Pulse Height Error on Pulse Height CPC 3750

[gfacheris]

Dear All,
I have the following issue on the DMPS.
Since few weeks the Total CPC (TSI 3750) is returning an error/warning related to pulse height value.
The value itself is varying during the day from very low values (30% to 80%) and from time to time the error acknowledges itself (see attached image).
On the other hand comparing the TOTAL CPC and the TOTAL DMPS count it seems that the problem is not affecting considerably the measure.
Following the indication of TSI we replaced the Wick and we cleaned the nozzle but the problem is still there.
By change did someone experience something similar? Do you have any suggestions/check to perform before sending the instrument to maintenance?
Thanks
Best regards
Giacomo Facheris

CPC_TOTAL vs DMPS_TOTAL.png (96.52 KiB) Viewed 29449 times

CPC3750_PULSE_HEIGHT_ERROR.jpeg (239.97 KiB) Viewed 29449 times

[gfacheris]

UPDATE

I managed to solve the pulse height issue by completely dismounting the optics and cleaning the optical chamber, the laser and the optics.
In my case I did not had to realign the laser by means of an oscilloscope but it could be the case.