Meteor Display Not Working

[The pinballist formally known as Dean Morgan]

Guys,

Turned on my Meteor today after some months and the displays are not working.

Checked all voltages on TP on displays 160v and 5v etc are there, i.e displays get the illumination right down the bottom.  The MPU boots i.e 7 flashes and then dims, machine plays but no displays.  Occassionly and I mean very rearly when in attract mode they will come on dimly and then slowly drop out, but usally just blank.  Both PIAs are OK.

Any ideas?

Thanks in advance for help, I will have a look later as I havnt had a good look, but thought you guys may be able to point me in the right direction.

Dean

[ajlaird]

Nearly thought I was going to have to go there with the Dirty Harry but it all came good.

I guess start with the obvious - connectors. Rule that out first.

If the machine is playing, the voltages are there for the displays but the displays aren't lit, that would suggest a breakdown in the output from MPU to display driver board, or a problem on display driver board (assuming this is separate).

[Strangeways]

160 Volts is waaaaay too low. Thats probably why they glow dimly.

Crank up the voltage to at least 180 Volts from the trimpot on the Solenoid driver. Be careful around this area of the board - use a plastic screwdriver, and don't go over 195 Volts.

[The pinballist formally known as Dean Morgan]

160 Volts is waaaaay too low. Thats probably why they glow dimly.

Crank up the voltage to at least 180 Volts from the trimpot on the Solenoid driver. Be careful around this area of the board - use a plastic screwdriver, and don't go over 195 Volts.

Done, adjusted to 180v has not made a differance still blank.  Seems like a prob with the MPU board to me, PIAs are Ok may try changing U29 and U20 next any other ideas

[ajlaird]

Check any electrolytic capacitors in the area for bulging - over time with some heat these can go open circuit.

[Strangeways]

Check the fuse on the Solenoid Driver - it is a strange value 3/16 Amp -Hard to find

Do they work in test mode ?

[The pinballist formally known as Dean Morgan]

All fixed U20 was the culprit

[Strangeways]

All fixed U20 was the culprit

Well done Dean !

 

[ajlaird]

Good work, too easy in the end!