Pin-bot

I have spent the day disassembling the playfield to prepare it for cleaning and polish. It has  a mylar sheet protecting it for wear so the paint is in good nick. The sad thing is that the mylar has bubbles by some of the inserts, which is a bit tricky to sort out.  One option is to remove the mylar completely and clear coat the playfield. This is a lot of job since the playfield has to be completely stripped from all parts on both sides. This mylar also seems to be mounted at the factory and if the paint wasn’t completely cured when it was done then I will probably have paint following the mylar when removing it leaving me with a lot of touch up job. Another option I have read about is to make a small hole in the mylar and drip in clear lacquer to glue the mylar down again. Maybe it would work but it might cause problems in case someone would like to remove the mylar in the future. I will leave it as it is for now, leaving both options open.

 

 The lock down bar receiver was incredibly dirty, I have cleaned and polished it the best I could do. It’s not 100% but much better than before. I have also gone through the ball shooter. All parts cleaned and polished, new sleeve for the shooter rod and a new barrel spring on the outside.

 

 

 This is the current state of the playfield. There are still some parts to remove and then a lot of cleaning to do.

 

 

 



 

Pin-bot

Dirty Harry is out of the house and the next project is a Pin-bot. I have just got it in to the workshop and have just taken a quick look at it. When it arrived the display texts was in German, probably due to some lost settings. I checked the batteries and all three of them were just above one volt and one of them showed signs of starting to leak. So it might have been a last minute battery exchange.

 

 

The owner left the back box glass at home to avoid transport damages.

 

When I first looked at the game it looked quite good but when the glass is taken off for a closer inspection I can see some problems. A couple of playfield posts are missing and they seem to have been missing for a while, there is a quite big ball formed dent in the ball guide at the picture to the left. Of some reason also some posts and other parts are lose and some plastics are cracked or broken.

 

Dirty Harry

The pinball gremlin had a last trick up in his sleeve, the start button stopped to work. I tried it in the switch test and nine times out of ten it wasn’t registered as closed even though I heard the click from the switch. It was the switch that failed and after changing it the game was up and running again.

Dirty Harry

I found low magnetic balls at web shop in Germany which I ordered. And once I got them in to the game it’s a pleasure to play it again. I have played about 20 games and can’t see any tendencies of magnetizing in the balls and I will continue to play the game to make sure until it is picked up by the owner. But I think the machine is haunted by an evil pinball gremlin of the worst kind. Once the new balls was in there I decided that it was ready for delivery. I cleaned the playfield glass and put it back on the game using gloves to make sure not making any fingerprints at the inside and since then I have had to take it off three times. First the left flipper stopped working and the cause was a loose wire at the flipper coil. I fixed it and also fixed a wire at the right flipper coil that was about to break. The glass was put back on again and after a few games one of the bullet target lamps failed. Glass off, changing the lamp, glass on. A few more games and then the left flipper didn’t hold in the up position. Another wire was loose at the coil, but this one was absolutely fine when I inspected it when the first wire came loose. Glass off, solder wire, glass on. On top of this also the service menu buttons inside the coin door stopped working. This was caused by a loose ground cable in the coin door and didn’t require taking off the playfield glass.

 

I couldn’t resist the urge to clean of the rust of the tilt pendulum. Ten seconds in the glass bead blaster and it was like new again.

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.