Monitor Discharging - Golden Tee Fore! cabinet - First Time

[AracadeCrazy]

Hi,

I'm going to be attempting to discharge my first arcade monitor which is housed in a Golden Tee Fore! cabinet.  I've read a lot about how to discharge a monitor (probably too much) and feel pretty comfortable, but do have a few questions.  The way the Golden Tee cabinet is, the back access panel does not extend very high and the monitor is slanted back quite a bit so I would need a longer tool to reach all the way up (without having to shove my arm up there).  I was planning on modifying the standard discharge tool by adding a PVC pipe (or something similar) as an extended handle and using a small piece of a rubber hose as a coupler to the screw driver handle, I would then go the standard route of using the aligator clips and attaching one end to the braid surrounding the monitor touching the dag and the other end attached to my screw driver.  Questions are, are there any safety reason why my "modified" tool should not be used, PVC pipe does not conduct electricity and neither does rubber so I figured there'd be no issue there, plus it would keep me further away (hopefully) should anything jump.  Also, is the best route to connect to the braid around the dag, or to the monitor frame or does it even matter?  Has anyone else ever tried to discharge a monitor while it's housed in a Golden Tee cab?  Did you have any problems or do you have any suggestions.  Thanks in advance for any help!

[lilshawn]

the residual charge is quite a bit, but it's not going to kill you. granted i am RIGHT handed, and perhaps it may be different for someone getting shocked with their left...

as a multiple offender, i can say for certainty, that the worst that happens is you get a really bad hand cramp for about 1/100th of a second. it leaves your hand weak for a few minutes, but it's more scary than anything else. and my hand is still attached.

if it's off your chances are pretty good that the tube has discharged itself... the flyback often has a bleed off resistor to discharge the tube after a while.

if your really REALLY uncertain, perhaps have someone in the field do it for you. but really, all i do is attach a short length of wire with alligator clips on them to a flat screwdriver and clamp the other end to the metal frame. i stick the screwdriver under the cup and touch the metal clip, if it's going to spark it does it now. (tic.... it's not particularly spectacular unless you have a giant 30" something tube like the big dynamo showcase) and then bend the screwdriver up and use my other hand to turn the suction cup inside out. i then use the screwdriver to push in the side of the clip to release it. sometimes i get lucky and when i push the screwdriver under the cup, it touches the clip and it releases like magic! TA DA! I will touch the wire/screwdriver to the "button" again before re-attaching the clip, as the tube can build charge back up again. as mentioned the giant dynamo tubes build up a particularly large charge and after discharging i'll actually attach the clip to the edge of the button to keep it grounded. not really necessary on a smaller 25/27 tube, but it does happen.

as far as your extension goes, i'd be more concerned that it would fall apart or bend in an unusual way while in use and you end up knocking the fragile narrow glass part of the tube off. it doesn't take much.

[AracadeCrazy]

Thanks for the reply, so it sounds like as long as my extension handle is securely fastened and is sturdy that you don't see anything misguided with my approach.  I would actually take it to a repair tech to have it done but I want to have it discharged before I handle it, so that kind of defeats the purpose of me taking it someplace to have it done.  The monitor has been off and unplugged for a week now, so hopefully some of the charge has dissipated.  I'll be heading up to Home Depot in the next few days to buy the supplies, any idea on what a good gauge wire would be to use from the dag strip to the screw driver?  Thanks again!

[lilshawn]

I want to have it discharged before I handle it,

as long as you don't poke around it while it's plugged in you will do fine.

any idea on what a good gauge wire would be to use from the dag strip to the screw driver?

uhm, anything... speaker wire, lamp cord, magnet wire... a chopped off piece of anything really as long as it's conductive. you don't need...like jumper cables or anything.

this is what i use....



and mainly because they are hanging on my parts board and easily accessible. the ones i have are a little small, i have to open the alligator all the way to fit it on the screwdriver but it works alright...



out in the field where i don't have them (since i can never remember to grab one and throw it in my toolbox) i usually just use a length of random wire i have in the toolbox (since i almost always have that junk in there) strip off 4 inches off one end and wrap it around the driver... unplug the ground lead off the neck card and jam the wire in there and zap it that way. in a pinch i've used an RCA patch cord. 

