HP Portable PLUS - Page 107

Portable PLUS Computer Troubleshooting 8-41
The serial number located on the recharger indicates the month that the unit was manufactured. The
format is described below.
Y Y M M
T f
L
_____ Month manufactured.
- Year manufactured (years since 1960).
To determine whether the recharger is functioning properly, perform this procedure:
1. Plug the recharger into an outlet of the proper voltage. (Refer to table 8-13.) Measure the power-
outlet voltage (VIN) using an ac voltmeter.
2. Measure the recharger ac output voltage (VOUT) under no-load conditions using an ac voltmeter.
VOUT should be between 9.9 and 13.3 Vac at power voltages of 110.0 or 220.0 Vac. More gener-
ally, VOUT should equal
(VIN / 110) x 11 .6 Vac ± 1.7V or (VIN / 220) x 11.6 Vac ± 1.7V
where VIN is the ac voltage of the power outlet.
• If VOUT is inside the allowable range, proceed to the next step.
• If VOUT is outside the allowable range, the recharger is bad and should be discarded. Stop
testing here.
3. Connect a 12-ohm, 5%, 5W resistor across the recharger output contacts.
4. Measure the ac voltage (VOUT) across the load using an ac voltmeter. The voltage should be
between 5.3 and 7.3 Vac at power voltages of 110.0 and 220.0 Vac . More generally, VOUT should
equal
(V IN / 110) x 6.3 Vac ± 1.0V or (VIN / 220) x 6.3 Vac ± l . OV.
• If VOUT is inside the allowable range, proceed to the next step.
• If VOUT is outside the allowable range, the recharger is bad and should be discarded. Stop
testing here.
5. While measuring the ac voltage across the load, wiggle and pull the wire at the transformer and
at the connector.
• If the voltage stays above 5 Vac, the recharger is good.
• If the voltage drops below 5 Vac, the recharger is bad and should be discarded.