I recently picked up a Nikko NA-700II with a defective LED VU meter.
I’ve traced the problem down to dead LEDs… now the problem is… i’m not sure what to replace these with as they just appear to be a bare die on the PCB with a bit of clear epoxy blob on top. I assume i can scrape it off and replace it with a 402 SMD LED in its place.
Problem is that i’m not sure what sort of specs I should be looking for (forward volts, mcd, test current, etc…) I don’t want the replacements to be too bright or draw too much current…
My only hint is that is that the supply voltage is about 10VDC and there’s an 820 ohm resistor in-line on the middle LED that’s just a power indicator. I figure a 3v chip should be ok?
I’ve traced the problem down to dead LEDs… now the problem is… i’m not sure what to replace these with as they just appear to be a bare die on the PCB with a bit of clear epoxy blob on top. I assume i can scrape it off and replace it with a 402 SMD LED in its place.
Problem is that i’m not sure what sort of specs I should be looking for (forward volts, mcd, test current, etc…) I don’t want the replacements to be too bright or draw too much current…
My only hint is that is that the supply voltage is about 10VDC and there’s an 820 ohm resistor in-line on the middle LED that’s just a power indicator. I figure a 3v chip should be ok?
As an aside, I regret overlooking Nikko gear… this one is well built, sounds great, and a breeze to work on (minus these LEDs!)
The basic red, green and yellow LEDs ran at 1.4 - 1.7 to about 3V steady.
Use Ohm's law to work out the current.
There are posts about the new ones being too bright, but lower brightness diffused type parts..
Use Ohm's law to work out the current.
There are posts about the new ones being too bright, but lower brightness diffused type parts..
I am sorry, that should read 'buy lower brightness diffused type parts', and you can always roughen the top with abrasive paper to diffuse the light even more if needed.
There are chips like the LM3915/3916, and modules like this (from a random search): https://thinkrobotics.in/products/10-segment-bargraph-light-display-module-bright-red-yellow-green-blue?variant=39514836697174.... so making a new one with a new PCB should not be an issue, the parts are commonly available.
Work out if it is linear or the more common log scale, and there you are...
A link to somebody's post, no ties to them:
https://solderingmind.com/simple-vu-meter/
There are chips like the LM3915/3916, and modules like this (from a random search): https://thinkrobotics.in/products/10-segment-bargraph-light-display-module-bright-red-yellow-green-blue?variant=39514836697174.... so making a new one with a new PCB should not be an issue, the parts are commonly available.
Work out if it is linear or the more common log scale, and there you are...
A link to somebody's post, no ties to them:
https://solderingmind.com/simple-vu-meter/