EdGs
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- Aug 9, 2012
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Hello to all,
A friend of mine asked me to take a look at his Motordome machine for him. It had been working, then was powering on, but not starting the game.
He told me he tried to check the fuses on the power supply board, and when he tried to test the first fuse, there was a sizzle sound, followed by a burnt component.
I pulled the psu board out and upon inspection found R2 (2.2 ohm 1/4W) cooked and the LM323 reg shorted on the input side. I replaced those components, reinstalled the board, and got good readings on all psu voltages.
The CPU board however, did not have the green power on LED lit. The sound board gives 3 flashes. I had a spare 6803 chip and also replaced the dead battery (which was probably the only thing wrong in the first place).
I then was able to get the power on led to light, but no flashes.
I have not had a chance to go into it deeper yet, and I would like to make up a power supply so I can power it up on the bench, but I have been preoccupied with life's other problems.
I am thinking when the regulator shorted it may have taken out some of the 74 series chips and/or the PROM's or more.
.
Are there any quick checks I can do to narrow it down a bit once I can power up on the bench? Thanks for any help you can give
A friend of mine asked me to take a look at his Motordome machine for him. It had been working, then was powering on, but not starting the game.
He told me he tried to check the fuses on the power supply board, and when he tried to test the first fuse, there was a sizzle sound, followed by a burnt component.
I pulled the psu board out and upon inspection found R2 (2.2 ohm 1/4W) cooked and the LM323 reg shorted on the input side. I replaced those components, reinstalled the board, and got good readings on all psu voltages.
The CPU board however, did not have the green power on LED lit. The sound board gives 3 flashes. I had a spare 6803 chip and also replaced the dead battery (which was probably the only thing wrong in the first place).
I then was able to get the power on led to light, but no flashes.
I have not had a chance to go into it deeper yet, and I would like to make up a power supply so I can power it up on the bench, but I have been preoccupied with life's other problems.
I am thinking when the regulator shorted it may have taken out some of the 74 series chips and/or the PROM's or more.
.
Are there any quick checks I can do to narrow it down a bit once I can power up on the bench? Thanks for any help you can give