I have a Cobra 29 NHST. I upgraded to UV LED's and a blue display. The display is way too bright on the dim setting. How do I dim it down into the realm of reason?? Is there a resistor I can change?
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Too bright.. Help
- Thread starter Raven69
- Start date
you could try increasing the value of R115 which is near TR22.
it is a 2.7k ohm resistor.
you might try values from 3.3k to 6.8k and see how that works.
this will only affect how bright the channel display is when the bright/dim switch is in the DIM position.
it will not affect the brightness of the meter light.
just so you know, i have not done this myself, just got it from looking at the schematic.
also, what kind of diffusion are you using?
when you removed the stock display, there was an orange or green piece of plastic that snaps over the display.
are you using this?
if not, what are you using?
i have found that an 1/8" thick piece of blue plexiglass works great for blue displays.
im just saying that you might be able to dim your display down without changing any electronic components.
hope this helps,
LC
it is a 2.7k ohm resistor.
you might try values from 3.3k to 6.8k and see how that works.
this will only affect how bright the channel display is when the bright/dim switch is in the DIM position.
it will not affect the brightness of the meter light.
just so you know, i have not done this myself, just got it from looking at the schematic.
also, what kind of diffusion are you using?
when you removed the stock display, there was an orange or green piece of plastic that snaps over the display.
are you using this?
if not, what are you using?
i have found that an 1/8" thick piece of blue plexiglass works great for blue displays.
im just saying that you might be able to dim your display down without changing any electronic components.
hope this helps,
LC
Thanks, I'll try that.
What I used is a blue ziploc container lid. I cut it down and hot glued it to the inside of the bezel. Looks and works great. The blue displays are just soo darn bright..
What I used is a blue ziploc container lid. I cut it down and hot glued it to the inside of the bezel. Looks and works great. The blue displays are just soo darn bright..
yep, i have tried that stuff before, but it doesnt really reduce the brightness very well.
if you live in a city that has a plastics supplier, you can usually get a piece for free by telling them that you work for an interior design firm or something like that and that you want to buy a bunch of blue plexi from them, but you need to get an approval from your boss first.
they will usually give you a piece for free.
even a 6"x6" sample will be plenty to do lots of displays with.
hope it all works out for ya.
LC
if you live in a city that has a plastics supplier, you can usually get a piece for free by telling them that you work for an interior design firm or something like that and that you want to buy a bunch of blue plexi from them, but you need to get an approval from your boss first.
they will usually give you a piece for free.
even a 6"x6" sample will be plenty to do lots of displays with.
hope it all works out for ya.
LC
Maybe you can wire a 20k pot -internally- and adjust from there? Using the existing resistor and wire the pot in series with it. That will cost about $.50. Or nothing if you can take one out of an old radio...
you can use either.
with resistors, as long as you meet or exceed what the requirement of the part is; you can use any resistor as long as the resistance value is the same as the part you are replacing.
so, in the schematic i looked at, R115 has no special wattage value next to it, and that usually means 1/4 watt.
if you have 1/2 watt resistors available, use those.
good luck,
LC
with resistors, as long as you meet or exceed what the requirement of the part is; you can use any resistor as long as the resistance value is the same as the part you are replacing.
so, in the schematic i looked at, R115 has no special wattage value next to it, and that usually means 1/4 watt.
if you have 1/2 watt resistors available, use those.
good luck,
LC
Well, I used a 1/2 watt 3.3 ohm resistor. It worked pretty good. I swapped it for a 4.7 ohm, it worked even better!
Now I need to test drive it in the car for a while.. It may need a bit more..
Thank you for your input guys!
Now I need to test drive it in the car for a while.. It may need a bit more..
Thank you for your input guys!
Here's the proper way to do things:
To adjust both the BRT and DIM settings, change R117.
If you want to adjust only the DIM setting, change R115.
If you want to adjust only the BRT setting, change R117
and then check the DIM setting and adjust R115 as needed.
To adjust both the BRT and DIM settings, change R117.
If you want to adjust only the DIM setting, change R115.
If you want to adjust only the BRT setting, change R117
and then check the DIM setting and adjust R115 as needed.
The original poster was only concerned about the brightness of the dim position,which loose cannon answered correctly.
so how is your way the proper way?
you obviously didn't read the original question.
Thanks to all.
What I gather is the if you reduce R117, both BRT and DIM would be reduced equally. If R115 is reduced, only the DIM is reduced.
I did the R115. It works great for the dim setting!!
What I gather is the if you reduce R117, both BRT and DIM would be reduced equally. If R115 is reduced, only the DIM is reduced.
I did the R115. It works great for the dim setting!!