[ PROBLEM SOLVED ] V-Hold not stable - arcadevga + jpac on nanao/sega 26"

[breech]

arcadevga + jpac on nanao/sega 26"
Everythings fine except for the vertical scrolling. i can adjust the v hold but it eventually starts scrolling again.
the v-h- (composite),v-h+, v+h-, v+h+ (garbled display) switches dont help as they dont lock the hold. any ideas?
also which switch position should i be using?

cheers


 

[MrArcade]

How do you have it wired?

[breech]

arcadevga card -> jpac - Jamma harness (power supply is on)

i guess my monitor requires a different synch.
any suggestions?

[menace]

What pin(s) on the monitor (v-, h-, v+, h+) is wired to the
v. sync line coming into the jamma harness?  for the WG K7191 I had to wire V- AND H- to the v. sync on the jamma harness for stability.

[breech]

k. jamma pin 13 (white) goes to a 6 pin header with the 3 RGB cables & gnd

1= V.D (none)                 (PDF says yellow??)
2= H.D sync (white)
3= GND (black)
4= B
5= G
6= R

.. there is no mention of +/- in the manual & i cant see much in the chassis. what am i looking for exactly?

[breech]

i tied the vga h & v syncs together & v-hold is behaving correctly (like a TV)

i soldered a switch & ribbon cable to pins 13 & 14 on the j-pac vga connector.

if you have the same problem with v-hold not snapping to top/bottom of screen, let it roll slowly, use a small screwdriver & carefully short pins 13 & 14 on the j-pac.
see if the v-hold locks when it gets to the top or bottom.

SOLDER SIDE OF VGA CONNECTOR:


05-04-03-02-01- soldered pins
-10-09-08-07-06 soldered pins
15-14=13-12-11- soldered pins << carefully short pins 14 & 13 & v-hold should lock.

-------------------- pcb edge
15-14-13-12-11- gold pins
-10-09-08-07-06 gold pins of vga connector
05-04-03-02-01- gold pins