Booting problem - is this unit dead?

[Luminen]

Hi
A well used OXO just arrived on my desk and as I tried to get it to start, there seemed to be problems.
The red power led is on and when I press the power button it turns green, but doesn't stay green when I release the button.
I can hear a relay switch clickin with the power button and again when releasing the button.
Both of the fans are working. There is no HD.
CPU is M3 (flash date code is 632) and I tested this with only the CPU-card installed with the same results.

I would be really thankful for any ideas on what's wrong with this one.

[Luminen]

I suspect this might be a power supply problem, but what's the correct method for measuring the voltages?
The lead batteries were very old and I have removed them.
I suspect this unit has never been serviced.
I'm doing this just as a hobby and this area doesn't even have landlines anymore (most of Finland is like that), but it would be nice to make this work again.
We have a 4200E unit installed here. I bought it with some other things in an auction in 2006 and it was in storage for many years and as my father is now disabled and needs often a bit of help, we use it in this big old house for him to call us.

[Luminen]

Works now (the switch was faulty).