Old Motifator threads are available in the Archive.
5pinDIN
![]() Total Posts: 11891
Joined 09-16-2010 status: Legend |
Welcome to the forum.
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The voltage regulators don’t tend to fail.
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The electrolytic caps previously mentioned are typically what needs to be replaced. It’s not necessary to order such parts from Yamaha. Your member profile doesn’t indicate your location, so making recommendations for parts suppliers is difficult. In the US, Mouser Electronics and DigiKey Electronics are usually good choices. |
m1muzik
Total Posts: 3
Joined 11-24-2018 status: Newcomer |
5pinDIN - Thanks for the fast reply! Yes, I am located in the United States. I’ll check those two places to order the rest of the capacitors that I need to replace. I have noticed on PSU board that there are darker lines coming from one of the regulators, I figured the regulator in that section would be burnt or needs changing. I’ll continue to replace the capacitors in my case and see it that resolves my power on errors. Thanks again! -M1muzik |
5pinDIN
![]() Total Posts: 11891
Joined 09-16-2010 status: Legend |
You’re welcome. Have you checked voltages to determine if the regulator is/isn’t functioning correctly? Sometimes bad caps can cause excessive dissipation in such a device, or heat sinking is insufficient due to a mounting issue. Typically Yamaha doesn’t manufacture the power supply, it’s purchased from another supplier. Therefore there’s usually no schematic or parts information for it in the SM. Yamaha provides a part number for the entire PSU. If you need to replace the regulator, what identification do you see on the part? |
m1muzik
Total Posts: 3
Joined 11-24-2018 status: Newcomer |
Hello, Sorry for the late reply, I had forgotten my password and tried several times to reset my password and finally I was able to login back. Thank God I had found my password written somewhere in my phone, the password reset on this forum doesn’t work. Here is a picture of the PSU board. The middle section looks alittle dark especially around the voltage regulator area. |
avanlooveren
Total Posts: 1
Joined 12-31-2021 status: Newcomer |
Howdy, folks! Joined the forum just so that I could report the successful repair of my S90 based on this thread. So, first, thank you all! For the link to the service manual and also the descriptions of the issue and solution (replacing capacitors). My S90 also (over the course of a year or more) began displaying the unregistered interrupt error screen over a year ago. And the “solve” of leaving it powered up to “warm up” and then be stable was getting more protracted and inconvenient over time. Came across this thread, found some time and a cheap O-scope (FNIRSI DSO Pro), and then replaced some 47uF surface mount caps, and voila! My S90 boots up straight away now. So, 1) I wanted to thank y’all and 2) I thought it might be helpful to someone to have some details on my findings in this fix. I looked at IC’s 2, 36, 46, 47, and 57 (all voltage regulators).
IC Vin P-P Vout P-P CAP fix_P-P_in fix_P-P_out
(I tried to use BBCode for tables, but that didn’t work out.)
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adi_h
Total Posts: 1
Joined 02-16-2023 status: Newcomer |
I just signed up to report another successful repair of an S90 based on this thread. Thanks a lot to everybody in this thread for sharing all this valuable information! It’s hard to google the error message, because the codes in it can change. One day I had this error:
=== system down ===
Another day this one:
=== system down ===
I used the service manual to find the three capacitors C9, C124 and C125 (see page 35 and 36). I don’t have any device to measure anything on the board, so I just replaced the capacitors with new Panasonic ones (radial, not SMD). I removed the original SMD capacitors first.
That’s what I used as replacement:
It’s important to put the new capacitors with the right polarity.
Attached images:
Thanks again! Image Attachments
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