Repair Log… (7/4/11)
MPU4 – MOD 2
Slides pulse on start-up.
Slides continue to randomly pulse and chatter during operation.
Incorrect caps fitted from a previous repair. (C9-C15)
Some battery residue.
Otherwise MPU boots and runs normally, no lamp faults detected, all other aspects
of the board seem OK.
Clean up battery residue with fibre-glass pencil.
First replace incorrect capacitors C9-C15 1000pF
Replace T12-T19 = BC338 (transistor pre-drives for payout triacs). No slide pulse
on start-up. OK.
Slides still pulse on startup, so replace C1-C8 = 1000pf (.1uf) – Poly Cap. OK
Run board, slides remain calm. OK.
Soak test – 2 hour (short test) OK.
Battery not fitted as board is not needed at the moment.