Change Resolution for a CRT via AV output of P3+

[korkri]

Hi,
I'm using a P3+ and I want to output video AV.
I cannot find the right way to change the resolution so I can see the full screen.
I'm missing some data on the up and down part of the screen.
I tried all sdtv settings from 0 to 3 (my CRT is supposed to be pal/secam, but it seems it also recognize NTSC)
I tried to set up DMT 4 : 640x480@60 in the config.txt but apparently it doesn't affect the AV or maybe it is still to be big.
anyone knows if it is possible to change that?
thanks

here is my config.txt:

uncomment if you get no picture on HDMI for a default "safe" mode

#hdmi_safe=1

disable_overscan=1

uncomment to force a specific HDMI mode (this will force VGA)

hdmi_group=2
hdmi_mode=4

Sound output. Set to 0 or comment for autodetect, 1 for DVI, 2 to force HDMI.

#hdmi_drive=2

Using /etc/modules is deprecated and no longer supported on 4.4 kernel

So manually enable audio

dtparam=audio=on

#config_hdmi_boost=0

force hdmi while the tv can take time before sending the signal on the hdmi output

#hdmi_force_hotplug=1

uncomment for composite PAL

sdtv_mode=2
hdmi_ignore_hotplug=1

uncomment for lirc-rpi

#dtoverlay=lirc-rpi

if you plug your tv at the same time as your rpi and that the rpi switches from the hdmi or give a low resolution because tv had no enough time to initialize it

boot_delay=3

uncomment if you don't want the rainbow at startup

disable_splash=1

default CEC name

cec_osd_name=recalbox

Overclock

gpu_mem_256=128
gpu_mem_512=256
gpu_mem_1024=384

avoid_safe_mode=1

kernel=zImage

Raise the first security limit up to 70° instead of 60°

temp_soft_limit=70

[acris]

Hello
Please https://forum.recalbox.com/topic/18395/resolution-av-sur-p3/
No double post.