NIM Setup and Testing

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Jeremy Sims
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Real name: Jeremy Sims
Location: Southern Ohio

NIM Setup and Testing

Post by Jeremy Sims »

Long story short because I typed out the long story and the forum logged me off as I was about to post....
Just spent the last month thinking my bin power supply was bad and was going to replace the +/- 12v regulator boards when I realized I had a bad TC 246 NIM that is somehow cutting out the 12v supply to all other NIMs when plugged in.
So instead of using the 246 as was used in Richard's FAQ, I'm trying another SCA.

Current setup:
Mechatronics Nuclear Nim Bin
Russian CH18 3HE Tube
Ortec 456 High Voltage Supply
Tennelec TC 175B Pre-amp
Tennelec TC 452 Quad SCA
Tennelec TC 595 Auto Ranging Ratemeter
Siglent SDS 1104X-E 100 MHZ Scope

Gamma source is a vial of old watch hands purchased from an HEAS years ago.

Testing:
Followed the FAQ exactly except for the 452 SCA. I'm hoping this will be usable as funds are currently running low and I still have to finish a moderator. The 452's windows are adjusted using tiny trimmers? located on the front with the setting being read on an LED screen. They both have a range of 0-10. I set the upper to 10 and started the lower at 0.02. After ramping up the voltage slowly on the tube to 1600V and laying the vial of watch hands directly on the tube, the scope definitely started reading. I then used the lower trimmer to adjust till I was no longer getting any reading. A good thing about the 452 is that each SCA output has an LED that blinks with every pulse. The ratemeter was reading about 80cps when it was hooked up.
Does everything look up to par?
Edit: I was using the Lower Window Output port on the back of the 452 to hook to the scope in the pictures
Attachments
Vial of watch hands laying directly on tube
Vial of watch hands laying directly on tube
20230312_192535.jpg
20230312_192701.jpg
100mV div
100mV div
20230312_192807.jpg
20230312_192904.jpg
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Richard Hull
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Re: NIM Setup and Testing

Post by Richard Hull »

Looks good to me. Nice setup. The scope is a big help.

The original 246 SCA undoubtedly had a bad tantalum cap messing with the 12 volt supply. Might be an easy fix.
Do you have the 12 volts back with the new SCA? I assume so.

Richard Hull
Progress may have been a good thing once, but it just went on too long. - Yogi Berra
Fusion is the energy of the future....and it always will be
The more complex the idea put forward by the poor amateur, the more likely it will never see embodiment
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Jim Kovalchick
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Re: NIM Setup and Testing

Post by Jim Kovalchick »

Remember to be kind to your preamp by only disconnecting and connecting cables with the power off and ramping up voltage after power on and even ramping down when you are done. Some preamps can take a lot, but not all can.

I have experienced the same thing with bad modules dragging the whole crate down. It's really the first thing I check now when I have problems.

Good luck with your system.
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Richard Hull
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Re: NIM Setup and Testing

Post by Richard Hull »

I have enough NIM modules on hand that I built a test bin such that I can lay the open module of the table in front of it for probing and repair.
See my old post on this.

viewtopic.php?t=14638

Richard Hull
Progress may have been a good thing once, but it just went on too long. - Yogi Berra
Fusion is the energy of the future....and it always will be
The more complex the idea put forward by the poor amateur, the more likely it will never see embodiment
Jeremy Sims
Posts: 34
Joined: Mon Jan 19, 2015 4:54 pm
Real name: Jeremy Sims
Location: Southern Ohio

Re: NIM Setup and Testing

Post by Jeremy Sims »

Thanks Richard and Jim
The 12v is working again once I pulled the bad NIM.

I will definitely keep that advice in mind Jim as I was moving BNC's back and forth between the ratemeter and scope while powered. Don't want to loose that preamp, they seem to be hard to find now.
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