Electronics Repair (sci.electronics.repair) Discussion of repairing electronic equipment. Topics include requests for assistance, where to obtain servicing information and parts, techniques for diagnosis and repair, and annecdotes about success, failures and problems.

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Jason Turner
 
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Default Handspring Visor Prism Repair

Hi, I only have a little experience with electronics repair, so please
bear with me if I don't make any sense

I recently acquired a Handspring Visor Prism. 5 days after receiving
it I knocked it off of my desk at work and the backlight was about
only half as bright as it was. At first I thought this problem was
related to problems that I have had with Palm III and IIIx where the
video cable will get knocked loose, so simply resetting it would get
rid of the problem.

I proceeded to take the Visor apart and reset the video cable. After
several attempts, and some looking on the internet I realized that it
was actually the backlight itself that was having issues and not the
LCD panel.

By this point the backlight had stopped working completely.

After getting the device home, I pulled out the multimeter and
completely disassembled it. I have confirmed that the power leaving
the connector to the motherboard is the same as the power reaching the
lamp, which SEEMS to be approx 3VAC. By the was, the Lamp is a
flourescent tube.

Now I am thinking that the lamp as gone bad.

So I start looking for new lamps on Mouser.com. The one in the device
is 2mm x 80mm. The closest that I can find on Mouser.com is 3mmx75mm,
which seems like it should fit, but I notice that all of the lamps I
can find on the internet are something like 500v starting and 300v
running power.

So, to make a short story long, can anyone help me figure out if the
power supply to the lamp is bad?

There is a transformer with markings like T085 B059, but I have no
idea what that means. Also, there seems to be a capaciter across the
transformer (which I would think serves to supply the starting power)
but I cannot measure anypower off of it, AC or DC.

This probably doesn't help any, but this is what I'm looking at. There
is a picture about half way down where the Backlight attaches to the
motherboard, unfortunately the transformer is on the back side of the
motherboard.

http://www.gethightech.com/Merchant2... de=_PRISMTAKE

Thanks.

Jason Turner
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Jerry G.
 
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Default Handspring Visor Prism Repair

I would try to get the original part from the manufacture. If they
refuse to sell you the part (very common practice), you will have to
send them the unit for them to service.

If you want to take the chance, order the lamp that is close. I have no
idea if the supply inverter will be damaged, or if the lamp may not work
or be damaged. If it's voltage rating and length are not the same,
logically this tells you that in any case, the performance will not be
the same.

I myself use original parts if they are available. Because we are not
authorized for all makes of equipment, we pack it up, and send it off
for service, providing the client does not refuse the estimate.

--

Greetings,

Jerry Greenberg GLG Technologies GLG
==============================================
WebPage http://www.zoom-one.com
Electronics http://www.zoom-one.com/electron.htm
Instruments http://www.zoom-one.com/glgtech.htm
==============================================
"Jason Turner" wrote in message
om...
Hi, I only have a little experience with electronics repair, so please
bear with me if I don't make any sense

I recently acquired a Handspring Visor Prism. 5 days after receiving
it I knocked it off of my desk at work and the backlight was about
only half as bright as it was. At first I thought this problem was
related to problems that I have had with Palm III and IIIx where the
video cable will get knocked loose, so simply resetting it would get
rid of the problem.

I proceeded to take the Visor apart and reset the video cable. After
several attempts, and some looking on the internet I realized that it
was actually the backlight itself that was having issues and not the
LCD panel.

By this point the backlight had stopped working completely.

After getting the device home, I pulled out the multimeter and
completely disassembled it. I have confirmed that the power leaving
the connector to the motherboard is the same as the power reaching the
lamp, which SEEMS to be approx 3VAC. By the was, the Lamp is a
flourescent tube.

Now I am thinking that the lamp as gone bad.

So I start looking for new lamps on Mouser.com. The one in the device
is 2mm x 80mm. The closest that I can find on Mouser.com is 3mmx75mm,
which seems like it should fit, but I notice that all of the lamps I
can find on the internet are something like 500v starting and 300v
running power.

So, to make a short story long, can anyone help me figure out if the
power supply to the lamp is bad?

There is a transformer with markings like T085 B059, but I have no
idea what that means. Also, there seems to be a capaciter across the
transformer (which I would think serves to supply the starting power)
but I cannot measure anypower off of it, AC or DC.

This probably doesn't help any, but this is what I'm looking at. There
is a picture about half way down where the Backlight attaches to the
motherboard, unfortunately the transformer is on the back side of the
motherboard.

http://www.gethightech.com/Merchant2... de=_PRISMTAKE

Thanks.

Jason Turner


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Michael
 
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Default Handspring Visor Prism Repair

I had this happen to a Visor Prism too. The problem in mine was that,
after it was dropped, that little transformer you mentioned (059) was
broken, tearing the incredibly fine wires inside from their posts. I tried
to fix it but to no avail. Yours is probably the same way. If you find a
source for those transformers, I'd sure like to know about it. I'd love to
fix this Prism.
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