Author Topic: DIY Help . . . .  (Read 1932 times)

Offline longjohn

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DIY Help . . . .
« on: January 06, 2020, 14:21 »
Hi, I've a burned Light Bulb and now my amp has no RED light status indicator.

From the photos I have no clue what size and voltage or any specs. However the connecting socket on the PCB stated -12V and +12V.


Any ideal which shop in SLT can i buy to DIY?

Many thanks in advance.





« Last Edit: January 06, 2020, 14:37 by longjohn »

Offline Audio

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Re: DIY Help . . . .
« Reply #1 on: January 06, 2020, 16:15 »
I think your LED is OK.  I think the burnt only occurred at the resister which is heat-shrinked into your black headshrinker jacket.

If you are pumping +12V and -12V into that LED with such a small voltage dropping resistor, it is no wonder it gets burned out.  The LED runs on around 1.2V to 1.5V, poor resister was handling at least a 22V drop....it will get pretty hot!

Just buy a LED of the correct size and used a higher wattage voltage drop resistor.    Working on a 16mA operating current for the LED, it's 1375 ohms by calculation.  You can use a 1.5K or a 1.2K resistor but use a higher wattage like 1/2 to 1W power rating.   Calculation gives 0.352 W power dissipation.  The assumption is that both wires are wired onto +12, -12 supply lines.  You should measure the voltage to confirm the values.

(Audio)

Offline longjohn

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Re: DIY Help . . . .
« Reply #2 on: January 06, 2020, 18:15 »
I think your LED is OK.  I think the burnt only occurred at the resister which is heat-shrinked into your black headshrinker jacket.

If you are pumping +12V and -12V into that LED with such a small voltage dropping resistor, it is no wonder it gets burned out.  The LED runs on around 1.2V to 1.5V, poor resister was handling at least a 22V drop....it will get pretty hot!

Just buy a LED of the correct size and used a higher wattage voltage drop resistor.    Working on a 16mA operating current for the LED, it's 1375 ohms by calculation.  You can use a 1.5K or a 1.2K resistor but use a higher wattage like 1/2 to 1W power rating.   Calculation gives 0.352 W power dissipation.  The assumption is that both wires are wired onto +12, -12 supply lines.  You should measure the voltage to confirm the values.

(Audio)

Ohhhh Man ??? ??? ???. . . . . . that is beyond me :'( :'( :'(

I was thinking of buying and replacing the bulb or some sort of drop-in replacement. Now I'm face not only with where to buy the bulb and also the visible burned resistor.

All these calculations are beyond me as I'm not engineering or technical trained.

Guess i'll have to live with an amp with no light! :-\ :-\ :-\

Thanks for helping out with such detail explanation, u r the best!!! ;D ;D ;D

Offline wizardofoz

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Re: DIY Help . . . .
« Reply #3 on: January 06, 2020, 19:00 »
bro take your whole cable and burnt resistor and led to Koba at Peoples Park Centre #03-06 12-9PM every day bar Sunday I think


tell them you need a replacement resistor and the voltage is 24V and they will make you something for a few $ only. can look for Wei Kok but uncle or auntie can help too with the young helpers there.
I have a pile of stuff that pushes out squiggly waveforms from smaller squiggly waveforms that sometimes come from 1's and 0's.
It's wonderful to behold as long as you don't let the magic smoke out.

Life is short! Enjoy the music while it plays, when it stops, there might be a chair for you...or  maybe not.

Offline longjohn

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Re: DIY Help . . . .
« Reply #4 on: January 06, 2020, 19:53 »
bro take your whole cable and burnt resistor and led to Koba at Peoples Park Centre #03-06 12-9PM every day bar Sunday I think


tell them you need a replacement resistor and the voltage is 24V and they will make you something for a few $ only. can look for Wei Kok but uncle or auntie can help too with the young helpers there.

Thanks for the lead bro. . . U R another super nice guy ;) ;) ;)

So I should get a replacement resistor with voltage of 24V?

OK I will bring down the whole bulb cable with the burnt resistor to koba and ask them to fabricate replacement with new led bulb, resistor and cable! Hope they will entertain me and not scold me ;) ;) ;)

Offline Audio

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Re: DIY Help . . . .
« Reply #5 on: January 07, 2020, 09:31 »
Koba Store is a "nice guy" stall....no scolding one.

They have been a "lifesaver" to me with their loads of stuff, some "hard to find".....you hardly have room to go explore the shop.

They will be able to resolve your issue if you bring down your LED cable.  They can replace the LED and the voltage drop resistor ....and they can even pump in 24V from their DC supply to show you that it will work.

The only thing that concern me is the voltage coming out of the connector.  Is it really +12V, -12V?  (+17V, -17V?)  Best if you can bring down the whole set if it is not too heavy.

Resistor is not really voltage dependent.   So there is no such thing as a 24V resistor.  Rating of a resistor is the value of resistance and the power handling capacity.  If there is really 24VDC coming out of the connector, the resistor should be A 1.2K ohms (brown, red, red) or 1.5K ohms (brown, green, red), 1/2 W or 1W.

(Audio)

Offline longjohn

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Re: DIY Help . . . .
« Reply #6 on: January 07, 2020, 13:08 »
Koba Store is a "nice guy" stall....no scolding one.

They have been a "lifesaver" to me with their loads of stuff, some "hard to find".....you hardly have room to go explore the shop.

They will be able to resolve your issue if you bring down your LED cable.  They can replace the LED and the voltage drop resistor ....and they can even pump in 24V from their DC supply to show you that it will work.

The only thing that concern me is the voltage coming out of the connector.  Is it really +12V, -12V?  (+17V, -17V?)  Best if you can bring down the whole set if it is not too heavy.

Resistor is not really voltage dependent.   So there is no such thing as a 24V resistor.  Rating of a resistor is the value of resistance and the power handling capacity.  If there is really 24VDC coming out of the connector, the resistor should be A 1.2K ohms (brown, red, red) or 1.5K ohms (brown, green, red), 1/2 W or 1W.

(Audio)

Thanks (Audio), this is getting v interesting. . . . to be on the safe side here are the photos info and pdf for connections label VCC and VSS. It's an ICEpower Amp.

https://www.parts-express.com/pedocs/manuals/326-104--icepower-500asp-class-d-amp-module-1x500w-data-sheet.pdf













Offline Audio

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Re: DIY Help . . . .
« Reply #7 on: January 07, 2020, 16:59 »
Yap!  There is 24VDC across those terminals.  Thanks for sharing the charts.

Here's the calculation.




(Audio)

Offline longjohn

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Re: DIY Help . . . .
« Reply #8 on: January 07, 2020, 19:30 »
Thanks for sharing the charts.
(Audio)
No. . . It's me who must thank U for the calculation :D :D :D Though I must say I don't understand a thing  :P :P :P but really appreciate ur kind effort :D :D :D

I'll go Koba soon and request for their service.

Credit to both (AUDIO) + WIZARDOFOZ and a million thank U :) :) :)

Offline steel2000

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Re: DIY Help . . . .
« Reply #9 on: April 30, 2020, 19:17 »
Since you used the word "bulb", yup. look for Koba they can help.

 

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