ELTRA CS-2000, Руководство по обслуживанию

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Faults
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The filament lead (socket) connected to the chassis, is the upper one of the two which are
connected to the multimeter. The grownd connection is done by using a small copper sheet. It is
on one side soldered to the socket and on the other end it is fixed on the chassis with a screw.
Fig. 18: Socket top view
7. Loud buzzing sound when the generator turns on
If during integration (combustion period) the high voltage transformer is making exceptionally
loud buzzing sound when the generator turns on, also when running the furnace empty still the
loud buzzing appears, this means that obviously for some reason, the triggering of the triac has
changed.
If you are sure that the noise appears only during integration period (combustion period) then
the problem could be in the generator. The unusually loud noise could be due to current
limitation by phase angle control.
The oscillator tube may not be oscillating due to a tube fault so that it takes a very high DC
current causing the current limit circuit to reduce the phase angle. Replace the tube. This is also
the easiest thing to try so that it can be done by the customer.
NOTICE
The oscillator tube can be damaged due to overheating if for some other reason the new tube
may not be able to oscillate. For testing after installing the new tube, put crucible with sample
and accelerators into the furnace like you use to do with every normal analysis. After starting
analysis watch carefully the furnace to see the light of the burning sample/accelerators. If a
couple of seconds after generator start (transformer noise, base lines for peak on the PC
screen) there is no combustion to see in the furnace then STOP the generator by clicking STOP
on the screen.
NOTICE
When testing for induction power, always test with closed furnace.
NOTICE
When looking to find out whether there is combustion or not, STOP the analysis cycle about 3
seconds after it started. If there are oscillations, after 3 seconds the sample (steel or iron chips)
will have visible signs of starting burning. But if you wait up to the end of the analysis cycle in
order to check whether there was combustion, it could be already too late for the tube due to
overheating.
When there are no oscillations, the tube takes a high DC current, so that after several seconds,
the anode of the tube starts glowing from the lower end. This can be visible when the
environment is not bright or it is dark.
It is practically not possible to do any measurements on the generator due to very high voltage
and due to high frequency in the oscillator (in case of functioning). So we have to solve the
problems by looking and trying.