Maintenance—2246 1Y and 2246 Mod A Service
Conditions:
All vertical channels can be successfully dis
played and positioned independently.
The A and B sweeps both free-run and trigger
successfully.
Both A and B Trigger COUPLING and SOURCE
operate properly.
Normal-appearing readout text and cursors can
be displayed.
Definition of terms:
Type 1 volts m easurem ents are:
l<- VOLTS-H and
rk
VOLTS-H
Type 2 volts m easurem ents are:
DC
Type 3 volts m easurem ents are:
+PEAK, -PEAK, PK-PK
Type 4 volts m easurem ents are:
GATED +PEAK, GATED -PEAK, and GATED
PK-PK
Measurement value accuracy is the accuracy of
number displayed in top line of readout on the
crt.
Measurement cursor accuracy is the accuracy
of the match between cursor position and the
measurement value.
Trigger value accuracy is the accuracy of the
number displayed on the trigger level cursor.
Trigger cursor accuracy is the accuracy of the
match between cursor position the value dis
played on the cursor.
A TL is the A trigger level measurement system.
B TL is the B trigger level measurement system.
Table 6-9
Measurem ent Error Troubleshooting Hints
Circuit
Problem
Sym ptom s
VERTICAL INPUTS (schem atic Diagram 1)
Ground relay stuck in
signal position
Gross value problems for Types 1-4 volts measurements.
Gross value problems A TL and B TL.
Test: Use “ EXERCISE VOLT REF.” Check that the ground relay is in
ground position.
Defective X I 0, X I 00,
X I, X2, X5 Relays
and Attenuators
Gross value problems for affected channel for Types 1-4 volts
measurements.
Gross value problems in A TL and B TL.
Test: Check channel accuracy at all VOLTS/DIV settings.
ZERO HYST line stuck
low (U173-13)
In Type 4 measurements, minor value problems for +PK cursors
when gating interval is at negative end of waveform, and for
-PK cursors when gating interval is at positive end of waveform.
Test: Turn off all measurements; use the A Horizontal Mode. U431
pin 28 should be -3 .0 volts.
Switch to ALT Horizontal Mode. U431 pin 28 should be -0 .7 volts.
6-26
Summary of Contents for 2246 1Y
Page 13: ...2246A Service 7062 01 X The 2246 1Y or 2246 Mod A Portable Oscilloscope ...
Page 35: ......
Page 139: ......
Page 185: ......
Page 187: ......
Page 278: ...Figure 9 5b Detailed 2246 1Y or 2246 Mod A block diagram part 2 R E ...
Page 287: ......
Page 304: ...A D D J U N 1991 ...
Page 311: ...2246 1Y and 2246 Mod A Service WAVEFORMS FOR DIAGRAM 1 0 V r l III B f e I l i 6555 39 ...
Page 319: ......
Page 320: ......
Page 321: ...2246 1Y and 2246 Mod A Service WAVEFORMS FOR DIAGRAM 2 SET READOUT CONTROL CCW OFF 6555 40 ...
Page 323: ......
Page 324: ......
Page 326: ...A B C P E F G ...
Page 327: ......
Page 331: ......
Page 337: ......
Page 340: ......
Page 343: ...C l rti ...
Page 347: ...BEV JUNE 1991 7062 18 ...
Page 349: ...2246 1Y and 2246 Mod A Service WAVEFORMS FOR DIAGRAM 6 6555 43 I ...
Page 355: ...I BOARD LOCATION 8K 8J 8H 7H 8H 8H 7J 8D 7H 8H 8J 8J 7K 8K 10D 6L 6K 6L 6K 6G 5H I ...
Page 362: ......
Page 372: ...2246 1Y and 2246 Mod A Service WAVEFORMS FOR DIAGRAM 9 MORE ...
Page 373: ... 6555 72 6557 88 ...
Page 375: ......
Page 380: ...WAVEFORMS FOR DIAGRAM 10 ...
Page 387: ...WAVEFORMS FOR DIAGRAM 11 6555 73 6557 48 ...
Page 394: ...WAVEFORMS FOR DIAGRAM 12 2246 1Y and 2246 Mod A Service i f I S 1 f c i 4 i ...
Page 395: ...WAVEFORMS FOR DIAGRAM 12 cont 2246 1Y and 2246 Mod A Service ...
Page 397: ......
Page 398: ......
Page 400: ...REV JUNE 1991 7062 39 ...
Page 401: ......
Page 403: ......
Page 404: ......
Page 406: ...B 2246 IV AND 2246 MOD A ...
Page 407: ......
Page 408: ......
Page 414: ... _ 5 ...
Page 415: ...2246 1Y 2246 MOD A ...
Page 416: ......
Page 423: ...2246 1Y 2246 MOD A ...
Page 424: ...2246 1Y 2246 MOD A ...
Page 425: ......
Page 433: ......