Hello, I’m trying to adjust the luminance on the core module, but turning the trimpot all left or all right makes litle diference, I already changed the BC337, verified the circuit and tested the trimpot… what can be? its normal?
Thanks!
More information please…
Which make of core board?
What type of LCD?
Thanks.
Oh sorry, I really forgot!
Its core V3
LCD HD44780
Thanks and sorry :-[
I actually meant the make of the core board, as in: did you make the board, or buy a ready-made board and assemble it.
Also, I meant the model of LCD, but this is less relevant… they should all work.
Triple check for any wiring errors or shorts… sorry, not much else I can recommend.
Any chance of photographs??
I made the board with the layout from here, opened in Eagle, printed and made using the toner transfer method…
I verified many times already, all connections looks ok, also tested with multimeter, changed the bc337 for another one… it gives less than 1volt from max to min adjustment.
I will try to get photographs, but dont think it will help much
could it be:
different pinout for adjustment pot?
different pinout for BC337
Hi again Tilted…
It is very very strange… I verified eveything, the circuit, pcb, the my pcb, looked in bc337 datasheet, and looks ok!!!
But, I rotated the BC337 and now its working… for me looks inverted in every where it appears (Colector in emiter and emiter in colector)!!!
STRANGE STRANGE STRANGE… I always worked with BC337 and used this: The chamfer facing top, pins facing me… then pins are CBE…
Well… it is now working… Thanks!
It’s one of the weird things about transistors. CBE is about as likely as EBC. then there are the flat packs, which are more often BCE…
Here’s a kinda useful link:
http://hamradio.lakki.iki.fi/new/Datasheets/transistor_pinouts/
OH MY… I Cant understand… the way I put it its right to what I think, and to datasheet… but still inverted in the schematic for me!
Off hand I can’t recall the specific model designations, but beware of suffix letters attached to (especially transistor) model numbers.
Sometimes you’ll get something like “BC337” and “BC337A” or “BC337-D”, and they might have different pinouts, for some reason…
It could also be that you have a mis-labeled of even counterfeit transistor (which isn’t really much of an issue in this application).