Donkey Kong diagnosis, please...Blue Screen

[Klassic]

just picked up a Donkey Kong with the following issues. It powers up, but the screen is all blue, just solid blue. No response to coins or any butons. I do get a constant quiet "alarm" sound out of the speaker. I searched, but have not found anyone that had this sympton before in a DK.

 

[Klassic]

Upload of pic

uploaded a pic of the screen and added a video of the constant sound that DK emits: http://tinypic.com/player.php?v=k4fckz&s=5

 

[hamish_nz]

check you voltages

My Mario bros came up with a white screen last week

checked the power supply -5 12 but no 5v

put the power supply in my donkey Kong with the same result

 

[Dokert]

Reseat the Z80, and check all of your connectors on the boardset.

 

[TheDrewster]

The constant alarm noise is due to a failing resistor on the PCB. Q4 I think. Mine does the same thing. Lower pitch, but still there. Its more trouble than its worth if you try to replace it. Its just gonna be one of those things youll have to put up with.

 

[lutus]

Is the color inverter board installed on the monitor?

 

[Klassic]

thanks for all of the input. hamish_nz was right, i have bad solder joints for the pins coming off of the power supply. i'll get that fixed up, and will repost with new info.

the z80 chip appears fine, good legs, good seat. i can deal with the noise, but once i get video, i'll check out the resistors and swap them out.

by propping a block against the pins (video pinset) on the power supply, i got scrambled video, so once i resolder the PS, that fix will get me closer to where i need to be, hopefully.

 

[Klassic]

Donkey Kong is all fixed. Good sound, full picture. Man, i love this site.

for future reference, for a Donkey Kong with a solid blud screen, check your 10 pin CLK wiring harness and plug. Mine came unsoldered from the power supply.

 

[Dokert]

Donkey Kong is all fixed. Good sound, full picture. Man, i love this site.

for future reference, for a Donkey Kong with a solid blud screen, check your 10 pin CLK wiring harness and plug. Mine came unsoldered from the power supply.

Hmmm, that is odd but Good for You!

 

[Klassic]

well, minor update. i still have the quiet alarm sound (which i didn't hear after i placed the fixed power supply back into the cabinet), so soon i will check this advice out from thedrewster0: The constant alarm noise is due to a failing resistor on the PCB. Q4 I think. Mine does the same thing. Lower pitch, but still there. Its more trouble than its worth if you try to replace it. Its just gonna be one of those things youll have to put up with.

playing the donkey kong is much better than staring at a CRT sea of blue...lol.

 

[lutus]

what is your top score on DK now that it is up and running?

 

[Klassic]

what is your top score on DK now that it is up and running?

5100. look out, billy and steve!!! could i be the king of kong? nope, i'm just a donkey dumb*ss. i suck at this game...lol.