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Re: Shaper Boards
Hall D Electronics:
Hi,
After a phone call with Gerard the measurement was redone but now with an
extra 50 Ohm termination on the multimeter; here are the results:
pin-pair# | Volt (V) (18 m cable)
===========|=========
0 | 0
1 | 0.1082
2 | 0.1511 --> has a problem
3 | 0.1401 --> has a problem
4 | 0.1498 --> has a problem
5 | 0.1233
6 | 0.1311
7 | 0.1208
8 | 0.1202
9 | 0.1175
10 | 0.1187
11 | 0.1195
12 | 0.1118
13 | 0.1180
14 | 0.1177
15 | 0.1104
16 | 0.1239
Cheers,
Yves
/--------------------------------
/ Yves Van Haarlem
_--~~--_ /
/~/_| |_\~\ / Carnegie Mellon University
|____________| / Department of Physics
|[][][][][][]|:= / Wean Hall room 8404
__| __ |__ \ Pittsburgh, PA 15213
| ||. | == | | \ USA
(| ||__| == | |) \
| |[] [] == | | \ Tel.: +1 412 268-6949
| |____________| | \ +1 412 641-9252
/__\ /__\ \ Fax.: +1 412 681-0648
~~ ~~ \-----------------------------------
On Tue, 19 Feb 2008, Yves Van Haarlem wrote:
> 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
>
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>>
>> 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/
>>
>