How to diagnose problems?

[fjaust]

Hi everyone,

I'm having issues with my MR16.

I've run the address utility a dozen times but I'm not sure if it actually did anything or not. How do you tell? After addressing the board (starting channel 1) and then running Vixen, nothing happens and all channels appear on all the time. I followed the instructions in the other thread about disconnecting negative power lead first after programming but it made no difference.

I have flashed and re-flashed the PIC and got the correct checksum both times.

I'm also using a new dongle so it could also be that is not functioning correctly, although, the data light does flash on the dongle when Vixen is sending data.

I've got  the data cable plugged into 'DMX In', terminate DMX jumper is set and mode is set to Operate. Red power light comes on, but green data lights never changes when Vixen sends data. The COM port settings are set to 115200 baud rate, parity none, stop bits 1, flow control none. Vixen is set to match the same.

What's the best way to attack this problem?

Thanks, Scott

[rmp2917]

I could be wrong, but I believe the default start address is 1. So, you shouldn't even need to run the address utility if you are setting it to channel 1.

When programming the address be sure that the address utility is sending data before powering the controller in program mode.

If the data LED is not lighting and all channels seem to be on all the time, there may be an issue with the board. If you post pictures, someone may be able to see if there is something wrong.

[rrowan]

Hi Scott,

Start with the basics

1 - check, double check, triple check all solder joints, use a magnifying glass
2 - verify all parts are in the correct location and orientation

The firmware defaults to start address 1

Rick R.

[dowdybrown]

To start with, don't worry about the address utility. After flashing the pic, the board will be set to start at address 1. You need to establish whether your issue is with your new dongle or with the controller. If you have a dmx device that is known to be working, now would be the time to plug it into your dongle and verify that the dongle can talk to it. This would establish your dongle as "known good", and you can concentrate on your getting your controller working.

I will let others chime in on what to do if these are your first 2 pieces of dmx equipment.

Good luck,
Matt

[fjaust]

i'll try all those suggestions in the next few days and see how it goes.

thanks for the help

scott.

[fjaust]

I've checked soldering, re-flashed pic, re-programmed start address, checked orientation of all directional parts - and still no control of lights, all of them on all the time.

i put together another two MR16's, used the same dongle as above, and both the new boards are working flawlessly - so this means dongle is ok.

i'll have to troubleshoot some more later on but I have too much to do right now in preparation for this season !! it's only two weeks away until switch on !!

[rrowan]

swap out the RS-485 chip

Rick R.

[RJ]

Swap the pics from a good pcb to the bad one. If you see it still it could be a bad 5940 ic.

RJ

[fjaust]

Swapped all the chips from a good board, and still no good. Put the chips from the bad board into the good board and the good board still worked, so chips weren't a problem.

i measured the voltage across the caps at the top of the chips and they only read 1.9v. The good board cap voltage read 5v. so there is a difference there. what can that mean? the 5v regulator is no good?

i double checked all the resistor values and they are as they should be.

i have some spare voltage regulators to try and swap over but they are not exactly the same - they are L7805CV instead of L7805ABV. can i still use them on the MR16?

anything else i can try?

thanks, scott

[dmaccole]

i measured the voltage across the caps at the top of the chips and they only read 1.9v. The good board cap voltage read 5v. so there is a difference there. what can that mean? the 5v regulator is no good?

Sounds like it. Of the dozens and dozens of 7805s I've dealt with over the years, the one that went bad on me was in a ... MR16 ... probably just a coincidence, but you never know ;-) ...

i have some spare voltage regulators to try and swap over but they are not exactly the same - they are L7805CV instead of L7805ABV. can i still use them on the MR16?

I just looked at the specs on both ... they appear to be the same (with the exception of a higher output amperage, but that shouldn't be a problem, as amperage is potential, not absolute).

HTH.

\dmc

[fjaust]

replaced the voltage regulator and we have lights !!!

thanks for the help everyone. the 4 controllers that i have built are working great so far in this years display (and with the added bonus of wireless too which makes life a lot easier not having to run data cables everywhere).