theatre of magic fuse 104 blowing

[pinball god]

Cannot disconnect all magnets as spirit ring plug is under ramps so heaps to remove, but with the two drain magnets it still gets hot. She cooks if the ball trough eject activates, when the knocker activates etc.

[Strangeways]

Swap the drain magnets.

With the RHS Drain magnet disconnected and a new 3A SB fuse installed, you should be able to play a game. Also, solenoid 14 (Trapdoor hold) is part of the same F104 circuit. Check that the trapdoor mechs are working 100% and there's no friction of the moving parts.

You could also check the voltages at the lugs of any solenoids. With the playfield raised and the front door closed, you should see the same DC voltage on both lugs on just about every coil.

From memory, the magnets should read 7.5 Ohm (game off and measure with the magnets disconnected).

[The pinballist formally known as Dean Morgan]

Swap the board sounds like a crook bridge rectifier

[pinball god]

Measured all magnets except the trunk and they measure 4.5ohms. Swapped the drain ones and still problem. Disconnected spirit ring still problem. The good news is the fuse blows once high voltage is present (coin door closed). I noticed by just being in solenoid test with it on stop and closing the coin door, there is a major hum and the fuse lights up. Like I said the good thing is the problem is worse and constant.

UPDATE did a pcb swap and all good I think. Thanks Dean.

My question now is I have a tiger saw motor croc clip that connected to a resistor on 12vp on the rottendog pcb. Where do I connect it on my original williams driver pcb? I have tp1 and 3 label 12vu and 12vr which I'm guessing mean regulated and unregulated. Please advise if you can or if you need more info. See photo

Also where and what bridge rectifier is stuffed on this rottendog pcb. I can't seem to find where the br's are on this board. See photo. Thanks

[pinball god]

Other two pics

[pinball god]

Solved tiger saw question tp1, but can't figure how to fox the power drive pcb re bridge rectifier etc.

[robm]

No bridge rectifiers on the rottendog board, just diodes.  Do diode test on all the large diodes at the top left of the board.

Yet another story as i posted earlier regarding issues with rottendog boards...

[pinball god]

No bridge rectifiers on the rottendog board, just diodes.  Do diode test on all the large diodes at the top left of the board.

Yet another story as i posted earlier regarding issues with rottendog boards...

thanks Rob will have a look. Is it an easier job than replacing br's? Does jaycar sell replacements and if so what should I ask for? Thanks

[pinball god]

Quickly tested the large diodes and found D51 and D53 showing .700+ instead of 0 but also D52 and D54 reading starts low and climbs until it reads OL like the rest. Can someone explain if any are in trouble etc. I cannot see how these involve the 50v problem with the solenoids??

[robm]

Hmmm they may be ok. Find the driver transistor that drives the magnet. Should be a tip102. Put multimeter in continuity mode and see if there is continuity between the metal tab and ground. If so it is shorted on. Replace it and its predriver transistor a 5401. Also test the legs of those transistors in diode mode, just see that it tests the same as other ones the same around it.

[The pinballist formally known as Dean Morgan]

How are u testing the diodes?  With meter on diode setting red lead on the end of diode with line and black common lead on other end record all the readings and let us know

[pinball god]

How are u testing the diodes?  With meter on diode setting red lead on the end of diode with line and black common lead on other end record all the readings and let us know

as mentioned earlier all read ol except D51 & D53 0.712 & 0.704 and D52 & D54 start around 0.8 and climb until the read ol. Once this has occurred they will read OL.

D53 and D54 are linked as are D51 and D52

Also Q91 to Q98  tip 107's show ranges in 0.5 for outside legs and 0.00 middle leg except Q64 13N10L right leg reading 0.46 or so. All the other Q's 13N10L's read OL and 0.00 for middle leg

[andypinboy]

I'm getting the feeling that rottendog boards may not be the best in the business...

[Gemini2544]

From my experiences, one leg of the diode should be de-soldered  from the PCB prior to testing. Leaving it on the board & testing means your measuring the resistance of the whole PCB circuit. Can give you the wrong reading leading you up the garden path so to speak.

[Gemini2544]

I'm getting the feeling that rottendog boards may not be the best in the business...

I've got a Rottendog power supply for my System 1 Cleopatra, had no issue with it or the quality.