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HandyWriter hardware modification
This
document shows the steps involved to upgrage the Handywriter REV:C and REV:D to
REV:E. Please follow the steps below and consult the appropriate circuit diagram below to
implement these changes.
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To upgrade Handywriter REV: C to REV:E follow the circuit diagram
below:
 
The track from pin 3 of the 7812 Regulator U5 should be cut and a Resettable Fuse inserted
into this line as shown. For the correct type of fuse see the table below.
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To upgrade Handywriter REV: D to REV:E follow the circuit
diagram below:
The track from pin 3 of the 7812 Regulator U5 should be cut and a Resettable Fuse inserted
into this line as shown. For the correct type of fuse see the table below.
The 7806 Regulator U6 should be replaced with a 7805 type.
| Manufacturer |
Product |
Model No. |
| Polytronics Technology |
EVERFUSE |
RLD60P020X |
| Raychem Corporation |
PolySwitch |
RXE020 |
| Bourns Inc. |
Multifuse |
MF-R020 |
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