[CAD_CAM_EDM_DRO] OT: Hi Freq. Centrifuge

Hello Friends,
This is OT but I hope somebody may help me.
I have to repair a high frequency induction centrifuge for to cast
chrome cobald dental parts. In 10 years I got these things Dentaurum
Megapuls memorized already but I would not like to make all coils new
again like 7 years ago.

This time the hole electric system is working fine without trouble.....
EXCEPT..... the heat comes up too slow and often the metal not even
melts.

Humidity here in Costa Rica is breaking everything. These units in
Europe have no trouble at all.

All electrical components are OK. I changed a few parts of the coils
that seamed to be internally oxidized and things became better.

But how to tune the frequency if there is nothing to measure it with?
(4500 VDC, 4KW, supposed to bee 1,3 MHz (that is beyound every
Osciloscope's capacity I have ever seen.))
I would appreciate every help off line.
Thanks
Sven Peter