MM+ R2H doesnt work at 1.5V

[PeterB]

I've 2 MM+ R2H modules, and one of them doesn't work with one AA cell. The other work's fine, therefore I'm sure it is not a problem of my host. The current draw of the module is about 100mA and I measure about 1.5V at the LED leads.
The module works at 3 Volts.
Has somebody an idea how I could fix this behavior? Could there be some high ohmic short somewhere?

 

[vcal]

Assuming that you have checked and cleaned ALL of the electrical contacts..-Is this the first time the module has not worked on just one cell??

If it is the first time you've tried it, there is the definite possibility that you were mistakenly shipped a BadBoy instead of a MadMax.

Here's an indicator:
If it's possible to have two flashlights going at the same time,
-activate both lights (with TWO Equal batteries each), and see if the MadMax+ is noticeably brighter than the other one.

If the MadMax+ (which draws 800mA+) is Still noticeably brighter than the other one, it's probably a BadBoy 400, 500, or maybe even a 700mA that was sent to you by mistake. /ubbthreads/images/graemlins/frown.gif

 

[PeterB]

Hi Doug,

yes the module is new, therefore this could be a very good explanation! I will try you test this evening.

 

[shiftd]

Ah ye, make sure you use Brand New battery, because as far as i knoe, the MM+ only drives the lux at 800 mA when the batts are still fresh.

Also, AFAIK the MM comes in red epoxy while the BB comes in green.
There is also other possibilities, so i suggest better ask the creator of the sammich /ubbthreads/images/graemlins/smile.gif

 

[dat2zip]

It sounds like poor contact. Check the perimeter of the outter top edge of the module. It's possible to find a burr all the way around the perimeter. Remove this burr first and then try it.

Next, ensure the top of the module is dirt, debris and free of any AA grease. It is possible that there is some contaminate on the top surface giving poor contact.

Lastly, check the anode connection. Sometimes a residue of flux can be left behind. If it has a solder blob the blob may have solder flux on it. A quick scrape with the flat portion of knife or exacto will clean this up.

I don't recall if that was an adjustable or not. IF they are both adjustables, you can carefully inspect the two trim pots and verify they are both set the same.

 

[PeterB]

Thanks for your inputs! Unfortunately I couldn't resolve the problem.
Here are my new findings:

They are both Madmax+ adjustables (red epoxy).

The pots have the same setting (from an optical point of view).

I've checked and cleaned all surfaces. Everything looks ok(also the solder blob is ok).

At three volts I have the same current with both modules (970mA).

At 1.5V I have 100mA input current for the bad module and 50mA for the good one (the brighness is lower, if I measure the current with the fluke. This is probably caused by the series resistance). As already mentioned, the LED voltage for the bad module is 1.58V in this case.

My theory: The converter is working, but there is a relatively low resistance path between the plus and minus output of the madmax. At low input voltage, the converter is relatively weak and reaches only the 1.6V and therefore the LED is dark. The output reaches higher voltages, at higher input voltages => the led is working at 3V input.
The lower output voltage also explains the higher input current (at 1.5V input).

This "short" (should be around 20Ohm from the measured characteristics) could be caused by a defective LED or by the converter itself.

I hope you have new suggestions for me /ubbthreads/images/graemlins/smile.gif

 

[Doug S]

[ QUOTE ]
PeterB said:
Thanks for your inputs! Unfortunately I couldn't resolve the problem.
Here are my new findings:

They are both Madmax+ adjustables (red epoxy).

The pots have the same setting (from an optical point of view).

I've checked and cleaned all surfaces. Everything looks ok(also the solder blob is ok).

At three volts I have the same current with both modules (970mA).

At 1.5V I have 100mA input current for the bad module and 50mA for the good one (the brighness is lower, if I measure the current with the fluke. This is probably caused by the series resistance). As already mentioned, the LED voltage for the bad module is 1.58V in this case.

My theory: The converter is working, but there is a relatively low resistance path between the plus and minus output of the madmax. At low input voltage, the converter is relatively weak and reaches only the 1.6V and therefore the LED is dark. The output reaches higher voltages, at higher input voltages => the led is working at 3V input.
The lower output voltage also explains the higher input current (at 1.5V input).

This "short" (should be around 20Ohm from the measured characteristics) could be caused by a defective LED or by the converter itself.

I hope you have new suggestions for me /ubbthreads/images/graemlins/smile.gif

[/ QUOTE ]
Peter, your theories sound reasonable to me. This sounds like it might be ESD damage to the LED. You can check for this by using the diode function of your DMM. It is OK to do this with the LED on the module [but not energized, of course]. If it reads under 2V, I would take this as evidence of ESD damage. From what you have described, I expect that it may measure less than 1.5V.

 

[PeterB]

Doug,

very good idea!

Good module: 2.45V and a nice glowing LED
Bad module: 0.03V

=> Very probably your described ESD event.

My Madmax will need an LED transplation...
Its only a pity that the valuable R2H is damaged...

 

[dat2zip]

Peter,

It sounding more like the LED might be bad or the module. I did test every R2H that was built.

Either way, I can work with you to replace the defective unit.

You have several options.

1) I make another module for you, and send it to you if you are willing to send the one back to me.

2) I can give you shoppe credit towards another purchase. I can't promise you anything at this point, but, I am planning on a run of MM and MM+ in the garage with the new 3Watters.

Wayne

 

[PeterB]

Hi Wayne,

thanks for you offers, I really appreciate it.

Some questions from me to clarify it:

1: I would send the module back and you use the LED (if it is ok) to build a new module, right? Would you have a new R2H available if the LED made the problem?

2: You would give me credit for the module (minus optics) and I could use it for the new modules you described, right?

I have to think a little bit about that (also considering the shipping costs from Germany) /ubbthreads/images/graemlins/smile.gif

 

[Raindrop]

[ QUOTE ]
dat2zip said:
Peter,

It sounding more like the LED might be bad or the module. I did test every R2H that was built.

Either way, I can work with you to replace the defective unit.

You have several options.

1) I make another module for you, and send it to you if you are willing to send the one back to me.

2) I can give you shoppe credit towards another purchase. I can't promise you anything at this point, but, I am planning on a run of MM and MM+ in the garage with the new 3Watters.

Wayne

[/ QUOTE ]

Wayne,

Will there be a List like the R2H special builds ??? If so please put me on it for 3 MadMax with III's /ubbthreads/images/graemlins/wink.gif

 

[PeterB]

BTTT,

Hi Wayne,

I think option 2 would be easier for both of us, please give me feedback (I've also sent you a email).

best regards,

Peter

 

[PeterB]

bump