HP HP-67

316 Service and Maintenance
The magnetic recording head is similar to magnetic recording equip-
ment. As such, any collection of dirt or other foreign matter on the
head can prevent contact between the head and card, with consequent
failure to read the card. The head cleaning card consists of an abrasive
underlayer designed to remove such foreign matter. However, the use
of the card without the presence of a foreign substance will remove a
minute amount of the head itself; thus, extensive use of the cleaning
card can reduce the life of the card reader in your HP-67. If you suspect
that the head is dirty, or if you have trouble reading or recording cards,
by all means use the cleaning card; that’s what it is for. If one to five
passes of the cleaning card does not clear up the situation, refer to
Improper Card Reader Operation in this appendix.
Service
Low Power
When you are operating from battery power, a bright red lamp inside
the display will glow to warn you that the battery is close to discharge.
1.23 -23 Low Power Display
°
You must then either connect the ac adapter/recharger to the calculator
as described under Recharging and AC Line Operation, or you must
substitute a fully charged battery pack for the one in the calculator.
Blank Display
If the display blanks out, turn the HP-67 OFF, then ON. If
does not appear in the display in RUN mode, check
the following:
1. If the ac adapter/recharger is attached to the HP-67, make sure it
is plugged into an ac outlet. If not, turn the calculator OFF
before plugging the recharger into the ac outlet.
2. Examine battery pack to see if the contacts are dirty.
3. Substitute a fully charged battery pack, if available, for the one
that was in the calculator.
4. If display is still blank, try operating the HP-67 using the
recharger (with the batteries in the calculator).
5. If, after step 4, display is still blank, service is required. (Refer
to Warranty paragraphs.)