Hello folks,
I'm slowly getting there with this mini-project, my EmoxTX v2 is built and I've now got some CT clamps to start testing. In the meantime, I had also ordered a GLCD board and display with the thinking that I had most of the other components in my parts drawers so have duly built this up too. I loaded up the SolarPV demo sketch and tried the old pins against the board trick and the display powered up fine with the four quadrants etc. However, when I'm now trying that I get nothing. As I remove the power the LCD blips one or two black lines horizontally across as it loses power. I'm a bit stumped as it was working ok and now it seems to have gone caput. I've re-soldered every joint and lightly soldered in the LCD to see if it was a bad contact but no joy. Any pointers as to what to try next?
Thanks!
Re: GLCD faultfinding
One thing you can check is the voltages across the 3 electrolytic capacitors C13-C15. They are part of a voltage quadrupler so the should be 12V across one of them (I can't remember which right now). You also need to check that they are in the right way round as V1.4 of the board had them labeled incorrectly.
Re: GLCD faultfinding
Thanks Martin, it's the v1.5 board so the caps are ok. It might be a bit tricky to measure across the cap with the LCD in place - once I know which cap I can find where it leads to. I've delved into the schematics of the GLCD but couldn't shed any light on the voltage quadrupler?
Re: GLCD faultfinding
The voltage quadrupler is built into the display module with the external capacitors forming part of the charge pumps. There are actually 4 capacitors used, not 3 as I said above, with the final 12V appearing across C16.
Glyn provided a useful list of voltages on this thread somewhere if you search for "GLCD voltages"
Re: GLCD faultfinding
You said the LCD functioned when it was held in place and not soldered, now that you've soldered it it doesn't work?
In that case, surely you are looking for something like a whisker of solder or a solder splash.
Re: GLCD faultfinding
Thanks Martin, the voltage across C16 is only 3.71V :/ wondering if the GLCD is foobar
Robert - yes it worked when held in place and then stopped working (not soldered), so I then soldered it to check if it was a connection issue which it seems it isn't (not looking forward to de-soldering!)
Off to look for GLCD voltages...
Re: GLCD faultfinding
Well I de-soldered the LCD (just about) and the board is in a bit of a mess now :( I replaced the 10uF caps on the off chance they were bad (they were quite old) but no joy.
Just wondering if there's any other diagnosis that can be done to check that the board is functioning properly without the LCD? I'd be a bit gutted if the LCD is caput :( The board and components are relatively cheap to replace the LCD on the other hand...