John's Arcade Forum - Classic Arcade and Pinball Collecting and Restoring Discussion Forum - RETRO MAME - Nintendo Vs Forum

Hey guys, I'm about to by an AD and the seller states that it started humm louder than normal, text started to flash on the screen and then the screen went dead. That happened after being on for an hour after not being turned on for months. After starting it up again after there's still no screen.

Any info you guys could give me would be great, I don't want to buy something that's going to need a whole new monitor.

the letters might been a glitch caused by a fail power supply.
also check the inside of the cab for loose metal debris  , I always do that before I even plug in a new machine.
one time I found 188 bux worth of quarters rolling around in a cab when I got it home.

I guess that could cause the Humm as well maybe?

Okay guys, I got it!! It's a really really nice machine. The art is amazing and still shiny and bright, the whole things looks awesome except it don't work as we already knew.

At first I would get the beeps on start up with the 1 and 2 player lights lit up solid and the spot killer led active signifying that I might have a connector issue or a main cap on the power supply. Restarting a couple times seems to have killed it further so now I have no 1 and 2 player lights, no beeps, no lights on the pcb. The monitor neck glows (phew) with spot kill active and the marquee and black light turn on.

I've checked the voltages at the two test points on the regulator board. With the pcb disconnected I only get 4.0 volts at the 5 volt test point and the same 4.0 volts at the 10.3 test point. With the pcb connector connected I get next to nothing for voltages at those two points. I guess I have an issue on that board. As per this website it states to change a transistor. http://www.ionpool.net/arcade/asteroidtech/asteroidsrepair.html#P3


Here is the schematic from this area, can anyone lend a hand to anything else I should check.

(https://dl.dropboxusercontent.com/u/85675826/2014-03-20%2023%3A16%3A59.jpg)

Okay so went out and got a new transistor and popped it in. I still can't get the voltage to 5v on the test point and adjusting the pot does nothing. However replacing the transistor fixed something and now it's gone into this state:

Problem: P1/P2 Blink Flash. No Game Play.

Once you get the voltage issue sorted out (rebuild the power supply) you wanna start looking at sockets. They are a common failure point on the PCB. My game occasionally beeps and a chip reseat also fixes the issue. Eventually I'll replace the PCB sockets.

are you still getting 4V at the 10.3V unregulated? I would remove the 5v regulator completely and start with the power brick. Make sure you are getting the right AC voltage. Make sure the bridge rectifier is working correctly.

Yep still getting the same voltages sadly. Gonna put in a new lm305 voltage regulator tomorrow and see if that helps. Going to pull out the psu and check everything. Then going to pull the pcb and reseat all the chips and check the solder joints.

the 10.3v is unregulated from the power brick. disconnect the power supply completely from the power brick and test that. if you aren't getting 10.3v  there then you need to figure out whats wrong with the brick. the power supply could very well be working just fine but without enough voltage the 5v regulator can't do anything.

I've tested the output voltage from the main brick at the fuses and I think everything is good there. At one point I got the symptoms of the regulator failure but my electronic store didn't have one.

Going to take out and isolate the brick and check "big blue" for its connection. Now when I look at the schematic for the power supply it shows brackets on two fuses showing one voltage of 36v.  If I check them one at a time they read 18 volts each is that normal? I should be checking both of them at the same time right since they are bracketed on the diagram. I'll post a pic.

https://www.dropbox.com/s/csemw6xakuq4gqa/Screenshot_2014-03-21-15-26-51.png

Ah okay I get what you're saying here. Can you take a look a my pic and see if I'm measuring the brick correctly.  I'd like to eliminate as I go. I wish there was a generic idiots guide to troubleshooting these machines.

No that's usually a line filter

Alright guys it's working!!!  ;D

All I did was take out the main psu and check all the connections which were good and put it back in and I saw the game on the screen. There is a slight possibility that the last time I just looked at the flashing buttons and didn't give the screen time to warm up  :-X Of course the buttons are going to flash when it's in free play  ;)

Anyways so if we're going to deduce any fix here it was the voltage transistor causing the issue. I still don't get why my voltage was only 4.2 volts vs the 5 that is should be at that test point. Maybe I should check it again. Idunno.

It's working great though. Thanks to all for your help here.

Amazing work!! I'm really happy for you! WOW!

Thanks John, amazing support from this forum made it possible.

Ian is the man!!

I didn't do crap, he ended up figuring it out on his own!

LOL! Well, somehow your encouragement helped him, I know it! :)

It's nice not being alone with these sort of endeavours. Gives strength to persevere.

I do this to all my ar2 psu's, keeps your edge connector from burning from overvoltage. http://www.stickycarpet.com/pinx/ar2mods.html might want to bulletproof while your in the mood for tinkering

Awesome thanks, will do that for sure.