HP 214B User Manual

Appendix
The other 'zero detect' circuit (U309, U311) clears U319, setting the 0 output low again, and thus
allowing the
counter to be loaded once more f rom the thumbwheel switches.
TROUBLESHOOTING
1. With oscilloscope set to 1I1S / division, set the 2148 to exactly 1 MHz.
2. Set 2148 to 8 urst Mode.
3. Connect the 2148 TRIGGER OUTPUT to the 2148 TRIGGER INPUT .
4. Disconnect the
base connection of transistor A60304 and leave as 'open base'.
5. Disconnect pin 13 of A6U312 from socket X302 and leave as 'open circuit'.
6. Wire·connect the open track (from which A6U312 pin 13 is disconnected) to ground.
7. Set Scope to internal trigger.
8. Check the waveforms detailed in the following list:
r---·----------T-------------.--~~~~~~
L_2_14_B_B_O_A_R_D_A_6 __ ... l __ 0_SC_il _loscope Screen ..J OSCI LLOSCOPE
,--- L I Time/ Oi ... . Tr igger Slo pe
U318 Pin 1
U315 Pin 4
U322 Pin 4
U324 Pin 4
U324 Pin 7
U302 Pin 8
U301 Pin 8
l.fLruu uuumnr
L!0 ~ Sc reen Wi dth-4l:-
L
10 "" SCleen Widlh 11.-
L 20% Scre en Width ~
---lf1%Screen Width
-U-l% Screen Width
U
II
U312 Pin 10 + ' , 'OO %S< 'HnWid ,h ----.l
U309 Pin 8
f I " ~ 50een W,dth
If
U319 Pin 2 -""1- " ' 00% S"",n Wi,"h
0303 emitter ± "'00 % So"n W,d,"
U319Pin13 111I1I11111
U319 Pin 6
+ 1/ 100% Screen Width ~
0303 collector + " 'OO %S<,~nWid'h
U319 Pin 8 + ' I100%S,,,,nW 'd'h----r
NOTES: 1. To get the signals at U319 adjust EXT INPUT LEVEL Vernier.
2. Some duty cycles are difficult to see on oscilloscope screen.
A1 - 10
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Model 2148
Scans by ArtekMedia => 2009

HP 214B Specifications

General

Brand	HP
Model	214B
Category	Portable Generator
Language	English