What should I do to fix a M@G 85?

I would be thankful for some advice on trying to fix a M@G 85. I have two identical lights 3C host with three AW cells, KIU switch mod. The problem I am having with one light is it will not light for 5 or more clicks, sometimes more. I have searched and found the thread on the tailcap spring mod and also the one with hose inside a hose, would one of these help this situation or am I looking at a switch or other problem? I am aware of the overcurrent protection built into the cells on cold start but this light did not require multiple taps when new.

Darien

Darien said:

I would be thankful for some advice on trying to fix a M@G 85. I have two identical lights 3C host with three AW cells, KIU switch mod. The problem I am having with one light is it will not light for 5 or more clicks, sometimes more. I have searched and found the thread on the tailcap spring mod and also the one with hose inside a hose, would one of these help this situation or am I looking at a switch or other problem? I am aware of the overcurrent protection built into the cells on cold start but this light did not require multiple taps when new.

Darien

Click to expand...

• You're referring to heater hose so you're using 18650's or 18500's, correct?
• So initially that one light would power-up on the first click, correct?
• Both lights are identical in every way, correct?

First, I would test the cells by placing the ones from the light that single-clicks into the light that requires multiple-clicks. This will rule out if the protection circuits are tripping in one or more of those cells.


Gary

Darien said:

I would be thankful for some advice on trying to fix a M@G 85. I have two identical lights 3C host with three AW cells, KIU switch mod. The problem I am having with one light is it will not light for 5 or more clicks, sometimes more. I have searched and found the thread on the tailcap spring mod and also the one with hose inside a hose, would one of these help this situation or am I looking at a switch or other problem? I am aware of the overcurrent protection built into the cells on cold start but this light did not require multiple taps when new.

Darien

Click to expand...

I use a M@G85 with AW "C" cells on a daily basis and have never had a problem with start up......I would mark the batteries and try to isolate them to search for a cell that may be shutting down. Install the entire 3 battery set from the defective light into the light that functions properly, etc....

I also have a M@G C switch that I use just for test purposes. ALL my switches have all the resistance fixes done and are identical. I use the test switch to install in a light that may be suffering from 'gremlins' to isolate the problem. (BTW I use the stock switch, resistance fixed, and download's C tower/heatsink. I always run Litho's potted 1185 lamps because they seem to withstand shock and vibration much better than the bi-pin version. Plus, they are much easier to replace in the field)

Also, you may want to try another lamp. Not long ago I had a 2 AW "C" cell ROP HOLA that wasnt firing up on the first click. I checked, double checked, and triple checked everything, except the lamp. I fianally installed a new lamp and have not had a problem since. I found the lamp to be defective when bench tested.

Good luck.

I swapped the batteries and also tried another bulb, it is doing the same thing. Anything else I can check?

Darien

Could it be a mechanical problem with the switch? A small piece of plastic left over from cutting the tower off wedged in the switch somewhere?

Jay T said:

Could it be a mechanical problem with the switch? A small piece of plastic left over from cutting the tower off wedged in the switch somewhere?

Click to expand...

I guess that is about the only thing left, and I will check that out.

Darien

Darien said:

I would be thankful for some advice on trying to fix a M@G 85. I have two identical lights 3C host with three AW cells, KIU switch mod. The problem I am having with one light is it will not light for 5 or more clicks, sometimes more. I have searched and found the thread on the tailcap spring mod and also the one with hose inside a hose, would one of these help this situation or am I looking at a switch or other problem? I am aware of the overcurrent protection built into the cells on cold start but this light did not require multiple taps when new.

Darien

Click to expand...

Are you refering to the tail cap mod I published with the braid around a snubber made from reinforced hose?
If you are, you have reduced the resistance. Reduced resistance trips the protection circuit in some protected cells. The AW cells are not all alike some are more sensitive than others.
With the above tailcap mod and a 5761 you cannot single click an AW C cell. I added an NTC to fix that problem.

Have you swapped the batteries around to determine if the problem is the protection circuit of one set or the light?

If your problem is tripping the protection circuit because of reduced resistance than you need to add resistance. The Ametherm AL12 1R010 always has a remaining resistance after soft start. That or reverting to the standard tail cap and spring or adding a plain resistor will help. Resistance does use up lumens however.

Low resistance is what a short circuit is and that is what protection circuits protect against.

Hope this helps isolate the problem. Good luck.

Northern Lights said:

Are you refering to the tail cap mod I published with the braid around a snubber made from reinforced hose?
If you are, you have reduced the resistance. Reduced resistance trips the protection circuit in some protected cells. The AW cells are not all alike some are more sensitive than others.
With the above tailcap mod and a 5761 you cannot single click an AW C cell. I added an NTC to fix that problem.

Have you swapped the batteries around to determine if the problem is the protection circuit of one set or the light?

If your problem is tripping the protection circuit because of reduced resistance than you need to add resistance. The Ametherm AL12 1R010 always has a remaining resistance after soft start. That or reverting to the standard tail cap and spring or adding a plain resistor will help. Resistance does use up lumens however.

Low resistance is what a short circuit is and that is what protection circuits protect against.

Hope this helps isolate the problem. Good luck.

Click to expand...

Yes I was refering to that tail cap mod, but I have not made to either light. But I apprecitate the info on the possibility of too low resistance. I just had a hard time thinking the light could be very low resistance (especially when I haven't done anything to lower it in my mind). I will do some reading (if available) on the Ametherm AL12 1R010. Mine has the stock spring. What is the easiest way to check total resistance minus batteries?

Darien

Use jumper wires and an Ohm meter. Measure the resistance of your jumpers, some cheap ones use crimp connections and have significant value of resistance.
Then hook jumpers to tail cap to the light housing. Put your meter between the two. Some meters do not zero but will also read the internal resistance of the meter. Subtract the resistance of the jumpers and meter for the total and you should now have an idea of your total resistance.

If you have a supply of resistors, you can put your batteries into the systme in place of the meter and add resistors until you find what it takes not to trip the batteries protection circuit. This is the value you will need to soft start. If you leave the resistance for a protection circuit that needs high resistance you will loose so many lumens you would have defeated the whole purpose in building the high out put light.

AWs soft start drivers are well worth the money. If you enjoy your hobby and the purpose of the powerful light is to have fun then invest the money and have fun and enjoy the light.

If you enjoy your hobby and the purpose of the powerful light is to have fun then invest the money and have fun and enjoy the light.

Click to expand...

Thanks. You are exactly right, I do have fun and enjoy lights. I remember seeing the soft start drivers when they came out but didn't give them much thought at the time. I see that I need to reconsider investing in one.

Darien