MPU4 - REPAIR LOG(1).pdf

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4.02.2021

MPU4 - REPAIR LOG

Home mpu4 Ace mpu3 mps sys85 em Restore Close-up sys80 Collection Battery

Repair Log… (7/4/11)

MPU4 – MOD 2

Fault diagnosis.

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.

Repaired

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