Hello everyone, I will start off by introducing myself since this is my first post. I have been in the process of building a light twin cockpit for several months. Up intil now I have found all the answers to my questions via this forum and other great websites. So I would like to thank everyone for the great amount of information you have shared.Here is my problem I am trying to flash the fsbus led board. I am getting a read after write failure. It seems (I think) that it is a voltage problem. Pin 4 (MCLR) on the PIC16F84A is getting 8.3V and it is supposed to recieve 13.5 in flash mode (I think). I have checked the ComIII booard with a multimeter. I am getting 14v from 78L12 the voltage drops down to 8.3v after passing R2 680ohm. My question is this, is the resistor the problem or is a current problem or am I totaly of base? I am new to electronics and I am learning as I go. Please help. :-zhelp Thank you, John

Hi John,1. Is it the FIRST board you are flashing ?2. have you checked the PCB thorougly ?3. Which OS are you using ?4. have you set the COM Board AND the controller to flash mode ?cheersMathias

Thanks for your reply Mathias. 1. Yes it is2. yes, but it won't hurt to do it again.3. Windows xp pro4. yes they are both in flash mode.Also, I am using a 9v 300ma power supply and I may not be using the correct transitors I am going to change those today and see if that produces any results. Any more suggestions are welcome.Thanks John

Hi John,well then this seems to be the typical problem which is not yet solved - a not known problem with some PC

Transistor TR1 is propably in open state for some reason.Check diode D7 near transistor. Should be attached as in this diagram:http://mikkila.wabbits.org/fsbus/doc/COMIII.jpgCheck that you have not overheated that transistor.Meaning of that TR1 is to give 13.5 volts or 0 volts to MCRL line. Depens what state is on serial cable TX line.Ofcourse. Check also all normal things. Components are right way aligned. There is no cold solderings. No shorcuts and so on.- Jhttp://www.mikkila.org/fsbus