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Author Topic: Tube Ground Strap Missing  (Read 3675 times)

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MKFan4Life

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Tube Ground Strap Missing
« on: September 09, 2021, 12:00:45 am »
I was wondering if anyone had ever had to create their own ground strap for a tube they received that didn't have one and how they went about it.

I have a 19" tube that was mated with a "knock-off" K7000 by Sharp Image in an old bowling cabinet that I MAMED a few years back. From what I remember the monitor had an outstanding display, but I wanted to plop a 25" in the cabinet, and removed the 19" tube and chassis.

I didn't notice at that time that the tube had no ground strap or wire that most tubes have contacting the dag and encircling the back of the tube. I honestly don't remember removing any connection like a ground when I removed the tube and chassis. Both had obviously been retrofitted into the cabinet, as there was a piece of wood cut to bolt the tube to, and the chassis was mounted to the inside wall of the cabinet on one side.

If you look at these pics, there's some type of copper grounding device bolted at one corner of the tube that has little fingers contacting the dag, and it has 3 spots that appear to accept a female spade connector.

I know sometimes the ground strap is connected directly to the upper corners of the tube, and then the lower corners of the ground strap are connected via either springs or zip ties to the tube lower corner eyelets. Generally I guess braided ground wire with no insulation is used so it makes good contact with the dag, and then a wire is soldered to that at a point and routed to a ground connection on the neck board.

Have any of you guys had to make one of these for a tube lacking one, and what was your process? THANKS!

bobbyb13

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Re: Tube Ground Strap Missing
« Reply #1 on: September 09, 2021, 12:46:34 am »
As I imagine you have seen, the largest finger on that funky metal skeleton hand is a male terminal connector and if the whole piece is bent in the proper fashion the skinny fingers will ground to the dag coat on the back of the tube.

It's a simple means to ground the tube without having a spring loaded wire that runs diagonally from one implosion strap flange across the dag material to the strap flange kitty corner.

Find a female spade connector that fits and crimp it onto a wire(s) to connect to the chassis ground and/or neck board and Bob's your uncle.
Relax, all right? My old man is a television repairman, he's got this ultimate set of tools! I can fix it.

MKFan4Life

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Re: Tube Ground Strap Missing
« Reply #2 on: September 09, 2021, 01:57:59 am »
I thought that might be an option. I have just never seen this, as I guess smaller monitors (tubes) employ this sometimes. I've mostly worked with 25-27" monitors using the springs/zip ties and a braided ground strap or wire.

One thing I didn't know Bobby... that you're my uncle!! Hi, Uncle Bob! Nice to meet you!  :laugh:

bobbyb13

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Re: Tube Ground Strap Missing
« Reply #3 on: September 09, 2021, 03:51:16 am »
One of the weirdest of sayings-
Entertainingly appropriate!

The second real arcade monitor I encountered intimately actually had this style of tube grounding.
In fact, of the four legit monitors I now have (not the Franken-screens I am forced to try to build out here) three of them use this method.

One is a 25" and two are 27"s.
Now that I look, even one of the 27" consumer tubes I have to try to convert uses this style.

Not sure if it is something later gen or more so that Panasonic decided it was a good plan (many people here with more wisdom than I- maybe someone will see this and comment.)
All of my 19" tubes actually use the braided wire/spring technique so I can't say for sure.

For reference, picture here is a tube out of one of the RUSH 2049 cabs that originally had a Sharp Image 727 chassis (which has been swapped out for a functioning Hong Eun.)



Think of your monitor as its own little island in your cabinet which needs a ground connecting tube, chassis, and neck board.

Different manufacturers had them connected in various places in different ways so just check that you are covering the bases for your model items.
Relax, all right? My old man is a television repairman, he's got this ultimate set of tools! I can fix it.

MKFan4Life

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Re: Tube Ground Strap Missing
« Reply #4 on: September 09, 2021, 06:01:28 pm »
I honestly never came across one. I've only been in the arcade scene for about 12 years or so, so it's not like I've seen that much in reality. It actually appears to be a decent way to do the grounding. I imagine you just need to confirm the little fingered "thingy" has a good tight electrical connection to the bolt in the corner, and that it has decent pressure against the dag on the tube.

I kept most of the wiring I stripped out of the bowling cabinet it came out of when I removed it and MAMED the cab. I need to check that wiring, as there may indeed be a ground wire in there with a female spade connector already on the end, and the years that have past possibly made me forget about it.

Thanks for the help!
 :applaud:

bobbyb13

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Re: Tube Ground Strap Missing
« Reply #5 on: September 10, 2021, 03:24:05 am »
Happy to help (if it is helpful.)

Bear in mind that you don't want to mix your monitor ground (or any logic board ground for that matter) with your power supply/main ground.
Be mindful of any stray ground connectors you find.  They may have been intended for cabinets lights or some other a/c only item in there.

Your monitor chassis almost certainly has a fuse to deal with short circuit issues and hopefully your house has breakers that a healthy ground wire will trip if the need arises.

If you wonder about a ground lead you find just post a picture and someone here will help.
Relax, all right? My old man is a television repairman, he's got this ultimate set of tools! I can fix it.

MKFan4Life

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Re: Tube Ground Strap Missing
« Reply #6 on: September 10, 2021, 05:32:45 am »
After a little confusion years ago about Earth Ground VS. Chassis Ground, I think I have it down pretty good. It can still get a little confusing at times, but I don't think I would ever have a problem with any of that. If I do find myself in that situation, I will surely seek advice. Better to find out and look dumb than to stay dumb and end up dead, or worse, end up with a dead cab!  :laugh2:

And yep, all my games have chassis fuses & cabinet fuses. And unless someone's been down to the basement recently and stole them, I remember distinctly installing several single and double-pole breakers for the circuits below the main 200 Amp breaker around 1998 when we built this house.  :timebomb:

Pokeric

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Re: Tube Ground Strap Missing
« Reply #7 on: October 01, 2021, 03:05:10 pm »
Kinda belated but I was just working on that exact same monitor chassis tube combo. No one said specifically, but the big tab goes to the ground pin on the neck board.

Iím not a huge fan of the k7000 sharp image knockoff, because some things are just slightly different than the WG, so making assumptions will sometimes bite you.