CX6325 amp for driving G120DTs

[mixedgas]

There is a hint in that picture you posted. . Those are possibly the LC low pass filters that first filter the position detector output currents.. Would make sense.
A bit of probing by eye and by Ohm meter would give you signal ground, and +/- X out and +/- Y out. The position sensor excitation inside the Galvo runs at a very high frequency, and the first step in processing the PD signals from the Galvo is to eliminate any trace of it by low pass filtering, passing only the signal.

Steve

[lasermaster1977]

Parts comparison as detailed in the CX660 manual between the CX6120 and CX6325 controller circuit boards for driving either the GSI or GSI Lumonics G120PD/D or G325PD/D position feedback galvos.

Notice that some components are listed that are the same for both. HOWEVER, on the GSI CX6325 S/N 56256 that I have, R157 is 150K instead of the table's 332K value. This is visible in the photo below.


G120D/DT G325D/DT
-------------------------------------------
Different
C101-470PF .001uF
C113-.0033uF .015uF
C114-.0022uF .01uF
C115-220PF .001uF
R103-4.99K 1% 1.82K 1%
R146-20.0K 1% 37.4K 1%
R162-30.1K 1% 25.5K 1%
R164-30.1K 1% 25.5K 1%
R157-332K 1% 249K 1%

Same
R106-4.99K 1% 4.99K 1%
R107-4.99K 1% 4.99K 1%
R119-619ohm 1% 619ohm 1%
R154-100K 1% 100K 1%
R185-1M 1% 1M 1%

Photos showing components in the CX6325 that need to be changed to those used in the CX6120. Components on circuit board are circled in red along with their CX6120/6325 component labels and their CX6120 values. You will notice the actual resistor values in the photos of those in the CX6325. The CX6325 capacitor values are hard to see in the photos. These component types and values are readily available from Mouser.com.

R103, C101


R146, R157, C113, C114, C115


R162, R164