Roland F140R piano won't start up

[Nyqusit5]

Hi all,

I am looking for a service manual for a Roland digital piano that won't start up.
This one has a front panel power switch that actually controls the 5V (regulated from 12V) power to the digital section. Power is present in the piano and the 5V is effectively switched on by pressing the switch but nothing lights up (even the switch itself) and no sound is produced... A schematic would be of great help!

[nosaj]

Roland schematics seem very hard to come by. I've usually had to wing it. I usually find the Voltage regulators and see what the outputs are from there. So find your 5v regulator and see if it is putting out 5vdc, if not see what the input voltage is to the 5v regulator If lower than 7v or so you will have to check check the transformer by disconnecting it from the PCB's Then see what the secondaries measure that feed the 12v.

nosaj

[Nyqusit5]

Thank you for your input Nosaj, but I have already been through this. As I mentioned, the 5V is definetly present on the output of the regulator (as well as on the digital board) and switch on as it should be.

This is why I am looking for a schematic now.

[nosaj]

Ok. I'm pretty sure there are more than one regulator in that circuit. What about a 12v,15v,or even a 3.3v?
You will fly blind on this one. as roland won't likely give you one.
Good Luck
nosaj

[Nyqusit5]

Hi Nosaj, thank you for tipping in.

As long as I know it is out there, I will keep on looking and asking for it!

The keyboard is supplied by a 12V input and there is only one regulator. Rest assured that I have checked out all of the obvious as I have repaired litteraly hundreds of keyboards. This is a recent generation keyboard with a dense smd board and navigating through it requires a schematic.

Still looking!

[Kevina]

If you know a tech who does actual warranty work for Roland, they will be able to get the service documents for you. Sadly, I am retired now, so I no longer have access.

[Jazz P Bass]

So where does the 5vdc from the switch go?
If it goes to a microcontroller you may be out of luck.
Then again it may go to a jfet.

[Nyqusit5]

This is not your traditional keyboard/digital piano with one in and simple multiple output potentials.

The 12V goes from the "in/out power board" to the digital board and back to the "in/out power board" where it is regulated to 5V if the mains switch is depressed (it works here). The 5V then goes back to the digital board (it does here).
It seems one brach of the power supply is missign because even the power contact switch doesn't light up red when power is connected AND before it is depressed. But the digital board is so densely populated and the smd part of the "in/out power board" is so complex that it cannot be traced.

This is the reason why a schematic is sorely needed...

[Nyqusit5]

Still looking for the schematic of this electronic piano...

[Jazz P Bass]

Maybe there is a circuit that is something close that they have used in a previous model.
https://www.synthxl.com/manufacturers/roland/

[Nyqusit5]

Yes, that's a good point. I already had a look around and couldn't find one that was even close. The F140R is fairly recent and I couldn't find a digital piano or synth that used the same type of circuit and that had an accessible service manual (the F701 seems to be a candidate for exemple).

[Nyqusit5]

Still looking for this schematic... At least, the power distribution and start-up part....!

[Enzo]

Did you directly contact Roland to ask if they could provide or sell the service manual?

[Nyqusit5]

Yes, but they won't...

[Nyqusit5]

Still looking for the schematic.
The power distribution and start-up part would be enough!