Checks On The Card Reader; Pin Numbering For Card Rea - Pace MSS100 Series Service Manual

Test Point 20: Negative side of C319 (main circuit dia- 20A. VIDEOCRYPT MAIN PCB
gram)
Description: The trace shows the video signal with a scale
of 2 ms per division on the time axis. There are two areas
of peaks. The first (left most) is the vertical sync. and VITS;
the other is the graphics. Oscillogram 20B (see next
oscillogram) is a larger scale version of the graphics portion
of oscillogram 20A.
The test needs to be carried out when an encrypted
programme has been chosen but the viewing card is not
inserted (so that graphics messages appear on the screen).
Note the voltage level of the inserted graphics.
If the voltage level is not as shown on the trace, i
check:
ii
OMS.
Description: This is a larger scale version of the graphics
portion of oscillogram 20A (see preceding oscillogram).
Checks on the Card Reader
If the receiver is showing the "CARD INVALID" message, but testing at the test points 15 to 20 has given traces
as shown and you appear to have found no faulty components in the VideoCrypt circuitry, you can then carry
out some further checks on the card reader circuitry as described below.
Ic:
Supply to the card reader, IC: Pin Numbering for Card Reader
© check that the 27 V (switched) supply is present at pin 3 of
U305 and 12 Vis at pin 7 of U305; if the 27 V is absent, eeuoeucese
check Q314 and Q315 (VideoCrypt circuit diagram) and @ + 8 2 6
that the reset line (at LK333 on the VideoCrypt circuit 18
diagram) is high.
Supply to the card reader:
Note
For the first of the two tests below we recommend that you
use a dummy card (or a SKY card upside down), because a
good, valid card could be damaged if there is a problem with
the levels of VCC and VPP (which could go as high as 27 V).
© with the dummy card inserted, check that VCC and VPP ecccccece
at pins 9 and 5 respectively of the card reader reach 5 V
temporarily as the card is inserted (they do not remain at
5 V unless the card is valid); if they do not reach 5 V, check
that VCC and VPP are 5 V at pins 8 and 2 respectively of
U305;
if VCC and VPP are not 5 V (or they are 5 V at U305 but This is the view of the pins on tht
there is still a problem), check the path from U305 to the solder side of the board (the pis are
card reader and also check that the card detect line not accessible from the componat
(CARDDET) at pin 17 of U305 goes to 5 V when the card is side),
inserted.
Clock to the card reader:
© check that incoming clock is present at pin 1 of U306 and
the buffered clock output (approx. 3.5 MHz) is present at
pin 4 of the card reader (CH3CLK line). If there is a prob-
lem the clock will be intermittent.
If there is still a problem and the above signals are
Present, contact the Pace service centre.
CARD INSERTED THIS SIDE