Lightning striking twice on a NIM Amp

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Dennis P Brown
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Lightning striking twice on a NIM Amp

Post by Dennis P Brown »

Well, since my TC-246 wasn't working I ordered another. The one I was sent neither works but once more, shorts out my NIM box. It too shorts 120 VAC to ground. I found the issue - this TC-246 is modified as "CE" (see pic.) They have some type of circuit inside that is not NIM compatible at all. This happen once before to me some years ago. NOT fun - should be more clearly marked as not compatible with a NIM box.

I did disconnected the extra circuit board so the unit does not short. But the unit didn't give any response to any generated pulses either for the Input or the SCA. So, unit is likely dead anyway. At least it can be returned.

E-bay pickings for usable NIM amps is extremely sparse, to say the least (only one 246 unit available and they don't accept returns so they know they sell often sell junk.)

Anyone with a few hints on what to look at in a TC-246 that can be done by an inexperienced person that can read circuit diagrams and understands a bit of electronics - because it sure looks I'll need to try and fix my old unit.
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Note decal on front that says CE Modified (give away.)
Note decal on front that says CE Modified (give away.)
Note grey circuit board added
Note grey circuit board added
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Richard Hull
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Re: Lightning striking twice on a NIM Amp

Post by Richard Hull »

Any NIM module that has a single non-power pin run to its cage plug is a custom piece of gear. Do not buy such modules unless your are well tuned in on electronics as a developed skill set.

The add on board here is just such a custom add on. Such boards can act totally alone as an added feature by an OEM "custom" NIM cage item designed to be used and sold only within their custom assembled and loaded cage. I have seen these before and in only one case was the custom board, upon not seeing a custom signal on their custom buss, was designed to blow the 120 volt cage fuse! A tell that the board was not NIM compatible outside of their custom buss and other modified NIM-like plugins. In most instances they are just extra boards designed to do something special and send their useful signals onto their custom, modified buss. As such they will in no way interfere with the normal function of the general NIM module prior to modification.

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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Dennis P Brown
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Re: Lightning striking twice on a NIM Amp

Post by Dennis P Brown »

Makes sense. Well, maybe abandon the NIM rig since the Ludlum 2000 appears to be work - maybe.
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Dennis P Brown
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Real name: Dennis Brown

Re: Lightning striking twice on a NIM Amp

Post by Dennis P Brown »

Well, I'll keep an eye out for any TC-246's ... ugh.
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Richard Hull
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Re: Lightning striking twice on a NIM Amp

Post by Richard Hull »

I would say I encounter custom modules, once in 20 purchases and all will function as normal in a transparent manner. I typically disconnect the power runs from their custom board to not have their little add-on take up bin power. The one NIM module that would blow the 120v fuse was fixed by snipping of the 120 volt power leads. All NIM modules use no more than 8 power leads most use only 5 and I have seen a few that use 3 power leads from the big NIM plug. +12,-12, Ground. 98% of all modules only have power leads going to the top of the big plug. Very few need the 120 volts found at the base of the plug as that means they need a real power transformer in the module or seek to voltage multiply directly from the line for HV.

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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