Had a monitor come in (Makvision D3129) that someone else has worked on. I switched out most of the electrolytic caps and got the B+ flowing again. a few voltages are ever so slightly low, but within a margin of error I think.
+25 @24.8
+12 @12.0
+7@6.78
+150@155
the monitor doesn't seem to switch video modes it appears to stay stuck in default 15k scan regardless of the video sent in. no video appears to be going through. if i crank up the brightness to view the raster I can see the following:
the top and bottom of the raster scan are rock solid...nice and even, but the middle of the scan jitters around and crosses over itself. I suspected the vertical deflection IC...It appears someone has had a go at replacing the vertical deflection IC (IC

and a transistor (Q 29)... I'm unsure if it's original or replaced but there is fresh solder and flux there. I double checked the diodes and resistors feeding the power in and out and all seems good. still does it.
I went ahead and replaced the vertical deflection IC and it's power resistors that feed it voltage (sometimes they get fried when the chip starts to go) still does it.
The only thing coming to mind is those stupid mystery chip boxes that weiya stick on there. (labled as IC5) it's a micro controller that reads the sync coming in and switches the scan rate from 15k to 25k to 31k. I'm just thinking it's dead and running random.
FOR FUTURE INFO:
the pinout is:
1 out to Q17
2 out to Q16
3 out to Q21
4 Vert sync
5 Horiz sync
6 +5v
7 GND
the truth table for the microcontroller is as follows:
at CGA:
Pin 1 LOW
Pin 2 HIGH
Pin 3 HIGH
at EGA
Pin 1 HIGH
Pin 2 HIGH
Pin 3 LOW
at VGA
Pin 1 HIGH
Pin 2 LOW
Pin 3 HIGH
I'm going to jump the pins high to CGA (there are pads for it on the backside of this chassis) to see if it comes around.
if so, the micro is dead. if not
