(Topic ID: 234690)
Linked Games
Star Wars Trilogy
Sega, 1997
Topic Gallery
Albuquerque, NM
Sounds like the display controller is continuously rebooting due to low 5VDC. Try re seating the 3 pin connector CN2 on the Display controller board. If you have a meter, see what voltage you have between pins 1 and 3. Meter on VDC.
Also reseat P1 on the back of the DMD. And check the connector pins 5 to 6, and then 5 to 7, to see the Voltage...should be 5VDC and 12VDC.
Quoted from robertmee:Sounds like the display controller is continuously rebooting due to low 5VDC. Try re seating the 3 pin connector CN2 on the Display controller board. If you have a meter, see what voltage you have between pins 1 and 3. Meter on VDC.
Also reseat P1 on the back of the DMD. And check the connector pins 5 to 6, and then 5 to 7, to see the Voltage...should be 5VDC and 12VDC.
Just checked and I'm getting 5.06VDC at CN2. At P1 I get 4.93VDC from pins 5 to 6 and 12.01VDC from pins 5 to 7.
Quoted from 1iblind:To eliminate a few things I tried another DMD and got the same results. I also tried a known good working DMD controller board. No difference their either.
Then it almost has to be the supply voltage to the controller board dipping...unless you have a bad cable that you're reusing....do you by chance have different ribbon cables to try?
Quoted from robertmee:Then it almost has to be the supply voltage to the controller board dipping...unless you have a bad cable that you're reusing....do you by chance have different ribbon cables to try?
No difference with different ribbon cables. I left my meter on CN2 and the voltage never dropped below 5.06VDC. How would I go about checking to see if the voltage is dipping or making sure the voltage doesn't dip?
Reading a little further and from your picture, it seems that the DMD displays the version info as part of the Display ROM, which means it may not be getting the signals from the MPU. You might read the wiki http://pinwiki.com/wiki/index.php?title=Sega/Stern_White_Star_Repair#Failed_74HCT273_buffer_IC_on_the_MPU_board and do the tests of the IC.
Did you replace the ribbon cable from the MPU, or just the one from the Display controller?
This is a common problem with the Sega displays. It is most likely what others are saying and is caused by a drop in the 5v power supply. Check the capacitors to see if any are leaking or shiny around them on the power supply board. I recently had to replace some on my Sega and it resolved the issue. Also check for any burnt connectors.
Quoted from robertmee:Reading a little further and from your picture, it seems that the DMD displays the version info as part of the Display ROM, which means it may not be getting the signals from the MPU. You might read the wiki http://pinwiki.com/wiki/index.php?title=Sega/Stern_White_Star_Repair#Failed_74HCT273_buffer_IC_on_the_MPU_board and do the tests of the IC.
I did the DMM test on U201 and everything checked out.
Quoted from Scoot:This is a common problem with the Sega displays. It is most likely what others are saying and is caused by a drop in the 5v power supply. Check the capacitors to see if any are leaking or shiny around them on the power supply board. I recently had to replace some on my Sega and it resolved the issue. Also check for any burnt connectors.
My initial thought too, although, I thought the large DMDs were more problematic to the 5V problem. But still leaning towards this.
Quoted from Scoot:This is a common problem with the Sega displays. It is most likely what others are saying and is caused by a drop in the 5v power supply. Check the capacitors to see if any are leaking or shiny around them on the power supply board. I recently had to replace some on my Sega and it resolved the issue. Also check for any burnt connectors.
I checked the capacitors with an ESR meter and didn't find anything out of the ordinary. Which capacitors did you end up having to replace?
Quoted from Scoot:[quoted image]
I bought a kit to replace all of the capacitors but these ones looked “wet”. I also replaced the idc connector.
That's an earlier power supply. Star Wars Trilogy uses the first Whitestar system. I've tried everything everyone has recommended but still no change. Anyone else have any tech tips?
Had a Jurassic park, lost world that would display the stat up, and then just go blank, game worked fine just no display.
Ended up, there was a problem with the mpu.
I sent to K's arcade for repair so I don't know what they fixed.
Did you replace the MPU cable as I suggested earlier.?..If the game is just showing the boot ROM display, sounds like it's not getting the signal from the MPU.
And I'm sure you've checked, but just as a sanity check, did you make sure the ribbon cable is installed the right orientation? Can't remember if they are keyed or not.
Quoted from robertmee:Did you replace the MPU cable as I suggested earlier.?..If the game is just showing the boot ROM display, sounds like it's not getting the signal from the MPU.
And I'm sure you've checked, but just as a sanity check, did you make sure the ribbon cable is installed the right orientation? Can't remember if they are keyed or not.
I think wdennie is right. It's an MPU problem. I did check all the cables and orientation.
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