And the RGB signals are sometimes also DC-Biased... ugly... get a /" from EBay with Digital interface, less problems

If you really want to drive that display, and you haven't found a datasheet,
then the driving board, if you still have it, is what you have to analyze.
With patience and an oscilloscope capture every waveform for every pin.
Some pins will have higher than 5 V voltages, maybe even all different
driving voltages (no charge pumps in the TFT itself).
Little story: I had a photo frame, something like 5" with a 480x243 TFT.
It had an analog interface. There where 3 pixel clocks, those were 3
sinusoids with a few MHz, three biased color signals and various bias,
sync, and some other alternating signals.
The display had RGB analog input but these signals had alternating polarity,
if I remember correctly. The display is as dumb as it gets, there is no driving
there at all just a DAC, so you have to provide all this information yourself.
From the German forum mikrocontrollernet, you can get a (maybe similar who knows)
pin out of a 7" with 26 pins interface analog TFT:
Das Display ist ein InnoLux AT070TN07 7".
Pinbelegung:
1 GND P Ground
2 VCC P Supply voltage for scan driver
3 VGL P Negative power for scan driver
4 VGH P Positive power for scan driver
5 STVD I/O Vertical start pulse Note 1
6 STVU I/O Vertical start pulse Note 1
7 CKV I Shift clock input for scan driver
8 U/D I UP/DOWN scan control input Note 1, 2
9 OEV I Output enable control for scan driver
10 VCOM I Common electrode driving signal
11 VCOM I Common electrode driving signal
12 L/R I LEFT/RIGHT scan control input Note 1, 2
13 MOD I
Sequential sampling and simultaneous
sampling setting
14 OEH I Output enable control for data driver
15 STHL I/O Start pulse for horizontal scan line Note 1
16 STHR I/O Start pulse for horizontal scan line Note 1
17 CPH3 I
Sampling and shifting clock pulse for data
driver
18 CPH2 I
Sampling and shifting clock pulse for data
driver
19 CPH1 I
Sampling and shifting clock pulse for data
driver
20 VCC P Supply voltage for scan driver
21 GND P Ground
22 VR I Alternated video signal (Red)
23 VG I Alternated video signal (Green)
24 VB I Alternated video signal (Blue)
25 AVDD P Supply voltage for analog circuit
26 AVSS P Ground for analog circuit