Section
VIII SEBVICE GROUP
E Model 34S5A
f. Check for a dock
signal at A10UI5 pin 9. If the signal appears to be good, the processor (U26)
and/or the ROM (U2S) may be defective. If the clock signal is missing, check for 500 nano second
pulses at the device select lines of U26 (pins 12 to 15). If the
pulses are
good, U14
may be at fault.
8-E-13.
Inguard logic Troublashooting with an A/D Wavaform.
a. Check the
light isolators and
associated
circuits as explained in paragraph 8-E-12a.
b. Check for a
defective
A10U26.
c.
Check for
an
open A10CR41 and CR42. These diodes may cause glitches on U26pin
29,
causing
the processor to be
interrupted continuously.
8-72
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