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Reviewing a cheap CRT degaussing wand

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  Reviewing a cheap CRT degaussing wand Rayner Lucas <usenet202101@magic-cookie.co.ukNOSPAMPLEASE> - 2021-01-12 20:48 +0000
    Re: Reviewing a cheap CRT degaussing wand John Robertson <spam@flippers.com> - 2021-01-12 14:00 -0800
      Re: Reviewing a cheap CRT degaussing wand Ralph Mowery <rmowery28146@earthlink.net> - 2021-01-12 17:27 -0500
        Re: Reviewing a cheap CRT degaussing wand Rayner Lucas <usenet202101@magic-cookie.co.ukNOSPAMPLEASE> - 2021-01-13 00:56 +0000
          Re: Reviewing a cheap CRT degaussing wand John Robertson <spam@flippers.com> - 2021-01-12 22:47 -0800
            Re: Reviewing a cheap CRT degaussing wand Rayner Lucas <usenet202101@magic-cookie.co.ukNOSPAMPLEASE> - 2021-01-13 08:05 +0000
    Re: Reviewing a cheap CRT degaussing wand Trevor Wilson <trevor@rageaudio.com.au> - 2021-01-13 12:48 +1100
      Re: Reviewing a cheap CRT degaussing wand John Robertson <spam@flippers.com> - 2021-01-12 22:50 -0800
        Re: Reviewing a cheap CRT degaussing wand Trevor Wilson <trevor@rageaudio.com.au> - 2021-01-13 19:21 +1100
    Re: Reviewing a cheap CRT degaussing wand Rob <nomail@example.com> - 2021-01-17 18:26 +0000
    Re: Reviewing a cheap CRT degaussing wand Mike Garcia <mike@mgarcia.nospam> - 2021-01-22 07:14 +0000

#2260 — Reviewing a cheap CRT degaussing wand

Hi all. This post is a review of the cheap "green stick" CRT degaussing 
wands, as I haven't found much discussion of them and some other 
repairers of vintage monitors may find it useful.

CRT degaussing tools seem to be hard to find these days. Occasional used 
ones come up for sale, and there are still some to be found in the US. 
However, in the UK they're near-unobtainable. The main source seems to 
be eBay sellers in China, all of whom are selling the same type: a wand-
style degausser in a green plastic shell. So, having a couple of CRTs 
with purity problems, I bought one to see if it would do any good.

The wand cost about 15 GBP and arrived within a couple of weeks. There 
was no documentation included, leaving me with just the specs given in 
the eBay listing, which read:
-Relative magnetic field: 70MT
-Load current: 1A
-Working hours: 20 seconds
-Power: 220V
-Specifications: About 31*31*200(mm)

The outer shell is some soft semi-translucent plastic (polythene?), and 
feels extremely cheap. A momentary switch pokes out of the top of the 
casing (a momentary switch is good, as it stops me accidentally leaving 
the coil energised).

The wand came with a moulded two-prong plug, which I had to cut off to 
fit a UK plug. And... I have never seen mains cable that thin before. It 
is, at least, double insulated, but the conductors are at most 28AWG and 
possibly even thinner (it's hard to measure stranded cable, but the 
diameter is somewhere around 0.25mm to 0.35mm). The strain relief clamp 
in the UK plug wouldn't even hold the cable until I wrapped some extra 
plastic around it. Oof. Looking at the ampacity ratings on the Wikipedia 
article for American Wire Gauge, that cable must be very close to, if 
not exceeding, its recommended current rating. It feels worryingly 
plausible that someone, somewhere made the calculation "it's fine, if 
they push the button for too long the coil will burn out before the 
cable insulation melts".

However, the tool does what it's supposed to and noticeably reduced the 
blotches visible on the CRT display. I used the standard technique of 
powering the coil from a couple of metres away, bringing it up to the 
CRT face, circling it around a couple of times, then smoothly backing 
away two or three metres before switching off again. I definitely 
recommend sticking to the stated maximum of 20 seconds continuous 
operation and letting the wand cool fully before using it again. The 
heat seems to take a few seconds to conduct to the outside of the 
casing, so it's not until after you've switched it off that you feel how 
warm it's really getting.

I popped the end cap off the casing to take a look inside, but haven't 
disassembled it further. Strain relief is just a knot in the mains 
cable. I don't see any current limiting apart from the coil itself. The 
coil is wrapped around a core of steel plates, and seems to have some 
more plastic insulation around it. The non-business end of the coil 
seems to have some copper mesh shielding. Hooking the whole thing up to 
a component tester, coil resistance measures around 140 ohms, with an 
inductance of 320mH.

