The auxiliary power board supplies the voltage to the sound board. I would replace the LM340T ( or 7805). this is the +5 volt reg. Also the op-amp MC3403 (or LM324AN or NTE987) can be blown. Double check all your connections!!!

Looks like the 7805 has a lower amperage. I get all my parts from digikey. Heres the link:

http://www.digikey.com/product-detail/en/LM340T-5.0%2FNOPB/LM340T-5.0-ND/6237

Here is the datasheets for both:

http://www.ti.com/product/LM78L05

http://www.futurlec.com/Linear/LM340T-5.shtml

If you click on the datasheets it will show you the different versions of this part. The link was to the part you are looking for, just add the quantity.

You can start with a new POT as it should be replaced anyway (and check the male connectors at both ends of that board) but/and I might be wrong but I had a similar problem on a Rock Encore. Ended up being a couple of things but the main problem was one of the sound chips was bad and the other unstable. My recommendation would be to send it to coin service technology in Bensalem PA. When it comes to sound fixing is a lot more complicated than a cpu or driver. There is a couple of transistors on the driver board that activate sound but I don't remember what they are off the top of my head. GL.

Rock Encore is a System 80B so different sound architecture than Sys3.

You are supposed to get a dual screech on power up on a Sys3 - that tells you the sound boards have booted. If you don't the sound hasn't booted. Sound needs +5, +12 & -12 volts to work. The 5v comes from the main A2 power supply and the 12v comes from the A5 aux power supply. Make sure fuses F10 & F11 are good. They provide the 12.6v AC for the aux power board that gets rectified into the +12 & -12. Make sure you have +12 coming out of pin 10 and -12 from pin 5 on P1 on the aux power supply.

Once you know the voltages are good turn on the game and see if the LED on the sound board flashes. If it doesn't then it's either not receiving or responding to the reset signal from the MPU. You can manually reset the sound board by pressing the reset button on it. If it resets, reseat/change the cable between P4 on A1 and P1 on A6.

If it boots but still no sound, before you change VR2, check and see if you're getting source 5v at pin 1 of U10 (serial DAC.) If that's ok I'd suspect VR1 as the culprit.

Also check the connector on the A26 game control board as well as the volume control on it. Hope this helps.

viperrwk

_{Post edited by viperrwk : Added more info.}

I'm an idiot...sorry. Don't know what I was thinking.

Is ok - half the time I don't know what I'm thinking either. The other half I ask myself the question "what was I thinking?!?"

I should clarify this for people reading this in future searches (and I think justjoe knows this anyway.)

The +5v provided from A2 is for the logic side of the sound boards. If this voltage is off, the boards won't boot.

The +12 is regulated to 5v by VR2 on the A20 aux sound board and is used as the reference power source for the U10 DAC (which is fed data from the U9 sound chip) and to power the U1 speech chip. According to the datasheet for the DAC that voltage has to be between 4.75 and 10v with 5v as standard in order for the DAC to operate.

+12 and -12 are used to drive the op-amps which are fed from the sound chip/DAC and the speech chip.

So if the boards boot (blinking LEDs) you know your logic 5v from A2 is good. If your F10 and F11 fuses are good your aux power supply is getting what it needs to convert to +12 and -12. And if you have the last two going into A20 but still no sound then chances are the problem is on the aux sound board.

viperrwk

Pull the fuses to check them. Do not check them installed. I also give them a little twist on the ends to make sure they are attached to the element.

What you've outlined to check the voltages is fine. It will be tricky to get a probe in the back of the connector but it's better than risking shorting the regulators by measuring the output on them directly.

Also, if you don't have caps at c22 and c25 you can measure +12 on the plus side pad of c22 and -12 on the minus side pad of c25. Manual lists c22 as optional.

viperrwk

When you power up the game and the light locks on, does pressing the reset button get it going without fooling with the voltage? A1 has to reset A6 at power up. If it doesn't but pressing the reset button gets it going, the problem is in the reset circuit from A1 to A6. If the reset button does nothing the voltage at A6 is suspect so you need to check 5v at the sound boards - you might be getting a voltage drop from the PS to the two of them which is why it's not booting when you have 5v on P1 on the MPU.

Also you can crank the voltage up to 5.15 and leave it and then power cycle to see what happens if the boards boot at that voltage level - you're only 3% above 5v so you're ok.

Check the source 5v on pin 1 of U10 on the aux sound board. If that's good the 5v regulator (VR2) on that board is ok. If not, that's what you need to change. Rereading your post, since you said speech is ok but not sounds, and you didn't get the tones, I don't think this is the problem but perhaps either the U9 sound chip or the U10 DAC or both are fried. If VR2 is dead you wouldn't get speech or sounds.

viperrwk

You're looking at Digikey's part number there. The parts have identical function, but the second part you list is actually LM340T-5.0-NOPB. The NOPB is a lead-free part. Normally a lead part is preferable because it will solder better. You can use lead-free if you have to.

For future reference, Digikey sells identical parts in different packaging, as below. They will have different Digikey part numbers, but identical manufacturer part numbers.

