Trident
Stern Electronics, 1979You're currently viewing posts by Pinsider Quench.
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Quoted from Rikoshay:turns out i was wrong
Quoted from Rikoshay:J3 pin 13 on rec board goes to credit knocker (solenoid bus) white with yellow tracer
Actually you were originally correct 
The knocker was in the head on previous Stern games hence solenoid power came from J3 pin 13 on the rectifier board. Trident has the knocker in the lower cabinet near the speaker and it gets solenoid power from the rectifier board J2 pin 2. That's the reason A2J3-13 is empty.
Quoted from Nihonmasa:On the CPU I have those values: TP1 @ 4,9 V, TP4 @0V, TP6 @ 22V
If on the Alltek MPU board you have 5 volts on TP1 and 0 volts on TP4, then the 1.1A F1 fuse on the Alltek MPU board is blown.
Quoted from Nihonmasa:Now you have me puzzled; cause I can't see any fuse on the alltek MPU
The F1 fuse isn't a normal glass type fuse. See the picture below:
When the Alltek MPU board sees an over voltage on the 5 volt supply, it trips a short circuit protection that purposely blows the fuse to prevent the over voltage from damaging semiconductors on the MPU board.
This now leaves you with a non-standard fuse to source and replace.
Quoted from G-P-E:Cycle power to reset means the board has a solid state fuse, you don't change this fuse.
Thanks Ed, below are pictures (front and back) of the fuse taken from an Alltek I have and also the Alltek the crowbar schematic.
@nihonmasa, might be an idea to post all your test point voltages on the rectifier board, solenoid driver board and the MPU board like emsrph did above.
Alltek_MPU_Fuse_a.jpg
Alltek_MPU_Fuse_b.jpg
Alltek_VCC_Protection_a.png
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