Diode Replacement..

jckjohn · 10/08/2019, 01:53 PM

Hey Guys,

I have the "Black Box" Mars Aqua 300 watt led light. I had a couple of diodes go bad on my board. At first I thought it was the bulb so I switched out the bulb. Still Wouldn't light.. Then I noticed the diode above the light not looking good. I checked it and it is dead...

I've checked in all the forums, and looked on which diode to buy/how to replace it. I haven't found any.. Maybe I didn't look hard enough?

But there is a tiny diode above each light. I have 2 that are burned out. I was wondering if anybody has changed any and where can I buy some..
Thanks.

jckjohn · 10/08/2019, 01:58 PM

Here is a pic - which I'm sure most of you have seen.. But, a close up of the diode above the led bulb..

jckjohn · 10/08/2019, 03:01 PM

I actually think it is a thermal fuse resistor.. But, not sure..

mcgyvr · 10/08/2019, 06:22 PM

Oops...read wrong

tkeracer619 · 10/09/2019, 04:40 PM

It’s a zener diode. It’s To protect the leds string against surges I think.

jckjohn · 10/09/2019, 09:27 PM

Cool Thanks!

Do you have any idea where I can get them?

RobbyG · 10/09/2019, 09:29 PM

It certainly looks like a Zener diode but what voltage it is would have to be determined. If I had one of the good ones I could tell you very quickly what voltage it is and what current it can handle. If you test the voltage from ground to the blue banded side of one of the working ones you might be at the right voltage but I would assume it's not yet clamping the voltage yet but is instead just there in case it gets too high.

Here is a video that explains it in layman's terms what your dealing with.
Please Note do not try this the way he is doing it because unless you have a bench power supply that can limit the current (which is what he is doing) it will burn out the zener if you go too high on the voltage. You would normally drop a high value resistor like 1K to 5K in series with the diode to limit the current.

https://www.youtube.com/watch?time_c...&v=WdDFI1IRQds

If your handy with a soldering iron, have a volt meter and a 1K resistor you can remove a good one and do the same procedure using some 1.5V AA batteries and just adding one at a time in series. So 1.5V to 3V to 4.5V to 6V and see what voltage the meter stops changing value at.

Once you have that you could try something from Amazon which might be at least a voltage equivalent. Here is a 2V Zener diode':

https://www.amazon.com/2500pcs-ZMM2V.../dp/B071VVFHKR

Yes that is the price for 2500 of them but if you try to order just 10 of them on Digikey or Mouser the price on shipping alone is going to bring the price to about the same, although the quality would be better if you get the best brand of Zener's with the same ratings. The good thing about digikey or mouser is that they have great look up tables so you can get the exact physical size right. Other aspects of the Zener diode like break down current etc are beyond the scope of a post. You will probably be fine if you get one that just has the right voltage and the same physical size.

Rob

jckjohn · 10/09/2019, 09:56 PM

Thanks Rob..

You might have just solved my problem..

RobbyG · 10/09/2019, 11:42 PM

Quote:

Originally Posted by jckjohn

Thanks Rob..

You might have just solved my problem..

Your Welcome. Please just let us know how it turned out.

Rob

jckjohn · 10/27/2019, 10:49 AM

Quote:

Originally Posted by RobbyG

Your Welcome. Please just let us know how it turned out.

Rob

Hi Rob,
Just wanted to let you know we got the new diode's and replacement bulbs from China. We switched both out at the same time. They work!!

I think we switched out like 3-4 total, but now all my lights are on.. Just wanted to thank you for helping me..
Jon

RobbyG · 10/28/2019, 08:07 PM

Quote:

Originally Posted by jckjohn

Hi Rob,
Just wanted to let you know we got the new diode's and replacement bulbs from China. We switched both out at the same time. They work!!

I think we switched out like 3-4 total, but now all my lights are on.. Just wanted to thank you for helping me..
Jon

Great news, glad it all worked out.
BTW just so this thread is useful for someone in the future with the same lights and problem, what diodes did you buy and what was the voltage? You might also want to link in the LEDs. This stuff can be a life saver to the next person with the problem. Heck I have even used some of my own old posts to remember what part number I had purchased years ago.

Rob

jckjohn · 10/29/2019, 01:37 AM

Ok.. I used the 2.7 volt .5 watt Zener diode..

50 PCS ZMM2V7 2.7V 1/2W 0.5 Watt 2.7 Volt SMD Zener Diode 1206 Silicon SMT

And the bulbs are kinda common..

3W White Red Blue UV RGB Green High Power LED COB Chip Light With PCB USA..

Jon

RobbyG · 10/29/2019, 11:03 AM

Thanks
Rob

10/08/2019, 01:53 PM	#1
jckjohn Registered Member Join Date: Sep 2005 Posts: 55	Diode Replacement.. Hey Guys, I have the "Black Box" Mars Aqua 300 watt led light. I had a couple of diodes go bad on my board. At first I thought it was the bulb so I switched out the bulb. Still Wouldn't light.. Then I noticed the diode above the light not looking good. I checked it and it is dead... I've checked in all the forums, and looked on which diode to buy/how to replace it. I haven't found any.. Maybe I didn't look hard enough? But there is a tiny diode above each light. I have 2 that are burned out. I was wondering if anybody has changed any and where can I buy some.. Thanks.

