[Solved] No LCD Output and Power Switch Not Working (Unit just power on)

[Todd5314]

No to battery and multimeter (though I can buy one.)

Pi boots in both positions I can see it via the HDMI out but with standard retro Pi image. I haven't put yours on yet.

The device boots without the backboard attached in any way.

[kite]

Ok right, well at least the Pi is ok

Getting a multimeter would be useful to continue debugging.. where are you based? UK? If so it would be quicker to return to me, if you're in the US or anywhere else perhaps getting your hands on a multimeter.. I'd get you to measure the voltage from GND to the solder holes at the top of the board next to the battery connector (the ones for POWER SWITCH and MODE), and also the resistance from GND to those pins..

[Todd5314]

I'm in the US - I'll grab one today. What would the instructions be so I can get you answers while you are sleeping...

[kite]

I'm in the US - I'll grab one today. What would the instructions be so I can get you answers while you are sleeping...

1. With the back board NOT connected, and NO power applied anywhere.. measure resistance on the POWER SWITCH and MODE SWITCH pads that are at the top of the board.

They are expected to read something like 90-110k ohms..

2. With the power plugged IN and backboard NOT connected.. measure the voltage on the POWER SWITCH and MODE SWITCH pads that are at the top of the board.

The are expected to read about 3-5v (somewhere in that range)

3. With the power plugged IN and backboard IS connected but the switches are OFF.. measure the voltage on the POWER SWITCH and MODE SWITCH pads that are at the top of the board.

You should get the same results as #2

4. With the power plugged IN and backboard IS connected and the SWITCH is ON.. measure the voltage on the POWER SWITCH and MODE SWITCH pads that are at the top of the board.

You should get 0v on POWER SWITCH and should get 3-5v on MODE

[Todd5314]

Thanks! I'll grab the info today.

[Todd5314]

Also I presume you mean between those 2 points and the GND on the Pi near the SD slot?

[Todd5314]

Ok - PG = Pi ground solder point; BG = SAIO ground above power or mode point.

1)
Power - PG=127-128; BG = Same
MODE - PG = .47; BG = Same


Using AC mode not DC
2)
Power - PG=.015-.02; BG = Same
MODE - PG = .001; BG = Same

3) Extra Blue LED off
Power - PG=.009-.012 BG = Same
MODE - PG = .001; BG = Same

4) extra blue LED on
Power - PG=.001; BG = Same
MODE - PG = .001; BG = Same

[Todd5314]

Using DC

2)
Power - PG=0; BG = Same
MODE - PG = 0; BG = Same

3) blue LED off
Power - PG=4.7 BG = Same
MODE - PG = 177.x; BG = Same

4) blue LED on
Power PG=0; BG = .3
MODE - PG = 177.x; BG = 177.x

[kite]

Just to clarify, those tests were with the back board not connected? It looks like the mode button pin is shorting somehow.. I'm not 100% certain on why, and perhaps the next best thing would be to send in for repair and I can take a look? If you send me a PM/Email we can work from there. If it's a hardware problem from my end it will be a free repair, otherwise it'll be return postage (£9) + a small bit for time

[Todd5314]

#1&2 didn't have the backboard connected, 3&4 did per the instructions.

Thanks for all your help. I'll PM you.