TE/PCE GT 5v mod?

[fluxcore]

I've recently replaced my TE screen with a 3.5" LCD running of 5v, and naturally my next thought is "ok, how about a lipo battery?".

I'm wondering if anyone has modded their TE/PCEGT to run off 5v, and has any details. I imagine it ought to be capable of doing so, there are probably only a couple of issues:

* Does any of the old backlighting/LCD power conversion circuitry need to be removed
* How to handle the power switch

My plan is to use a single lipo w/a 5v booster board, and a micro usb lipo charger. I've found a 6000mAh pack that damn near fits in the battery compartment (will just need to dremel down the plastic battery holder nubs). Should be easy enough to fit the rest of the stuff in the shell.

There's remarkably little in the way of detail of how other people have modded TEs for rechargeable batteries. But I suppose they typically use a 7.4v pack and shove it straight into the input of the power switch. Maybe that's a far simpler way to go - but I think that wasting 2.4v through the diodes and regulator is probably less efficient than the ~87% efficiency of the booster board, and then you've got cell balancing to deal with.

Any ideas appreciated.

[NightWolve]

turbokon put significant effort into a competent lithium-ion battery mod, you can read up on tech details in his thread:

/forums/index.php?topic=19910.0

[fluxcore]

Yeah, I've already seen that thread, but to be honest it's very light on actual implementation details. Where does the powercharge 1000c get connected to? I've found some 5v points, and the system will function when powered from these, however the audio is kind of distorted when doing so, so I imagine there's somewhere better.

There are  mentions of "bypassing the internal 5v regulator", but it's not clear where this regulator is. There's a big transistor Q502 which kind of looks like a regulator, but, well, isn't. Hopefully I'm missing something obvious.

I'm also interested in more details about how to separate the power switch from the circuits. The board must have several layers, because it's really hard to tell where traces come & go. I'm considering pulling the switch out and cutting all the pins off so nothing touches the board, and then solder to what remains...

I would post in that thread but it has a NecroPhile warning.

[NightWolve]

You can post in it, that's fine. The warning is just FYI (in my experience, mainly trolls with a grudge exploit a thread necro), and turbokon has been active here in recent days so chances are he'll see your questions, if not, try a PM.

[SignOfZeta]

What exactly is the point of this?

[fluxcore]

What exactly is the point of this?

To supply 5v directly to the PC engine GT (from USB, or a 5v boosted battery) without going through the voltage rectification circuit, for efficiency reasons. As I stated in the OP.

[SignOfZeta]

So you'll get more battery life?

[fluxcore]

So you'll get more battery life?

Correct. And also so that a 1S lipo battery (3.7V) can be used, rather than needing 2S (7.4V) which means balancing when charging (which needs a more complicated charger circuit).