Roadblasters PS sending 15v instead of 10.3v

[clanggedin]

My roadblasters died a few months ago when a token accidentally bridged the gap between a couple of the fuses on the PS/ I replased the fuses and I get the 5v and 15v  that the game needs except when I check the line that supplies the 10.3v with a multimeter I am getting 15v. I know that this line is unregulated, but 15v seems too high. The game won't power on at all either, just the marquee and the monitor. When I check the test points on the mainboard I am not getting 5v either.

I do have a switching PS that I was thinking of installing just to test the 10.3v line with 12v. Would that possibly work??

Could 15v have fried my ARIII board and mainboard too?

[RayB]

Take them out and examine everything real closely for burnt up parts...

[Ken Layton]

The 10.3 volts is indeed unregulated so that means approximate. There's probably something wrong on the audio regulator board.

[clanggedin]

I dunno 15v doesn't sound approximate to me. 12v sounds approximate, but you know your stuff Ken so I'll check the Audio Regulator board to see if I can find any problems with it.

[clanggedin]

OK I pulled the AR III board and it looks like the big resistor at R20 is cracked, it is also brown around it. According to the System 1 schematics it says the resistor is a 2.7 1w. What does that mean??

[Rocky]

I get around 14v on the 10.3v unregulated line on my Food Fight. I don't think that is your problem.

If your AR board is putting out +5v, but you aren't getting +5v on the main board, it sounds like you fried something on the main board.

It's easier to troubleshoot if you know which board/part is bad. Do you have any spare boards or AR III's to test with?

[Ken Layton]

OK I pulled the AR III board and it looks like the big resistor at R20 is cracked, it is also brown around it. According to the System 1 schematics it says the resistor is a 2.7 1w. What does that mean??

Sounds like 2.7 ohms at 1 watt to me.

[clanggedin]

Unfortunately I don't any spare boards to test with and I am getiing tired of buying spare test boards. Lately everytime I buy a spare or a replacement part I end up fixing the broken one without the need for the other one at all.

I would rather purchase a working AR III board, than try and hunt for a place that will sell me this resistor without having to buy 50 or pay $10 in shipping.

[ChadTower]

I dunno 15v doesn't sound approximate to me. 12v sounds approximate, but you know your stuff Ken so I'll check the Audio Regulator board to see if I can find any problems with it.

What it means is that the 10.3V is unregulated at the source.  It could be 11v, it could be 18v.  It gets regulated down at the destination by something like a voltage regulator, some resistors, etc.  The destination board's input is what does the regulating, not the source board's output.