World Rally back to Millipede Power problems

dethfactor

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Millipede Power brick problems

So I picked up a Millipede cab that was converted into a World Rally which I wasn't a huge fan of and decided to convert back. The atari power brick was left in the cab but I think the iso transformer was used on the monitor and the rest was run off of a switching PSU. I removed all the world rally stuff and the hacked harness, and put in an original Millipede harness, Millipede PCB and cage, a working AR2-02 I had rebuilt recently, a populated CP and a G07 I had lying around and when I fired her up the monitor and marquee lit up but the board is getting no power. I ran a 5v test on the test points on the board and I'm getting something like .648mv on it. I assume it has something to do with the brick. I checked it and there's a cap across the two larger caps and I'm not sure if that's original or not. I'm wondering if it's been rigged to bypass it's output. I just rebuilt the brick recently for my asteroids and there wasn't a cap attached parallel to the huge one in the brick like this one has.

Any help or insight would be greatly appreciated.

Here's a picture of the bottom of the brick:
ae2297c9.jpg
 
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That cap should not be there, remove it.

Test your BR while you have the brick out to verify that it is good.

Removed the cap and used the meter on continuity mode to test the BR. I had to think about what a BR was for a minute because it was late and was wondering how to test Baskin Robbins with a meter.
Anyhow, I got "Open" across all 4 leads in both directions which makes me think she's bad.



Prior to seeing your post Dokert, I looked up the voltages for brick testing and found this thread:
http://forums.arcade-museum.com/showthread.php?t=121666&highlight=Dokert+testing

and tested the brick with and without that cap and got similar results:
(I have an auto rangefinding meter, not sure if that makes a difference)
R,B
Pins 1,4 = 10.07 VAC
Pins 2,4 = 17.41 VAC
Pins 3,4 = 45.2 VAC
Pins 1,5 = 37.8 VAC
Pins 2,5 = 10.47 VAC
Pins 3,5 = 17.26 VAC

Pins 6,7 = 8.94 VAC

Pins 8,9 = 7.89 VAC

Pins 10,12 = 6.54 VAC

Pins 13,15 = 1.684-1.685VAC

These readings for the most part are WAY off. Which either means I'm doing something completely wrong (which I'm not so sure of) or I need to replace some stuff.
I'm probably going to order a rebuild kit from good ol' Bob Roberts in the morning.
If you or anyone thinks it could be something else, let me know ASAP.

I'd like to get more that 67.5mv going to my PCB.

Lastly, for the record. I know for a fact it is not the AR-II. I just swapped it out of my working centipede.
 
Ok, I've just come to the realization I used the continuity test and not the diode test on the BR, last night. I tested it via the diode test (after testing a diode just to make sure I was doing it right) and saw that there was a .45-.47 voltage reduction across each set of pins on the BR (swapping leads as I go). The opposite had no results, which gives me reason to believe that this BR is working actually.


The first 12 VAC tests were a mistake on my part as I
had my meter set to VAC. It was late and I was out of it.

At this point I may just buy the rebuild kit and be done with it but I'd like to get my diagnosis methodology down for the next time.

The BR is bad, replace it. You did use diode test?

Your meter may be bad too. The first 12 voltages should be DC
 
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Ok so I swapped out some parts with another brick i had including the cap and BR and the board started up but with a garbled picture. Saw someone else have the same problem so tested the 5v test leads on the board and saw they were off by a couple of volts. I ended up just pulling out my rebuilt brick from my centipede and she fired right up. Going to rebuilt it's brick and put them back where they belong next week. Thanks for all the help. Now back to my troublesome Tron.
 
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