Safe?: Canned Air in CRT Without Discharging


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Safe?: Canned Air in CRT Without Discharging

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televisionman
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May 5, 2012, 3:20 AM

Post #1 of 20 (6653 views)
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Safe?: Canned Air in CRT Without Discharging	Can't Post

Hello Everyone,

I have removed the back of an old tube television to clean it. I don't plan to touch anything inside the TV, so I feel it's unnecessary to discharge the high voltage from the tube (right?).

Here's my question:

Is it safe to use my can of Maxell compressed air to remove dust from the internal components and the back of the tube WITHOUT discharging the tube first? Is there a chance that the high voltage could discharge through the air stream (e.g. if it contains some moisture), shock me, and explode the can?

Please advise. Thank you.

televisionman
New User

May 5, 2012, 6:30 PM

Post #2 of 20 (6623 views)
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Re: [televisionman] Safe?: Canned Air in CRT Without Discharging [In reply to]	Can't Post

There are differing viewpoints on the safety of using canned air to clean a television that holds a high-voltage charge.

The following link suggests that it's OK, but suggests waiting for the TV to discharge (which doesn't necessarily happen on its own, right?). It does warn not to touch internal components, however:

http://www.ehow.com/...v-circuit-board.html

The following link warns of the potential danger and suggests using only a special type of canned air:

http://animalchatters.smfforfree3.com/...rintpage;topic=157.0

What's the verdict? Also, is it alright to tip the television onto its screen to facilitate easier access to the internal components?

Ron.M
Veteran

May 5, 2012, 7:01 PM

Post #3 of 20 (6610 views)
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televisionman(?);....

To be 100% safe , do this;....
Get a long thin standard blade screwdriver....
Attach an end of a jumper wire to the metal shaft of the screwdriver...
Connect the other end to chassis ground...
(The tuner cover or antenna coax fitting are excellent chassis grounds)...
Keeping your fingers away from the metal shaft , slide the blade end of the screwdriver under the rubber cup on the side of the CRT that has a thick red wire going to it...
That is the HV wire connection...
You may hear a "tick" , "pop" , "snap" or a loud "BANG"...
Then the HV has been discharged & the set is safe to clean...

Most of the canned air that I've seen is just that & nothing added...
READ the label to be sure....
Air by itself will NOT explode !!!!

Quote

Also, is it alright to tip the television onto its screen to facilitate easier access to the internal components?

Impossible to give you a straight answer as I have NO clue what type of TV you have....
To be 100% safe , clean it in a normal upright position...

Hope this helped.... Sly

....

Later...Ron.M.... Cool

...
Veteran & Retired TV technician

televisionman
New User

May 5, 2012, 8:16 PM

Post #4 of 20 (6604 views)
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Re: [Ron.M] Safe?: Canned Air in CRT Without Discharging [In reply to]	Can't Post

Thanks for your response, Ron.

I'm familiar with the procedure for discharging the tube, but I didn't want to damage the seal between the rubber anode cap and the tube. I thought that doing so could potentially cause operation problems in the future (arcing, etc.). Is this not the case?

Let me rephrase my question about tilting the TV to set it on its screen. The screen is flat and does not protrude beyond the "frame" that surrounds it. That is, nothing would touch the glass if I tip the TV onto its front. In this case, is it safe to rest the television in that position?

Thanks again for your assistance.

mel
Veteran

May 5, 2012, 8:38 PM

Post #5 of 20 (6601 views)
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Using a compressed air can is not very efficient. Try using the discharge side of a vacuum cleaner with the crevice nozzle on the hose. It gives a lot more volumn over a wider area and you don't have to worry about high voltage arcing.

Ron.M
Veteran

May 5, 2012, 9:05 PM

Post #6 of 20 (6596 views)
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Re: [televisionman] Safe?: Canned Air in CRT Without Discharging [In reply to]	Can't Post

televisionman;......

