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“LONG
POP”
Instrument Preset Check
This check is very similar to the normal Instrument Preset Check: an additional processor
check is performed, all of the RAM locations in Digital Storage (A3A4 Memory) are checked,
and the RAM memory on the Al5 Controller is verified.
Since these more extensive checks require altering information that has been stored in RAM,
LONG POP requires an internal jumper on the Al5 Controller. To perform a LONG POP:
n Set the LINE switch to STANDBY.
w
Place a jumper between ST or STS to T3
q On Al5 Controller (HP part number 85660-60209) jumper
A15TP4
(STS) to
A15TPl-7
PO
q On Al5 Controller (HP part number 85660-60245) jumper
A15TPl-9
(ST) to
A15TPl-8
P-3).
q (Refer to Al5 Controller Component Location Diagrams for location of test points).
n Set the LINE switch to ON.
When LINE switch is set to ON, the two red INSTR CHECK
LEDs
are forced on and the
main processor steps through the Self Test routine, expanding the normal POP with the
additional tests mentioned above. The expected results for a LONG POP are exactly the
same as for the normal POP of Instrument Preset as described above in the Instrument Preset
Check.
Because LONG POP is a “destructive test” (it alters any information that has been stored in
RAM), it should be performed only as a last resort effort in troubleshooting what appears to
be a memory or processor related problem.
Digital Storage Verification
The Instrument Preset Check does a fairly complete verification of the Digital Storage
controller and memory. An additional check can be done, independent of the RF section, by
jumpering
A3A6TP3
to
A3A6TP6
and pushing
A3A7Sl
momentarily. A test pattern should
appear on the display. Refer to the A3 Digital Storage Troubleshooting Section in the HP
856628 IF-Display Section volume of the service manual for a more detailed description of
this procedure. Note that when the jumper is connected, the left check LED always stays
on following an INSTR PRESET,
since in the test pattern mode, Digital Storage ignores all
instructions from the Al5 Controller.
2 Digital Troubleshooting