Replacing Sega "Jumbo" DMD

[Pintoxicated]

I thought with that particular display version the blue wire didn't have to be moved??  Double check the instructional diagram to make sure the blue 12V wire is in the correct spot.

[Homepin]

Display specs and power connections straight from the datasheet

I would leave pin one disconnected:

[Pintoxicated]

The confusion with these large replacement displays is that there are two versions.  One version requires just the removal of the 5V wire whilst the other version requires the 12V wire be put where the 5V wire was.

Unfortunately they aren't as simple as replacing a standard sized display which is plug n play.

[delarge]

Sounds like the bridge is sorted but here is a pic of mine to double, triple check.

Can you test the connector with the blue wires to see what reading you get.
Set meter to volts AC, doesn't matter which probe goes on which side.

What reading do you get?

Was in bed, but had to duck out and check this.

That connector is only registering 0.03. It goes up to that, drops and goes back up to 0.03 repeatedly....

[Steevsee]

Sorry Adam but was your meter set on AC volts?

The AC volts here comes direct from the transformer.

[delarge]

Ok, total multimeter n00b. It wasn't on AC. From that connector I am now getting 15.06.

Thanks everyone for persevering with this. Appreciate the help.

Adam.

[Steevsee]

OK. Good you are also learning about your meter because there's more fun to be had.

Still with meter on AC, probe the two blue wires on BR3.  You should get same or similar reading as before.

[Steevsee]

Now time to switch to volts DC on your meter.

The bridge rectifier changes the AC volts to DC volts.

You could probe the black wire at BR3 with your black probe, but easier to connect to a common ground, like....
.....the ground braid.

Then use your red probe on the purple wires on BR3.

Check your reading.

I probably should also mention to be very carefull, when probing around with the power on.

[delarge]

It's that time of night again....pinball time!

It's been interesting. I think we are narrowing the issues down, but I'm still clueless as to the solution. Here are my findings.

Blue wires on connector (tested previously): 15.06V AC

Bridge rectifier:
Blue wires: 15.08V AC
Black wires: 0.04V DC (red on black leg, black on cabinet braid)
Purple wires: 0.16V DC (red on purple leg, black on cabinet braid).

[beaky]

what pin does the 12 volts go to on the power connector to the dmd?
remember the jumper W1?
you will have to make sure the jumper settings match up with the power input connector.
if you have the W1 jumper set to supply pin 4 then you will need your +12v on pin 4 if you have it set to supply pin 1 then you will need your +12v on pin 1
Please wait until this is verified before changing the jumpers


also make sure you are getting the +5 volts to the display driver board,

[delarge]

what pin does the 12 volts go to on the power connector to the dmd?
remember the jumper W1?
you will have to make sure the jumper settings match up with the power input connector.
if you have the W1 jumper set to supply pin 4 then you will need your +12v on pin 4 if you have it set to supply pin 1 then you will need your +12v on pin 1
Please wait until this is verified before changing the jumpers


also make sure you are getting the +5 volts to the display driver board,

Heya Beaky,
as it's been a few weeks since I did that jumper on the board, I decided to go and check the actual machine. The machine was jumpered to supply pin 4, but I have moved the +12v wire to pin 1. There is no wire connected to pin 4 currently.

So...should I now put the +12v wire to pin 4?

Cheers!
Adam.

[Steevsee]

Maybe you also have dodgy capacitor.

Try swapping the connections on the big blue capacitors.  So swap the black and purple wires from the right side cap to the left side and put the ones that were on the left onto the right.
You may already know that these caps are polarized - black wire must go to negative and purple wire to positive (which is marked on the top of the cap).

Try testing the voltages again(DC) once the wires are swapped and let us know result.

[Steevsee]

Also I'd leave the pins how it is, as you said you followed the intructions that came with the display, in you first post.

Surely these should be the most reliable data source.

[delarge]

It makes sense what Beaky said. The points that I jumpered are making the +12V connection on the track. Otherwise, if it wasn't jumpered, there's be no power going anywhere. Excuse me if I have used the wrong terminology there.

Will check that capacitor.

Cheers!
Adam.

[delarge]

Maybe you also have dodgy capacitor.

Try swapping the connections on the big blue capacitors.  So swap the black and purple wires from the right side cap to the left side and put the ones that were on the left onto the right.
You may already know that these caps are polarized - black wire must go to negative and purple wire to positive (which is marked on the top of the cap).

Try testing the voltages again(DC) once the wires are swapped and let us know result.

Just switched the wires over on the big blue capacitors and still getting similar 0.03 readings on the purple and black legs of the Bridge Rectifier. What's happening there?

Cheers!
Adam.