HP (Hewlett-Packard) 6205B ユーザーズマニュアル

5-47 To check the output stability, proceed as

a.

Connect test setup shown 

b. Turn CURRENT controls 

 clockwise

and adjust VOLTAGE controls for 40Vdc output.

c .

Allow 30 minutes warm-up then record

the differential voltmeter indication.

d. 

 8 hours, differential voltmeter

 change by less than 

 from indication

recorded in Step c.

5-49 Before attempting to troubleshoot this in-

strument, ensure that the 

 is with the instru-

ment and not with an associated circuit. The per-
formance test (Paragraph 5-10) enables this to be
determined without having to remove the instru-
ment from the cabinet.

5-50 A 

 understanding of the principles of

operation is a helpful aid 

 troubleshooting, and

it is recommended that the reader review Section
IV of the 

 before attempting to troubleshoot

the unit in detail. Once the principles of opera-
tion are understood, refer to the overall trouble-

shooting procedures in Paragraph 5-53 to 

the symptom and probable cause.

5-51 The schematic diagram at the rear of the

manual (Figure 7-1) contains normal voltage 

ings taken at various points within the circuits.
These voltages are positioned adjacent to the ap-
plicable test points (identified by encircled num-

bers). Component and test point designations are
marked directly on the main printed wiring board.

5-52 

 a defective component is located, replace

it and re-conduct the performance test. When a

component is replaced, refer to the repair and re-

placements and adjustment and calibration para-
graphs in this section.

5-53 OVERALL TROUBLESHOOTING PROCEDURE

5-54 To locate the cause of trouble 

 Steps

1, 2, and 3 in sequence.

(1) Check for obvious troubles such as

open fuse, defective power cord, input power fail-
ure, or defective voltage or current meter. Next
remove the top cover (held by four retaining

screws) and inspect for open connections, char-
red components, etc.

If the trouble source cannot

be detected by visual inspection, proceed with
Step 2.

(2) In almost 

 cases, the trouble can be

caused by improper dc bias or reference voltages;
thus, it is a good practice to check voltages in
Table 5-2, before proceeding with Step 3.

(3) Disconnect the 

Table 5-2.

Reference Circuit Troubleshooting

METER

METER

NORMAL

NORMAL

STEP

COMMON

POSITIVE

INDICATION

RIPPLE

IF INDICATION ABNORMAL, TAKE THIS ACTION

1

+s

33

6.2   0.3Vdc

. 

Check 12.4 Volt bias or VR1 (See next paragraph)

2

31

+s

6.2   

. 

Check 12.4 Volt bias or VR2 (See next paragraph)

3

+s

37

12.4 *1. 

Check Q8, Q9, 

 CR23, C1O, 

4

38

41

7.5   .7Vdc

Check C12, CR8, CR24, CR25

Table 5-3.

Overall Trouble shooting

SYMPTOM

CHECKS AND PROBABLE CAUSES

High output voltage

a.

Front 

 meter defective.

b. Series regulator feedback loop defective. Refer to 

 output voltage

a .

Fuses blown (Check 

 or C14 for short).

5-9