Need help, ARC LS PCB fried ??

[the avatar]

/ubbthreads/images/graemlins/help.gif

As shown in the pic above, the board is really messy... (a result of my poor soldering skills...) and the leads on one side of the LT1618 has come off from the PCB !! (I actually think that the LT1618 itself has been fried... as some smoke came out of it...) /ubbthreads/images/graemlins/crazy.gif

I really love my ARC LS.... does anyone still has a spare PCB ??? (I know it's a rare item nowadays..... /ubbthreads/images/graemlins/icon23.gif)

Otherwise, can this board still be fixed ?!

What else can I do ?



*** below is how the board got to the current state ***

I replaced the LED with a TV1J and although it worked, there seem to be some contact problem as it would sometimes get very dim unless I apply some downward force on some part of the PCB...

I noticed some peeling of the PCB from the heatsink and so I applied some arctic alumina epoxy in between.

After that, it only came on for brief moments and later, some smoke came out of the LT1618 /ubbthreads/images/graemlins/crazy.gif

Come to think of it... I suspect that the initial contact problems might be due to some breaks in the traces of the PCB.....

 

[shiftd]

maybe you did not solder the lux tightly? open circuit may be the one that caused your board to get burned out.
sorry to hear that /ubbthreads/images/graemlins/frown.gif

 

[matrixshaman]

Once the life force (smoke) of an IC has been released it will cease to function /ubbthreads/images/graemlins/frown.gif You might want to try getting one of the mods for your Arc since replacing something like that IC is very difficult. Doing surface mount soldering is hard although I managed to mod a scanner one time that involved replacing a resistor the size of a pepper flake. It took a magnifying glass under another magnifying glass and a very good soldering iron to accomplish. I felt lucky that it worked. I would use a triplett to examine everything very closely to see if you have missed something but it's likely that if the chip smoked it won't work and you'll want to pick up a custom board for it. Good luck..

 

[mahoney]

The chip can be replaced. You will also need to track down the problem (an open circuit to the LS?) that made it blow in the first place. For someone with the proper equipment, the chip replacement should not be a big deal. If the traces are broken, the board may not be repairable.

 

[the avatar]

Thanks for the replies /ubbthreads/images/graemlins/smile.gif

Now that you guys have mentioned about the open circuit, I think this is highly likely to be the root of the problem. As the soldering of the LS looks ok, I guess there's probably a broken trace on the PCB that leads to the LS... (which could probably be fixed with a wire on top) let me do some checking later...

if that's really the case... I might be able to fix it if I can get a new chip and inductor (request for samples ?)

btw, I remember hearing a story about putting a sandwich inside an ARC-LS with a suitable heatsink ? is this mod available to the public ??

 

[ZuluWhiskeyFox]

The putting a sandwich into an LS is do-able. However a little tricky. I've only done it with a twistyed body I bought from CY. The twisty itself must be machined deeper to allow for the added length. For a clicky it may not be necessary to modify the body. I don't know about that one. Next you'll need a heat sink thingy to hold the pill in place. I got the machinist I use for my shop repairs at work to make me one. In the past CY has talked about putting together a kit for this purpose. As yet I don't believe he has done this.

If that were my light I wouldn't give up on the pcb just yet.

 

[the avatar]

Thanks ZuluWhiskeyFox, I think I haven't given up yet... it's just that I always have a feeling that a sandwich would provide more efficiency and flexibility in upgrading

I'm trying to look for the LT1618 chip and the Coilcraft DO1608C-333 inductor.. don't know if I can get them as I live in Hong Kong... especially the Coilcraft inductor... does anyone know if I can use some other inductor instead ?