problems downloading to a FET 18 pin board

[avaient]

I'm having problems downloading to an 18 pin pre-manufactured FET board. Leads are all in fine. correct voltage, chips, however the computers i'm downloading from are saying the the hardware on the com port is not found, i've tried of three different computers in three different places at home and two in school but no luck. has anybody had this problem before and overcome it. help. cheers

 

[ylp88]

Have you tried downloading the program onto the chip in a basic external circuit (ie. *just* the two resistors and +5V regulator and capacitor). I'd assume you have already have tried this an this is how you have concluded that the PICAXE chips are okay.

Also try to program the chip with no peripherals connected: such as motors, globes and other devices, especially those which usually have a relatively high current draw.

ylp88

 

[ylp88]

Also, have you got enough power supply filtering - on a board such as yours with high current drawing components, it is necessary to have sufficient ripply smoothing capacitors (say, 0.1uF) right up close to the chip, not just near the regulator. I would think that the pre-manufactured FET board already has these but I am not familar with this board.

ylp88

 

[BeanieBots]

That board can have two independant power supplies, one for the high current side and one for the PICAXE. By default, the board is fitted with 100R connecting the two supply +Ve's so that only 5v is require to be connected to the high current side.
Check that you have 5v actually on the chip.