Troubleshooting Astro Blaster

dochowl

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I've got an Astro Blaster which uses the 5 G-80 boards inside a cage. The board is not booting as far as I can tell. Challenge is you can't get into the cage to test much of anything. Lots of ICs were replaced due to corrosion and rust. At this point I think all is well with that.

The sounds, speech, and eprom boards are all known working.

Any ideas how to proceed? You can see the picture below. This comes up immediately with no changes.

Thanks

874ef00da46bc6657486d5202f19e9c0.jpg
 
On the CPU-board there's a little button that you can push (reach in with a pen or something to trigger it). This will trigger the self-tests and could help you narrow down the problem. For the first few tests a LED will blink. The manual explains the tests executed. Obviously, if you can't get a picture, most of the tests will be unaccessible to you, but looking at the LED is a good start.

Also, how's that power supply? Both the two Astro Blasters that I've worked with have had bad caps and/or voltage regulators on the power supply.
 
Thanks for the input. Unfortunately, no LED coming on at any point. I've checked the voltages where they come into the top of the cage and those are all good. I've also checked the +5V on ICs on the CPU board and all is well there. Z80A is tested good.

On the CPU-board there's a little button that you can push (reach in with a pen or something to trigger it). This will trigger the self-tests and could help you narrow down the problem. For the first few tests a LED will blink. The manual explains the tests executed. Obviously, if you can't get a picture, most of the tests will be unaccessible to you, but looking at the LED is a good start.

Also, how's that power supply? Both the two Astro Blasters that I've worked with have had bad caps and/or voltage regulators on the power supply.
 
life would be a lot easier if they didn't cram all these boards into a cage so you can't get to anything for testing. I've replaced quite a few ICs, sockets, transistors here as they were quite rusted. No change, no LED, screen shows bars. Will figure this one out eventually.

So just to confirm my direction, if I remove the CPU board and turn on the power, I get the same screen as above. Am I right in assuming that points to the CPU board not booting? It may be about time to take the top off the cage and get out the probe.
 
Update - I was able to procure another CPU board and all is well. The original board in this thread still has similar issues noted above, although slightly different now that I've repaired the video board. I will circle back to this one at a later date.
 
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