You have answered the question on how to test the equipment for
sustainability.  Your customer has given the equipment the test and it has
failed it.  The latch-up state is the demonstrated failure.  The latent
damage is not identified, but can be anticipated.  What kind of equipment is
this duster?  I have not encountered any dusters with the voltage generation
that you have indicated. Have you tested the duster in a 10 to 20 %
humidity?
I recommend that you provide cleaning instructions that do not include the
use of a cleaner that will generate a charge. You should warn your customer
that they should not use the duster on your equipment.
What is the designed immunity of your equipment to a charged field?

I recommend you review the following references:
     IEC 61340-5-1 "Protection of Electronic Devices from Electrostatic
Phenomena"
     EN 1000015-1 "Basic specification Protection of Electrostatic Devices"

Al Cash
President
Midwest Chapter ESD Association
Rolling Meadows, Illinois
USA
Tel: 847-259-9600 X-6764

-----Original Message-----
From: Kiiski Jarmo [mailto:[log in to unmask]]
Sent: Tuesday, May 23, 2000 2:19 AM
To: [log in to unmask]
Subject: Re: [TN] Brush dust off on equipment with duster


It wasn't a typo! It was measured with a handheld charge meter in a short
distance from a duster in a low humidity (30 % R.H.) environment. Increasing
the humidity to 50 % will degrease the charge to 35 kV.

The problem is that our customer has used a duster to wipe of dust from the
equipment and the LCD-drivers goes to Latch-Up-state with undesired
consequences.

Now there has been discussion about the sustainability of the equipment
against such operation. There are solutions to improve the sustainability
but the question is how to test it.

I have a strong feeling that instead of making any changes to equipment we
should give instructions to user how to clean our products (with damp towel,
not with duster).

B.R.
Jarmo

> -----Original Message-----
> From: Phil Bavaro [SMTP:[log in to unmask]]
> Sent: 22. toukokuuta 2000 18:36
> To:   [log in to unmask]
> Subject:      Re: [TN] Brush dust off on equipment with duster
>
> That has to be a typo.....70 kV is way too high to be generated with a
> simple duster.
>
> Please tell us how this 70kV was measured and who makes it if in fact it
> does generate that type of charge.
>
>
> No matter what the actual number is, I would not want it around our ESDS
> components.  As far as equipment which is sealed up is concerned, it
> really
> depends on what it is.
>
>
> Our policy is not to allow the dusters in our factories as we use a
> topical
> cleaner and a lint free wipe to remove dust.
>
>
> Regards,
>
> Phil
>
> At 09:04 AM 5/22/00 +0300, Kiiski Jarmo wrote:
> >Hi,
> >
> >Is there any ESD specialists listening!
> >
> >Should the electronic equipment sustain the use of duster?
> >
> >Is there a method to test the durability of equipment against duster?
> >
> >According to our experience the charge of a duster can be over 70 kV.
> >
> >B.R.
> >Jarmo Kiiski
> >
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