Fluke ScopeMeter 123 Service Manual page 169

123
Service Manual
Revision 12
Changes:
New software version V01.02. No hardware changes.
Revision 13
Changes:
For the 8M FlashROM D474 one of the following types can be used:
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•
The part number of D474 has not been changed.
Revision 14
A new version of the Printed Circuit Board (PCB) is used in the Main PCA. The version
of the PCB is the last digit of the 12 digit number on the PCB edge near N501. The new
version 12 digit code is 4022 245 0443.8 (version 8).
The part number of the Main PCA has not changed. Old and new PCA versions are fully
compatible.
See Section 9 for the circuit diagrams and the parts location drawings of the old and new
version PCB.
The following changes have been made:
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•
•
•
•
10-2
AM29LV800B-120EC
E28F800CV-B70
HNWT800T
M5M29FB800VP-120
In the Backlight Converter circuit R605 and R606 are added to provide a more
reliable start-up of the backlight. See the Power Circuit diagram figure 9-6.
The 12 V program voltage (+12VPROG from N501 pin 22 to D474 pin 13), and the
RESET ROM circuit have been removed. See the Digital Circuit diagram figure 9-4,
and the Power Circuit diagram figure 9-6.
A delay circuit for the Rom Write Enable end edge has been added: D480 and
related parts between D471 pin 149 (ROMWR) and FlashROM D474 pin 11
(ROMWRITE). The delay is required to make the circuit suitable for FlashROMs
that need a large delay between the write data and the write enable end. See the
Digital Circuit diagram figure 9-4.
Capacitor C476 was missing in the Digital Circuit diagram, and has been added near
C474.
Another shape for the 4041 reference diode is used. The shape was a 2x4 pin DIL
mounted on the Main PCA side 2, reference designator V301. The new shape is a
transistor shape mounted on the Main PCA side 1, the reference designator becomes
V302. The reason is the availability of the diode versions. The PCB layout still has
the possibility to mount V301 is place of V302.
Note:
In some units having PCB version <8, the reference voltage
diode can have the transistor shape, and has reference
designator V302 then. In this case it is soldered on C312
(see the adjacent figure, and Figure 9-8 location C3), and