Key Jammed; Ram Test; Eol; Timing Tests - HP 8112A Operating, Programming And Servicing Manual

Key Jammed

0
Possible faulty A3 Processor Board (ROM reset circuit) or power
supply fault (restart signal)
A front panel key is stuck. The instrument cannot be used until it is
freed.

RAM Test

The microprocessor is unable to load a test pattern into the RAMS
or main board, remove the device-bus cable from the main board
Al at connector J2 (See Chapter 10.2. mainlayout\) and from the
control board A2 at connector J5 (See Chapter 10.5.

Timing Tests

Period generator U200 is not able to supply a period of 1 ms in MAN
mode with a software trigger. Possible failure of Period control
circuit U4, U7, Error feedback U141 or trigger input stage UlOl, LDO
and QlOO. See Chapter 10.3.

El2

Delay generator U220 is not able to supply a pulse of 3 ms when
in positive trigger mode and triggered via the Period generator.
Possible failure of Delay control circuit U5, U7, Error feedback Ul
or level shifter Q200. See Chapter 10.3.

El3

Width generator U240 is not able to supply a pulse of 9 ms when in
positive trigger mode and triggered via the Delay generator. Possible
failure of Width control circuit U6, US, Error feedback U141 or level
shifter Q220. See Chapter 10.3.

El4

The Slope IC U301 in function mode, is unable to produce pulses
with a period of 2.5 ms and rise/fall times of 1 ms. Possible failure of
Slope control circuit U12, U13, U14 or U302, Slope range switching
circuit Q305 to Q309, U300, or reference circuit U320. See Chapter
10.3.
Instrument Overview and Troubleshooting Guide
40
10.1-5