The JXD S7800 is a quad-core, 7-inch Android tablet and portable game console produced by Chinese manufacturer JXD. The device was announced in mid 2013 with the first shipments occurring in mid October. It is available in two models, the S7800A (with an AllWinner A31s SoC) and the S7800B (with a RockChip 3188 SoC and more RAM). The device runs Android 4.2.2.
The JXD S7800 is the successor to the JXD S7300B. Support from JXD has left some early customers wanting. This page was created to help owners of the device who need some assistance with technical matters. The device is particularly suited to Android gaming and retro gaming with key mapping.
The S7800's main improvement over the S7300B is the addition of dual thumb joysticks. A covered microphone, MicroSDHC slot and reset button are found on the bottom left side. Along the top of the top is a power socket, headphone jack, micro usb port and hdmi port. The back of the device can get warm after extended periods of gaming. At half a kilogram the unit is heavy.
|CPU||RockChip 3188, Quad Core, 1.6 GHz|
|GPU||Mali 400 Dual core|
|RAM||2 GB DDR3|
|Internal Memory||8 GB|
|Expansion Slot||MicroSDHC Card, officially limited to 32 GB|
|Display||7" IPS LCD, with a maximum resolution of 1280x800|
|Battery||5000 mAh lithium-polymer|
|Audio Output||Stereo speakers, 3.5 mm headphone jack|
|Display Output||micro HDMI 1920x1080|
|Input||5-point touchscreen, direction buttons, game buttons, left and right joysticks, function buttons, microphone, gravity sensor|
|OTG||Allows for the connection of keyboard, mouse, ethernet, 3G dongle, USB disk and powered external hard disk|
|Dimensions||Length: 245 mm (9.6 inches) Width: 120.5 mm (4.7 inches) Depth: 16.5 mm (0.64 inches)|
|Weight||500 grams (1.1 pounds)|
|Update the firmware||Download the firmware from here. Extract the update.img file from the .rar and put it on the root of an SD card. Powered off the device and insert the SD card. Then boot up and it will prompt you to update. If using the RKBatchTool and a USB connection use a USB port at the back of the pc instead of one on a hub. Within RKBatchTool to select English language press the first button at the bottom left of the window and select the second option. Also avoid USB 3.0 ports if possible.|
|Reveal the hidden menu bar||Long press the power button and choose the bottom option, or swipe your finger from the bottom of the screen upward.|
|Charging||Don't play games when charging.|
Issues and solutions
|Wifi strength||Wifi signal reception isn't so great (similar to issue present on the S7300).||None so far. According to stpat, you can try changing the band on your router from narrow to wide, but you need to have a fairly recent router with N mode that supports this usage.|
|Light leakage||Light leaks out from the corners of the screen so that when you view the device in a dark room, the corners are brighter than the center of the screen.||Open the device and un-tighten the screws that are holding the screen in place. The screws are so tight that they cause the screen to bend very slightly, enough to allow light to bleed from the corners, or to cause a wavy pattern along one border of the screen.Also for the colors not displayed correctly re-seat LCD ribbon cable make sure it is even and all the way in.|
|Wave screen patterns or color not displayed correctly||There is a visible wave or distortion along the bottom, or one other side, of the screen.Or colors are weird and blotchy|
|Analog dead zone||You have to push the analog sticks very far out before some programs react to the input||This is largely a software issue, not a hardware. Some programs have no problem at all, while others who treat the analogs like digital joystick set a very high threshold for input. FW 1.0.9 addresses the issue somewhat, and future firmware updates will probably improve the matter.|
|Right stick recognition||Very few games recognize the right analog stick as a configurable control, or as a camera-look control.||No known solution at this time.|
|Slow performance after update to FW 1.0.9||After updating to FW 1.0.9, the device feels slow or unresponsive.||Use SetCPU to change the minimum speed, and/or switch the CPU governor from interactive to on-demand.|
|Won't charge via USB||Plugging the device in to a power socket will charge the battery, but plugging in via USB will not.||This is a hardware design issue, power from USB to battery has been disabled. JXD chose not to hardwire the charging trigger to the USB.|
|Won't charge at all||Even plugging the device in to a power socket won't charge the battery.||There's a chance that your AC adapter is faulty. Try replacing it with any adapter that is rate 5 Volts and 2 Amps and has the proper connection to your device.|
|Short of storage space||While the device has 8GB internal storage, it's been partitioned and the main partition is only 1GB.|| Short of using an android app like gl2sd that does a directory bind, there's not much you can do to solve this. Keep moving apps off the main memory to "external" SD which is really the extended partition of the internal memory. Games over 1GB in size may be difficult, if not impossible to install. From Skelton: In s7300 is just doing SWAP, editing vold.fstab file. In s7800 can be edited to make swap too because some folks in spanish forums do it and works.
Just edit vold.fstab like this:
dev_mount flash /mnt/sdcard auto /devices/platform/rk29_sdmmc.0/mmc_host/mmc0
dev_mount sdcard /mnt/external_sd auto /devices/virtual/mtd/mtd9/mtdblock9
|Icons disappear and reappear||Icons for pre-installed apps, or newly installed apps, disappear or reappear seemingly at random.||Seems to be a FW problem, try using an alternative launcher like Nova or Apex. Alternatively, delete the folder "mnt\sdcard\apks" but be aware that you will be deleting software off your tablet.|
|Launcher and keyboard not remembered||Even if you set an alternative launcher and/or keyboard, they will not be remembered when you reboot, and you must reapply them.||No known solution at this time.|
|SuperSU does not update properly||Apply updates from Google Play to the pre-instaleld SuperSU app does not allow SuperSU to update the binary properly.|| Here is tansoftware's solution (see here for drivers):
|Google Play compatibility||Many apps which should presumably be compatible with the S7800 are marked as incompatible, and thus can't be installed from Play.||Try using the app "Market Helper" developed by "codekiem" (download link). It seems to work for some users, but not everyone. Alternatively, use APTOIDE or F-Droid.|
|GameX or Happy Chick app missing||After updating to FW 1.09 the retro gaming app is icon is missing or apk file is not found at internal Memory/apks/4_1||Download and install from here or here.|
|Mapping tool||The mapping tool doesn't provide the degree of functionality it should.||Use Tincore. Download it from Google Play and make sure the built-in keymapper is disabled (call it up, and then select clean/close instead of save/hide),In order for Tincore to work on the 7800, you have to go into the settings section, and under DEVICES:TOUCHSCREEN, you have to tick the checkboxes for "Invert touch generated X" and "Invert touch generated Y". If you don't do this, not only won't the joystick mapping work, but buttons won't work either, despite the fact that they seem to be set up properly.And to leave the Tincore screen back to your game and have the profile active, you have to click on the checkmark in the top right corner of Tincore. Simply dismissing Tincore using a key sequence with dismiss Tincore, but not have the profile active, so you will have no control.|
|USB connection to storage||USB connection only appears to be able to view an inserted SD card, and not the internal storage on the device.||
Rockchip has recently released a new drivers auto-installation tools to improve USB connection to storage. It supports Windows XP, Windows 7 and Windows 8 You may install the driver without any devices attached to your computer. A guide is available here and the tool is available for download from here with the password: geekbuying.com
An overview of emulation on android devices is covered this thread.