defender blue screen

tron guy

Super Moderator
Staff member

Donor 12 years: 2011, 2015-2025
Joined
Jun 26, 2007
Messages
23,145
Reaction score
2,593
Location
Eureka, California
I looked for this problem but couldn't find the solution via the search on here.

I just picked up a defender brought it home. (it appears to have a switching power supply)

I turned it on, it came up after a few seconds and said:
unit appears to be ok

then I had to scroll through 28 options with a button on the coin door, but it never came to the game screen after that.
So I went and bought new batteries, replaced them.
Now it just comes up with a blue screen. I should mention it came up with only a blue screen 1 or 2 times prior to changing the batter ies as well.
The main board has an eldorado games tag on it, lol.

Where should I start?
 
I looked for this problem but couldn't find the solution via the search on here.

I just picked up a defender brought it home. (it appears to have a switching power supply)

I turned it on, it came up after a few seconds and said:
unit appears to be ok

then I had to scroll through 28 options with a button on the coin door, but it never came to the game screen after that.
So I went and bought new batteries, replaced them.
Now it just comes up with a blue screen. I should mention it came up with only a blue screen 1 or 2 times prior to changing the batter ies as well.
The main board has an eldorado games tag on it, lol.

Where should I start?

First, check potential [voltages] at the 4 corners of a couple of RAMs. Next, reflow the solder on the power header. Recheck the potential [voltages] at the 4 corners of a couple of RAMs. Report back.

Good Luck,
Saltbreez
 
on the power supply board? or directly from the switcher?

both?

this will be for tomorrow at this point.
thanks
 
Sounds like there is at least a dodgy connection somewhere. Could be the ribbon cable connector from the ROM board to the CPU board, one of the socketed chips on the CPU board, quite possibly one of the EPROMs on the ROM board (they always have lousy sockets), etc. Maybe a dry solder joint too.
 
Ok, I have messed with the power, checked the connections and so on.
Still have an all blue screen.
here are some pics of my new defender

This machine did come with a bunch of extra ram. The guy who had it said that had been the problem in the past, I just haven't messed with
that part of it yet.
 

Attachments

  • defender 001.jpg
    defender 001.jpg
    96.1 KB · Views: 40
  • defender 002.jpg
    defender 002.jpg
    94.9 KB · Views: 46
  • defender 003.jpg
    defender 003.jpg
    95.7 KB · Views: 46
  • defender 005.jpg
    defender 005.jpg
    94.9 KB · Views: 42
  • defender 004.jpg
    defender 004.jpg
    98.7 KB · Views: 45
Blue Screen? Reboot...

No wait... sorry, I work for Microsoft... force of habit. Nevermind... :D:rolleyes:
 
Carefully, pull and reseat all of the cables one at t time with the power off. Pay particular attention to the power cables and look for signs of burning or scortching.

Also try carefully removing and reseating the Decoder Chips (the ROM chips in the next row below the CPU chip) and the CPU chip.

If it still will not come up. Power it up, push on the ROM cable and press the reset button on the CPU board (the big board).

ken
 
me? i'd replace that big orange capacitor there on the power supply first. while i was at it i'd replace all those electrolytic capacitors on the power supply and reflow any cold solder joints. then i would remove the switcher and start testing voltages.
 
Last edited:
me? i'd replace that big orange capacitor there on the power supply first. while i was at it i'd replace all those electrolytic capacitors on the power supply and reflow any cold solder joints. then i would start testing voltages.

SG: Have you been drinking tonight? Do you even know what the big orange cap does? or the cost to replace it? The failure rate of that cap is very very low.
 
me? i'd get rid of the switcher and rebuild the PS. i would start by checking the +5VDC on the original PS. then reflow any cold solder joints and replacing the electrolytic capacitors. clean the fuse holders and test the fuses. look carefully at the connectors and see if there is any oxidation at the pins and the wire going into the pins. if there is, replace. any burnt pins in there? any resistors look/smell burnt? unsolder one leg of a resistor and test.

Dokert, there you go being mean, AGAIN. hehe. i think your post breaks forum rules.
why not just post more help to this fellow?
 
me? i'd get rid of the switcher and rebuild the PS. i would start by checking the +5VDC on the original PS. then reflow any cold solder joints and replacing the electrolytic capacitors. clean the fuse holders and test the fuses. look carefully at the connectors and see if there is any oxidation at the pins and the wire going into the pins. if there is, replace. any burnt pins in there? any resistors look/smell burnt? unsolder one leg of a resistor and test.

Dokert, there you go being mean, AGAIN. hehe. i think your post breaks forum rules.
why not just post more help to this fellow?

Still waiting for Dylan to post the voltages that he found, before moving on. YellowDog has already given him the next step in the process.

If the power is good on all four corners of the RAM, then most likely either the ribbon cable or the header for the ribbon cable is the culprit.

I still Love ya, but shotgunning parts is never a good answer in this economy.;)
 
Last edited:
seems like the voltages on the legs are good now.
I am going to go yellowdog's route tomorrow hopefully, and report back.
thanks Dokert and others. I appreciate the help.
 
seems like the voltages on the legs are good now.
I am going to go yellowdog's route tomorrow hopefully, and report back.
thanks Dokert and others. I appreciate the help.

One thing I have noticed on several PS rebuilds lately. The voltages look good, but the boards won't boot. This is due to a small amount of AC coming down the +12 line. If you have a digital voltmeter, this will show up as the tenths digits flicking up and down. Some meters react faster than others so it may not be very apparent unless you hold the probes on it for a few seconds. 0.2 V difference will be enough to mess the RAMS up.

The AC usually comes from the 4700 uF (the second biggest) cap starting to go bad.

ken

The voltage pattern (sorry I thought I had posted this here but it was in a Stargate thread):

Measure the voltage at the 4 corners of one of the RAM chips.

The voltages should be
Pin 1 = -5V,
Pin 8 = +12V
Pin 9 = +5V
Pin 16 = Ground

The pins are numbered starting in the upper left corner (notch being up), going counter clockwise.

If any of them are low or are fluctuating more than 0.1 V you need to check your power supply. There are 3 LEDs on the power supply. If any of these are out, check the corresponding fuses. If the fuses are good, the PS probably needs rebuilding.
 
Last edited:
I have measured the ram chips and thought the voltages were good but now I better check for more certainty.

all 3 lights on the power board are good. There is a switcher wired up in there as well.
I will look again tonite.
 
Back
Top Bottom