Topic: RED Problem

[Ian.]

Hi Guys,

Had an elecrical glitz which took my RED out of service, I've replaced the discovery board on advive from the blitzortung forum and now it's back, but the LCD display only half of the display works, (the centre of the display to the right is completly blank, yet on start up it shows that it is capable of working), I have re-flashed the discovery board but to no avail, my question is where does the display get it's information to display, is their a chip on the RED PCB that I could change?

One other thing to mention is that the waveform on the red channel is like the edge of a saw with very tight, regular peaks and troughs, it wasn't like that before it got fried

Cheers

[miraculon]

This is strange, because the Discovery board is directly interfaced to the display module.

What do you mean exactly by "on start up it shows that it is capable of working"?

Does it display normally and then go blank?

Do your power supply voltages check out? Does the contrast circuit generate the proper voltage? (the diode/capacitor circuit, see the controller schematic)

See the FAQ near the end of the Blitzortung document:

Problem 2: I don’t see any readable information on the LCD!
First check, whether the board is powered via the mini USB jack of the controller, and not
via the mini USB jack of the STM32F4DISCOVERY board. Then check, if you accidentally
set the LCD contrast to 0 in the settings. Measure the contrast voltage with a volt meter.
It has to be around -4V. If this is ok and the display still doesn’t show anything, then the
communication between controller and LCD might be broken. Carefully check every pin.

Greg H.

[miraculon]

I downloaded and checked the documentation for the display.

 http://www.mouser.com/ProductDetail/ELECTRONIC-ASSEMBLY/EA-DIP122-5HNLED/?qs=sGAEpiMZZMt7dcPGmvnkBngmo%2fJGB9YAp0HFs4zfmd8%3d

In the Pinout table there is something interesting that may have some relevance to what you are experiencing.

Check the status of Pin 15 "Enable right side". See if it is either stuck low, or transitions low when the RH side goes blank.

I would check the solder joints on the connector header, the Discovery board etc. tracing this back through the circuit.

Greg H.

[Ian.]

Greg,

What a great pointer, thanks for taking the time and effort to research this for me, I'll check this out tomorrow and let you know how I get on.

[Ian.]

OK, Checked the output from the Discovery board (P2 header pins 43 & 45) and they are at the same value to each side of the display and track continuity is good, I'll get a new display when it really bothers me, at least its working and I can access the web interface.

Thanks for your help, but it looks like when the discovery board failed, it took out half the display with it. (event though I still don't get how it can perform a display test on start up which included the right hand side?)

Regards

[miraculon]

OK, Checked the output from the Discovery board (P2 header pins 43 & 45) and they are at the same value to each side of the display and track continuity is good, I'll get a new display when it really bothers me, at least its working and I can access the web interface.

Thanks for your help, but it looks like when the discovery board failed, it took out half the display with it. (event though I still don't get how it can perform a display test on start up which included the right hand side?)

Regards

I am inclined to agree that the display has gone bad. What is the "display test? I don't recall seeing anything like this when the RED boots up. Can you describe what you see prior to the RH side going out? Is it all segments on?

I see the segments faintly when I restart the system. Maybe that is some start-up artifact that is independent of the display controller.

Greg H.

[Ian.]

Sorry for the delay, I was waiting for a new version of firmware so I could record exactly what the display shows, simply powering off and reapplying the power did not always make the display show fully.

Applying power to the discovery board for the first time in preperation to flash, made the LCD display show solid blocks using the full display, after a short while the display went blank and then showed a single unbroken line in the centre of the display for the full length.

Flashed and it's back to only showing half of the screen.

Most odd, problem is displays cost £31.00 ($48) including posting, so it will stay as is I think.

[Ian.]

Quick update, sourced a new display which cost £26 including postage, and it's all up and running with a full display.

Display EA DIP 122-5NLED from www.MMS-e.co.uk

[miraculon]

That's great news. I am glad that you were able to get it running correctly.

Greg H.