flickering GC 1000? could be my mistake

[Greta]

Copied from HERE.

MrMimizu07-19-2007 07:35 PM
flickering GD 1000? could be my mistake

When I first tested my GD before I installed it, I don't think it was flickering.
This was after I soldered on my 2 led leads to the board.
Now that I've got it soldered and potted into my ecan and hotlips, when I power up, it is solid for about .25-.50 seconds and then it flickers at a frequency that i can notice. Any idea why it may be flickering and what I can possibly do?

LED Zeppelin07-26-2007 10:51 PMRe: flickering GD 1000? could be my mistake

If you're using a Seoul or Cree, are you sure the bottom is isolated from any electrical path?

MrMimizu08-10-2007 09:49 PMRe: flickering GD 1000? could be my mistake

weird, I dropped it a few days ago and suddenly it works fine..
not sure what happened but since the flicker is gone, I can't complain.

DonShock08-10-2007 11:06 PMRe: flickering GD 1000? could be my mistake

I had a flickering problem with a Cree light that would appear and disappear at random. I finally found the problem to be a bad solder joint between the wire and the pad on the Cree. I didn't have a good bond to the pad and it came loose. But the soldered wire held it's shape and position and would sometimes make contact with the pad even though it wasn't actually soldered to it.

[morelightnow]

I'm having the same problem with my GD500. I outputs 2 seconds of good light then starts flickering at about 30Hz. I popped the led off just to be sure it wasn't caused by the arctic silver epoxy i used. I also checked all the soldering connections to see if they were within their boundaries and not overflowing to other parts of the board. My batteries are charged and everything seems normal. FYI - I'm using a high cri souel p4 and aw imr rcr123 batteries. Just noticed after testing again that the board is super hot after just 10 seconds of use and it is flashing the entire time.

Any ideas of what may be causing this?

[yazkaz]

Someone built me two MagAA modules last year. These modules feature GD917 and GD1000 (both built in 2007) driving different LEDs respectively. Absolutely no flickering at all.

I do however have a similar module housing an NG1000 which gives some degrees of flickering with the bezel fully screwed down. Couldn't figure out what happened inside. The module is now dead, pending repair.

[morelightnow]

It acts like it's swinging from full blast to nothing. I tried direct drive to the emitter and its not a whole lot brighter even with an imr. I have soldered it in place about three times so its probably my fault, but I'd like to solve the issue if i can before I order another.

[morelightnow]

Fuhgettaboutit. I just killed it completely by shorting the led + and main + together. By accident of course. When this happened it shorted the battery to itself and burned a nice image of the wire into my finger. At least I have a scar to talk about around the campfire this weekend.

[dat2zip]

If the GD driver ever had a no load condition for more than an instant the driver could be broken and still appear to work. The on/off condition could be symptomatic of this condition and overheating with flickering or unstability is usually a good indicator that the GD IC has blown.

Wayne

[yazkaz]

I bought a few GD1000s last year, which are still sittng idle (brand new unused).
I don't however have the necessary skills/tools to test them. How do I know if those boards are indeed bad?
And, is there any QC issue on GD boards? Because I intend to stick to GD primarily and will plan on ordering some more.

[dat2zip]

A purchased board either works or doesn't work. Testing before installation is highly recommended.

That means hooking up an LED to the output and applying power and making some measurements. If the board test fails we will replace it. If you install it into a light and then test it you assume all responsibility


Applying power to a light engine with poor solder connection to the LED is more than likely going to present a no connection at some point in time and this will damage the driver which may flicker, partially light up and more than likely get very hot.

The GDuP due to the control loop topology is safe to operate with no load. I don't recommend to do this with the GDuP, but, that is how I reprogram the GDuP. I put it in a fixture and there is no LED load when I re-program the board. I also set the power current limit to 20mA just in case there is a component misload and the converter is not working correct.


Wayne

[yazkaz]

Well I finally got the first sour taste of a bad GD1000.

Had a friend do me another module. Has soldered the necessary wires (LED+/- and GND) and hooked it up to an LED on the heatsink. Emitter is double-checked to be electrically isolated on the slug's base. All soldering points rechecked and are nicely done. When powered on, emitter lights up for a second or two, then flickers, followed by reduced output. Repeating the test shows the same result.

Replacing with another GD1000 (from the same batch) shows a different result. Driver operates nicely without any problem (ie. no flickering).

So Wayne, any chance the bad GD1000 can be repaired or replaced? See pics below:



If the driver cannot be replaced for whatever reason then I'll have to send it to someone else to fix it.

[dat2zip]

Send Cindy an email. We will send you another one.

Wayne

Well I finally got the first sour taste of a bad GD1000.

Had a friend do me another module. Has soldered the necessary wires (LED+/- and GND) and hooked it up to an LED on the heatsink. Emitter is double-checked to be electrically isolated on the slug's base. All soldering points rechecked and are nicely done. When powered on, emitter lights up for a second or two, then flickers, followed by reduced output. Repeating the test shows the same result.

Replacing with another GD1000 (from the same batch) shows a different result. Driver operates nicely without any problem (ie. no flickering).

So Wayne, any chance the bad GD1000 can be repaired or replaced? See pics below:



If the driver cannot be replaced for whatever reason then I'll have to send it to someone else to fix it.

[yazkaz]

Send Cindy an email. We will send you another one.

Already sent in an email but so far no response at all...

[dat2zip]

Cindy is taking care of it now. You should be getting an email.

Wayne

[Ms_SS]

Email sent