416 replies to this topic

[Carny_Priest]

Yes, to be more clear I also directly tested a hard drive 4 pin molex from a computer power supply and I read 10V/24V instead of 5V/12V. So it is not just the cheap $10 adapter. I don't have these connected to the DMD Piggy, so it is not a blown trace. I don't believe that it is a faulty meter as the voltage coming from the transformer is what I expect, 80V and 100V.

The label on the cheap adapter indicates that it is double insulated. I don't know if that means that it is isolated.

Any ideas?

Edited by Carny_Priest, 16 August 2013 - 04:42 AM.

[antropus]

Are you using two different transformers or you got one of those transformers from RoccoC? My setup was having all kinds of problems until I installed the transformer that Rocco ordered. Worked straight away after that.

 

-Kris

[randr]

can't be 10v/24v off a pc supply...crazy! Test a battery or something else dc with meter is it correct? Aliens maybe! Lol

[Carny_Priest]

I tested the PSU installed in my cab and it reads 10V/24V AC as well. Nothing wrong with the cab, so it must be the meter after all. It was reading the low voltage sources correctly two days ago. The meter is a Velleman DVM850BL, same make and model as sold by Pinball Life.

 

I have a Rocco transformer. The meter reads the output of the transformer as expected, 80V and 100V AC. I do not have the power sources connected to the DMD Piggy.

 

I tested a 9V battery and it reads as expected, 9V DC.

 

Weird. I guess I'll go ahead and make the hook-ups today.

[russdx]

Ac? Psu out is dc make sure ur on dc hehe

Edited by russdx, 16 August 2013 - 07:11 PM.

[antropus]

Yep, make sure your meter is set to DC when you read from the PSU and AC when you read from the transformer
Once you got everything plugged into the piggy, remember that all currents produced by the piggy that output to your Plasma DMD are DC as well, so keep the setting as DC...

Edited by antropus, 16 August 2013 - 07:20 PM.

[Carny_Priest]

Duh! Told you I was a noob.

 

Output from transformer is still AC. Got it.

 

Output from adapter gets switched to DC. The meter measures the low voltage output as expected if I measure in DC. Got it...  now.

 

Nothing to see here. You all can move along now. 

 

Edited by Carny_Priest, 16 August 2013 - 08:00 PM.

[randr]

Lmao!!!

[clutester]

Carny, many people on this forum that are building these amazing machines, this is the first time really working with this level of wiring and electronics as well. I'll admit it myself, but I've learned so much from it.

[randr]

So did you get it working!?!?!?

[Carny_Priest]

Yes! Yes, I did. I can confirm that the cheap switching adapter with the 4 pin molex connector seems to work OK.

Edited by Carny_Priest, 17 August 2013 - 05:08 AM.

[antropus]

Good job! I'm glad

Have fun and give our thread some stars!

 

Yes! Yes, I did. I can confirm that the cheap switching adapter with the 4 pin molex connector seems to work OK.

[randr]

awesome. 

[zebulon]

A little late to the party but....if you measure dc with your meter set to ac it will double the output as it's looking for a complete phase (- to + and + to - on a sine wave). On DC it's just looking for linear voltage (1/2 of the sine wave).

 

Redundant I know....but I'm full of that kind of useless info.... 

[Carny_Priest]

Yeah, I was conscious of the fact that I was measuring DC off of that adapter when I was first making connections. I was getting the readings I expected. Came back to the task a couple of days later and completely forgot about it.

But at least I'm making some progress now!

[The Loafer]

Finally got off my butt and ordered that Vishay plasma from mad amusements. Can't wait!

[jlaydon]

I'm having a lot of issues with powering up the display board.  If anyone has any suggestions, I would greatly appreciate them!

1) I'm using the Piggyback, but accidentally overdrove resistor R3 and need to replace it.  Does anybody know its resistance?

2) For the +12V that is referenced to the -110, does that mean that I should ground the +12 to the -110? This question won't apply once I fix the Piggyback.

3) Is there a default display that should be showing once it's receiving the correct voltages?  Because before I overdrove the resistor, the DMD was definitely getting the correct voltages, but nothing getting displayed.

 

THANKS FOR YOUR HELP!!

[clutester]

I was having the same issue with the DMDpiggy (Piggyback?) I contacted Troy Kellogg about it and he gave me these resistor values.

R1 100 ohm

R2 5.1k ohm

R3 51 ohm

R4 118 ohm

R6 121 ohm

R5 & R5a 22k (should measure 11k)

R7 & R7a 20k (should measure 10k)

 

My problem is everything is powered but for some reason the Piggy isn't outputting the 12V difference in the negative values on pins 1 and 2. I have a feeling that is what allows the entire display to light up. I have a feeling if you power everything up and then pull out your PinDMD cable you'll get a line lit up across your DMD.

[jlaydon]

Thanks!  Do you know what the 51 Ohm resistor is used for so that I can calculate the power? Or do you know if it's 1/4W, 1W, etc.

[randr]

I think a diode is on that 12/5v side..its small red and clear did you test that?