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Re: Shaper Boards
Hall D Electronics:
Hi Gerard,
> p.s. Your question about a simple fix prompts me, I should have said it
> earlier... Yves, I recommend that (with the preamp board connected and
> powered but with chamber HV off and no pulser or anything connected) you
> measured the DC voltages on the pins of the second (0.1" header) connector on
> the shaper board. I think you will find that the voltages on the problem
> channels do not match those on the good channels. This would basically
> confirm a cable/connector problem. You could then try to check the cable
> connections directly, though that may be a little difficult without some
> smaller multimeter probe leads than I believe you have.
Here are the results:
pin# | Voltage (18 m cable) (V)| Voltage (Gerards cable - 1.5 m) (V)
=======|===========================|===============================
0 | 0 | 0
1 | 0.2243 | 0.2292
2 | 0.3120 | 0.3268 --> has problem
3 | 0.2888 | 0.3028 --> has problem
4 | 0.3092 | 0.3237 --> has problem
5 | 0.2543 | 0.2625
6 | 0.2703 | 0.2750
7 | 0.2495 | 0.2613
8 | 0.2480 | 0.2581
9 | 0.2423 | -
10 | 0.2450 | -
11 | 0.2463 | -
12 | 0.2306 | -
13 | 0.2434 | -
14 | 0.2432 | -
15 | 0.2280 | -
16 | 0.2562 | -
The channels wich have a problem are pin# 2,3, and 4. They indeed have a
higher voltage than the other channels. To check the cable is difficult
without a proper probe, as you mentioned. However, both cables have the
same problem which I think points towards a problem with the connector on
the shaper board.
Cheers,
Yves
>
> Curtis A. Meyer wrote:
>> Dear Gerard
>>
>> as Yves mentions late last week, several of the channels
>> on the shaper board that we have here appear to not work.
>> The noise is signifcantly larger than the other channels. You
>> had mentioned that this might be an issue with the differential
>> receiver part of the board.
>>
>> Is there a simple fix that we can do here for this, or can you
>> send us a board where all the channels work? If it does come
>> to sending us a board, getting it here quickly would be very good.
>>
>> thanks in advance - Curtis
>>
>> --
>> Professor Curtis A. Meyer Department of Physics
>> Phone: (412) 268-2745 Carnegie Mellon University
>> Fax: (412) 681-0648 Pittsburgh PA 15213-3890
>> cmeyer@ernest.phys.cmu.edu http://www.curtismeyer.com/
>