Index EVEREST, Service Manual

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Index Everest Servicemanual v 3.0
BOX 155 • S-954 23 GAMMELSTAD • SWEDEN • PHONE +46-(0)920 203080 • T46-(0)920 203085 • E-MAIL info@indexbraille.com • http://www.indexbraille.com
Our problem was on hammer six.
In below table you can see that it can be a result of driving circuit no U38.
NOTE!
To go further and check it is necessary to have a good knowledge in computer hardware and a proper
oscillochope with a probe available. Faulty handling on the board with power may damage the board
and are not covered by warranty.
For a fault on hammer 6 (our example) check the in signal (pin 24+24) and out signal (18+23). These pins
shall be on a logic 0, (below 1,8 V) after power on of the unit. We do not recommend to check the FIFO
and Buffer circuit as they are very sensitive and soldered on the board.
After repairing a printinghead run the self-test again, POWER ON + ON LINE. Check the printout and
if necessary, adjust the impact level and the vertical alignment on the printer via the support software.
Hammer Transistor Driving circut Buffert step (FIFO)
MTP 3055E (x13) UDN2916 (x7) 74AC843 (x2)
No:1 Negative T12 U39 in 1+44 out 3+6 U32 out pin 22
No:2 Positive T13 U40 in 24+25 out 18+23 U32 out pin 21
No:3 Negative T14 U40 in 1+44 out 6+3 U32 out pin 20
No:4 Positive T11 U39 in 24+25 out 18 +23 U32 out pin 23
No:5 Negative T10 U38 in 1+44 out 3+6 U31 out pin 16
No:6 Positive T9 U38 in 24+25 out 18+23 U31 out pin 17
No:7 Negative T8 U37 in 1+44 out 3+6 U31 out pin 18
No:8 Positive T6 U36 in 1+44 out 3+6 U31 out pin 20
No:9 Negative T7 U37 in 24+25 out 18+23 U31 out pin 19
No:10 Positive T3 U35 in 24+25 out 18+23 U31 out pin 23
No:11 Negative T4 U35 in 1+44 out 3+6 U31 out pin 22
No:12 Positive T5 U36 in 24+25 out 18+23 U31 out pin 21
No:13 Negative T15 U41 in 24+25 out 18+23 U32 out pin 19
Transistors