Quote

I'm familiar with the procedure for discharging the tube, but I didn't want to damage the seal between the rubber anode cap and the tube. I thought that doing so could potentially cause operation problems in the future (arcing, etc.). Is this not the case?

I've done this thousands of times with NO consequences...
IF you slide the screwdriver in against the side of the CRT so you are NOT raising the cup up , you will not have a problem....
It's that or use care when you are near the cup....

mel has a good idea that will save you money buying cans of compressed air...
Just do what he says OUTDOORS or you could have a dust storm in your home that others may not like...

When I commented about laying the set on is face , I was not refering to the CRT....
I am concerned about the weight of the chassis causing the set/chassis to lean into the CRT & maybe cause damage to the cabinet , CRT or the chassis itself...
I stand by my earlier statement;=>....
""Impossible to give you a straight answer as I have NO clue what type of TV you have....
To be 100% safe , clean it in a normal upright position"""...

Later...Ron.M.... Cool

...
Veteran & Retired TV technician

televisionman
New User

May 7, 2012, 4:00 AM

Post #7 of 20 (6583 views)
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Re: [Ron.M] Safe?: Canned Air in CRT Without Discharging [In reply to]	Can't Post

Canned "air" typically consists of difluoroethane, not plain air. Difluoroethane has two primary risks:
1. It can ignite in the presence of sparks or an open flame (the can warns not to use around paper shredders)
2. It can spontaneously ignite if released in enclosed spaces

My main question now is whether a high-voltage arc can be "triggered" by a cloud of difluoroethane from my gas duster. If not, there should be no problem. Does anyone have information on this?

Has anyone here commonly used "canned air" to remove dust from inside tube television sets without discharging them?

jts1957
Veteran

May 7, 2012, 10:49 AM

Post #8 of 20 (6571 views)
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I blow air from a very old paint sprayer system. No sprayer attachment, just a plastic nozzle at the end of a four foot rubber hose. Smile

-------------------------
Location: Far, Far Away

Ron.M
Veteran

May 7, 2012, 6:02 PM

Post #9 of 20 (6562 views)
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televisionman;....

Well , it looks like you read the labels....

Why don't you try what mel & jts1957 suggested instead of taking a risk ????

Haven't you given some thought to using "Air" air ????
You know , the stuff we breathe ????

GOOD LUCK.... Smile

.....

Have a GREAT day & week..... Sly

....

Later...Ron.M.... Cool

....
Veteran & Retired TV technician

mel
Veteran

May 7, 2012, 8:08 PM

Post #10 of 20 (6558 views)
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Frankly, I wouldn't try it. I have had sets where moisture accumuleted in the dust on the top of the CRT causing arcing to the nearby metal casing. You might be creating a giant flamethrower.

jts1957
Veteran

May 7, 2012, 9:23 PM

Post #11 of 20 (6555 views)
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The MANUAL version:

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Location: Far, Far Away

televisionman
New User

May 7, 2012, 11:07 PM

Post #12 of 20 (6550 views)
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Re: [mel] Safe?: Canned Air in CRT Without Discharging [In reply to]	Can't Post

Thanks for the suggestions everyone. I agree with the consensus that using this flammable canned "air" is not a good idea. As my television only has a light coating of dust on interior components, I may choose to leave the dust in place. I have new questions now:

1. What problems, if any, are likely to be caused by a LIGHT coat of dust inside a tube television?

2. Is the dust currently inside the television likely to be expelled through the vents into my home during operation? Or is it most likely to "stick" in place?

3. If I discharge the tube, does there remain a charge in the other components (capacitors, etc.) that could be just as dangerous around a flammable air duster?

Ron.M
Veteran

May 8, 2012, 12:54 AM

Post #13 of 20 (6546 views)
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televisionman;......

I'll try this one more time....

""1. What problems, if any, are likely to be caused by a LIGHT coat of dust inside a tube television?""
NONE !!!

