HP Portable PLUS - Page 86

8·20 Troubleshooting
Portable
PLUS Computer
Table 8·6. Repairing the Power Supply (Continued)
Step
1. Note the symptom that indicated a power
supply problem.
Charger Problem:
2. Connect a good recharger to the computer.
3. Measure the voltage at A2C50 "+ " lead.
4. Measure the voltage at the cathode of
A2CR51 (striped end).
I
Response
If a good recharger, when connected to the unit
with a low battery, doesn't increase the battery
voltage, go to step 2.
If the VccDS supply always stays at its power-
down level (3 .2-3.4 Vdc) but VBAT is above 6.2
Vdc, skip to step 5.
If the VccDS supply is outside its proper range
(4 . 9-5 .1 Vdc or 3.2-3.4 Vdc) but VBAT is above
6.2
Vdc, skip to step 5.
If the VccS supply is outside its proper range
(4 .9-5.1 Vdc) but VccDS is proper (4.9-5.1 Vdc),
skip to step 7.
If the VLCD supply is outside its proper range,
but
VccDS and VccS are proper (4.9-5.1 Vdc),
skip to st ep 8.
If the contrast adjustment doesn't operate prop-
erly, but Vc c DS, VccS , and VLCD are proper,
skip to step 10 .
If the voltage is between 10 and 20 V dc, go to
step
4.
If the voltage is 0 Vdc, check the connections at
the
I/0 plate (RECH receptacle), check A2CR64
thru A2CR67 (rectifiers), check
A2C50; replace
the motherboard
PCA.
If the voltage is greater than 0 Vdc but not be-
tween
10 and 20 Vdc, replace the motherboard
PCA.
If the voltage is between 10 and 20 Vdc, check
A2Q50; replace A2U50; replace the
motherboard
PCA.
If the voltage is 0 Vdc, check A2C51, A2CR51,
and A2CR52; replace the motherboard PCA.
If the voltage is greater than 0 Vdc but not be-
tween
10 and 20 V dc, replace the motherboard
PCA.