Mag85 bulb rest time?

[AMD64Blondie]

I bought 4 replacement WA1185 bulbs from CPF's B/S/T section to replace my WA1185 that had burned out in my 3D Mag85. After installing the new bulb,do I have to wait before turning it on, so I don't instaflash my newly installed bulb? (If so,how long do I wait?) I don't have my new bulbs yet,but I'll update you when I do receive them.

Update 4-6-2008: I actually received my new replacement bulbs back on March 6th,2008..but I'd forgotten about them until now. Will latex surgical gloves work to protect my hands,from getting skin oil on my replacement bulb when I install it?

 

[DM51]

The bulb itself doesn't need to rest, if that's what you mean. Just make sure it is clean - don't get finger marks on it (clean them off with IPA).

Some NiMH battery packs need to rest after charging, as the voltage is higher straight off the charger. This depends on the voltage of the pack you want to use with the bulb.

You don't need to rest Li-Ion cells in this way.

 

[LuxLuthor]

Yes, as the DM-Meister said :devil:...the issue with "resting" a setup is related strictly to NiMH cells which may have a voltage hot off charger that is too high for bulb, and may 'instaflash' it. An example is 9 AA cells with an 1185 bulb. NiMH hot off charger may be (9 x 1.46V) 13.23V which will flash that bulb.

What makes these situations confusing for people to figure out is that there is a certain amount of resistance in most light setups, which is a mixed blessing. The resistance can lower delivered voltage/current to the bulb....helping to protect it from flashing....but at the cost of reduced lumen output.

One last issue which you may hear about is a instantaneous (mV's) voltage spike when light is first turned on, and which can be enough to flash a bulb, even if the steady state (once bulb is heated up) voltage/current would not flash it.

People have dealt with that issue by using something that gives a so called "soft start" such as a cheap (50 cents) "NTC" electronics part, or more elaborate "drivers" that have additional features....such as the drivers being sold by CPF member AW for "C" and "D" Maglites...see this link.

 

[AMD64Blondie]

I'm using a 9AA to 3D adapter in my Mag85,with 9 Sanyo HR-3U 1.2V NiMH AAs.(total:10.8 volts..) When I first got my Mag85,I waited a day before turning it on for the first time. How long do I need to wait after installing the new WA1185 bulb,before I turn the light on?

 

[LuxLuthor]

It partly depends on which 9AA adapter you are using. Cheap ones have more resistance. For a stock Maglite, and using a typical Fivemega adapter, and one of his bipin bulb holders, I would let the batteries drop to about 12.8V. So you can guage your situation compared against that. It only took 3-6 hours to drop to that from a full charge.

 

[AMD64Blondie]

Sorry for the 2-week bump.. but I'm wondering..how do I remove the Mag head to access the bulb for replacement? (I still don't have my new bulbs yet..I thought I'd ask ahead of time before replacing the bulb.)

 

[Fenris]

Twist to the left.

 

[DM51]

Just unscrew the head all the way, and it will come off. Inside you should see the bulb sticking up out of the socket, like the one 2nd pic down in post #1 in this thread, or maybe like the pic in post #1 in this thread.

Whichever it is, the bi-pin bulb seats into the 2 small holes as shown in the pics. Push it all the way in, being careful not to bend the pins.

When it is seated, make sure it is vertical, not leaning sideways in one direction or another. Check this by eye, and if it is leaning, adjust it (very gently) until it is vertical.

If it doesn't look like either of those types, you may have a potted bulb set-up, where the bulb is fixed into a disposable holder, in a ceramic compound like this pic in post #1 here. There are different sizes of bulb socket, so you will need to get the right version, or convert to bi-pin with a FM socket.

Grease or oil from your fingers could cause the bulb to shatter when you switch it on, so either be careful not to touch it, or (what I do) don't worry about touching it, but clean it properly afterwards.

To clean the bulb, you will need some Iso-propyl alcohol, also known as IPA or rubbing alcohol. You should be able to buy a small tin or bottle of it from a pharmacy or somewhere. Clean the bulb with a little IPA on a soft cloth, and allow it to dry completely.

When it is dry, switch it on to test it before replacing the head. Hold it away from your face when you do this, in case the bulb shatters (unlikely, but it has happened). If it works, replace the head, being careful not not to let the head or reflector touch the bulb.