Barcrest MPU6 - REEL Lamp Interface - Starpoint and Gamesman Reels

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4.24.2 REEL Lamp Interface – Starpoint and Gamesman Reels
The lamp matrix is a 5 x 3 matrix comprising five reels each having three lamps, and is
connected to the REEL5 board via a red 15-way connector having a keyway at pin position 9.
The typical lamp drive and select circuit shown in Fig. 33, is similar to that on the MUX5
board and functions as described in Sect. 3.1.2 However, the series diode for each lamp is
located on the REEL5 board and the drive inputs for the three lamps on each reel are
commoned on the REEL5 board to allow for easy replacement of unserviceable lamps.
Select line
From cp
To current
sensing
circuit
+34V
LAMP DRIVE
TRANSISTOR
1.0 ohm
From
Drive line
Other select
lines
SELECT
MOSFET
(1 of 3)
KEY
1
4
2
3
LAMP
Fig. 33 Typical LAMP interface for one reel