Trying to boot an old HTC PDA...

[gaopegn]

Hi guys.
I have an HTC apache(xv6700) which contains very important informations, and now it refuse to boot.
This happened 3 times before, and the main cause should be the battery, because the device is usually run with USB power, and every time the problem happens when AC power were removed for more than 2 months.
Sometimes the red LED light on, or half-boot, and this time the red LED flash for 0.1 sec, and then silent.
I used to charge it for a long time to solve the problem, but now after a whole day the battery is more than 4v and it still not boot.
Also, it do not power on without battery and with USB, the red light will flash continuesly.
There are some relevant cases online:
http://www.tomsguide.com/forum/id-975549/htc-apache-6700-boot.html
https://forum.xda-developers.com/showthread.php?t=309830
I tried to block some of the 6 pins on battery, the PDA will have different light such as solid red, but no way to boot.
Are there any way to trick the device to boot? I need imformations in it.
Thank you.

[Zaddy]

Instead of repairing yourself I would recommend you check with the genuine service centre. Let them have their say. Seems they will have a solution for this.