For Hobbyists:
Bulk (Loose parts, small or large quantities)
Cut Tape (Parts on a strip of tape, small quantities)

For Manufacturing:
Digi-Reel (Costs Extra. Custom reel for automated processing.)
Reel (Full Reel for automated processing.)

VR2 is not your problem. It's either U9 or U10.

But first you need to get to reliable booting of the sound cards - need to check the logic 5v going to those boards. Check 5v on pin one of P1 on the Aux Sound Board and pin 5 on P2 of the sound board. Also check for +12v on pin 4 and -12v on pin 3 on connector P2.

viperrwk

OK - crank the voltage up again to about 5.15v and boot the machine. Do you get the dual squelch? Do the LEDs blink?

Don't press the reset button.

Start the game - do you get any sounds? Do you get speech? Are each ok or is there a problem with either/both?

Is the U10 DAC or U9 sound chip getting really hot?

When the sound and/or speech goes out or becomes garbled, check all the voltages again to see if they are in spec. If they aren't that will need to be addressed. If they are I'm guessing U9 or U10 on the aux sound board will need to be replaced. You can get those from arcadecomponents.com - $9 for the sound generator and $5 for the DAC. A new aux sound board from PB Resource is $71 by comparison.

viperrwk

At the end of the first video when you measured the voltages had the boards stopped blinking again?

Did you measure the 5v at pin 1 of the DAC at the end of the first video?

If the LEDs locked on and you still had 5V @ the DAC, I'm thinking the problem is U9 or U10 for a couple of reasons:

1 - when you turn it on you're only getting one screech not two.
2 - when you play the game you're getting callouts and some sounds but never any music. I'm guessing the speech chip does some sounds in addition to speech.

Last thing to try: reseat EVERYTHING (ROMs, connectors, ribbon cable between sound and aux sound esp.) If that doesn't solve the problem (I don't think it will) then you'll have to replace U9 and/or U10. I'd go with U9 first since speech is ok (I'm guessing you didn't fry the DAC.)

BTW the 74HC123 at U11 on A1 is part of the watchdog circuit for the display digit strobe and lamp strobe and for low voltage. It shouldn't come into play here.

viperrwk

I've been following this thread because I also own a Stargate. Sadly it appears that chip is out of production, but fairly high demand. You should probably start a separate thread looking for the chip.

Be careful buying chips from China. You can't really be sure what you're getting.

This is the best I can find right now:
http://andysarcade.net/store/index.php?act=viewProd&productId=1366

Seems like you're on the right track. Glad you have it under control!

There's something unique about the sound chip used in the Gottlieb but I can't remember what it was or if there's something special you need to do.

No worries ordering from Big Daddy - just hope it's the right one.

viperrwk

That sucks and is annoying too! Damn!

If it wasn't U9 then it should be U10. Clock output exits from U9 to U10 and if it doesn't respond properly the data gets backed up in the sound chip and then hangs.

For now I think you're doing the right thing by getting a new board. I still think the problem is on the Aux Sound Board and when you get a new DAC, can swap that in and see if that fixes it.

Dammit - if I were closer to you I'd come over with my boards to confirm where the problem is!

Just checking - you reseated the ROMs on the main sound board? That's where the data comes for the game sounds.

viperrwk

P3 is the audio out and volume control from the front panel. P1 are your +5, +12 & -12 in. Not sure what happens when you try to boot with those two disconnected. You should double check that -12 is getting to the amps at U7 and U11 on pin 11. Beyond that, all you can do is wait.

viperrwk

Pins 4 & 8 are analog ground, pins 5 & 6 are DC ground and pin 7 goes to U3 pin 12.

viperrwk

I've got a Stargate making a loud hum in attract too, seems to be specifically coming from the main cab speaker.

I actually have two machines, I think they both do it - the second one is in bits at the moment but I should be able to get an answer for you tomorrow when I hook the looms back up. The boardset from the second machine is currently sat arranged around the one in my lounge.

So far from swapping boards around and disconnecting others:

It's not the aux power supply.
It's not the aux sound board.
It's not the sound board.
It's not the driver board.
It's not the dot matrix board.
It's not the CPU board.

So on the upside, all the above is ruled out (or has a problem in both cases which seems unlikely as the magnitude of the problem has not changed during any test).

Actually I'm expecting it to be related to the power supply and grounds.

Hooked the other machine back up.

Exactly the same, and I mean exactly.

+1.

My machine has the ground mods outlined on Pinwiki, but still has the hum.

I was looking for info on the quad optos earlier, and I found this video:

Aside from the freakish heavy breathing, something else is clearly to be heard. I'm going to write this off as an irritating non-problem.

One other thing you may try: replacing the LM7809 voltage regulator on the Aux Sound Board. The pinrepair guide had this as a solution for the constant hum. Even though the VR tested good, replacing it fixed the problem.

Makes sense it was the main sound board after eliminating the aux sound board. Trick now is finding the problem on the main sound board!

viperrwk