voltages at Asteroids fuseblock?

[mc300baud]

yeah, replacing the Big Blue was the first thing i did.

and the hum seems to originate at the transformer which is why i suspect that even with good voltages it may be bad.

 

[orion3311]

Not saying its impossible, I'm sure it is but other than physical hum from a transformer I kinda doubt it. The AR board should be filtering all the outputs of it at least to an extent. The 10v unreg is filtered by big blue even before it gets to the AR. The 36v gets turned into 22v and -22v by the AR2 and then used for the x-y section of the pcb, and some people reported having to replace the caps in the x-y section to clean up hum.

If you have an o-scope that would be the end-all to see what the output of the AR looks like, both unloaded and loaded. You could also check for AC on the DC outputs as well to see if any noise is showing up. It seems there's a crapload of different ways Asteroids can hum...

Big blue cap on brick
Caps on PCB
Caps on AR
Bad edge connector not making good contact, or burnt contacts
Bad or incorrect light bulbs in the coin door
Bad transistors/ICs on the AR (had this on my AD)
Bad grounds
Marquee light

 

[mc300baud]

it hums even with everything but the power brick unplugged (monitor, AR, PCB, marquee, coin door, etc.) the hum gets worse when the AR is plugged in (it's then through the speakers) but no worse when anything else gets connected after the AR.

i'm taking the main electronics up to Dokert's tomorrow and hopefully we'll be able to isolate the issue.

 

[mc300baud]

ok, a partial update and then i'll start a new thread even though i have little hope:

- replaced the line filter
- installed a rebuilt AR-I-01
- had Dick Millikan do a bunch of repairs to the board which fixed disappearing objects and bad RAM issues.

game now plays well with no flicker (don't know if this is due to PCB repair or the new line filter; i suspect it may be the later.)

still has a very low-level hum that disappears when the saucers appear then reappears when the saucers disappear.