 Notice. New forum software under development. It's going to miss a few functions and look a bit ugly for a while, but I'm working on it full time now as the old forum was too unstable. Couple days, all good. If you notice any issues, please contact me. |
Forum Index : Microcontroller and PC projects : ORG MM, power LED on, but no video...
| Author | Message | ||||
Grogster Admin Group  Joined: 31/12/2012 Location: New ZealandPosts: 9307 |
Hi everyone. 
I am playing with an original MM assembled by a friend(yes, really - I am not referring to myself here!  ), and the power LED lights about half-a-second after power up, but there is no video.
Monitor reports "OUT OF RANGE" if that helps. The LCD does not shut down, which is the norm with no video at all, which suggests there must be SOME kind of output from the unit, or the LCD would go to sleep. I have tried a couple of monitors, all report the same kind of error. The 4:3 LCD I have reports "Unsupported mode" Voltages are correct. Any ideas at all? I am guessing that this is probably fixable, but if not - well - that's life. EDIT: With an SD card in the unit, on power-up, green power LED lights after half-a-second or so, then red LED blinks for about quarter a second, but still the same errors on the VGA output. Smoke makes things work. When the smoke gets out, it stops! |
||||
| MOBI Guru  Joined: 02/12/2012 Location: AustraliaPosts: 819 |
I have the CG model and the video won't come on unless I switch the display on first and then power up the CG. Don't know if this is your problem too? David M. |
||||
Geoffg Guru Joined: 06/06/2011 Location: AustraliaPosts: 3194 |
Sounds like it is set to composite video. Geoff Graham - http://geoffg.net |
||||
| Grogster Admin Group Joined: 31/12/2012 Location: New ZealandPosts: 9307 |
Worth a try!
Did not work though. I turned on the LCD first, then fired up the MM, and got the "Out Of Range" message(I have reconnected to the original LCD). This is an odd one - all the other MM's I have played with always worked on the video output. Could this be related to the cap on the PIC32? I know that Geoff had reported that SOME MM's would not fire up with the tantalum cap, and you had to replace this with a ceramic. This kit has the tantalum cap. Still - not sure this is the problem either, as the green LED lights, which indicates that the PIC32 is running the code - correct? Smoke makes things work. When the smoke gets out, it stops! |
||||
| Grogster Admin Group Joined: 31/12/2012 Location: New ZealandPosts: 9307 |
Excellent point - I will check.
EDIT: Nope - makes no difference. JP2 WAS bridged with a solder blob, so I thought "A-HA! That's the problem!!!". Sucked up the excess solder with wick, and put the jumper on one pin only, but I still get the same error message on the LCD.  Smoke makes things work. When the smoke gets out, it stops! |
||||
| Geoffg Guru Joined: 06/06/2011 Location: AustraliaPosts: 3194 |
The green LED shows that the MMBasic is running OK. So, if J2 is not jumpered it can only be something between the pins of the PIC32 and the monitor. It sounds as if one of the sync signals is not connected but check all connections to the VGA socket. Also, try swapping the VGA cable. Geoff Geoff Graham - http://geoffg.net |
||||
| Grogster Admin Group Joined: 31/12/2012 Location: New ZealandPosts: 9307 |
Thanks - I will check that area of things and post back with the results. Smoke makes things work. When the smoke gets out, it stops! |
||||
bigmik Guru Joined: 20/06/2011 Location: AustraliaPosts: 2914 |
Hi Groggy, Is it working via USB terminal mode? If so then it really HAS to be something between the PIC and the VGA connector.. Check the Values of the following Resistors. R3 120 Ohm R4 680 Ohm R5 1k Ohm Also check the polarity of diode D1. Regards, Mick PS. Also try powering it using the USB port instead of an external plug pack which are sometimes very noisy Mick Mick's uMite Stuff can be found >>> HERE (Kindly hosted by Dontronics) <<< |
||||
| Grogster Admin Group Joined: 31/12/2012 Location: New ZealandPosts: 9307 |
I have never used serial terminal mode over USB. Can someone refresh my memory as to the application I should use and the settings I need to use to get the MM to talk this way? I see TeraTerm being mentioned on Geoff's site, so I downloaded a copy of that, but it refuses to install on Win7 - just keeps moaning that the INF file is missing. I would be interested to see if it works OK in terminal mode. Smoke makes things work. When the smoke gets out, it stops! |
||||
 Print this page |
