At the moment i’m constructing the mbhp pic burner on a piece of exp.board.
I’ve got a question regarding the trimpot.
How does this go on the board? When i look at the schedule pdf you’ve got the 3 pins of the LM317, I*,A*,O*.
The trimpot should go between A* and O* but how?
There are 3 legs on the trimpot, two on one side and one is solo. I’m figuring that one of the two should come from O* (with a 220 ohm R in between) and the solo one should go to A* and the negative line. The third leg goes to ground. In the pdf it seems that the resisting value of the trimpot is between O* and the negative line. But do i have to connect that leg also to ground after J2?
Okay just downloaded the pdf for the trimpot(piher pt10) and the markings are as followed: solo pin is the wiper(S*), the two other pins are marked initial(A*) and final(E*).
Okay good you mentioned the regulator. Did some background work and came to the conclusion that a ‘normal’ LM317, which i’m using, has a different pinout then the LZ version. Correct me if i’m wrong…
But i might think that you’re right. Gonna turn it around and get back to ya’ll…
Just swapped the LM317 and ihaaaa 12V (one 9V battery is low) :o
So good voltages now 8)…Thnx DrBoom you’re right ;)…got the LM the other way around so this solved my problem to…it’s not quite finished my pic burner but good voltages are always nice.
So i’m wondering…instead of a 1N4002 i used a 1N4007…does that matter?
the higher the number, the higher the volts. i believe the 007 can do 1Kvolts, where the 001 does 50. However higher voltage diodes take slightly longer to turn around the current flow. In this case the voltage across the regulator will go higher before the diode actually conducts. will prob make the reg run hotter i guess.
just my 2c, id get this confirmed though as most of my electronics knowledge is derived from midibox.
I thought it had something to do with the amperage. At least that’s what they told me. Like 4002 is 2A and 4007 is 7A.
edit: you’re right again with the voltages. But isn’t it the same as with elco’s? You can use a 400V cap for a 12V application, everything above the appropiate voltage isn’t needed. Don’t know if the same counts for diodes though.
I don’t know how much the voltage drop differs on the different diodes, but I’ve used different ones in all osrt of layouts and never had any problems.
Btw: “Building mbph Burner” - What’s this “mbph” you are talking about?
So just finished up the burner and everything seems fine.
At start the burner is recognized.
On the Vdd test the yellow light goes on and the voltages are ok on the pins. ;D
Except on the Vpp test the red light goes on but burns faintly and i’m not getting good voltages. Way to low as a matter of fact. So i measured the voltage at the C pin of the BC547 (which i’m using) and its to low to.
What is happening here?
When Vpp is of i’m still measuring voltage on the line and not 0V. >:(
Clock and data behave normal.
Okay just checked the board and one resistor isn’t placed right…gonna change that and report again later. But there is life in my burner.
So just checked that resisitor but its good in place so something else was(read was) wrong.
Recently i’ve bought BC547’s…at least thats what i thought and ordered…but it seems they are BC557’s so no good for this project. Swapped it for the right BC547 and everything is working just fine.
Vpp test is right, Vdd test is right, clock and data voltages are right, so i have a working MBHP Burner.
