This causes a problem if the laser is out-of-range on startup.

1. Determine the serial number of the head you're working on. Type TH2> set sys serialnumber.
   If the serial number appears in this list: TH2 serial numbers, complete the rest of this procedure.
   
2. Run an ldd calibrate. Type the following commands:
   TH2 >laser on
TH2 >stroke cal
TH2 >laser off
TH2 > bpd mode on
TH2 > lvd mode local
TH2 > ldd calibrate
3. At the prompt, type y:
   Turn on the laser (Y/N)?
y
Y-Intercept=5.9254 Amps, Slope=1.815 Amps/Watt
*** Command Success ***
4. Update the BPD Hold current. Type:
   >>bpd mode on
>>lvd mode local
>>ldd mode current 18
5. Wait for 1 minute.
6. Type TH2 >bpd mode update
7. Turn the laser off by typing
   TH2 > laser off

If the error persists after following this procedure, the thermal head needs to be replaced.

1. Turn the BPD stream on using the following commands:
   TH2> eng
TH2> bpd mode on
TH2> lvd mode local
2. Turn the laser on using the command ldd mode current 15.
   DANGER: Follow all necessary laser safety procedures.
3. The two numerical values in the 5th column should add up to more than 60.
4. Type TH2> laser off
5. Run LDD calibrate (see How to Run LDD Calibrate).
6. Update the BPD hold current (see the procedure below).

If the incorrect value for the BPD holding current is used, the system will take longer to settle. This may cause a time out.

Do the following:

1. Type the commands:
   >> bpd mode on
>> lvd mode local
2. Turn the laser on using the command ldd mode current 18.
   DANGER: Follow all necessary laser safety procedures.
3. Wait 2 to 3 minutes.
4. Type bpd mode update.
5. Type laser off.

Note: This will change the value of holding current to the correct value.

1. Check the following:
   • Is the laser enabled or disabled?
   • Is the voltage for the write laser available? Type TH2> volt
   • Is there a temperature-related error, or any other laser-related error? Use ldd info to check the WLP status.
2. Turn on the laser in current mode. Type the commands:
   TH2 > bpd mode on
TH2 > lvd mode local
TH2 > bpd stream on
TH2 > ldd mode current 30
3. Confirm that the laser is detected on the bpd sensors. Use the following code samples to determine if the laser turned on correctly.
   Code samples:
   Laser turned on | Laser did not turn on
   If the bpd sensor readings are in the single digits (as shown in the example Laser did not turn on), replace the thermal head.