Rear "H2 Trim" Output; First Power-Up Tests - ONE EOSC10KV3 User Manual

3) Rear "H2 trim" output.

The "H2 trim" output is dedicated to set H2 to minimum value by using the RV1 trimmer.
This trimming is not mandatory. Practical tests show very low sensitivity on H2 level to the trimming.

4) First power-up tests.

To avoid parts failure at start-up, it is important to make some tests to and verify that nothing is wrong.
The first thing to do is to make a complete visual soldering inspection !
Check all polarized components (diodes, capacitors and of course IC !).
If not already done, clean meticulously the PCB to remove any soldering flux trace.
 Note that flux trace can corrupt the oscillator to working.
Turn fully clockwise the trimmer RV3 (Gain) to disable oscillator.
Then, take a current limited variable power supply. Set the current limit to /-100mA and the output
voltage to 0V. Connect it to EOSC10KV3 and switch it ON.
(It is preferable that you could read current on both rails of the power supply when powering)
Now, increase slowly the symmetric voltage and verify that input current doesn't rise up more than few
tenth of mA. You must also see the front Led becoming luminous.
Stop increasing the voltage when you arrive to +/-14V, and verify that you have +12,4V on C49
and -12,4V on C51. (If you have used LM317/337 regulators, you must stop at +/- 15V).
The current consumption on each rail must be around + 60 mA(+14V) and – 60 mA (-14V).
Connect now one output to an oscilloscope.
Start to turn counter-clockwise RV3 (Gain) slowly until you look the oscillation appear an the output.
Do not be surprised if the output change fast and clip to rail voltage !
Verify that you have the right oscillator frequency and also no high frequency (MHz) oscillation.
(If you note HF oscillations, you may need to clean again the PCB).
Then now, go to next chapter (4) for complete adjustment procedure.
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