analogue_mo Posted September 25, 2009 Report Share Posted September 25, 2009 (edited) I think I've burned my PIC BURNER My problem is that when performing the hardware tests on PBrennerNG software I allways get the same Voltage value between PIC MCLR and PIC GROUND pins. I supose that once the Vpp button  is off, there should'nt be any Voltage between this two pins, am I right? I'm not an electronics expert I only know few basic stuff but I've  tried to 'read' the circuit layout and assumed that the BC337 is working as a gate that once it is opened drains all the Voltage to the Ground, closing the Power supply circuit, so that MCLR PIN never gets to have any Voltage available. I've tried to short the BC337 emiter and collector pins and successfully got 0V between PIC MCLR and PIC GROUND pins.... So I've measured all important Voltages in order to try to understand where the problem was and got the following values: --------------------------------------------------------------------------------------------- --> VPP OFF: Voltage between IC3 pin 9 (ground) and IC3 pin 4 and 5 (goes to BC337 base pin) = 5V (4.96V) Voltage between IC3 pin 9 (ground) and IC3 pin 6 (red led) = 0V Voltage between IC3 pin 9 (ground) and BC337 base pin = 5V (actually it goes around 4.38V) Voltage between BC337 collector and emitter pins = 0V voltage between PIC MCLR and PIC GROUND = Vpp (12.47V ) <-- --------------------------------------------------------------------------------------------- --> VPP ON: Voltage between IC3 pin 9 (ground) and IC3 pin 4 and 5 (goes to BC337 base pin) = 0V Voltage between IC3 pin 9 (ground) and IC3 pin 6 (red led) = 5V (4.71V) Voltage between IC3 pin 9 (ground) and BC337 base pin = 0V Voltage between BC337 collector and emitter pins = Vpp (12.47V ) voltage between PIC MCLR and PIC GROUND = Vpp (12.47V ) <-- --------------------------------------------------------------------------------------------- So, my conclusion is that I need to replace the BC337 cause it's flowing current trough emmiter collector even though the base Voltage is 0V, and current doesn't flow when Vb = 4.38V .Shouldn't this be happening the oposit way? Before I start unsoldering I've decided to ask some advice from the experts out there, so that I don't make a bigger mess out of this. I think I've managed to destroy 3 16F84A so far.... Any help is apreciated, thanks in advance. Edited May 29, 2010 by analogue_mo Quote Link to comment Share on other sites More sharing options...
analogue_mo Posted September 26, 2009 Author Report Share Posted September 26, 2009 Solved!It really was a bad baaaad BC337! replaced it, and now I get 0V between MCLR and Ground when the VPP is off....Hope this can help anyone else out there.Cheers ;) Quote Link to comment Share on other sites More sharing options...
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