Dead flexdrive???

Lasers and Masers · Nov 19, 2010

So this is my first time dealing with a flexdrive, or any driver built by any one else than me..

I set the current setting resistors part of the circuit to max, then adjusted to 1.4 amps.

I attached it to a gold dollar with arctic thermal adhesive and made sure there were no connections between circuit and coin. Then I attached all wires and put heat shrink on all of the wires ends.

Put together the host (making sure not to twist wires) installed battery, and there was a dim line projecting from the diode/aixiz module, I moved the head of the host a little and Blam! it came to (assumed) full power, then instantly as I was moving the head it went off (it all happened before I could react and stop moving).

Is there anything any one can see I did wrong?

I have a v5 flexdrive, an a140 diode, and a guidesman host form Mohrenberg.

I'm pretty good with circuits and of the like. This is just so small I don't know what happened.

I think I might have ruined it with the adhesive if nothing else, I put a little much.

udanis · Nov 19, 2010

What esd precautions did you use?

Lasers and Masers · Nov 19, 2010

I was pretty intense with esd, made sure to wait for a higher humidity day for where I live, made sure to discharge on a cold water pipe before picking diode or driver, nothing around to make a charge other than carpet and my glass table.
Oh yeah for got to mention that I took it apart and theres no current running through the flex when I put power to the +/- leads. So I do not think that is what went wrong.

DTR · Nov 19, 2010

I am assuming you are using the case pin to make the ground either by bridging it with the negative pin on the diode or running a line back to the driver negative input. I would rule out that you are not having a connection issue first. You can unscrew the head and take the heatsink and press it against the bare metal on the host body and see if it comes to life. Also you can scrape the top of the host body that the heatsink sit on to remove the paint for a better connection.

I would also check the host with a DMM and make sure it is getting power through the switch and the body of the host.

daguin · Nov 19, 2010

If it was "dim, then bright, then dim", without you changing anything but the position of the head, you have (or had) a loose/bad connection or a short somewhere.

Peace,
dave

DTR · Nov 19, 2010

daguin said:
If it was "dim, then bright, then dim", without you changing anything but the position of the head, you have a loose/bad connection or a short somewhere.

Peace,
dave

Dave is right. Neither driver or diode will spring back to life from dim to full to dim. If the diode is LED it stays that way forever same with the driver.

My first thought was bad connection as well.

You said it went bright when you moved the head. That says to me the ground is not flowing into the heatsink.

Pontiacg5 · Nov 19, 2010

If I remember correctly driving a flex with no load or a short could kill it. You need to make sure all of your connections are perfect before applying power.

DTR · Nov 19, 2010

Try scraping the lip that is pointed to with the yellow arrow with a razor blade and touching the heatsink to it while the unit is on. Make sure you are pointing it away from yourself when you do this. The paint on the lip will prevent you from having a good connection with the heatsink as it sits on this and centers itself in the head so it does not get contact with the threads in the head. And definitely make sure all your connections are solid before powering the driver.

daguin · Nov 19, 2010

DTR said:
Dave is right. Neither driver or diode will spring back to life from dim to full to dim. If the diode is LED it stays that way forever same with the driver.

My first thought was bad connection as well.

You said it went bright when you moved the head. That says to me the ground is not flowing into the heatsink.

Unfortunately, if he shorted something on the driver he may have blown both the driver AND the diode

Pontiacg5 said:
If I remember correctly driving a flex with no load or a short could kill it. You need to make sure all of your connections are perfect before applying power.

Yeah. If the flexdrive is run without a load, it keeps boosting the voltage (trying to get it "right") until it burns itself out

Peace,
dave

DTR · Nov 19, 2010

daguin said:
Unfortunately, if he shorted something on the driver he may have blown both the driver AND the diode

Yeah. If the flexdrive is run without a load, it keeps boosting the voltage (trying to get it "right") until it burns itself out

Peace,
dave

That is certainly a possibility. But from the many of these that I have done when they do not light up after being assembled it is because of the paint on that ledge and a good scrape with a razor blade clears it right up. Thought it might be a good place for him to start.:beer:

daguin · Nov 19, 2010

DTR said:
That is certainly a possibility. But from the many of these that I have done when they do not light up after being assembled it is because of the paint on that ledge and a good scrape with a razor blade clears it right up. Thought it might be a good place for him to start.:beer:

He said that he disassembled it and is getting no voltage through the flexdrive when he attached power directly to the input side.

Peace,
dave

DTR · Nov 19, 2010

daguin said:
He said that he disassembled it and is getting no voltage through the flexdrive when he attached power directly to the input side.

Peace,
dave

Missed that part.:cryyy:

AUTO XX · Nov 19, 2010

I am having a similar problem, I have connected the negative terminal of the diode to the case pin, I also ran a negative to the Vout of the driver but I get nothing on the dummy load.
I have tried grounding the host to the negative of the dummy load and I got a reading but even grounding the host directly to the dummy load all I can get it ~1.1V output across the resistor(s) Is it possible there was a broken trace in the circuit board? If so, how can I find/fix it?
I tried contacting lava 3 days ago via the google response but haven't gotten an answer yet.
I'm going to try a different build with the same wiring tomorrow and see if it works. By my reckoning, this shouldn't be this complicated. :whistle
The other problem is the first flexdrive is already thermally adhered to the "driver heatsink" and I can't make another of those parts because it came with the host, I just added a bit to it....

Pontiacg5 · Nov 19, 2010

1.1v across a 1ohm resistor is 1.1A of current through the driver. Seems to be working to me...

DTR · Nov 19, 2010

Yup that sounds like it is working. You can drop it down to the 2V setting and it should now be saying 1100mV which equals 1100mA.

Lasers and Masers · Nov 19, 2010

K sorry didn't mean to post and run, well actually post and pass out

I am assuming you are using the case pin to make the ground either by bridging it with the negative pin on the diode or running a line back to the driver negative input.

Yep you're right.

I would also check the host with a DMM and make sure it is getting power through the switch and the body of the host.

That's one of the first things that I did, measured + contact to threads of host. got full voltage.

Also I knew about the flex breaking without a load. I had a test load attached every time I gave it juice.

If it was "dim, then bright, then dim", without you changing anything but the position of the head, you have (or had) a loose/bad connection or a short somewhere.

Also It went from dim to bright to off, sorry if I was not clear about that.
I'm assuming I blew it some how.

If any one has a similar problem and figures out it's not blown, please post about it here.

Thanks for the help every one!!
I'm gonna do a little more testing, check it out, then probably order a new flex..

Hey also dose any one know if Dr.lava will attach leads to his drivers for a little fee like the current presetting he dose. I'll ask him. Just thought I'll ask here before I bother with a PM, you know?

Dead flexdrive???

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