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Have Zeiss replace the replacement with a new unit (both PMT and HV 
board) that works correctly.

On 12/13/2012 6:07 PM, Ben Melchior wrote:
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>
> Hi Listers,
>
> I have a technical question regarding the tuning of PMT modules on a confocal
> system.
>
> We have recently replaced a PMT module on our LSM5 system.  Although we
> now can get a signal and observe our cells we still having what looks like
> electrical interferences (horizontal stripes) that impact the quality of our
> images when scanning.
> The image acquisition now requires a much lower laser power (633nm line)
> than previous, but inversely, an extreme detector gain was needed (over
> 1100!). If I try to increase the laser power and decrease the PMT voltage it
> looks like the PMT saturates or there is no more signal.
> Other channels/lines have clean signal. Nothing wrong with the optics.
>
> Is there any electronic engineer or specialist with any thoughts regarding
> adjustments, tweaking, or calibration of the PMT module? Or any pin on the
> board that I should check to see if the control voltage to the PMT is right?
>
> Thank you,
>
> Ben
>
>