HP 8340A Service Manual page 283

instrument processor which pulls down HSP
Marker Band cross
AMP 2 line to go LOW.
TP12) LOW, turning on the Current Shunt
(Low Sweep LED U32A pin 3)
sweep LED.
At the appropriate time the instrument processor asserts LRSP
(Low Reset sweep,
go LOW. This allows Reset Amplifier 1
output of U9 to ground.
turning off the Current Shunt.
During the re-phase-lock sequence,
releases LBX and LRSP.
the Sweep Generator
Model 8340A - Service
board. HSP going LOW causes the LOW ENABLE RESET
This in turn forces LHLD
goes HIGH,
TPll) which causes LRESET
LRESET going LOW
These events do not cause any changes on
board.
Scans by HB9HCA and HB9FSX
(High sweeP)
(Low Hold Sweep,
(Block
Q).
turning off the front panel
(Low Reset,
(Block R) to pull the
causes LHLD to go HIGH,
the instrument processor
on the A57
Finally LSPLD
TP13) to
8-369C