Service manual

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