Something worth checking before you apply power
The Q1 MOSFET ....... double check the pinout of the legs against a datasheet for the exact component you have.
I have spent more than 2 months pestering both Richard and Gary with PM's and e-mails because my boards did not work ( I have three of them) It seemed that the circuit was faulty and was not doing what it was supposed to. I even bought more, and built from new, and the problem was still there...three times. It turned out to be a component specification change issue.
I finally solved it a few days ago, the new versions of the MOSFETs BS107P's have pins 1 & 3 swapped on the component, so although the component was fitted correctly according to Richards instructions, in reality it was in backwards
Richard originally used a BS107A, but that is now obsolete and Mouser now supply a BS107P. The Source and Drain are swapped when compared to a BS107A.
So if you have a BS107P, you will need to fit it the other way around.
Pin 3 three where the board is marked Pin1 or the square pad. If you have any other components as an equivalent, then check a data sheet for it and make sure the Source and Drain are corrct way round
auraslip wrote:I used the BOM for the 24v boards. I didn't get the zener diode.... is that a necessary part for 24v boards?
Depends what voltage you are running your Meanwell at. if you are running over 24 volt then you will need it to control the supply voltage to the LM78 voltage reg
Check back a few pages of this very thread, half way downviewtopic.php?f=31&t=21768&start=15
fechter wrote:For over 35v operation, we just add the 24v Zener diode and no longer use the FET or 100K resistor.
For under 35v, place a piece of wire through the 24v jumper holes. You can use a piece of wire snipped off of one of the resistors. The jumper goes here:
For over 35v, place the zener diode like this:
It won't hurt if the zener diode is installed and the 24v jumper is added. It will be in the under 35v mode with the jumper.
For odd voltages, the value of the zener might need to be changed. To calculate, take the highest output voltage for the supply the board is connected to, and subtract 35v. This is the value you should use for the zener. If this doesn't work out to an available value, use the next higher zener voltage. Multiple zeners can be put in series to increase voltage. Try to keep the input of the LM78L12 between 24v-35v.
auraslip wrote:Second, instead of using a trim pot to adjust the current limiting resistor inside the meanwell itself could I jump it and use the current limiting boards only? I ask because I've been using the pots to control current, but with the proper cooling I'm at the limit at which the stock meanwell limits to.
yes you can use this board as current limit instead of pot in the Meanwell, that is what it is designed for. But I would not jumper the original resistor on the meanwell, that will be final safe guard if the board failed for any reason.
auraslip wrote:Where/how on the board does it tie into the sense line?
you can just see the picture of the red wire going off the board, into the Meanwell, and you can just make out where it is soldered to the resistor behind the voltage adjustment pot. on to a leg of the resistor, the outer leg, closest to the case side
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