2. Is the dust currently inside the television likely to be expelled through the vents into my home during operation? Or is it most likely to "stick" in place?
Presuming there are NO fans inside the TV , it will "stick" in place...

3. If I discharge the tube, does there remain a charge in the other components (capacitors, etc.) that could be just as dangerous around a flammable air duster?
YES !!!!

Now go give it a Royal Blow Job !!!!

Later...Ron.M.... Cool

...
Veteran & Retired TV technician

jts1957
Veteran

May 8, 2012, 1:43 AM

Post #14 of 20 (6543 views)
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He's talkin' about a CRT TV - not a Zenith Royal Radio.

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Location: Far, Far Away

televisionman
New User

May 9, 2012, 12:13 AM

Post #15 of 20 (6526 views)
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If I choose to brush away the dust with an unused paintbrush, how long must the bristles extend beyond the metal ferrule in order to avoid risk of high-voltage arcing from the TV to the metal paintbrush ferrule? Will a wooden brush handle protect me from shock even if I haven't attached a grounding wire to the metal paintbrush ferrule? Is it safe to hold a vacuum hose relatively close to the components to suck up the dust?

jts1957
Veteran

May 9, 2012, 1:29 AM

Post #16 of 20 (6521 views)
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How 'bout purchasin' some life insurance? I'll volunteer to be your beneficiary. Shocked

-------------------------
Location: Far, Far Away

Ron.M
Veteran

May 9, 2012, 1:31 AM

Post #17 of 20 (6519 views)
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jts1957;.....

I think we're being punk'd here , so I'm out......

Later...Ron.M.... Cool

....
Veteran & Retired TV technician

mel
Veteran

May 9, 2012, 1:51 AM

Post #18 of 20 (6516 views)
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Take it out on the front lawn, hose it out real good and let the sun dry it out for a couple of days Frown

NO MAS

televisionman
New User

May 9, 2012, 3:06 AM

Post #19 of 20 (6511 views)
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Everyone,

I appreciate the help and suggestions I have received here thus far. I understand why some have now chosen to regard my questions as "trolling," but I assure you that is not the case.

I purchased a can of compressed "air" for the express purpose of cleaning out a television, but briefly researched television repair online prior to opening up the TV set. As I had some unanswered questions, I decided to join this forum. I have been very pleased to receive timely help from friendly people. I especially appreciated mel's comment: "I have had sets where moisture accumuleted in the dust on the top of the CRT causing arcing to the nearby metal casing." This observation convinced me not to risk using the canned "air" that could (potentially, albeit improbably) expel liquid.

The two options I'm considering now are (1) a brush and vacuum (2) a camera lens air blaster (hand-powered air pump). My latest question about the brush was stated in all seriousness. If anyone wishes to offer an answer, I would still appreciate it.

Thanks again to those who offered their expertise in this thread. I assure you your time was not wasted, but rather has helped me make a decision about my cleaning project. I look forward to continued participation in this useful forum.

Thank you.

Ron.M
Veteran

May 9, 2012, 4:30 PM

Post #20 of 20 (6481 views)
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televisionman;.....

I think you are "trolling"....
You have been posting questions for 5 days now on a simple job that should take you 10 ~15 minutes to do....
You are treating this like a science project for grade school....
Is your teacher watching ???
EVERY hurdle has been jumped thru so you could clean out the TV SAFELY , yet you still ask questions like an overly inquisitive 5 year old kid...
You have been advised by myself & mel (who you appreciated his help) & the irrepressable jts1957 , how to do this...
DO IT !!!!

It appears as tho even mel has had enough when he said;=>...

Quote

Take it out on the front lawn, hose it out real good and let the sun dry it out for a couple of days Frown

NO MAS

....Ron.M.... Cool

....
Veteran & Retired TV technician

(This post was edited by Ron.M on May 9, 2012, 4:35 PM)

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