Hi Darren,
I was using Dokert's instructions for testing,
http://forums.arcade-museum.com/showpost.php?p=1073965&postcount=5 this is where I got the 80 and 65 from. Like I said both of those on my brick are measuring half what they should be and not sure what they do.
So if the 12 comes from the 10.3 I guess it would have to be in the ARs I have or wiring as my 10.3 is perfect coming from the brick. At the AR and on the PCB I am only reading about 2v but my 5 is perfect so the game plays great.
Hope to see you at Gamewarp.
The linked post is part of a discussion about an Asteroids Deluxe power brick, and AFAIK is only true for early Asteroids power bricks (early rev drawings show the 80VAC taps, later ones have it blacked out). In any case, it's not (all) relavent to your Centipede power brick. And beside all of that, there's no real reason to check your 60VAC taps if your monitor is working--all they do is serve as an isolation xformer for monitor power, so if the monitor is working fine, don't sweat them.
Getting back to your original issue. I looked at the Centipede schems, and I now see that I contributed to some confusion about "12V". The confusion arises because the "10.3V" (aka 10.6V) line normally reads closer to 11.5V... which is nearly 12V.
However, I forgot that there is an actual 12VDC line on -02 ARIIs. It is totally seperate from the 10.3V line which comes from the power brick already rectified and filtered. Instead, it is derived from 36VAC on the ARII board (as Edward was pointing out).
SO... the you should have 36VAC on pins 6 & 7 of P5 (just as Dokert's post, and Ed, suggest). There should also be test points on the ARII board for 36VAC, check it there as well. If you don't have 36VAC, check your fuses (F4 & F5). If you do have 36VAC, then your ARII is the problem; either the regulator (7812, Q8), or the filter caps (C23, C22, C18).
This regulated 12VDC is not used ON the ARII board for audio amplification (it uses the unregulated 10.3VDC instead), BUT it IS sent to the game PCB where it powers an LM324 op-amp which pre-amplifies the audio.
Yup, I'll be at Gamewarp, Sat. & early Sun. Good to hear you'll be there as well... at least there'll be one person I know
