I’m sorry but a P250 or any electronic keyboard that takes “between 50 and 90 minutes” to power on, you cannot say “everything is working fine”... it’s broken.
Boot up time should be measured in seconds (2 or 3 maximum). Doesn’t sound to me that it’s a problem of it doing anything during that time (there is no system to load as in synthesizers). It sounds like a bad power source, a broken connection, or some other anomaly. And the range of 50 minutes to 90 minutes sound ridiculous... it may simply be that a loose or broken connection that finally makes contact when you jar the instrument. There is nothing it could be doing all that time... there is nothing for it to be doing.

You should take the instrument to a qualified authorized service center... we cannot give out service routines here, nor could we diagnose the issue from the description given. I couldn’t imagine something taking that long to power on

I have some video recorded with the starting time that proves the 01:31:19:14 starting time.

NO THANKS... to be perfectly honest I won’t watch a video for an hour and a half waiting for it to power On — please don’t waste any time or energy posting that!!! Why would you even film that? 🙂

Your best bet is to see a qualified authorized service center and if the cost is as much as, or more than, the 17 year old product is worth, you may consider updating the instrument, with a newer Piano. You can find that a Yamaha P45 or P125 will give you a quality sound for about what it might cost to repair. The P300 replaces the P250 if you need a similar feature set.

Hope that helps. Reach out to your regional a Yamaha office again...

Dear Yamahasynth people (Bad Mister)!

Thank you for your answer.
Reading your answer it was already clear that this service issue is far beyond your technical knowledge. No problem, how to solve it is in the air just please be open to manage it!
Please consider that the age of an instrument does not necessary determine it's state in quality or working condition (I have (and had before) older instruments that are working perfect as Kurzweil K2500X, Ensoniq TS-12, Roland W-30, Roland JD-800, Roland SH-101, Yamaha DX-7 and DX-21 and few of synth modules that I don't list here). If it is necessary, please ask any of those performers, who are playing on good, pro made stuff and not plastic Chinese bull...(I know, everything can be sold and that's fine for making good bussiness!). We all consider that a good instrument with a favorable take care is the base of our performance. (Like the well known evergreen melodies. If they live more than 5 years, they'll live forever!) I'm don't know anything about your experience in this field, so please inform me about your knowledge in this field! Me personally I am ready to learn new things, to know better the world I am living in.
So, as I wrote I already sent some messages to the Yamaha Service department from my country, but have no answer. I called them on phone, no answer. () These were online contacting methods, without any Covid 19 infection danger!
Please consider that if I could handle locally a problem, I don't loose extra time, extra nerves and stress for a far distance solution.

Dear Bad Mister!
I also think that belief in something That's not (could not be) the part of resolving an service issue! This is an material issue, that can be solved with knowledge, working mind and and a good partnership inside the tech personnel group!

So the problem is real (you believe it or not!). The delay in starting time is real! It is not bad contact, it;s not the power source, but it could be the test routine software is hooked up and waiting for some hardware answer (the engineer who made the software knows exactly what is about!), or it could be the bad FlashRom! That is the service tech departments task to help in resolving it. That's what I can't do by myself!

Dear Bad Mister!
You don't need to watch any video for that long amount of time, I have the recordings only as a proof if I will need it, I will use it.

It could be interesting for you to know that I am also a qualified service technician and I made service for an other well known electronic instrument company in Romania for 5 years, and I resolved all the problems that appeared in that time (believe me changing the mother board was the last thing that I made for a customer! I changed CPUs and other integrated circuits with more than 80pins, with soldering iron)!

I hope nobody's thinking that anyone who does not repair Yamaha is an enemy that is against somebody!
I know why I left servicing and became a musician praising God with my music. Now I want to do exactly this on my Yamaha P250 piano that I bought on money!
So is there any big deal in this?
I think all this service issue resolving procedure is an opportunity or you can call it a test in humanity, technical competence and off course time (we all have 24hours per day to live, to give).
It's not about selling, buying, marketing or who knows what kind of ordinary, every day routine.
I also know that repairing good stuff is better than throwing it out and buying a new one! Just imagine a mother throwing her child out and give birth to a new one, instead of washing that she has!

Finally I want to ask you, please send my service issue description to a qualified service tech employee of the Yamaha Service team, maybe if possible to the service department chief engineer.
God bless you and your beloved.
Thank you

Best regards

Csaba Langer
langercs@yahoo.com

I hope that your Bad Mister nickname cannot overwhelm the positive effects of your thoughts, your adherence and your helpfulness! Please don't let this to happen!
Thank you!

I had the same problem with my P-250. It takes hours to boot up but once it starts, all functions work properly. Local authorized tech looked at it and said it needs a new DM Board. Unfortunately, these boards are not available from Yamaha and are impossible to find anywhere on the Internet. Since they are surface mount technology, nobody will try to repair them. This was a fantastic instrument but unfortunately, is now an expensive boat anchor. I ended up replacing it with another brand product. tanglace at yahoo dot com.

Hello for everybody!

Dear friends, Yamaha P250 users.
I wonder if this service issue is only mine and a few people problem, or it is a factory procedure fail or poor quality parts? Known or unknown by the makers?
Are there any P250 users with this power on delay problem?
How did you resolve it?
Thank you?
God bless you all!

As I found: The PF500 has the same mother board than the P250!!!
Is there any PF-500 user with is service issue?
Thanks