanks
 
Q304,312 and 310 are suspected shorted... Resistors don't burn up " just because" ....
 
Look over the rest of the greenish fusibles that are mounted standing on end.On that board.
 
Fusible all “Look” good, no discoloring.
I’ll pull Q304 Q310 and Q312 out in the AM when I get home from work. I’ll have to do some reading on test procedure. Never checked any transistors let alone dual transistors.
NPN or PNP ?
Thanks
 
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