@oldturkey03 I have possibly the same issue. I have the 12V 1A supply from my other Yamaha that I expect should work. The previous owner did not have the power supply and stated she tried to plug in one from something else. The power light never lights up.
My board looks identical but shows YM752 instead of YJ422. Do you know the difference between them? I can't find anything on the YM752.
I have to hold down the power button to get any power to come through. If I do this, I measure about 11V at test point 1. I have 4.95V at test point 2. Test points 3, 4, and 5 all show only .13V. This indicates that IC26, IC24, and IC2 would all be bad on the DM board. However, I don't know if that is the case since the board number is different. Any advice here is greatly appreciated. I don't want to order a YJ422 board and have it not work. Or a new YM752 and have that not be the issue even.
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=== Update (10/01/24) ===
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@oldturkey03 The test procedure above states it is for "No power indicator with power switch on". I have no power indicator so I followed that procedure. The board with the switch is only a simple button and all the controls are back on the DM board.[br]
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Now, the YM752 that is in mine can be found online and is listed for the P125. I see that the YJ422 is listed for the P128 online. However, the service manual, it shows that the YJ422 should be in the P125 so this is why I am confused. The boards look identical from what I can see, but I expect the P125 and P128 must have different programming. [br]
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In the manual, the JK board shows mosfet Q104. Mine does not have this component at all. There is a place for it but just nothing there. R104 is also missing as well as a bunch of other components shown. My model is just P125B but I see the ones in the service manual are listed as P125B/P and others. I expect they are a bit different. It is all rather confusing.[br]
@oldturkey03 I have possibly the same issue. I have the 12V 1A supply from my other Yamaha that I expect should work. The previous owner did not have the power supply and stated she tried to plug in one from something else. The power light never lights up.
My board looks identical but shows YM752 instead of YJ422. Do you know the difference between them? I can't find anything on the YM752.
I have to hold down the power button to get any power to come through. If I do this, I measure about 11V at test point 1. I have 4.95V at test point 2. Test points 3, 4, and 5 all show only .13V. This indicates that IC26, IC24, and IC2 would all be bad on the DM board. However, I don't know if that is the case since the board number is different. Any advice here is greatly appreciated. I don't want to order a YJ422 board and have it not work. Or a new YM752 and have that not be the issue even.
@oldturkey03 I have possibly the same issue. I have the 12V 1A supply from my other Yamaha that I expect should work. The previous owner did not have the power supply and stated she tried to plug in one from something else. The power light never lights up.
My board looks identical but shows YM752 instead of YJ422. Do you know the difference between them? I can't find anything on the YM752.
I have to hold down the power button to get any power to come through. If I do this, I measure about 11V at test point 1. I have 4.95V at test point 2. Test points 3, 4, and 5 all show only .13V. This indicates that IC26, IC24, and IC2 would all be bad on the DM board. However, I don't know if that is the case since the board number is different. Any advice here is greatly appreciated. I don't want to order a YJ422 board and have it not work. Or a new YM752 and have that not be the issue even.