Power Supply Questions

I have been working on my 4-slot 25 big red recently and have noticed how quiet the sound is, and how dim the monitor is. I was cleaning it out today and decided to test the power supply and got 120 coming in (normal) but 5.04 and 10.20 respectively coming out of the power supply. i know that the cab needs to be at 5 and 12 and was wondering if the discrepancy could be causing some of the problems. I am pretty sure it is about time I did a cap-kit and if I were to do that, I may even toss a new fly back on it, seeing as they are so inexpensive, but I was still wondering is the power supply could also be causing some of this... Anyway, thanks for taking the time to read this!

-Jorge!

Wow, I was really hoping someone might be able to shed some light on this...

Anyway, I retested the power supply and got the same numbers. I set up a mirror in front of the monitor and started really trying to get the best colors I could from the monitor and ended up with a decent but still dim image. I was adjusting the colors with the tinted protective monitor glass removed, so I could see the colors better. After getting the most acceptable colors out of the monitor, I noticed that I was able to get the colors I wanted by cranking the contrast and black levels up on the pots located under the control panel. Unfortunately, I could get the colors to be bright, but the focus was terrible and any adjustments I made via the pots on the neck-board or fly-back wouldn't improve the focus problem, so I returned it to the best settings I could get and replaced the monitor overlay. Obviously it was just darker and with the glare the glass created, made the games near unplayable.

I have decided to pony up the cash for the power supply to remove that as a possibility and and to hopefully help me track down why the sound is so low. Once again, any insight would be greatly appreciated as I am kinda learning as I go. Luckily, I have been reading quite a bit and am picking up a lot of useful info. Thanks for reading!

-Jorge!

This is the psu I've been using:

http://www.happcontrols.com/powersupplies/80007200.htm

Power supply won't affect your monitor. You need a cap kit and if your monitor won't get brighter, a flyback.

If you sound is low and the volume control has no effect then you probably need to cap the sound section of the pcb.

Mitsurugi-w said:

Power supply won't affect your monitor. You need a cap kit and if your monitor won't get brighter, a flyback.

If you sound is low and the volume control has no effect then you probably need to cap the sound section of the pcb.

Click to expand...

Are you sure? I would have thought the audio section only getting 10v would be more than enough to make it very quiet.

Those massive PC-style power supplies are shit, unless you love hacking wiring harnesses. Use a standard arcade one.

SNK-Jorge said:

5.04 and 10.20 respectively coming out of the power supply.
-Jorge!

Click to expand...

Measure the 5 volts at the mobo not the psu as there will be voltage dropped in the harness. 5 volts at the psu could end up as 4.5 volts at the board.