Adjusting Power Supply

[lustreking]

I'm finally getting around to working on my Outrun machine.  I've replaced all the parts in the bottom, including the power supply.  I hooked up the ps and nothing else, and adjusted it to 5v. 

After I plugged everthing else in, including the game boards, it didn't work, and I noticed that the ps output dropped to around 1.7v.  Is this supposed to happen, or do you need to adjust the power supply with a load, or could there be a problem with the power supply?

Thanks,

-S

[SirPeale]

I'd say you have a problem with your PS.

Is it a switcher?

I have an Out Run in the shop that was dead.  Has a Peter Chou in it.  Opened it up...bloated caps everywhere.  Replaced them all, fired right up.

[RayB]

Well, you're supposed to adjust it with a load. Keep adujusting it up until it reads +5 at the board.

[lustreking]

Mine also has a Peter Chou in it.  I think I'll try cracking that open before I further adjust the voltage.

Thanks,

-S

[SirPeale]

Well, you're supposed to adjust it with a load. Keep adujusting it up until it reads +5 at the board.

This is true - BUT - if it was @ 5V before a load, and only 1.7V after, there's a problem with the PS.  On a healthy PS the drop should be quite minimal.

[RayB]

This is true - BUT - if it was @ 5V before a load, and only 1.7V after, there's a problem with the PS.  On a healthy PS the drop should be quite minimal.

But why would you assume he has a Peter Chou? He made no mention of this. Different power supplies would act a little differently. Some read 0.0 when there is no load.

I put in a ps in a Tron with an MCR kit and it read +7.0 at the power supply before the game would fire up. (Anything less just made garbage come up).

He should also check that all connectors are clean and secure.

[Q*Bert_OP]

This is true - BUT - if it was @ 5V before a load, and only 1.7V after, there's a problem with the PS.  On a healthy PS the drop should be quite minimal.

But why would you assume he has a Peter Chou? He made no mention of this. Different power supplies would act a little differently. Some read 0.0 when there is no load.

Mine also has a Peter Chou in it.  I think I'll try cracking that open before I further adjust the voltage.

Thanks,

-S

[grantspain]

i always test psu's by connecting a 6v bulb across the 5v and common just to see if your psu is running,if thats ok and when you connect the game board you have no voltage or low it could be a plug in the wrong place or some sort of short causing the psu to drag down

[lustreking]

Well, it definitely was the ps.  I had another one lying around and I put that in.  There was very little drop with the new one after plugging in the board.

However, it appears that I haven't gotten any farther...  Still no sound or anything on the screen.  Guess I have more work to do

Thanks!

-S

[SirPeale]

But why would you assume he has a Peter Chou? He made no mention of this. Different power supplies would act a little differently. Some read 0.0 when there is no load.

I never said he had a Peter Chou.  I said that if he had a PS that started off @ 5V with no load, then went to 1.7 with load, likely something was wrong with it.

[SirPeale]

i always test psu's by connecting a 6v bulb across the 5v and common just to see if your psu is running,if thats ok and when you connect the game board you have no voltage or low it could be a plug in the wrong place or some sort of short causing the psu to drag down

I had a Peter Chou that I connected like eight 6V bulbs, lit those fine, read 5V with no issues.  Connecting it to a board and it would drop *way* down.

Cool Guy recommends using a hefty resistor.

[SirPeale]

This is true - BUT - if it was @ 5V before a load, and only 1.7V after, there's a problem with the PS.  On a healthy PS the drop should be quite minimal.

But why would you assume he has a Peter Chou? He made no mention of this. Different power supplies would act a little differently. Some read 0.0 when there is no load.

Mine also has a Peter Chou in it.  I think I'll try cracking that open before I further adjust the voltage.

Thanks,

-S

Oh yeah...hey!  Confrontational much?   

[RayB]

Sorry. Totally missed his mention of pete chou. Must have been tired (and grumpy).