In summary,

Pros:
- Cheap.
- Does what it's supposed to.

Cons:
- Not particularly sturdy.
- Probably not the safest thing ever, use with caution.

If there were better-quality tools available, I would definitely buy 
those instead. But there weren't, and this one did at least provide the 
functionality I needed.

HTH,
Rayner

-- 
Big-8 Management Board: https://www.big-8.org
Homepage: http://magic-cookie.co.uk

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#2261

On 2021/01/12 12:48 p.m., Rayner Lucas wrote:
> Hi all. This post is a review of the cheap "green stick" CRT degaussing
> wands, as I haven't found much discussion of them and some other
> repairers of vintage monitors may find it useful.
> 
> CRT degaussing tools seem to be hard to find these days. Occasional used
...
> 
> If there were better-quality tools available, I would definitely buy
> those instead. But there weren't, and this one did at least provide the
> functionality I needed.
> 
> HTH,
> Rayner
> 

I use a large Weller Soldering Gun when I can't find one of the 
degaussing coils in the shop...

John :-#)#
-- 
(Please post followups or tech inquiries to the USENET newsgroup)
                      John's Jukes Ltd.
MOVED to #7 - 3979 Marine Way, Burnaby, BC, Canada V5J 5E3
          (604)872-5757 (Pinballs, Jukes, Video Games)
                      www.flippers.com
        "Old pinballers never die, they just flip out."

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#2262

In article <fpmdnckH4tWUgWPCnZ2dnUU7-K2dnZ2d@giganews.com>, 
spam@flippers.com says...
> 
> I use a large Weller Soldering Gun when I can't find one of the 
> degaussing coils in the shop...
> 
> 
> 

I also used the Weller or what ever Gun I had handy on the old CRTs.

Just about any coil of wire will work that does not draw too much 
current.

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#2263

In article <MPG.3a67ec6b38b8737098a116@news.east.earthlink.net>, 
rmowery28146@earthlink.net says...
> 
> In article <fpmdnckH4tWUgWPCnZ2dnUU7-K2dnZ2d@giganews.com>, 
> spam@flippers.com says...
> > 
> > I use a large Weller Soldering Gun when I can't find one of the 
> > degaussing coils in the shop...
> 
> I also used the Weller or what ever Gun I had handy on the old CRTs.
> 
> Just about any coil of wire will work that does not draw too much 
> current.

Oh, that's a neat idea, I never thought to try a heating coil. I did 
consider making my own, but with no idea what spec to aim for, buying 
one seemed like it had a better chance of success :-)

Rayner

-- 
Big-8 Management Board: https://www.big-8.org
Homepage: http://magic-cookie.co.uk

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#2265

On 2021/01/12 4:56 p.m., Rayner Lucas wrote:
> In article <MPG.3a67ec6b38b8737098a116@news.east.earthlink.net>,
> rmowery28146@earthlink.net says...
>>
>> In article <fpmdnckH4tWUgWPCnZ2dnUU7-K2dnZ2d@giganews.com>,
>> spam@flippers.com says...
>>>
>>> I use a large Weller Soldering Gun when I can't find one of the
>>> degaussing coils in the shop...
>>
>> I also used the Weller or what ever Gun I had handy on the old CRTs.
>>
>> Just about any coil of wire will work that does not draw too much
>> current.
> 
> Oh, that's a neat idea, I never thought to try a heating coil. I did
> consider making my own, but with no idea what spec to aim for, buying
> one seemed like it had a better chance of success :-)
> 
> Rayner
> 

You need something that puts out a large AC field - like the unshielded 
transformer used in soldering guns.

An electric heating coil has a very small magnetic field, I'd say it was 
most unlikely to be useful for degaussing...

John :-#)#

-- 
(Please post followups or tech inquiries to the USENET newsgroup)
                      John's Jukes Ltd.
MOVED to #7 - 3979 Marine Way, Burnaby, BC, Canada V5J 5E3
          (604)872-5757 (Pinballs, Jukes, Video Games)
                      www.flippers.com
        "Old pinballers never die, they just flip out."

