FNIRSI GC-01 (CA32F0502L3): J321 tube working at 700V

[boromix]

Thanks Gissio for v2.01. J321 tube data sheet reports recommendation work voltage 390V but measuring j321 voltage on my Fnirsi GC-01 I read 712V using 1 Gohm probe. https://www.theremino.com/wp-content/uploads/2013/03/Sensor_HvProbe.zip
That's weird because on Bosean FS-600 is 400V as espected. Any Idea?

[boromix]

Solved. removed R38 and put 10.68 Mohm. Now 402V at J321 tube

https://www.dropbox.com/scl/fi/c5epoyxuq8ehgfekaciri/FNIRSI-2024-06-25_003.jpeg?rlkey=j4anwttxj29zivwcmxqujpaf1&st=g1b0ypix&dl=0

https://www.dropbox.com/scl/fi/u9nta2fyf0t6aobu4nzjw/FNIRSI-2024-06-25-002.jpeg?rlkey=ksix03jo4oxn4fzdxs1xzo4d5&st=1tanntx4&dl=0

[gc01noob]

by any chance do you have a part number, supplier or listing for a 10.68M resistor?

I'm yet to test mine but would be good to know if required.

[boromix]

here the 712V measured with 1Gohm probe on J321 tube as arrive from aliex

https://www.dropbox.com/scl/fi/xsdsam25l77mo8ytnln6e/FNIRSI-2024-06-25_004.jpeg?rlkey=abqboku6iv19wq4hicmova8aj&st=aqjixgy6&dl=0

I removed R38, put different resistors in series until I obtained the value of 400V on my geiger than I soldered a 1/8W 10Mohm resistor plus a 680Kohm SMD 0805 as you can see in picture

https://www.dropbox.com/scl/fi/u9nta2fyf0t6aobu4nzjw/FNIRSI-2024-06-25-002.jpeg?rlkey=ksix03jo4oxn4fzdxs1xzo4d5&st=1zf27qzq&dl=0

fast and not bad reworking

[ioderey]

I have 630V default on FNIRSI GC-01 (CH32F103R8T6) J321. I set custom HV friqency 5000 and 0.30 duty cycle, HV is 405V now.