Yamaha CR-640 LED mod, an filter cap source

[goontron]

does anybody know where i can get 12,000uf 50v caps for this thing?
also, how would you do an LED mod to the dial lamps? IIRC the voltage on the bulbs is 14v.

[stj]

Re: Yamaha CR-640 LED mod, an filter cap source

so what size is the cap?

as for the led, just calculate the correct resistor size.
http://led.linear1.org/1led.wiz

[mariushm]

Re: Yamaha CR-640 LED mod, an filter cap source

You can buy capacitors from online stores like digikey.com , newark.com , mouser.com - all three in us.

That capacitor is for bulk storage of energy, it doesn't have to be exactly 12000 uF, you can go just a bit lower with let's say 10000uF or you can go a bit higher. Lower capacitance could affect the amplifier at extremes, let's say when you turn the volume knob way high, but that's about all.

The voltage rating must be at least 50v, the same as the old capacitors or more. The next voltage rating would be 63v.

So I'd say pick any 50v/63v 10000-15000uF and you'll be fine, just check diameter and height and maybe the spacing between the leads of the capacitor (but that can be worked around if you want to)

As for led mod ... it's simple ... formula is V = I x R

Any led needs a resistor to limit the current going through the led so it won't burn up, so you need to figure out what resistor to use in series with the led.

So let's say you want to use a blue led that has a forward voltage of 3v and you want to let about 10mA of current (0.01 A) flowing through the led... not too bright, not too dim.

Therefore you have:

Voltage - Forward Voltage LED = Current x Resistance
14v - 3v = 0.01A x R
=> R = 11v / 0.01 = 1100 ohm

So if you want to use a blue led and 10mA, you can use a 1000 ohm resistor or something close to this value to achieve the results.

[goontron]

Re: Yamaha CR-640 LED mod, an filter cap source

would this cap work?
http://www.mouser.com/ProductDetail/...52bJszroGWs%3d

for the LED mod im partly colorblind, it looks yellow to me, but others describe it as "a darker yellowish green" so should i use daylight white or green LEDs? i plan on keeping the original diffusers if that helps.

[stj]

Re: Yamaha CR-640 LED mod, an filter cap source

use a high CRI white led or any coloured bits wont look right.

[CapLeaker]

Re: Yamaha CR-640 LED mod, an filter cap source

Here is something you might be interested for the LED conversion: Onsemi makes an 20ma LED constant current regulator NSI45020. It can do up to 45V input but it has to be DC. Works great! Other than that, you have to work with voltage dropping resistors etc.

[stj]

Re: Yamaha CR-640 LED mod, an filter cap source

grab this:

[goontron]

Re: Yamaha CR-640 LED mod, an filter cap source

ok, i removed the large filter caps and both test absolutely spot on. im just going to replace the failed lamps with incandescent lamps. screw trying to match colors i can't even see!

[budm]

Re: Yamaha CR-640 LED mod, an filter cap source

Is it fuse type lamps or Grain of Wheat type?
http://www.audiolabga.com/data_html/PRB-FL6.html

[goontron]

Re: Yamaha CR-640 LED mod, an filter cap source

Is it fuse type lamps or Grain of Wheat type?
http://www.audiolabga.com/data_html/PRB-FL6.html

not fuse type, but not rice grain either. they are around 5mm(no calipers)

[stj]

Re: Yamaha CR-640 LED mod, an filter cap source

i will look at the manual later and give good advice.

[stj]

Re: Yamaha CR-640 LED mod, an filter cap source

the lamps are 14.5v 80ma and there are 8 of them.

[goontron]

Re: Yamaha CR-640 LED mod, an filter cap source

the lamps are 14.5v 80ma and there are 8 of them.

thanks for the info, i will order replacements and post results.

[goontron]

Re: Yamaha CR-640 LED mod, an filter cap source

Well, fuck sakes. I forget about a project for three years, and the thread for 4 years. I relamped it in '17 and just now remembered this thread.

Final outcome.
https://i.imgur.com/mQzYtwh.jpg

All warm white LEDs with the original diffusers. Sans dialpointer, anyway.

Im not sure why my camera picks up the dialscale as a sky blue. It's really not, but i couldn't really describe the color... I like it whatever it is.

[sam_sam_sam]

Re: Yamaha CR-640 LED mod, an filter cap source

Here is something you might be interested Onsemi makes an 20ma LED constant current regulator NSI45020.

Can you provide a link where you can buy them

When I googled it the first time I could not find any place that had any in stock

Never mind I found some here

https://www.mouser.com/ProductDetail...LmPs%2fA%3d%3d

Thanks

I have a question is possible to use just one LED @ 5 volt with this NSI45020
From what I read in the data sheet it has to 1.8 volts higher than the LED or LEDs hook to it if I read the data sheet correctly


If this is the case then it slove a problem about a LED project that I been wanting to build for a long time

[CapLeaker]

Re: Yamaha CR-640 LED mod, an filter cap source

Looking good! I like it!!!