Solved Technos - Dommy no blue background
- Thread starter Georgian2
- Start date
I'm not aware of the Dommy edge connector pinout, but check the 4 black transistors in the block here for continuity with the blue video signal pin.
For the transistors it's usually the left-hand most pin when looking at the flat side.
I've fixed video on a couple of boards by replacing the transistors because the legs had broken right under the plastic package part (sometimes hard to spot at a cursory glance, but can happen if they get snagged)
Thanks for your input. The color Blue apears to be working. I'll check tomorow anyway.
If I remove the eprom e30, the Background is all blue but other colors don't match. It's wierd how the data comes out of the 3 eproms then goes in 2 pairs of ls194 for each eprom. Only one output of each is then fed into one ls157.
On each pair, one shift register ist shifting roght, one left. Everything apears to be working. Color proms is ok too and so are all other eproms.
Another intersting thing is that the highest bit on an 2148 sram comes out of an ls367 and the input is floating an not connectrd to anything. They should have just tied it to vcc not leave it like this. Should be ok since this game has 3 bits per pixel acording to mame so the 4th bit is not used. Maybe the board is missing some patch wires?
If I remove the eprom e30, the Background is all blue but other colors don't match. It's wierd how the data comes out of the 3 eproms then goes in 2 pairs of ls194 for each eprom. Only one output of each is then fed into one ls157.
On each pair, one shift register ist shifting roght, one left. Everything apears to be working. Color proms is ok too and so are all other eproms.
Another intersting thing is that the highest bit on an 2148 sram comes out of an ls367 and the input is floating an not connectrd to anything. They should have just tied it to vcc not leave it like this. Should be ok since this game has 3 bits per pixel acording to mame so the 4th bit is not used. Maybe the board is missing some patch wires?
I replaced the 3 transistors with 3 C828 - same results.
Removing the E30 eprom results in blue background.
Removing the E40 eprom results in black background.
Removing the E50 eprom results in red background. Of course there are some other changes in sprites and text colors.
Here in this video I remove each color from the monitor, one by one. At first RED, then GREEN, then BLUE.
There is very little blue on the screen around the domy logo and one sprite is blue (from second 29).
This board is driving me mad...
Removing the E30 eprom results in blue background.
Removing the E40 eprom results in black background.
Removing the E50 eprom results in red background. Of course there are some other changes in sprites and text colors.
Here in this video I remove each color from the monitor, one by one. At first RED, then GREEN, then BLUE.
There is very little blue on the screen around the domy logo and one sprite is blue (from second 29).
This board is driving me mad...
That's very strange.
Looks like you colours aren't being mixed correctly.
Could it be the eprom selects aren't working properly so that's messing the colours up.
On the rastan I recently fixed multiple graphic eproms were being selected at the same time messing up the graphics,if I removed one of the graphics roms some graphics would improve but others disappeared.
Looks like you colours aren't being mixed correctly.
Could it be the eprom selects aren't working properly so that's messing the colours up.
On the rastan I recently fixed multiple graphic eproms were being selected at the same time messing up the graphics,if I removed one of the graphics roms some graphics would improve but others disappeared.
I'm guessing the LS194s are to just turn the graphics data buffer into a data stream for outputting in time with the display.
Later in burger time there's a colour control ram bus using a couple of 7489 rams.
Anything like that on your PCB?
Later in burger time there's a colour control ram bus using a couple of 7489 rams.
Anything like that on your PCB?
Only 3 srams on the board. Two 6116, one for program one for characters (maybe) and one 2148. When the 2148 is removed there are no sprites, all of them shrink in one line of pixels on top.
There is one JK flip flop LS112. 1K comes out of an LS04. 1J is conected to the input on that LS04 and nowhere else, its just floating. Again, maybe it's not used. Second flip flop on same IC is working fine. Many wierd things on this board. Next week I'll get one from a friend of mine and compare.
There is one JK flip flop LS112. 1K comes out of an LS04. 1J is conected to the input on that LS04 and nowhere else, its just floating. Again, maybe it's not used. Second flip flop on same IC is working fine. Many wierd things on this board. Next week I'll get one from a friend of mine and compare.
What a waste of time.
I had a chance to test and compare against another PCB and gues what, exactly same results. What are the chances that 2 PCBs have the same fault? Not many.
It turns out the RGB signal level is to weak for an kortek monitor. I tried 2 different models. I'll have a look if I can increase the input impendace on the Kortek chassis.
On Hantarex, everything looks great, so the PCB is working just fine.
Attached is an picture on an MTC9000 (ignore the high contrast)
I had a chance to test and compare against another PCB and gues what, exactly same results. What are the chances that 2 PCBs have the same fault? Not many.
It turns out the RGB signal level is to weak for an kortek monitor. I tried 2 different models. I'll have a look if I can increase the input impendace on the Kortek chassis.
On Hantarex, everything looks great, so the PCB is working just fine.
Attached is an picture on an MTC9000 (ignore the high contrast)
On this model there are no adjustment on the chassis. Fix 4k7 Ohm inoput impendance. If I turn the contrast up the colors are over saturated. Maybe I could get better results with the pots on the neck board but I won't bother. Not a big fan of kortek monitors. Hantarex made the best monitors.