Power Supply Issue that's Not

[cfh]

So like a crazy person, i bought 21 model 40x williams slots.
i have been working on them, getting them going. One
i had was a Magic Lamp dotmation. with the coin tray
removed, the game worked fine (no sound though as
the speaker is part of the coin tray.)  Hook up the coin
tray, and the game won't boot. The three center LEDs
on the driver board are out too.

I should mention i am running a switching computer ATX
power supply for both the lower and upper power supplies
(one power supply replaces both the original upper and
lower supplies).

What was the problem? the speaker!  i measured it with
a DMM and it was only 2.7 ohms (it is labeled as an 8 ohm
speaker). The speaker should obviously measure 7 to 8 ohms.
So the speaker was bad, and dragging the 12 volts down
(used for the amplifier) and not allowing the game to boot.
This happens because the computer power supplies will
shut down a voltage if that voltage is powered to a near
short (which this was). It also takes about 10 seconds of
power-off for these computer power supplies to reset
themselves and to turn the problem voltage back "on"
at next power-up.

Interesting stuff.

[stayouttadabunker]

CFH,
Can I ask you...I'm learning really,..what's a DMM?
Which model you have...I think I'd like to get one.
Thanks for any help you can give me...

[PWRSTROKE]

I am quite sure he meant DVM -Digital Volt Meter -Which we all know- .  I guess with 21 plus games you could get mesmorized---

[a69mopar]

digital multi meter would be my guess

[dpalmi]

Can I ask you...I'm learning really,..what's a DMM?

Digital Multi-Meter - same as Digital Volt Meter or DVM...

Dan #2

[PWRSTROKE]

Yea,  Ford calls em dvom's  --same diff.  volts/ohms etc. etc.