make sure your screwdriver doesn't have any fancy coatings... just straight chrome or metal. sometimes they will paint the shaft to keep it looking good for a long time. all it is is an insulator. not what we are looking for. if it's all you got, scrape or sand it off.

we aren't grounding out any serious amperage (which does the work) it's just high voltage. walking 20 feet on vinyl floor at 15% relative humidity causes buildup of voltage up to 12 kilovolts of static electricity. you could put a 1 amp fuse on your grounding wire and it probably wouldn't blow while discharging. but put a 50 amp fuse across a 12 volt automotive battery and it will... way more amperage (since amperage does the work)

really, the high voltage warnings and all that jazz are there for while it's plugged in and operating. mostly because of things like exposed wiring terminals and fuse holders that carry 120 volts AC (or 220v AC depending where you live) at 15 amps and the potential 25,000 volts (at a few miliamps) present at the anode. I am more concerned with the 1200 volts present in some horizontal deflection circuits of the digital monitors. since their voltages are usually higher amperage.

in conclusion, i forgot where i was going with this. oh ya,
 

[gazz292]

discharging your first ever monitor is a bit daunting, but once youve done it once, you'll wonder what all the fuss was about,

it dosent help some of the websites out there really try to scare you, i'm sure half of them are written by techs who want to scare you so much you take it to them to have discharged... then you may as well pay them to fix the fault etc.

anyhoo, if your in the uk, most golden tee cabs use a hantarex monitor, they self discharge within a few seconds of being switched off anyway,
i still do the discharge thing, but have never heard so much as a sparrow fart from the anode when the screwdriver touches it,

there's more to worry about in the high voltage cage of the psu part of the chassis, it's not recomended to short out the big capacitors in there, much better on them to bleed the charge off using a resistor in the wire to earth.

[AracadeCrazy]

Thanks for the replies and the positive vibes, so I just finished my first attempt and heard nothing, no pop, no spark, nothing, which I understand can be normal.  However, when I pushed the screw driver under the anode cap, I inadvertantly popped off the anode cap as well which I did not want to have happen.  I would like to remove the monitor from the cabinet and then replace the anode once I have it out in the open.  Is there anything I need to be cautious of when I put the cap back on?  I've read where monitors can build up a "ghost" charge once they've been discharged and I would prefer not to get zapped from the open hole.  Any tips on how to safely put the anode cap back on or what to watch out for would be greatly appreciated!!  Thanks again!

[lilshawn]

 

uh oh.

what you're going to have to do is build yourself a kind of grounding probe.

oh wait you already did that. 

just touch the screwdriver/wire super combo tool to the bellybutton and stick the clip back on.

the easiest way to do it is to turn the cup inside out and hang onto the flaps with your thumb and index finger... you will understand when you see it turned inside out. then just stick in one side and push, and clip in the other side. sometimes the tough ones need some help from the screwdriver to push in the one side.

TA DA!

However, when I pushed the screw driver under the anode cap, I inadvertantly popped off the anode cap as well

everytime i discharge i hope for this to happen. it shaves seconds off my day. 

[gazz292]

lol, told you it was easy, is it a hantarex monitor btw?? as they deffo self discharge so you'll never hear a pop,

i tried to get a pop about 20 times first time i removed the anode cap off my monitor, finaly gave up and poped the cap out... then moved it to the frame with the insulated screwdriver... again no pop, same when i poked the screwdriver in the hole before putting the cap back on after repairing the chassis, no pop... i was almost dissapointed.

[lilshawn]

I read stories all the time about how people say you should discharge, and wait 10 minutes and discharge again, and wait 10 minutes.... 

makes me laugh... do it, get it over with.

sometimes i get lazy and don't even discharge. take that grim reaper.

[AracadeCrazy]

Thanks again for all your help guys.  Finally, and I mean finally got the monitor out of the cab, they really build those golden tee cabs well and don't give too much finger room.  Was then able to put the anode cap back in place, now it's on to trying to fix the golden tee PCB.  Gazz, the monitor is actually a Wells Gardner, and much like you I was disappointed by the lack of a pop.  I had to psych myself up to do it the first time, but I guess it's better that it was safer for my first effort.  I'm sure I'll feel much more confident the next time.  Thanks again!!