Jump to content
Due to a large amount of spamers, accounts will now have to be approved by the Admins so please be patient. ×
IGNORED

Power Supply FAQ


Recommended Posts

Over the next couple of weeks, i would like the community as a whole to estblish a series of FAQ's related to arcade technical and repairs. I thought that power supplies would be a good place to start and if other want to start on Monitors etc then feel free to. Alot of this information is already posted on the site in various locations, but it would be good to have a central point of reference to direct new members to. Below is a priliminary FAQ that i will amend. Feel free to post your own questions and answers, or just questions.

The Big Bad Power Supply FAQ.

 

Many people underestimate the importance of a good quality power supply. In my time as a computer technician, many hardware faults were a direct consequence of a poor or failing power supply; arcade cab’s are no different in this respect.

 

Some boards/pcb’s are fussier than others when it comes to power supplies, especially late model Sega and Namco boards, but for the most part pcb’s will run just fine up until the power supply gives out. Some boards may act spasmodically, i.e. your game will often freeze or reset, or in worst case scenario’s your power supply may be responsible for destroying your pcb’s.

 

In this FAQ, we as a community will endeavour to answer all frequently asked questions relating to power supplies. As usual, the normal disclaimers apply. If you are uncomfortable with adjusting/troubleshooting your power supply issues then please ask a professional. The advice contained within this FAQ is always evolving to provide the best possible answers.

 

So here we go!

 

How can I tell if I have a faulty power supply?

 

What voltages does my board use?

 

This will vary from board to board, but basically if you have a JAMMA board then it will require 12V, 5V, and occasionally -5V. 12V is mainly used for sound and 5V for the logic functions of the board. -5V is used on older boards and is also used to run the light globe in your coin mechanism (assuming you have one).

 

Modern non-JAMMA boards often require an additional 3.3V line. These boards come under the classification of JVS or JAMMA+. The best examples of these are the Sega Naomi, Model 1, Model 2, Model 3 and Namco System 246, although there are many more. The majority of these boards will use custom power connectors.

 

All JAMMA and JVS voltages are DC (direct current).

 

Board pre-dating JAMMA can vary wildly. Some even use AC (alternating current). If your board does not use a Jamma connector then consult schematics or the games manual to find out what your board requires.

 

What voltages do I need?

 

As already mentioned, the main Jamma voltages are 12V and 5V, with some boards requiring -5V also. Depending on the application, an AT or ATX computer power supply can be used instead of an arcade psu, but this is not recommended for several reasons. First, computer power supplies cannot be adjusted or fine tuned like regular power supplies. Secondly, some computer power supplies will not even start unless they have enough of a load on the 5V line and probably most importantly PC power supplies have the ability to deliver a massive shock if you mess something up.

What are Volts, Amps, Ground and Watts?

 

What is a Multimeter?

 

What power supply should I buy?

 

How do I adjust my power supply?

 

What else does the power supply operate inside my cab?

Depending on the type of cab you have got, the power supply can be used to power many of the interals with the exception of the tube and fluro's (if you have one of course). The most common peripheral to be powered by the machines psu other than the actual gameboard is the coin mech followed by complex input peripherals such as optical joysticks or trackballs etc. Other items that are powered by the psu are...

 

Amplifiers

Ticket Machines

EL Panels (electro luminesant) -found in some neo geo's.

Optical Sticks

Credit Boards

Optical Guns

Video Converters

Alarms

 

When trying to find a suitable replacement power supply, you should find out which of these items you have and also see how power hungry these items are.

 

My power supply is making noises! What is going on?

 

What does the "FG" post on my power supply do?

 

The FG post is used to help counteract any monitor interference you are getting as a result of poor grounding. E.g. when i run my naomi gd rom, the interference caused by the gd rom unit causes lines to roll through my monitor. By bridging your ground post to the FG post, you can nearly always eliminate this type of interference. A tutorial can be found here

Link to comment
Share on other sites

CHECK YOUR WIRING

 

As someone who has blown up two power supplies becuase of a shorted coin counter, I have learnt the hard way why you need to check your wiring for shorts prior to installing a pwoer supply.

 

All you need is a contuinty test, a light and some patience to trace wires, partiuclarly strays to see where they ae going and what they may be attached to.

Link to comment
Share on other sites

  • 2 months later...
  • 3 weeks later...

How do I test my PSU? More specifically, how do I test -5V...Here's what I get on my PSU...

 

GND & +5V = 5.10V = good

GND & +12V = 11.90V = good

GND & -5V = 500mV = WTF?!?

 

Either there is something drastically wrong with the way I am testing -5V or my PSU is drunk.

Link to comment
Share on other sites

How do I test my PSU? More specifically, how do I test -5V...Here's what I get on my PSU...

 

GND & +5V = 5.10V = good

GND & +12V = 11.90V = good

GND & -5V = 500mV = WTF?!?

 

Either there is something drastically wrong with the way I am testing -5V or my PSU is drunk.

 

Shit, I have never had that happen before. Try putting ground on -5 and pos on ground.

Link to comment
Share on other sites

OK testing GND & -5V today gives flat 0. Tried the probes the other way around (as suggested) but still 0V.

 

So I test my cocktail and get -4.5V across GND & -5V. So maybe my upright's PSU is not doing the do. Or maybe its because the upright has -5V wired and the cocktail doesnt. Maybe there is a short somewhere (or the chassis is affecting the result). I will disconnect the -5V and try again.

------------------------

OK. I disconnected the upright's PSU and still get the same result :( Dodgy or not wired internally? Either way its why older shite aint working.

Maybe I will swap them as the cocktail is not in use, doesnt have -5V wired, and is gonna be a MAME2JAMMA cab one day anyways.

Link to comment
Share on other sites

  • 8 years later...
Shit, I have never had that happen before. Try putting ground on -5 and pos on ground.

 

A lot of the cheap arcade PSU's don't have -5 internally, when you order from Chinese suppliers you normally have to specify if you want -5v because most boards don't need it.

 

It will always have the terminal on the outside as normal but nothing connected inside and all the components needed are missing, sounds like this is what you have,

Link to comment
Share on other sites

  • 1 year later...
  • 5 years later...
On 13/10/2006 at 8:21 PM, MadMikeAU said:

How do I test my PSU? More specifically, how do I test -5V...Here's what I get on my PSU...

 

GND & +5V = 5.10V = good

GND & +12V = 11.90V = good

GND & -5V = 500mV = WTF?!?

 

Either there is something drastically wrong with the way I am testing -5V or my PSU is drunk.

Informative

Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
  • Recently Browsing   0 members

    • No registered users viewing this page.
×
×
  • Create New...