Hi Everyone,I've taken the plunge and gone ahead with producing the FsBus System. I've made the COMIII & Key board but didn't decide to make the PCB's. Instead i've made them from Vero boards and I'm pretty sure its wired correctly. I did find a couple of mistakes at first but they have been fixed up. The issue is the read after write failure again.I'm getting the right voltages on the IC's but the MCLR voltage (16F84 Pin 4) I'm only getting 12.14V. Would this affect the operation of programming? I'm getting 5V at all specified points in the schematic and from the Troubshooting page in Flash mode including Pin 12 & 13 on the PIC.I'm getting 5V from the 7805 and 14V from the 78L12. Should the voltage from the junction of TR1 and R2 drop to 12.16V, I thought that might be where the 13.5V should be?If anyone could help it would be greatly appreciated!!Kind Regards,

Hi Brad, Make sure your Bus cable to the controller board is as short as possible for flashing, 10cm or less should be good.Only connect one controller to be flashed at a time, make sure your jumper links are in the correct position for the flash, it's sounds abvious but can be overlooked, I've done it a couple of times here.On the comIII program position & the two on the controller in program position.Also check the transistors TR1, TR2 & TR3 they are all used during flash mode, so check & double check your circuits around these tranny's. Also verify they all measure good with a diode check on the multimeter, you may have to unsolder them to check properly. Do resistance checks around the circuit and study the circuit diagram to see that it is roughly what you would expect to see.You can supply the ComIII with 13.8V Regulated supply it will not harm the board, I have seen people say to keep the voltage high during program mode.One last thing many PC's com ports sometimes are not fast enough to do the flash, Nobody can explain why, try another PC if you can, My Celeron 500Mhz cannot flash a board, I have even seen people with 1Ghz systems have problems, so it could just be the workstation. My Pentium III 733Mhz does it fine & also a Pentium IV 2.6Ghz is OK too, My Pentium III Toshiba laptop is useless the serial ports aren't even recognised by FSBus for some reason.Good luck Glenn.

Thanks again Glenn, I've been tearing my hair out and you've been a life saver during this whole process!!Looking closer at the circuit I get 12.5V at the output of the 78L12 and 12.15 when I switch to program mode which is the voltage I get at Pin 4 of the PIC. There seems to be a 3-400mV drop at the input and output of the 78L12, is that normal? One other thing, I am getting 13.8V before the 78L12 until I go into program mode.So you think I should use a supply larger than 9V 800Mah? I get the correct 5V everywhere else that I guess is supplied from the 7805? What power supply do you use?If I get past making this thing work I think I'll help everyone else by posting a detailed testing process.Thanks again Glenn!Regards,

>One last thing many PC's com ports sometimes are not fast>enough to do the flash, Nobody can explain why, try another PC>if you can, My Celeron 500Mhz cannot flash a board, I have>even seen people with 1Ghz systems have problems, so it could>just be the workstation. My Pentium III 733Mhz does it fine &>also a Pentium IV 2.6Ghz is OK too, My Pentium III Toshiba>laptop is useless the serial ports aren't even recognised by>FSBus for some reason.Plus somehow I've got an impression that Win2000 and XP work better for flashing and WinME and 98 seem to have problems..Tuomas

Thanks Thomas for your time.I'm using XP Pro, I bought an old AMDK62 400Mhz for this exercise but I'm going to try it on my P 2.4G now and see if that fixes it.BRAD.

No joy with the new PC?

Do you think 12.13V at pin 4 of the PIC is a concern?BRAD.

I see that problem is voltages.PIC MCRL line shluld be between 12 and 14 volts. Your 12.14 volt is just over low level limit and i see that it is not high enough.You told that you get 13 and something when in normal mode. When you change jumper on COM card to program mode you get that little over 12 volts. This correct?Next things to check. Check that R1 and R2 is not swapped to any other values. Also look after TR1 base voltage. It should be 0v. Means that you get MCRL 13.5 volts to Bus connector pin 9. Also check that diode D7 is correct way aligned. If it is not, current go thru it to ground and will drop voltage at least some 0.6 volts.- J

Could I use an old charger that I have lying around, its 12V 780mA?BRAD.

9 volts and 800mA is enough. And it won't help if you increase incoming voltage when your outcomings are already high enough.But, for actual question. Yes you can use. But! You should add heat shield to 7805 because it could overheat if incoming is 12 volts.- J

Currently I get the following:Output of 78L12 in Program mode: 12.16VOutput of 78L12 in Normal mode: 12.63VBase of TR1 in Program: -.56VBase of TR1 in Normal: 0VCollector of TR1 in Program: 12.14VCollector of TR1 in Normal: 5V R1 & R2 are the correct values.Could C5 affect the voltage levels at all?Regards,BRAD.The diode is correctly biased at the base of TR1.

>>9 volts and 800mA is enough. And it won't help if you increase>incoming voltage when your outcomings are already high>enough.>>But, for actual question. Yes you can use. But! You should add>heat shield to 7805 because it could overheat if incoming is>12 volts.Yep. Using an old AT power supply makes sense in home cockpits otherwise too since a lot of stuff needs electricity, like lights and such. So I have an old powersupply for FSBUS as well. Like Jari said, 12V is OK for fsbus, but put a heatsink on the regulator. For example use 2mm aluminium and make your own like this:

 _________________|_____	   _____||_____	   _____||_____	   _____||_____  (_)  _____| < hole for bolt+nut which fixes this to the regu|_____	   _____||_________________

Everything seems to be just ok. Voltage is just too low.What is voltage when COM board is aloe without any other boards conneced to it?Is there Led between 78L12 ground pin and ground?- J

There is a LED and its always been lit.I have tried disconnecting the Key board and the voltage changed, I though that might have been the problem with the voltage drop when I switch between Normal and Program and it isn't. The voltage drop is caused with something on the Com controller.Do you think C5 could be causing the fault? What if I removed it?Brad.

I'm getting 13.54V at the input of the 78L12 when in Program Mode and it drops it to the 12.14V at the output. Could it be the transistor. What sort of drop do you guys get through your 78L12?Anyway of using the voltage on the input of the 78L12?Thanks again for all your help guys!!Brad.