10/08/2019, 06:22 PM	#4
mcgyvr Registered Member Join Date: Sep 2003 Location: North Carolina Posts: 20,050	Oops...read wrong __________________ Who me?

10/09/2019, 04:40 PM	#5
tkeracer619 Registered Member Join Date: Jan 2006 Location: Westminster, CO Posts: 17,289	It’s a zener diode. It’s To protect the leds string against surges I think. __________________ Hobby Experience: 9200ish gallons, 26 skimmers, and a handful of Kent Scrapers. Current Tank: Vortech Powered 600G SPS Tank w/ 100gal frag tank & 100g Sump. RK2-RK10 Skimmer. ReefAngel. Radium 20k.

10/09/2019, 09:29 PM	#7
RobbyG Registered Member Join Date: Jun 2005 Location: 600 Ft From the Reef Posts: 2,099	It certainly looks like a Zener diode but what voltage it is would have to be determined. If I had one of the good ones I could tell you very quickly what voltage it is and what current it can handle. If you test the voltage from ground to the blue banded side of one of the working ones you might be at the right voltage but I would assume it's not yet clamping the voltage yet but is instead just there in case it gets too high. Here is a video that explains it in layman's terms what your dealing with. Please Note do not try this the way he is doing it because unless you have a bench power supply that can limit the current (which is what he is doing) it will burn out the zener if you go too high on the voltage. You would normally drop a high value resistor like 1K to 5K in series with the diode to limit the current. https://www.youtube.com/watch?time_c...&v=WdDFI1IRQds If your handy with a soldering iron, have a volt meter and a 1K resistor you can remove a good one and do the same procedure using some 1.5V AA batteries and just adding one at a time in series. So 1.5V to 3V to 4.5V to 6V and see what voltage the meter stops changing value at. Once you have that you could try something from Amazon which might be at least a voltage equivalent. Here is a 2V Zener diode': https://www.amazon.com/2500pcs-ZMM2V.../dp/B071VVFHKR Yes that is the price for 2500 of them but if you try to order just 10 of them on Digikey or Mouser the price on shipping alone is going to bring the price to about the same, although the quality would be better if you get the best brand of Zener's with the same ratings. The good thing about digikey or mouser is that they have great look up tables so you can get the exact physical size right. Other aspects of the Zener diode like break down current etc are beyond the scope of a post. You will probably be fine if you get one that just has the right voltage and the same physical size. Rob __________________ The Optimist says the glass is half full, the Pessimist says it’s half empty, an engineer only see's a glass that’s twice as big as it needs to be! Current Tank Info: Insanely Automated Low Power Consumption 90 Gal Oceanic Bow System/Aquatronica Touch Controller/AQ Dosing Pump/AQT LEDS/AQ SMS/Seq Dart Pump/ASM G3/Ozotech Ozonizer/Koralin 1502/Chiller/Typhoon3 Ro/S.Squirt /Phos React/Rmt DSB

10/29/2019, 11:03 AM	#13
RobbyG Registered Member Join Date: Jun 2005 Location: 600 Ft From the Reef Posts: 2,099	Thanks Rob __________________ The Optimist says the glass is half full, the Pessimist says it’s half empty, an engineer only see's a glass that’s twice as big as it needs to be! Current Tank Info: Insanely Automated Low Power Consumption 90 Gal Oceanic Bow System/Aquatronica Touch Controller/AQ Dosing Pump/AQT LEDS/AQ SMS/Seq Dart Pump/ASM G3/Ozotech Ozonizer/Koralin 1502/Chiller/Typhoon3 Ro/S.Squirt /Phos React/Rmt DSB

10/08/2019, 03:01 PM	#3
jckjohn Registered Member Join Date: Sep 2005 Posts: 55	I actually think it is a thermal fuse resistor.. But, not sure..

10/09/2019, 09:27 PM	#6
jckjohn Registered Member Join Date: Sep 2005 Posts: 55	Cool Thanks! Do you have any idea where I can get them?

10/09/2019, 09:56 PM	#8
jckjohn Registered Member Join Date: Sep 2005 Posts: 55	Thanks Rob.. You might have just solved my problem..

10/29/2019, 01:37 AM	#12
jckjohn Registered Member Join Date: Sep 2005 Posts: 55	Ok.. I used the 2.7 volt .5 watt Zener diode.. 50 PCS ZMM2V7 2.7V 1/2W 0.5 Watt 2.7 Volt SMD Zener Diode 1206 Silicon SMT And the bulbs are kinda common.. 3W White Red Blue UV RGB Green High Power LED COB Chip Light With PCB USA.. Jon