I have a Roland FP-10 in for repair and it has a flashing power light only when the button is pressed.
I’ve tried another power supply and tried reset, firmware update procedure, but the keyboard is the same.
Has anyone looked at these boards for a similar fault?
Could it simply be the button ?
Did you check to make sure none of it’s capacitors is leaking fluid or bulging in size? That’s what usually causes power supplies to die. You may need to replace it’s capacitors if you are familiar with soldering. It’s a fairly simple process. Just make sure the new replacement capacitors are the correct power rating or higher. That’s what to check for first. Also check the machine to make sure it doesn’t have a burnt out fuse. Hope this helps
Thanks all for replies.
I’ve manually powered on the board only via the pins and the current jumps up and down using around 200mA. I don’t think it’s the power button in that case.
The caps are polymer and not bulging. Can’t see anything obviously wrong with it. Can’t see a fuse either, but current draw on xpwr-sw going low suggests power is getting to the voltage regulator.
I’ve only got schematics for the jack and button/led panel board, so struggling a little.
I did notice it has a TI TPS65251 triple buck regulator, so will look at this first. Google AI suggests it’s the power regulation.
I need to check PGOOD signal and 3 rails of 5v, 3.3v and 1.2v next.
OK, so there’s a short on the LX3 output of the TPS65251 triple rail regulator. The 3.3v rail to be precise.
PGOOD was bad, so I checked each rail voltage and then resistance.
LX3 measures 17R and with the inductor removed, still 17R. So I know that the chip is at fault, not the down leg circuit. The other rails are around 170K
I’ve ordered another chip which will take a week to arrive.
Just a few other things to check, but hopefully this fixes the issue.
Google AI is pretty good at this stuff! Gives some really useful tips to help repair circuitry.
