Hi,I have just finished my COMIII + Key boards,I created the cables, and pluged it all together,I tried to flash the PIC, but it didnt work...So i went to test the voltages of PIC16F84 and....Pin 12,13 + 14 are all 5v (good!)But pin 4 which should read 13.5vreads only about 0.1-0.02v what is going on??Any ideas?CheersVolkan

First thing to do is go back to the ComIII card and with it powered-up, measure the voltage on C5 or the output pin of the 78L12. Also is the LED connected to the "common" pin of the 78L12 lit-up? Without this info it's hard to suggest anything futher.Gus

Hi,The LED lights up fine, and the output leg of the regualtor is ~5v

Is that with the "flashmode" switch open or closed? If it's open, then that suggest to me that the 555 circuit isn't working. The 555 is set up as an oscillator so the voltage at pin 3 of the 555 would be about your "9V input voltage" minus the forward voltage drop across D4 (~.65V). Now, when pin 3 of the 555 is low, capacitor C10 is charged up via D2. Then, when pin 3 go high, the voltage that the capacitor was charged to is "stacked" on top of the "now" high pin 3 voltage. This will cause D2 to be "back biased" (turned off) and C11 is charged through D1 to this "higher stacked voltage".What do you measure on C11?Gus

Hi,I just realised a couple of mistakes I made...First of all, the ID cable + connector was on thewrong way, So, i put that right, andPin 4 reads 13.5vPin14 = 5vPin13 = 5vPin12 = nothing!!!Also....I mesured the wrong component (dont ask!)The 78L12 volatge fluctuates between10-15vI also replaced the 555 just to be sure.Can you help me with this new info?(Also, in the troubleshoot, if there is anvoltage without the box ticked, is that correct?)RegardsVolkan

OK...... Pin 12 of the PIC should connect back to the Comm III card (with jumpers in flash mode) to the junction of R7 and Tr3. Check the voltage there. If you see 0 volts, disconnect the ribbon cable from the Comm III and check again.Gus

Hi Gus,The voltage betweenR7 + TR3 is practly 0vJust like the reading at pin 12I dissconnect the ribbon cable from the KEY card,and still 0vThen i dissconnect it from the PC Ribbon Cable (to thePC COM port) and its upto 5v

That would suggest that there is a voltage on pin 7 of the 9 pin D connector that is turning Tr3 on and "pulling" the collector voltage low. Check the 9 pin D connector.... make sure there are no short's and that it is wired correctly.Gus

Hi Gus, thanks for the help,but I cant see anything wrong with my cabling!I have take hi-res pictures, please let me knowif you see anything ive done wrong.http://vk1.gotdns.com/10850324/

Good MorningI looked at PICT0570.JPG and the # 3 & 4 conductors might be shorted. "IDC" connectors("I"nsulation "D"isplacement "C"onnector) connectors can be a pain-in-the-"####" sometime. Ohm out adjacent conductors in that ribbon cable. After that, if there are no shorts, go to the configuration that gave you 0 volts the R7,Tr3 node. Unplug the serial connector from the computer and measure pin 7 of the computers serial port. If it has a positive voltage then I don't know what to suggest next.... the FSBUS circuit is doing exactly what the computer is telling it to do! I thought I read somewhere to make sure you have the right serial port selected.... you might want to check that out.Gus

The wires in the pictures, are ones I have re-made,im not sure on the old ones, but there is no arcing here.So hooked it all up, and now pins 4,12,13 + 14 allread about 5v!I still getRead after write failed!oh ye, and no other COM ports work.Only COMIoh, and alsoWhen Pluged to PC R7,Tr3 = ~5vUnplugged = 0vI feel we are getting closer! :)Have you got AIM or MSN?

Hi VolkanNot sure what you mean by "AIM or MSN"?Do you now see all the proper voltages on all the pins?Gus

Aim = Aol instant messangerMSN = msn instant messanger,Pins 12,13 + 14 = ~5v which is correctbut pin 4 should read 13.5v now reads5.82v exactly!!!And when i click on Write Flash,i get Read after write check failed

Ok.......No I don't have either.... I guess that's why I didn't know what "they" were!!! Without the 13.5V you will not be able to flash the PIC's. Have you checked that the Com III is set to flash and the FSKEY PCB has the jumpers in the correct position??I thought the 13.5V problem was fixed earlier. If it's a problem again recheck the voltages on C11 and C5 on the Com III PCB as well as the LED to see if it is lit.Gus

The LED lights up fine,Jumpers are in the correct possition according to these:http://mikkila.wabbits.org/fsbus/doc/COMIII-prog.jpghttp://mikkila.wabbits.org/fsbus/doc/Key-prog.jpgThe 78L12 is pretty hot,and also, when i remove the jumper(completely away) the LED still lights up,Is that right?If there is a problem, is it likely to be the COMIIIor Key?