I wonder if all M8 are like this?
I just got one today and it is - or was - as I just reversed the polarity of the left speaker and the sound is absolutely fine now.
This is not for the faint-hearted and I should point out that I am used to performing micro-surgery on things like this.
I would advise against anyone doing it unless they are very confident (or can afford to kill the tablet).
To do it properly you'd have to completely remove the main logic board so you can remove and re-attach one of the speakers which are front facing so not accessible just by taking the back off. This would involve disconnecting the tiniest of connectors.
I didn't fancy doing that, so after removing the six screws that hold the board in, I just lifted it away at the top, enough to be able to prise one of the speakers out of its mounting with a small screwdriver. With the speaker hanging out to the side on its blue and red wires I cut them about half way, soldered them together again crossed over, insulated them and re-fitted the speaker. Very tricky indeed as the wires are so thin. Instead of trying to strip the ends of the wires to rejoin them, I just burned the insulation off the cut ends with my iron.
One other thing to be careful of is that the buttons for home, esc and power are not attached to the case, so when you move the board away from them they are likely to drop behind the board. In hindsight I would have put tape along the outside edge to grip the buttons in place during the operation.
I doubt very much if Pipo would fix it via firmware, because any change that reversed the polarity of one of the audio channels would fix the speaker sound but completely ruin the headphone sound. If they could make it user selectable or detect when headphones were attached then perhaps that would be a different matter. I hope not anyway as I would have to reverse my wires again!
Such an easy thing to change during factory assembly too. Maybe they are OK now and mine rolled off the assembly line before anybody noticed.
I also have the much-reported crazy digitizer problem when charging. This is just AC leakage from the switch-mode power supply that gets into the tablet and then flows out to earth through you when you touch it. You can feel it as a tingle if you stroke the back of the tablet too. It's quite common on touch-screen devices. It's a combination of a noisy PSU and an intolerance of noisy PSUs by the tablet.
I have a multi-voltage linear PSU, i.e., based on a normal-sized transformer and a linear (not switching) regulator. That causes no such problems.
A suitable one from e#b#a#y would be the 9V/2.1A one for the Sinclair Spectrum +2 home computer. You'd have to take it apart and swap the lead from the Pipo one.
Another solution is to open the Pipo one and connect a wire at the DC ground at the output that exits the PSU. You would then connect this to mains earth at the socket. I tried this too. I wedged the other end of this wire in with the metal earth pin of a plug in an adjacent mains socket. This earths the tablet so no AC current flows through you when you touch the screen. The touch screen was again fine when I tried this. You'll also notice the tingling sensation has gone if you stroke the back panel. This method however could cause some issues (hum loops) when connecting the tablet to another earthed device such as a desktop PC with an earthed metal chassis, as your Pipo PSU is no longer floating but also earthed. A good quality PSU replacement (i.e., another SMPS as that is all you can get these days) may also cure it, but you'd have no way of knowing until you bought it. I don't have another 9V one to try.
Apart from that, very nice tablet!
Edited by Glenn2, 06 April 2013 - 06:27 PM.