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SOB advice. Thanks.

Greg G

Enlightened
Joined
Oct 17, 2007
Messages
772
Hi, been a while since I was in here. I wired up a new SOB917 into my EDC last night (Surefire L5 w/extension to make it hold 2 x 18650 AW batteries). The old board lasted a long time. I had a spare one on hand.

Anyway, it only draws about 400 ma when hooked up to my power supply set on 8 volts, which is roughly the voltage of my battery pack fully charged.

I've gone over everything. I installed new wires. I thought maybe the emitter was bad (Cree XR-E WH tint) so I desoldered the board and wired it to a new emitter. Same thing, ~400 ma and low light.

What do I need to look for?

Many thanks!
 

dat2zip

Flashlight Enthusiast
Joined
Jan 5, 2002
Messages
3,420
Location
Bay Area
Verify the sense resistors are correct on the SOB917. It's drawing 400mA from the power supply and the LED has low output?

Wayne
 

Greg G

Enlightened
Joined
Oct 17, 2007
Messages
772
Verify the sense resistors are correct on the SOB917. It's drawing 400mA from the power supply and the LED has low output?

Wayne

I checked that against the values on your site. I don't have the board in front of me but the resistors were correct.

Yes, drawing about 400 ma and low output.

Thanks Wayne.
 

Greg G

Enlightened
Joined
Oct 17, 2007
Messages
772
The setup is at home. I'll recheck the Vf on it again tonight, but the emitter isn't the issue.

I wired this board exactly like the old one. I bought two of these at the same time. Used one, it lasted for a few years and gave good service. When it finally went out I put my spare in.
 

Greg G

Enlightened
Joined
Oct 17, 2007
Messages
772
What I meant was that it appears that the LED is not getting the expected 917mA nominal drive current, based both on low output and Vf.


Exactly.



The board is wired correctly. The sense resistors are there and are the correct value.


Is there anything else it could be? I was just wondering if anyone has experienced this problem with this board and had some advice.
 

Greg G

Enlightened
Joined
Oct 17, 2007
Messages
772
No.

LED+ is soldered to J5.

LED- is soldered to J6.

The board sits in a P60 drop-in and the outer ring is soldered to the brass pill.

This is the pill:

Allpicsdigicam149.jpg


Mounted in the light:

Allpicsdigicam150.jpg
 
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