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FE Power Forums => Non-FE Discussion Forum => Topic started by: Clark Coe on November 10, 2017, 04:32:20 PM

Title: Help unsoldering xenon tube for Snap On timing light.
Post by: Clark Coe on November 10, 2017, 04:32:20 PM
Today I asked friends that are electronic techs to do the soldering to replace the xenon flash tube on a Snap On MT1261 timing light.
Problem is they cannot get the solder to melt and release the old tube. Tried 850 degrees F setting on the solder gun and cannot get the solder to go liquid.
Anyone done this before? What is this stuff?...silver solder? Sonic welded?

(https://s19.postimg.org/l3f07uew3/Snap_On_Timing_Light_Xenon_Tube650.jpg) (https://postimages.org/)

Back story on this situation is that I have borrowed this timing light from a friend. I was mapping the timing curve on my distributor and kept the timing light firing for a long time as I wrote down the rpm and degrees of advance. I think excessive heat built up and burned out the flash bulb. There was enough heat to unsolder the reflective shield behind the bulb.
Title: Re: Help unsoldering xenon tube for Snap On timing light.
Post by: Cyclone Joe on November 11, 2017, 01:24:12 AM
If it is anywhere a recent build, its probably silver solder or tin without lead.  Crank up the heat, since the modern solder has a higher melt temperature than the lead-based formulations.  I just hope its not a multi-layered board for your sake, otherwise you're fighting a loosing battle.

Joe
Title: Re: Help unsoldering xenon tube for Snap On timing light.
Post by: WConley on November 11, 2017, 01:45:22 PM
I would just cut the existing tube leads off with a Dremel disc.  Then you should be able to lay the new tube in alongside the cut-off tube leads and solder them together.

Stuff these days is not meant to be fixed.  I just got a low-battery warning on a smoke detector in my house.  Instead of being able to change the battery, you have to slide a plastic tab over to "deactivate" the unit.  That's the only way to shut it up.  Yup - that breaks a component inside and you have to go buy a new unit.  >:(
Title: Re: Help unsoldering xenon tube for Snap On timing light.
Post by: preaction on November 12, 2017, 05:59:55 PM
How old was the detector ? Like everything they have a service life.
Title: Re: Help unsoldering xenon tube for Snap On timing light.
Post by: WConley on November 12, 2017, 06:15:06 PM
The smoke detector was about seven years old. 

Funny - other ones that came with the house have batteries you can change.  I know they work fine because my wife doesn't turn up the vent fan over our kitchen stove very high.  The resulting smoke tests the detectors a few times a month...
Title: Re: Help unsoldering xenon tube for Snap On timing light.
Post by: Clark Coe on November 13, 2017, 03:43:47 PM
So far I am not convinced that standard 60/40 electrical solder would be appropriate. The white ceramic stands suggest a higher temperature level environment. A glob of molten solder on the tip of a 850 degree Fahrenheit soldering gun does not melt into that fused joint between the xenon tube lead and the ceramic standoff.

I am considering unsoldering the vertical leads from the PCB and trying an oxy acetylene torch to disassemble the old flash tube from the vertical leads.
Title: Re: Help unsoldering xenon tube for Snap On timing light.
Post by: shady on November 13, 2017, 04:02:09 PM
the reason you can't unsolder it is because the lamp is not soldered in the first place. it was probably brazed on. the lamp gets too hot for solder. A replacement lamp should come already mounted to the ceramic stand offs & all you would have to do is solder the whole assembly to the pc board under it.
Title: Re: Help unsoldering xenon tube for Snap On timing light.
Post by: Clark Coe on November 13, 2017, 05:57:14 PM
The vertical white isolators are not ceramic, but are very heat resistant. They melted a little when we tried to unsolder the flash tube. The joint at each electrode end of the xenon tube must be sonic welded or brazed. I am planning to cut the tube free with a Dremel tool like WConley suggested and then try silver solder.

(https://s19.postimg.org/dl01h4nwj/Snap_On_Xenon_Tube.jpg) (https://postimages.org/)

This has not been my month for electronics. The 6 CD changer in my Ford Five Hundred ate two CDs ( Jeff Beck and Stevie Ray Vaughn ) and then said goodbye. >:(
The cheap boombox in my garage has decided to stop playing CD also!  >:(