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Lamp Replacement on Equalizer

Rick79

Nov 26, 2014
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I have a yamaha EQ-630 with both back light bulbs blown. Theres no information on the voltage or amps written on the bulbs and nothing written on the circuit board. My question is, can these be replaced with LEDs? If so, would i need to use a resistor?

Thanks
 

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dorke

Jun 20, 2015
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These are usually AC lamps 6.3VAC or 8VAC ,current may be around 100mA
Put your meter to work and measure the voltage.
It can be replaced by a LED but you need to rectify the ACV first.
 

Rick79

Nov 26, 2014
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These are usually AC lamps 6.3VAC or 8VAC ,current may be around 100mA
Put your meter to work and measure the voltage.
It can be replaced by a LED but you need to rectify the ACV first.
Thanks. I measured the Voltage, Im get 16.39 VAC.
If i know the correct Voltage of lamps to use i would like to go find some. Then if i dont have any luck, i can probably build something for using LEDs.
 

dorke

Jun 20, 2015
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Rick,
you should measure with a load .
do you have any 100mA lamps?
note that you can connect 2 low voltage(3V,4.5V etc.) lamps in series.
 

Rick79

Nov 26, 2014
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Rick,
you should measure with a load .
do you have any 100mA lamps?
note that you can connect 2 low voltage(3V,4.5V etc.) lamps in series.
No, i dont have any lamps like that. I just have those LED lights that you plug into USB ports for power. Is it possible to just tap into a 5V rail somewhere and use the USB lights instead of building a rectifier?
 

Alec_t

Jul 7, 2015
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One thing to consider with LEDs is beam angle. They are usually quite directional, whereas a filament bulb has a broad spread of light. So you may well need either a LED array or an effective light reflector/diffuser.
 

dorke

Jun 20, 2015
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It is possible to tap into a low voltage DC rail and use an LED,
Use a low current white or yellow LED with a series resistor.

Note Alec_t words above.
And the fact that you will have a different color than the Yamaha orange.

Note also that a Yamaha service center near you may know the exact lamp you need and may have it as well.
 

Alec_t

Jul 7, 2015
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If you get a replacement filament bulb, I'd suggest wiring a low value resistor in series with it to prolong its life without significantly reducing the brightness.
 

CostinBos77

Sep 4, 2023
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Hi gents ,

I have the same problem as well . The schematic is saying just 'Lamp : PL 1,2 : XAMK4B' .
The voltage is less then AC 17 V .
I tested one with 18 V , 4 mm and 40 mA and is too dim .

So , filament lamp bulb : 18 V , 4 mm , 100-150 mA will be excellent .

Definitely use the orange silicon cover of bulbs , to protect the LCD !!!

The schematic shows Resistors already : R 406 / 407 : 12 ohms .
 

Externet

Aug 24, 2009
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You do not know the voltage supplied when loaded by two working lamps and that resistor in series... Keep looking for the ones rated with the voltage you like.
 
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