Hitachi Seiki Display / Monitor/ Screen Issue

Hi Folks,

I am having Hitachi Seiki TF15 with Seicos LIII control.
It's taking a number of tries before display actually displays anything.
It is very common on the morning; I am powering ON the machine on the rear panel, then powering it ON with the green button on the front control panel. After this button is activated a display should appear. Unfortunately it doesn't.
(I can put machine in to Standby mode without issue.)
So the machine must be powered OFF and powered back ON number of times before I actually get the display to display.
Seems to me like something needs to heat up to allow display to "switch on".
So I took display a part (as I was knowing what I am doing) and visually checked all the connections. They seems to be fine. I have also removed and put back all the connectors and this hasn't sorted my issue (well, I didn't expect it).
I have read similar topics and people are saying the voltage may be too low - fair, where to check this? If it is too low - what next?

I have had similar Issues with a Hitachi Seiki. But with a Fanuc control. There is a relay on the control side of the electronics that reacts to the on off button push. I'm guessing that's your problem and the relay is sticking. It's a pretty good size relay. I attached a couple pics. Tap on it and see if that makes your screen come up when its hung.

VTM said:

I have had similar Issues with a Hitachi Seiki. But with a Fanuc control. There is a relay on the control side of the electronics that reacts to the on off button push. I'm guessing that's your problem and the relay is sticking. It's a pretty good size relay. I attached a couple pics. Tap on it and see if that makes your screen come up when its hung.

Click to expand...

Hmm, I guess your case is different.
When I am pushing On/Off buttons the button is getting activated each time without fail.
Every time I push on the button the button illuminated with green and I can proceed to Standby.
The problem is once the button is activated the display should display like a Seicos start-up screen, but it doesn't.

Yep, could be a different problem. The buttons are not Illuminated on my machine so I couldn't tell that way. But sounds like the relay is doing it's job in your situation. Wish I could be more help. Good luck!

Most likely old leaky electrolytic capacitors on the screen PCB are causing this issue.
You should replace all these capacitors at first

Hi John,


"Power supply from the japanse manufacturer TOKO reference TOKO LW30-51. TOKO triple output Power supply who supplies (DC+5V - 5A) (DC+12V - 2A) (DC-12V - 0.5A). TOKO Power supply LW30-51 are mostly used on industrial equipments such as HITACHI Seiki CNC operator panel fitted with SHARP LJ64ZU52 EL Dsiplay unit."

When I measured the voltage after power on I wasnt getting the correct voltage. The correct voltage came with time... I have repalced all capacitors on TOKO unit and the issue is resolved.