When you get the new power resistors in, hereby some hints.
As Yamaha suggests, they should be kept off the board.
Well...... right..... then this would happen..... the PSU control board would clash with one or more resistors
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MUCH MUCH better would be to mount those resistors on the back side of the PCB, as they get plenty of free air and the heat is kept away from that confined space on the component side, avoiding all kinds of long term issues. The longer the legs the better to reduce the stress on the PCB tracks; those resistors get hot and expand. The large number of power on-off operations cause as many thermal cycles. Also less heat is dissipated to the PCB.
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Not the nicest piece of work regarding the tracks, but my board was really fried....loosing various pieces of copper tracks in the process. I had to insert special rivets (and to get the $300 PCB riveting tool for that). I did bent the legs of the power resistors towards each other for more mechanical hook-up strength and in some case replacing the lost tracks.
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Here a view after final re-installation; it shows the space and air the power resistors have; it really works out well: the components on the other side stay nicely cool, as does the PCB. Nice warm air flowing out of the top; they really do get hot.
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Now that I am on it; I have to warn you for an important **** up by Yamaha: one of the + marks for the left 50V/1000uF capacitor is on the wrong side.
And so did I wrongly install that cap:
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So what happened.... due to power resistor in front of it, it did not explode in my face (current limiter, for once....). I had one spare, replaced it, and all starting to work fine.....ooooffff
ESR value had tripled, though capacitance was still near 1000uF. When I opened up that cap 4 weeks later (for fun), it had a huge pressure inside ! Like it was boiling. No joke thus.
However, these caps are part of the power rails to the PSU control board which didn't work correctly at all (no surprise). It did afterwards, but only after the following happened as well:
Another BIG WARNING: do NOT power up the unit without the PSU control board inserted to the PSU capacitor board !!!! Because those 1000uF/50V will see ~65V in that case. In order to have the voltage below 50V, there must be a current flowing through those power resistors (i.e. the rails need to be loaded). In case the control board is not inserted, those power rails are not loaded and thus raise to the voltage upstream of the power resistors !!