Roland W30 problematic display and power supply

[WaveTemper]

Hi, I have a Roland W30, but there are some problems: when I turn it on, the display shows "Roland W30", it stays like this for at least 20 seconds, but also for longer, then suddenly it turns off (but the keyboard still remains on). It is as if the operating system does not boot.
I state that I had turned it on the first time days ago (I bought it used a short time ago), but I had not been able to verify if it was working at 100%, due to the fact that the system disk was supplied, but I could not use it as it was physically damaged.
This is the chronology of what I did:
1 - I turned on the W30 for the first time and the display showed the message relating to the request to insert the system disk, then I turned it off.
2 - I found that the contrast potentiometer was not working correctly, so I decided to replace it with another one, always 10k, but before soldering it on the pcb, I created a bridge with 3 cables and so I was able to do a test before fixing it permanently on the motherboard.
3 - In the test phase with the new potentiometer, I found the following: turning it to 50% the display was optimal, even if the backlight would have to be replaced, while turning it to 100% the display of the writings on the display was not legible. when they became too "clear").
4 - Here comes the problem, suddenly the display no longer shows anything and 2 to 5/6 LEDs light up on the left panel, all together, at the same time, so at first I thought of a possible short, but caused by what?
5 - In the meantime (having available a new display purchased on Buydisplay and reviewed in a well-known blog where it is shown how to make the change to be able to install it) I prepare the W30 for the installation of a new display, which I do but the result remains the same. same, only in this case the display turns on, it shows nothing, the contrast can be adjusted but sometimes the adjustment itself is not correct, because the intensity of the contrast changes by itself without my acting on the potentiometer. The display does not turn off after the same number of seconds as it did with the original one.
6 - I have restored the motherboard to the conditions in which it was originally (I'm talking about the changes to be made to install a new display, those indicated in the blog I mentioned earlier), but the situation is always the same.
7 - I noticed that a track (which does not affect the display circuit was interrupted, so I proceeded to make a jumper, everything is ok.
The transistor next to the cpu had a broken central pin, so I replaced it. The situation does not change.
8 - I checked the voltages in the connections between the front analog card where the switches are located, the analog one of the audio connections and they are regular, at least so it seems.
However, the fact that the display (and consequently the inverter activity, which is no longer possible to warn after the display is turned off) turns off after a few seconds, for me it could have one of its causes in a malfunction of the power supply board. , in particular regarding one or more voltage regulators, other transistors which in any case are somehow connected to the connector which is then connected via a cable to the motherboard, but it could also be the inductance on the secondary of the power supply board. The fact is that it could be all or nothing, but it is essential that after a few seconds both the display and the inverter turn off, but the keyboard remains powered.

Thanks

[WaveTemper]

I solved it, it depended on a transformer on the power board.

[DC10]

You mean the transformr on the Power Supply, correct?

It was bad - wow how interesting.

[DC10]

What did you replace, the POwer Supply board or the Transformer on the board. If you replaced the transformer which one was it?