Fusor Forums

Dear Group,

thanks in advance for collaborating.

I have just bought a canberra series 35 plus mca from ebay. i bought it from a professional seller so the item arrived well packed cleaned and working.

I read the manual and decided to change the backup battery, following the suggestion to reset the memory. When i plugged again the adc board again .. .nothing appeared on the crt. after some test, i saw that if i pressed the test button on the monitor board, i could see the test pattern, the canberra logo and two lines with strange characters on the lower part on the crt.

If i press a button i can heard only one click and then nothing happens.

definitely the mca can't work anymore... what shall i do ? do somebody have a cpu board for spare?

my father - who helped me to replaced me the battery, may have touched some ic with solder wiring... maybe could be that problem?

did somebody have a similar problems?

i have no services manual of the series 35 and i could know how to solve that.

Thanks Marco



thanks in advance for collaborating,

Marco

attachment

Marko,

Make sure the various boards are fully seated in their respective sockets on the motherboard. (I normally tap them in using a small block of wood and soft face hammer)

I have both the service and operator manuals. Once I find them I'll put them in my Dropbox and post the link here.

Jon Rosenstiel

Marco,

Dropbox link to Canberra 35 Plus manuals and schematics...

https://www.dropbox.com/sh/t9b3og7v5tko ... h6eGa?dl=0

Jon Rosenstiel

Dear Jon,

Could you please upload again the schematics for Canberra "Series 35" MCA?
The original link seems to have expired.
I would like to compare boards and circuits of "Series 20" with those of "Series 35".
Thank you very much in advance.

Dan

Dropbox link to Canberra Series 35 Plus schematics.

https://www.dropbox.com/sh/fw75vox8xnoy ... _Ds-a?dl=0

Jon Rosenstiel

I am having some issues with my Canberra model 35 MCA. I managed to fix the start up problem by removing the memory battery, cleaning the main board and replacing some components. The DC power supplies all test good. I have been gradually working on my gamma spectroscopy system, I acquired a NIM Bin, HVPS, a spectroscopy amp, pre amp, signal splitter and a 1x1 scintillation probe. Here are some pictures when I attempted to take a gamma spectrum of a Co 60 source. Both the spectroscopy and preamplifiers have been adjusted and pole zeroed using a pulser and an oscilloscope. I rebuilt the Canberra 2005 preamp, since all of the tantalum caps were fried, along with the FET. Not sure why I am not seeing a proper Co 60 spectrum. The MCA indicates a peak when a signal is applied via the pulser and the channel position can be varied using the voltage control on the pulser, the intensity can be varied with the frequency control. What is going on? Could it be the detector or is it the MCA? I get pulses on the scope screen that are Gaussian shaped when a rad source is placed near the detector. I have tried all sorts of adjustments to the ADC on the MCA, with no improvement of the spectrum.
Thanks,

David