BLACKOUT Audio ? Repair ?

RJ

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I recently picked this pin up and have started to dig into the problems

When I go into the audio test mode I can barely hear the audio coming from the speaker, as it cycles threw the sounds.
It looks like I have a bad audio IC.The audio IC is a 5 pin. It has a Motorola part number that I cannot seem to find a repalcement for. The machine dosenot have the audio extension board installed.(I am looking for one) I have checked the settings and the jumpers.It has the White Labeled Audio ROM.

The game powers up, I can go threw the test mode all of the lights and solinoids work. The displays work. I am able to start up a game, play it for a few balls and then it will stop and flash game over. restart a game and go threw all three balls.

The original owner indicated that he had sent the Driver board in to a place in Texas and they did an exchange.

On the main proccessor board the two 6810 40 pin chips were socketed and repalced by someone else(I reflowed the solder on the sockets. There is a 6808 in one socket and a 6820 in the other. I see the manual calls for 6810's. Were is a good place to pickup a pair?

When I depress the main board Diagnostis switch with the coin door open the lower Led stays on.

Someone has upgraded the caps on the Power Board and the Audio board. I have reflowed the solder on the edge connectors on the Audio, Power and Main boards.

The Main filter cap has not been replaced.

Thanks in advance for the Help

RJ
 
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If the sound is there, but quiet, it narrows it down a lot. I assume you already adjusted the volume control inside the coin door, and spun it around a bunch of times to clear off any carbon? The next option is IC1, whic is a TDA2002V audio amp. No longer available at all, but there is a valid substitude. Get a TDA2003V, which Great Plains Electronics has in stock. Same basic part, but with 10w output instead of 8w. Won't be available much longer, so snag it quick. I know that Kohut makes new production sound and speech boards, good price too.

Is the whole machine resetting, or it's just ending the game? If it's resetting, there's a few possibilities. The slam tilt may be too sensitive, or the 5v circuit may be dropping out. The tilt is easy to adjust. But what is your 5v reading with a DMM?

To fix that restart problem, you're going about it all wrong (randomly). You don't need to replace the 6810's, if they were dead the game wouldn't run. That LED pattern indicates one of the EPROM's at IC14, IC17 and IC20 are failing a checksum test. Resoldering the connector pins is good, but I wouldn't mess with any chip pins if you don't have to.

-Hans
 
Parts

Thanks Hans
I ordered the parts from Great Plaines. I was not able to find the Kohut site. Interesting search on Google though. between nuclear theory and psychology.

I will have to take a look at the 5 volt line.

I believe I have someone who can burn me a new set of Eproms down the road after the first wave of problems is fixed.

thanks again

RJ
 
If it's going to game over in the middle of a game check your flipper diodes.
 
Thanks for the Link.

Thanks for the flipper diode tip. I will have to dig into that when I pick up a flipper rebuild kit and several boxes of bulbs from Terry at pinballlife. Along with some leaf switches and flipper buttons.
I allways end up buying more than I have on my list, when I go there.

I am going to replace the 2 diodes that feed the 5 volt section on the power board and the 5 volt regulator. The 5 volt line is at 4.89 vdc. the unregulted 12vdc line is at 11.87 vdc.
Given the age of the machine I am also going to replace the two bridge rectifiers, not sure if it's worth replacing the large filter cap. I have a newer Big Blue (Atari) sitting round.

Thanks Again for your Help

RJ
 
That big filter cap, the size of a "Big Blue" has nothing to do with power filtering, it's just a bulk capacitor for the playfield lamps. The main 5v filter cap is on the power supply board.

Unreglated 12v is fine at that voltage, it's really anything over like 7v is all it needs. The 5v is a touch low, but not drastically out of spec. What voltage are you seeing at the 6808 on the CPU board?

-Hans
 
Blackout

I had a DVM clipped to the test point above the 6810's and I had a reading of 4.90 vdc.
The meter was left in place while I played a game and watched the meter. No change in voltage when the machine decided to end and flash game over. Do I need to use an analog meter to catch any sudden dips in the 5 volt line? When the game quits the ball had not made contact with anything and I was not leaning on the flipper buttons. It looks like the caps were replaced on the Power Board. I am going to check them with my Cap checker.

Not a bad price on the Voice Audio board from Kohout. When I get done fixing the other problems and the game and it has sound and is not resetting, I will have to order one.

RJ
 
Any extra buzzing or other noises that happens when it resets? Does the TILT light come on on the backglass?

Have you checked if the slam tilt on the coin door is too sensitive?

-Hans
 
game reset

I fixed the reset. I installed a lock on the coin door and now it dose not open up ever so slightly. I believe it reset the game. mmmhhh odd to me. The Diodes and the Bridge rectifiers got repalced along with the 5 volt regulator.

Now I need to move onto some playing field repairs. A few of Green arrows are sticking up on the playing field. A couple of the lane plastics are broke. The 2 metal posts behind the flippers are missing.One hole is loose were a post is mounted. I was going to use a light wood color wood putty, fill the hole and re screw in the post.

A Couple of the playing field plastics need to be slowly heated up and pressed flat. I have rebent plastic pieces in the past, but I am not sure how to do this without messing up the paint on the backside.

RJ
 
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A Couple of the playing field plastics need to be slowly heated up and pressed flat. I have rebent plastic pieces in the past, but I am not sure how to do this without messing up the paint on the backside.

RJ

heat gun (not too hot!) and then press in a book or in between books.

or put the oven on low (200-250) and put them on a piece of plain paper on a cookie sheet - keep a close eye on them and when they go flat pull them out immediately and press in a book or in between books.

or, put them between two pieces of glass and put them in the sun.

if you search threads on the forum using keywords like plastic and oven you'll find several old threads on how to do this.
 
Slam tilt

Door opening causing the reset? Guess where the 'slam tilt' is mounted :)

I do not recall seeing one. I thought they were mounted using the lock as a holder There was a lock installed but no key.

There is a white Spring loaded switch, that is mounted on the upper right of the coin door frame. Will that effect the play of the game? cause it to reset when the door opens during play?


I will have to give the plastic tips a try next week.

Thanks for the help

RJ
 
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