C8F build Problem

Stefan333 · 2019-08-25T21:19:40.000Z

Have an C8F Host, an Lexel driver and an MCPCB with Nichia LED.

When the MCPCB hanging in the “Air” all is ok, starts in Moon an can switch higher.

When the MCPCB contact the shelf it goes immedeatly on full power.

Have double checked soldering, can not find an obviously fault…

Any hint where i can start to search?

djozz · 2019-08-25T22:08:13.000Z

If no faults can be seen, it could be a short between led-minus and the central pad, under one of the leds. Try re-heating the board and lift all three leds up and put them back on the board, the short may be gone.

After I resolder a board with leds, I always check, using a cheap led-tester, if the leds light up when connecting the + and - solder pads, and check if they do not light up when I move one of the led tester clamps to the side of the board.

So maybe this is the solution maybe not. Good luck finding the fault!

chops728 · 2019-08-25T22:13:41.000Z

Are you puttin g the Reflector on when this occurs — if so check that it’s not shorting ground

Stefan333 · 2019-08-25T22:34:57.000Z

Because the MCPCB was my first reflow ever, i guess the problem is here.

Better start learning with single LED instead of triple, it was not so easy as i thought…

I will remove the LEDs, clean everything and make a new try next days…

Stefan333 · 2019-12-07T20:21:05.000Z

Little Update, after some burnt fingers and broken nerves i decided to buy a little Hotplate from Aliexpress.
10x10cm plate and worked like a charm, desoldered and cleaned MCPCB an LED and reflowed all again.

Now the light goes only on when pushing the switch….

Yokiamy · 2019-12-07T21:32:58.000Z

Good to hear, did you buy the uyue ?

https://www.aliexpress.com/i/4000086334114.html

Tempted to buy one, already have it in my basket for a couple of months, still didnt pull the trigger

Stefan333 · 2019-12-07T23:11:24.000Z

Yes, that is the plate. Takes some minutes to heat up, but thats ok for me.

Jerommel · 2019-12-07T23:40:52.000Z

Stefan333:

Yes, that is the plate. Takes some minutes to heat up, but thats ok for me.

It’s better for the LEDs to heat up and cool down slowly. :+1:

Jerommel · 2019-12-07T23:43:49.000Z

Yokiamy:

Good to hear, did you buy the uyue ?

49.74€ 23% OFF|UYUE 300W 100mm * 100mm Led anzeige Vorwärmen Plattform für Handy Reparatur BGA Rework PCB heißer platte vorwärmen station|Elektrowerkzeug-Sets| - AliExpress

Tempted to buy one, already have it in my basket for a couple of months, still didnt pull the trigger

Well, now it’s in my basket too.
Thanks for bringing it to my attention. :+1:
And with a range of 50°C to 350°C it’s just a very versatile hot plate.