Those 3800/4800 eBay buys can be risky, but not quite as bad as the recommended with-TBC decks. (Maybe only 25/75, instead of 15/85, where the 75-85 = odds of bad unit).
The 3800/4800 are probably my favorite non-TBC JVC NTSC decks.
- OFF = VIDEO CALIBRATION, SUPERIMPOSE, VIDEO STABILIZER
- PICTURE CONTROL = AUTO/NORM best (EDIT disables everything, picture is worse)
- BLUE BACK is preference. I sometimes leave on, sometimes off.
- N/A, turn if all OFF = 2nd AUDIO RECORD, AUDIO MONITOR, S-VHS MODE, AV COMPU-LINK, EDIT FUNCTION REC PAUSE, AUTOTIMER, AUTO SP -> EP TIMER
- s-video = FRONT AUX INPUT, REAR AUX INPUT
GV-USB2 is overbought lately. So many issues with it. Good luck to you. (That assumes it's not just one of the outright fake Chinese knockoffs, Easycap in disguise. Those exist.)
Easy thread to answer.