Missile Command

Muerto

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Im trying to fix my newly bought MC, though, i have some issues (!!!) with the voltage...
I think that maby the PS is gone.... :(

Missile Command PCB
-5V = -5.29V
+5V = +3.09V
+12V = -0.71V

ARII PCB
-5V = -5.17V
+10.3V = +8.77V
+12V = -0.57V
-22V = -15.06V
+22V = +15.02V
+36VAC = +11.48VAC

Also the feed to the monitor and florescent tube:
mcchart.png


Im also searching for the schematics for the ARII PCB, so i can see where and how much the voltage should be at the input plugs and output plugs...
 
You can get the schematics in pdf at
http://pdf.textfiles.com/manuals/ARCADE/K-R/
DP-158 is the one you want, I think. The only diffs for the different schematic packages are in cabinet wiring anyway, the AR-II and the main board are the same on all.

Check the connectors on the main board and AR-II, make sure the +5 return line isn't screwed up somewhere down the line, and DO NOT try to power up the AR-II without the CPU board connected - the AR-II takes feedback from the main board (that +5 return I mentioned) and uses it to adjust the +5 output to accommodate the load. If you power up the AR-II without the main board, it may eat itself. There is a mod that prevents this, but not everyone thinks it's a good idea. Search around for AR-II mod to find one of the many threads where it was debated.

If it hasn't had a rebuild, I'd start with a rebuild kit from Bob Roberts, and then debug from there.

Good luck!
 
I'd start with the power brick voltages - look for the 12 pin molex on the right hand side of the power assembly. There are 4 columns of 3 pins. Column 1 = pins 1-3 from top to bottom, columns 2 = pins 4-6 etc.

Test for:

Pins 1&2 = 10.3VDC
Pins 4&6 = 25VAC
Pins 4&5 = 12.5VAC
Pins 11&12 = 6.3VAC


I'd guess that the 10.3VDC on the power brick will read the same as it does on the AR2 (but it's still worth checking to see what the brick is sending out). IIRC the 10.3 is used by the AR2 to derive the +5. So that might be why the AR2 is struggling to give you more than 3V. If you are getting a low reading off the power brick then the obvious culprits would be the big blue, or one of the two diodes that sit on the rectifier board (that sits right underneath the big blue).

Re the -22 and + 22 – forget these – not used by Missile Command, so largely irrelevant.

Re the +12: the power brick should be kicking out 25VAC (pins 4 & 6) and I suspect that if you check the power brick then you'll find the correct voltage (because the AR2 takes that 25VAC and rectifies it into +12 and -5, and your -5 is present and correct). So … that would leave you looking at the section of the AR2 that produces the +12, most probably the 7812 regulator at Q8 (which you'll find bolted to the heat sink).
 
Have been busy, but finally got to check:
Thanks for your replys!!!!

Heres what i got:
Pins 1&2 = 10.3VDC MINE: 10.28VDC
Pins 4&6 = 25VAC MINE: 23.45 VAC
Pins 4&5 = 12.5VAC MINE 11.70 VAC
Pins 11&12 = 6.3VAC MINE: 6.12 VAC

So, it´s not the PS that is off, it´s the ARII....?
 
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