VFD's (Vacuum Florescent Displays) revitalized - observatio

[Tim Schwartz]

Hello all,

An odd way to repair something story. I have an old (1983) Canon desk
top calculator with a VFD. (Model CP-1230D) The display is 12 digits and
the digits that DON'T get used very often are quite a bit dimmer.
(Unfortunately, I don't get into the Thousand dollar range that often.)

One brand of equipment that I service has had similar problems with
some of their VFD's. Their cure is to update the unit with a version of
software that allows you to press a few keys and light up the entire
display, and leave it that way for 24 hours. I was very skeptical the
first time I did this, but within 5-10 minutes you can already see
improvement!

So, I decided to try this on my calculator by typing in all eights and
leaving it on over night. Much to my surprise it restored the dim
segments to the same brightness as the others.

I'm not saying that this is a cure all or will work on every dim VFD,
but it costs almost nothing and is simple enough to try. Please post
any results if you try this.

Best regards,
Tim Schwartz
Bristol Electronics

 

[N_Cook]

Tim Schwartz <tim@bristolnj.com> wrote in message
news:4CC98D32.4090101@bristolnj.com...

Hello all,

An odd way to repair something story. I have an old (1983) Canon desk
top calculator with a VFD. (Model CP-1230D) The display is 12 digits and
the digits that DON'T get used very often are quite a bit dimmer.
(Unfortunately, I don't get into the Thousand dollar range that often.)

One brand of equipment that I service has had similar problems with
some of their VFD's. Their cure is to update the unit with a version of
software that allows you to press a few keys and light up the entire
display, and leave it that way for 24 hours. I was very skeptical the
first time I did this, but within 5-10 minutes you can already see
improvement!

So, I decided to try this on my calculator by typing in all eights and
leaving it on over night. Much to my surprise it restored the dim
segments to the same brightness as the others.

I'm not saying that this is a cure all or will work on every dim VFD,
but it costs almost nothing and is simple enough to try. Please post
any results if you try this.

Best regards,
Tim Schwartz
Bristol Electronics

It begs the question - what makes cold cathode displays/ VFD go dim in the
first place ? I assume a surface chemical effect

 

[Cydrome Leader]

N_Cook <diverse@tcp.co.uk> wrote:

Tim Schwartz <tim@bristolnj.com> wrote in message
news:4CC98D32.4090101@bristolnj.com...
Hello all,

An odd way to repair something story. I have an old (1983) Canon desk
top calculator with a VFD. (Model CP-1230D) The display is 12 digits and
the digits that DON'T get used very often are quite a bit dimmer.
(Unfortunately, I don't get into the Thousand dollar range that often.)

One brand of equipment that I service has had similar problems with
some of their VFD's. Their cure is to update the unit with a version of
software that allows you to press a few keys and light up the entire
display, and leave it that way for 24 hours. I was very skeptical the
first time I did this, but within 5-10 minutes you can already see
improvement!

So, I decided to try this on my calculator by typing in all eights and
leaving it on over night. Much to my surprise it restored the dim
segments to the same brightness as the others.

I'm not saying that this is a cure all or will work on every dim VFD,
but it costs almost nothing and is simple enough to try. Please post
any results if you try this.

Best regards,
Tim Schwartz
Bristol Electronics


It begs the question - what makes cold cathode displays/ VFD go dim in the
first place ? I assume a surface chemical effect

VFDs aren't cold cathode. They have very thin filaments that usually run
across the display. They are coated with some sort of white stuff,
probably the same stuff in regular vacuum tube.