Memotech Limited MTX 500, Руководство по обслуживанию

Страница: 50 / 78

46
Timing chain modification
In October 1984 Memotech altered the timing chain
circuitry due to occasional faults occurring after about
2 hours of use - and poor fire up response. (esp; when
running in conjunction with F.D.X.)
We have since up-dated all our units to incorporate
this 'modification'. MTX 4000/06 P.C.B.'s are exempt
from this modification due to the fact that
multilayered boards are generally not affected.
However you may feel the need to replace the timing
chain with the modified circuit if your MTX is
suffering from intermittent fire ups (e.g. 1 fire up
failure in less than 5 attempts constitutes a possible
fault in the timing chain circuitry). The diagram
below shows what components have to be changed and to
what values:-
R14 680 Ohm resistor to be replaced by a 330 Ohm
resistor.
C6 68pf capacitor to be replaced by a 33 pf capacitor
(or left out completely).
MTX Service Manual