Repairing a damaged Microflex

[rocket689]

A few months ago, I was building a tiny keychain host with a lpc-815 and a Lava Microflex driver. Long story short, the fit for the driver was extremely tight. I insulated the driver with electrical tape and installed it into the host. When I powered the laser on, nothing happened. Upon disassembly, I saw the tape had holes where components had cut through it, which i figured had shorted the driver. The driver did not output any current, so it was thrown to the side of my worktable for salvage parts.

As of late, everyone, including me, is looking for microflex's, since the good Dr has had a shortage. So, I picked up that shorted flex today and started testing it's components. I discovered that the pot had been damaged by the tight fit and the rotary dial was almost off of its base.

broken pot after removal (diode for size comparison)

I searched around for a pot and found that a BDR-SO6J sled has several pots just the right size.

After desoldering the pot from the sled, I resoldered it to the flex.

I said a prayer, and powered it up with my test load attached....and it worked!!:wave: The flex doesn't have quite the range that it originally had, but it works and the current is quite adjustable thanks to the bridgeable resistors.

I just wanted to share this little discovery in hopes of helping someone else resurrect their dead flex. I do recall hearing others on LPF saying that they turned their pots one too many times and they broke off. This is a way to bring those back to life
Cheers!:beer:

 

[Mohrenberg]

+1 on that!
I have a damaged flex drive in the basement as well......

 

[rocket689]

Thanks Moh :thanks:

 

[Coherent Light]

If You just jumper the 2 pins on the outside edge You'll get MAX out from the Flex. I have one running like that now, because the pots are so fragile it's easy to damage them.

 

[anselm]

That's great that it works, even if the pot is of a different range.
Yeah most sleds have two or three of these SMD pots to fine tune the diodes current.

 

[rocket689]

If You just jumper the 2 pins on the outside edge You'll get MAX out from the Flex. I have one running like that now, because the pots are so fragile it's easy to damage them.

Thanks for that tidbit of knowledge, coherent. I needed a driver to run a lpc-815 at 420 ma on one Li-Ion, so I needed that adjustability. Ill remember your tip for the future though

I like fixing broken stuff and making it work again (that's pretty much what
I do for a living with high speed machinery) The other week, I was making a tiny focusable greenie in a custom host. I relocated the driver off of the module and arctic epoxied the driver to the sink. I accidentally put too much pressure on the board and broke the regulator chip. To fix it, I salvaged a regulator off of a early 1990's external cd rom. The driver now puts just 50 ma under what the driver was putting out new . Lol

 

[Bogart]

Nice. I just made a working MicroBoost yesterday from two dead ones. I had operated one with no load accidentally, and after 5-10 seconds the large resistor had cooked itself and cracked in half.

I transplanted the one from the other MB that had other problems (made too much current for some reason), and it now works again.

It's a good thing too because it's the only one I have left for testing.

I have 3 dead FlexDrives around, but I'm less hopeful for them. The cause and source of their failure is less obvious.

 

[Flaminpyro]

This is the best way to do it if you just want max power out

If You just jumper the 2 pins on the outside edge You'll get MAX out from the Flex. I have one running like that now, because the pots are so fragile it's easy to damage them.

 

[BShanahan14rulz]

I don't know about what ranges these come in, but to check the resistance of the pot, check the resistance between both ends of the resistive strip as seen in the photo in the Original Post. Your results may vary depending on the accuracy of your meter. Just for future reference :beer: