PCE GT Lithium Battery Mod Guide

[userofapples]

i got it working but it was way too bright even though i tried to adjust the brightness dial down.  after a certain point the screen just turned off, at the lowest setting when working the type of game that i was trying to select was not visible.  not worth the effort for my system at least.

[lamb2k]

This is great. Where did you find the resistor? I'm having trouble chasing down the exact part here in the US.

[MasterofBiscuits]

This is great. Where did you find the resistor? I'm having trouble chasing down the exact part here in the US.

If you mean the 1.8mohm resistor for the Powerboost board, I usually buy my components from Farnell, although there are lots of similar online stores (RS Online, Mouser etc).

https://www.newark.com/c/passive-components/resistors-fixed-value/chip-smd-resistors?resistor-case-package=0805-2012-metric-&resistance=1.8mohm

Any of these should be fine.

[kattare]

Really cool mod. Could you do this and still use the original adapter instead of USB power?

IE, split the original circuit at the regulator output. Route the regulator output into the 1000c 5v input. Then route the 1000c 5v output to the board where the regulator used to feed it?

Is the OEM adapter's 700mA too low to charge the batteries & run the system at the same time?

[lamb2k]

His second reply/post has a schematic for using the original adapter port for charging.

[kattare]

His second reply/post has a schematic for using the original adapter port for charging.

He's still using a USB power supply - just adding a barrel plug.

For charging I'm using a USB cable that has changeable barrel ports: https://www.amazon.co.uk/gp/product/B07GTKBVKN/ref=ppx_yo_dt_b_asin_title_o00_s00?ie=UTF8&psc=1

I asked if you could use the original AC adapter. The USB adapter is 5v whereas the original adapter is 7v, so you'd need to pass through the regulator before feeding the charging board.

My concern would be the current draw when charging and playing. Not sure the original adapter could supply both at once.

[MasterofBiscuits]

Really cool mod. Could you do this and still use the original adapter instead of USB power?

IE, split the original circuit at the regulator output. Route the regulator output into the 1000c 5v input. Then route the 1000c 5v output to the board where the regulator used to feed it?

Is the OEM adapter's 700mA too low to charge the batteries & run the system at the same time?

Hmm, techically you could since it would be a regulated 5v coming out of the original regulator, but as you suggested the 700ma is too low to power when playing & charging, which needs around 1.3a when the battery is at its lowest, and I recommend at least a 1.5a USB source.

The real question is why would you want to when there are so many better options. Nobody should be using the original unregulated PSUs from the 90s, they are old and inefficient. Just get USB cable with a barrel jack and you're done.

[kattare]

Hmm, techically you could since it would be a regulated 5v coming out of the original regulator, but as you suggested the 700ma is too low to power when playing & charging, which needs around 1.3a when the battery is at its lowest, and I recommend at least a 1.5a USB source.

Bummer

The real question is why would you want to when there are so many better options. Nobody should be using the original unregulated PSUs from the 90s, they are old and inefficient. Just get USB cable with a barrel jack and you're done.

Agreed that the old supplies are inefficient, but I've found newer switching supplies to be pretty hit or miss with regard to how clean the power is.  At one point I went through all my gear swapping in switching supplies so I could leave more stuff plugged in and not worry about it - but after a while realized that for several systems it had introduced static or rolling distortion in the picture. I went back to my old setup with a remote-based master on/off switch on the power strip where the transformers are plugged in.

I have found that not all switching supplies are like that - but it's easier (and cheaper, since I already have them) to just use the OG supplies than it is to iterate through brands trying to find good switching supplies.

Interference on the express probably wouldn't be an issue but USB supplies have the same issues - very hit or miss with specs and quality - look no further than the number of bricked TG/PC Engine mini's: https://www.reddit.com/r/TurboGrafx/comments/gojsub/my_second_pc_engine_minis_usb_ports_have_stopped/

Cheers

[lamb2k]

Thanks for this Master of Biscuits.

A few questions:
1) Where exactly does the wire for USB go for the scenario of aftermarket LCD with stock charging port?
2) Do you have any tips for removing Q502's resistor without damaging the PCB? Same for removing the resistor on the Adafruit. Th

[MasterofBiscuits]

Thanks for this Master of Biscuits.

A few questions:
1) Where exactly does the wire for USB go for the scenario of aftermarket LCD with stock charging port?
2) Do you have any tips for removing Q502's resistor without damaging the PCB? Same for removing the resistor on the Adafruit. Th

1) Not sure I understand the question, could you explain a bit more about what you're trying to do? Aftermarket LCDs can be powered from the Powerboost board, the USB input for the Powerboost should go to wherever your USB power is attached to the console.
2) Q502 can easily be removed with a soldering iron, just add flux and a bit of extra solder to the large end, hold for a few seconds, then put your iron across the pins on the other side. Just keep getting heat on there and it will just slide off in no time.
The resistor on the Powerboost is a bit trickier, ideally you need hot air. If you don't have one, add some leaded solder on both sides and use a large iron tip to heat both sides at once and push it off. Shouldn't be too difficult, the hardest part is actually getting it off as the board is so crowded.