[toc] | [prev] | [next] | [standalone]

#2267

In article <E6qdnUhTbNb5CmPCnZ2dnUU7-LPNnZ2d@giganews.com>, 
spam@flippers.com says...
> 
> You need something that puts out a large AC field - like the unshielded 
> transformer used in soldering guns.
> 
> An electric heating coil has a very small magnetic field, I'd say it was 
> most unlikely to be useful for degaussing...

Ah, thanks, I get it now! I don't have a soldering gun, but it would 
certainly have been a lot easier to find one for sale than a degaussing 
coil. Or I guess I could've looked around for something else with a 
transformer I could salvage.

Rayner

-- 
Big-8 Management Board: https://www.big-8.org
Homepage: http://magic-cookie.co.uk

[toc] | [prev] | [next] | [standalone]

#2264

On 13/01/2021 7:48 am, Rayner Lucas wrote:
> Hi all. This post is a review of the cheap "green stick" CRT degaussing
> wands, as I haven't found much discussion of them and some other
> repairers of vintage monitors may find it useful.
> 
> CRT degaussing tools seem to be hard to find these days. Occasional used
> ones come up for sale, and there are still some to be found in the US.
> However, in the UK they're near-unobtainable. The main source seems to
> be eBay sellers in China, all of whom are selling the same type: a wand-
> style degausser in a green plastic shell. So, having a couple of CRTs
> with purity problems, I bought one to see if it would do any good.
> 
> The wand cost about 15 GBP and arrived within a couple of weeks. There
> was no documentation included, leaving me with just the specs given in
> the eBay listing, which read:
> -Relative magnetic field: 70MT
> -Load current: 1A
> -Working hours: 20 seconds
> -Power: 220V
> -Specifications: About 31*31*200(mm)
> 
> The outer shell is some soft semi-translucent plastic (polythene?), and
> feels extremely cheap. A momentary switch pokes out of the top of the
> casing (a momentary switch is good, as it stops me accidentally leaving
> the coil energised).
> 
> The wand came with a moulded two-prong plug, which I had to cut off to
> fit a UK plug. And... I have never seen mains cable that thin before. It
> is, at least, double insulated, but the conductors are at most 28AWG and
> possibly even thinner (it's hard to measure stranded cable, but the
> diameter is somewhere around 0.25mm to 0.35mm). The strain relief clamp
> in the UK plug wouldn't even hold the cable until I wrapped some extra
> plastic around it. Oof. Looking at the ampacity ratings on the Wikipedia
> article for American Wire Gauge, that cable must be very close to, if
> not exceeding, its recommended current rating. It feels worryingly
> plausible that someone, somewhere made the calculation "it's fine, if
> they push the button for too long the coil will burn out before the
> cable insulation melts".
> 
> However, the tool does what it's supposed to and noticeably reduced the
> blotches visible on the CRT display. I used the standard technique of
> powering the coil from a couple of metres away, bringing it up to the
> CRT face, circling it around a couple of times, then smoothly backing
> away two or three metres before switching off again. I definitely
> recommend sticking to the stated maximum of 20 seconds continuous
> operation and letting the wand cool fully before using it again. The
> heat seems to take a few seconds to conduct to the outside of the
> casing, so it's not until after you've switched it off that you feel how
> warm it's really getting.
> 
> I popped the end cap off the casing to take a look inside, but haven't
> disassembled it further. Strain relief is just a knot in the mains
> cable. I don't see any current limiting apart from the coil itself. The
> coil is wrapped around a core of steel plates, and seems to have some
> more plastic insulation around it. The non-business end of the coil
> seems to have some copper mesh shielding. Hooking the whole thing up to
> a component tester, coil resistance measures around 140 ohms, with an
> inductance of 320mH.
> 
> In summary,
> 
> Pros:
> - Cheap.
> - Does what it's supposed to.
> 
> Cons:
> - Not particularly sturdy.
> - Probably not the safest thing ever, use with caution.
> 
> If there were better-quality tools available, I would definitely buy
> those instead. But there weren't, and this one did at least provide the
> functionality I needed.
> 
> HTH,
> Rayner
> 

**I have always been an audio tech. I have always avoided TV work where 
possible. However, back in the day, I would frequently perform a CRT 
degauss, using my Han-D-Mag head demagnetiser. I found that it could 
deal with any degaussing requirement.

https://www.ebay.com.au/itm/Tape-head-demagnetiser-demagnetizer-Han-D-Mag-220-240V-/271234117484

Geez, they're expensive nowadays. I still have mine.

