Polo 25 Wiring Questions

[DashRendar]

Hey guys,  I have a working Midway cab (NFL Blitz 99) that has an Hantarex Polo 25 monitor in it.  The monitor works great.

I am in the process of converting this cabinet to run off MAME.  I will be using an ArcadeVGA card in the pc.  I also have the VGA cable adapter that Andy sells to hook up to the monitor.

My question is about the wiring.  I would use Saint's book, but it's out of print, and unfortunately the Wiki doesn't talk much about monitor wiring.



(Sorry for this being sideways.)  So as you can see, I have an isolation transformer and an arcade power supply.



Here is the back of the monitor.

So, the black power cable is feeding into the iso transformer, then feeds to the power supply, right?  I assume the green and purple wires provide power to the monitor.

Is there anything I need to know about the wiring to the power block?



Last question, the cab has not been powered up for probably 4 months.  I've read that the anode will drain its charge slowly over time.  Should I be able to work on this monitor without needing to discharge it since it's been so long?

[njay]

First Off Always Discharge !!

which vga cable do you have the breakout one? if so the connector is to big for the chassis of your polo you need to solder some wires
do you still have a jamma plug in your cabinet? what i did i cut off the video wires running to the jamma harnass soldered them on the vga breakout cable and done ! sometimes you have to solder the h and v syncs together

http://www.solvalou.com/arcade_jamma.php

read this

[lilshawn]

Last question, the cab has not been powered up for probably 4 months.  I've read that the anode will drain its charge slowly over time.  Should I be able to work on this monitor without needing to discharge it since it's been so long?

actually it's quite the opposite. i have naked tubes that have been in storage for years and still "regenerate" the charge and can give you a jolt. it's the tube itself that carries the electrical charge not the electronics. it's basically a great big capacitor. and the electrical charge is stored deep inside the glass. it can take forever for it to naturally dissipate.

just get yourself a wire and attach it around a flathead screwdriver (by the handle) and then attach the other end to a monitor metal part. putting the screwdriver under the cap and touching the metal clip will discharge (if any) electricity built up in the tube.

most chassis have a bleeder system that gets rid of the charge after a few seconds of being off, but if it's older (or the bleeder system is defective) there will be a charge built up in the tube. so it's best to discharge. (discharge again before hooking it back up again... just touch the screwdriver to the bellybutton)

[DashRendar]

Hmm, getting conflicting information on discharging.

I'm not removing the monitor, I'm simply hooking it up to a VGA breakout cable.

Here's what I found on Andy's website:

Do I need to discharge my monitor?

I started my career repairing TVs and then computer CRT devices including computer vector displays. I can say that monitor techs do NOT discharge CRTs before working on a monitor UNLESS they are going to do one of the following:

Replace the CRT
Replace the flyback transformer
Separate the CRT from the main board for any reason

It is a dangerous process! It is perfectly safe to leave the charge in the CRT as it literally cannot escape unless you dive under that CRT rubber cap or poke around with the CRT neck board removed (the focus anode voltage is in this area) The charge cannot be distributed onto the main board because it is prevented from doing so by tripler diodes sealed into the flyback molding. (otherwise the charge would quickly drain away through the EHT winding on the transformer anyway). Discharging the CRT involves putting a screwdriver across 25000 volts, which is not something to be done unless there is a very good reason. This FAQ also warns that there is a risk of scratching the glass and therefore weakening it. Handling or removing a monitor is not a good enough reason to discharge the CRT. BUT beware! Monitors have plenty of other nasty voltages around that ARE stored, in various capacitors on the main board, such as the PSU caps. These are not discharged even if you do discharge the CRT. So always leave a monitor with power off for as long as possible before handling the main board, at least 15 mins and preferably an hour or two.

http://www.ultimarc.com/monfaq.html#monitorcable

I disconnected the RGB wires from the JAMMA connector (seeing now I should have used a JPAC instead of an IPAC4, ah well).  I'll connect those up to the VGA breakout cable, then test it out tonight.

It's interesting- my arcade monitor has an isolation transformer that it's hooked up to.  But the manual for the cab says specifically "This monitor does not need an isolation transformer, unless you remove the monitor to work on it" (or something along those lines).

Going to err on the side of caution and keep it in there.  No need to take any risks just to get a little extra room inside the cabinet. 

[grantspain]

no need to discharge if you are not removing the chassis
if you have an iso then keep it,its a fail safe

[DashRendar]

Got everything wired up--

Said 10 "Hail Mary's"--

Turned on the power, and...

IT WORKS! 

Wiring up the monitor was one of the most intimidating things for me.  Such a relief to see it in action. 

A nice side effect is that I was able to keep the wiring in place for the marquee light.  So I have that and the monitor running off the cab's power supply, then the PC and speakers will be running off their own.  One less thing to worry about wiring up.

I just need to install the PC speakers in the marquee and build a shelf to hold the tower, then it's basically done!

(Just in time too- I have a bachelor party coming up in 2 months)