HELPP!! Glitchy Grapichs on VA07 Saturn

Guys i need your help, my saturn had glitchy graphics. I suspect cold solder on vdps and i checked IC10 (315 5884) pins with multimeter in continuity mode and some of the pins giving me an ohm reading instead of beep. Also some of the pins are not beeping until i apply a pressure with my leads. So i think it could be cold solder issue and i reflowed the VDP2, checked for bridges carefully, then started it. Display was worse than the first. After like 3 secs it stopped displaying and it didnt produced sound anymore. Please help me to find the problem. Do you think flux residue can cause this? I cant clean the flux behind the pins so im thinking to wash the whole board with water.
(Photos are before the reflow and vids are after the reflow)
Green dots on top of the screen.PNG
IMG_20210219_001901.jpg
IMG_20210219_001911.jpg


 

Jameson

Gear Supporter
First things first, is the power correct and stable? Have you checked/replaced the capacitors? If not, check it first.

From the look of your glitches, i'd say it's either VDP2 or VDP2 VRAM. Cold solder is probably not the case, because the soldering was done with a wave. More probable scenarios are dead caps, scratched PCB tracks and shorted pins.

Multimeters can lie, especially with a thick probes on a tiny QFP pins. Do not apply the pressure to QFN pins unless you're ready to replace the chip with a donor from some dead PCB.
 
I checked the psu voltages they are fine. First pin 12,03v and other ones are 5,27v. Im pretty sure there is cold solder somewhere on the board. Because when i press the sound chip IC17 Glitches dissappear. Board looks brand new no scratched pcb tracks or shorted pins are unlikely. I reflowed many ICs but cant find which one is suspect. Thank you for your comment.
 
Last edited:
i finally managed to fix it today :D im so happy. It was the vdp1 rams. I reflowed them and picture become normal.
 

Attachments

  • FB_IMG_1617018114743.jpg
    FB_IMG_1617018114743.jpg
    56.7 KB · Views: 37
  • FB_IMG_1617018105817.jpg
    FB_IMG_1617018105817.jpg
    245.6 KB · Views: 37
Top