-- 
Trevor Wilson
www.rageaudio.com.au

-- 
This email has been checked for viruses by Avast antivirus software.
https://www.avast.com/antivirus

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#2266

On 2021/01/12 5:48 p.m., Trevor Wilson wrote:
> On 13/01/2021 7:48 am, Rayner Lucas wrote:
>> Hi all. This post is a review of the cheap "green stick" CRT degaussing
>> wands, as I haven't found much discussion of them and some other
>> repairers of vintage monitors may find it useful.
>>
>> CRT degaussing tools seem to be hard to find these days. Occasional used
...
>> In summary,
>>
>> Pros:
>> - Cheap.
>> - Does what it's supposed to.
>>
>> Cons:
>> - Not particularly sturdy.
>> - Probably not the safest thing ever, use with caution.
>>
>> If there were better-quality tools available, I would definitely buy
>> those instead. But there weren't, and this one did at least provide the
>> functionality I needed.
>>
>> HTH,
>> Rayner
>>
> 
> **I have always been an audio tech. I have always avoided TV work where 
> possible. However, back in the day, I would frequently perform a CRT 
> degauss, using my Han-D-Mag head demagnetiser. I found that it could 
> deal with any degaussing requirement.
> 
> https://www.ebay.com.au/itm/Tape-head-demagnetiser-demagnetizer-Han-D-Mag-220-240V-/271234117484 
> 
> 
> Geez, they're expensive nowadays. I still have mine.
> 

A bit cheaper on this side of the pond:

https://www.atrtape.com/products/han-d-mag

John :-#)#

-- 
(Please post followups or tech inquiries to the USENET newsgroup)
                      John's Jukes Ltd.
MOVED to #7 - 3979 Marine Way, Burnaby, BC, Canada V5J 5E3
          (604)872-5757 (Pinballs, Jukes, Video Games)
                      www.flippers.com
        "Old pinballers never die, they just flip out."

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#2268

On 13/01/2021 5:50 pm, John Robertson wrote:
> On 2021/01/12 5:48 p.m., Trevor Wilson wrote:
>> On 13/01/2021 7:48 am, Rayner Lucas wrote:
>>> Hi all. This post is a review of the cheap "green stick" CRT degaussing
>>> wands, as I haven't found much discussion of them and some other
>>> repairers of vintage monitors may find it useful.
>>>
>>> CRT degaussing tools seem to be hard to find these days. Occasional used
> ...
>>> In summary,
>>>
>>> Pros:
>>> - Cheap.
>>> - Does what it's supposed to.
>>>
>>> Cons:
>>> - Not particularly sturdy.
>>> - Probably not the safest thing ever, use with caution.
>>>
>>> If there were better-quality tools available, I would definitely buy
>>> those instead. But there weren't, and this one did at least provide the
>>> functionality I needed.
>>>
>>> HTH,
>>> Rayner
>>>
>>
>> **I have always been an audio tech. I have always avoided TV work 
>> where possible. However, back in the day, I would frequently perform a 
>> CRT degauss, using my Han-D-Mag head demagnetiser. I found that it 
>> could deal with any degaussing requirement.
>>
>> https://www.ebay.com.au/itm/Tape-head-demagnetiser-demagnetizer-Han-D-Mag-220-240V-/271234117484 
>>
>>
>> Geez, they're expensive nowadays. I still have mine.
>>
> 
> A bit cheaper on this side of the pond:
> 
> https://www.atrtape.com/products/han-d-mag
> 
> John :-#)#
> 

**That's more like it.

-- 
Trevor Wilson
www.rageaudio.com.au

-- 
This email has been checked for viruses by Avast antivirus software.
https://www.avast.com/antivirus

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#2269

Rayner Lucas <usenet202101@magic-cookie.co.ukNOSPAMPLEASE> wrote:
> Hi all. This post is a review of the cheap "green stick" CRT degaussing 
> wands, as I haven't found much discussion of them and some other 
> repairers of vintage monitors may find it useful.
>
> CRT degaussing tools seem to be hard to find these days.

Small wonder, as hardly anyone uses a CRT these days...
Normally when a CRT TV needs some form of repair, it will join its
fellows in the recycling bin.

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#2270

On Tue, 12 Jan 2021 20:48:30 +0000, Rayner Lucas wrote:

> Hi all. This post is a review of the cheap "green stick" CRT degaussing

Nice post!
Good to know!


-- 

Mike Garcia
http://mgarcia.org

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