The main mother card is connected to the hybrid through the two kapton
cables described elsewhere. This card provides for power connections to
the hybrid, Vref generation and 16 connectors for installation of 16 *
4 channel amplifier cards. It also provides power distribution to the amplifiers
and two separate logic cards.
---- more info later
Schematics motherboard
and 4 chan amplifier
slowcntl and clk/trig cards
NEW New amplifier with 2 stages, limiter
and gain
It is not possible to obtain the EL2141c amplifiers as specified in the
new amplifier design so EL2140c amplifiers have been substituted. This
gives a maximum gain of 2
which can be decreased down to any gain <=2 by inserting a
resistor. The PCB needs tracks cut between the two pins of the limiter
diode pack so that the -ve side of the diode pin is disconnected
from the positive input. Pin 3 of the second stage amp is lifted and connected
to the series resistor on the -ve output of the first stage. Pins
1 and 2 of the second stage are shorted together. pin 4 of the second stage
is connected to the pad under pin3 to give a ground. The effective
schematic is shown here Note that
there is now no limiter in the circuit, A modified PCB has been designed
to accommodate these changes and to implement the limiter but has not yet
been manufactured.
.
The layouts of the cards are contained in a single file adap2.cwk
This can be viewed using GCPrevue Version 7 which can be downloaded from
the PCBPOOL website
- look under downloads.
Known bugs
1) - there is an error on the hybrid end connector of the power kapton
cable and the same error is also present on the support card version 1
Detail The wide power and return traces should each connect
to 8 pins of the connector (odd pins 67- 81 and even pins 68-82 respectively)
The error is that they contact 9 pins eac and so the sense and Vref lines
on pins 63- 66 are displaced by one and are connected instead
to pins 61-64
FIX A small PCB confix2.cwk
allows two connectors to be mounted back to back to correct the shift and
one of these is required to be
inserted at each end of the kapton power cable.
2) Original amplifier had insufficient gain and RJ45 connectors could
not be mounted because there is insufficient room between amplifier boards
when they are plugged into the motherboard.
FIX a new design of amplifier board with two stages
has been designed. This board allows for the mounting of the RJ45 connector
in one of 2 positions and alternate boards have the unused position on
the PCB cut off so that the connector on the adjacent board will overlap
the edge of the board