Dirty Harry

I have open up the back box and as I saw already with the glass on half of the lights was very weak. The cause is a burnt connector at the driver board. The funny thing is that someone has already changed the female connector but didn’t change the male connector at the board. Also all lamps in the back box have been changed to LED’s. Maybe it was done to reduce the current through the connectors, instead of changing the male connector.

Changing the connector at the board solved the problem, all LED’s light as they should. But I found another problem with them. The CPU are able to dim the GI, when lit at max the LED’s light as they should but when diming them they start to flicker a bit. The back board lighting are connected to four GI strings, two of them are common with the GI at the playfield. For the other two, which is only used in the back box, the LED’s are flashing instead of flickering at the sixth light level. It’s a quite nice light show but it’s not intended to be in that way. The cause for the flashing is that the load from the LED’s is too low for the GI driver to work properly. I replaced one led with an ordinary light bulb in each string and then the flashing disappeared, they are still flickering though.

I have still not seen the reboot problem but to make sure I went through the 5 V supply at the driver board. The AC connector J101 is fine, this is a common cause of the reboot problem. The bridge rectifier BR2 and the filter capacitor C5 have already been changed and I checked the DC level and AC ripple after the rectifier and it was fine so no reason to change those again. The DC level after the regulator Q1 is 4.99 V and when measuring at the CPU board it is 4.97 V. Everything seems to be OK and there shouldn’t be any reboot problem in the game, I’ll continue to play for a couple of days and see what happens.

The only sad thing is that I have got the magnetized ball problem back. I bought new balls but the supplier couldn’t say if it was chrome steel or carbon steel balls. But they have been used in other games with playfield magnets and there hadn’t been any problem. I dropped the new balls in to the game and after 20-25 plays the new balls was magnetized and started to stick to each other in the ball through. They do also sometimes stick to the magnets core and isn’t released when the magnet is de energized. Incredible annoying problem… I’ll continue to search for carbon steel balls.