Re: red diodes

From: Frederic Preffer (preffer@helix.mgh.harvard.edu)
Date: Sat Nov 13 1999 - 15:07:03 EST


Dear Will

Thanks much for your input. I think it would be marvelous if you can fix
this problem! I do not mean to impugn the quality of these diode lasers,
nor do I  claim to know the overall 'engineering' answer to the problem.  I
do strongly feel that is the vendors job.  I am merely representing the
view of a lab director who is weary of the thousands of dollars spent, and
related downtime lost, due to the necessity of BD coming in and needing to
replace this component in the FACSCalibur.

 So, I will modify my statment; I honestly do not know that the lasers
'stink', but the numerous repairs required related to their failure
certainly do.  I know the manufacturer has nothing to gain related to this
failure- I am certain they do not wish it on themselves or us. I am a long
time user and fan of BD products; but this instrument is the first inwhich
I was forced to conclude that an outrageously costly service contract was
required, due to this problem.  If another component in the instrument is
causing this laser burnout, as you postulate, I feel we have been working
with a beta, not a  'finished' product, and should be reimbursed as such.
As you can see, our laboratory is not the only one with this problem. I
hope you can help.

Regards 
F Preffer


At 11:02 AM 11/13/1999 -0800, you wrote:
>Fredric/ Others:
>If memory serves me, the red laser module used is from a top name US
>manufacturer. The modules utilize some of the best laser diodes, Japanese-
the
>best in the industry. Even low cost modules imported into the US are better
>than the times given by Alice. Something is wrong if these units fail
after 5-
>6 months. Possibly they are receiving too much heat from surrounding
>components/ circuit boards. Diodes don't like excess heat, although most
>operate up to 40 degrees C, or beyond! There may also be a problem with the
>voltage being supplied to the module, maybe they are being over- driven by
too
>high a voltage.
>
>I am happy to look into this, since I distribute these modules, and imported
>ones to US OEM's.
>Will Roberts, Owner
>Creative Technology
>optical engineer, and designer of several optical blocks for flow systems.
>
>Frederic Preffer wrote:
>
>> Hello Alice, and everybody
>>
>> I know exactly what is going on. The red diode lasers available stink.
>> Average lifetime in our instrument is about 5 months.  My recommendation is
>> that no one purchase a FACSCalibur without demanding a 2 year warrantee on
>> the red laser; better yet, 15,000 hours of time.
>>
>> F Preffer
>>
>> At 08:39 AM 11/11/1999 EST, Alice L. Givan wrote:
>> >
>> >Hi Flowers,
>> >What are people's experiences with red diode lasers?  I have been told
>> >that the manufacturers rate their lifetimes at 15,000 hours --- but
>> >that they seem to need replacing in cytometers after about 6 months.
>> >Is this true?  Any ideas as to what is going on ?
>> >Thanks!
>> >Alice
>> >Alice L. Givan
>> >Englert Cell Analysis Laboratory
>> >of the Norris Cotton Cancer Center
>> >Dartmouth Medical School
>> >Lebanon, New Hampshire NH 03756
>> >tel 603-650-7661
>> >fax 603-650-6130
>> >givan@dartmouth.edu
>> >
>> >
>> >
>> `````````````````````````````````````````````````
>>          Frederic I. Preffer
>> preffer@helix.mgh.harvard.edu
>> Department of Pathology- Room 7140
>> 149 13th Street
>> Massachusetts General Hospital-East
>> Charlestown, MA 02129
>> v(617) 726-7481  fax (617) 724-3164
>> ~~~~~~~~~~~~~~~~~~~~~~~~~~~
>
>
>
````````````````````````````````````````````
Dr. Frederic I. Preffer 
preffer@helix.mgh.harvard.edu
Harvard Medical School
Department of Pathology-Room 7140
149 13th Street
Massachusetts General Hospital-East
Charlestown, MA 02129

v(617) 726-7481  fax(617) 724-3164



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