So, I haven't had sound in a while on my GTB Raven https://pinside.com/pinball/forum/topic/raven-no-sound
It used to come on every once in a while, but it played the wrong sounds or sounds that didn't belong in the game. Haven't heard anything in a while.
In a topic about logic probes, cody_chunn & wayout440 mentioned using a DMM to measure logic states, so I tried it last night.
First, I unplugged A6P1, turned it on, started a game & measured the pins on the connector. I got P1=3.46; P2=3.49, P3=0; P5=3.8; P8=0.67 & P9=3.95. However, measuring P18, the audio out, I got 0.
I also checked the 5v power supply & it was fine. On the aux. power supply, I measured between P2 & P3 & got 0, gnd to P4 = -0.13 & P6-P7 3.2. I don't think that it's the problem anyways, since the reset & test buttons on the sound board produce bongs.
I also randomly test caps on the SB. C6 = 0/11.46; C9 = -12.25/-0; C8 = 12.73/0; C10 = 12.73/0.01; C18 = 5.12/0.01; C19 = 0.01/-12.25; C20 = 2.15/0.15 & C27 = 2.15/1.6.
The problem is I have no idea how to interpret these readings or where to go from here. To me, the no audio out signal from the SB means the problem's on it. Any thoughts?

Crap. Read about checking caps & they have to be removed from the circuit. That's beyond my skill & there's a boatload of them.
What I did was stick the black probe in the ground pin of the connector & touch each side of the cap.
Anybody have an idea of what I should do next? There's an electronic supply/repair place in town, but they don't diagnose.

I printed out the spec sheets for Z12 & Z13 on the driver board. Pin 8 being the only one that's low bugs me, but maybe it's supposed to be that way. I'll try to check the logic states tonight.

Yep, the light blinks & both button produce beeps, but there's no sound.

Allllllrighty then.
I finally checked the logic on Z13 on the driver board (you get used to playing with no sound).
Leg =0.16; Leg 2=2.34; L3=0.16; L4=0.49; L5=0.12; L6=5.08; L8=5.08; L9=0.16; L10=3.97; L11=0; L12=3.99; L13=0 & the Vcc=4.99.
Legs 3 & 4 both being low, it looks like I need to have Z13 replaced, correct? Would this cause no sound at all or just the loss of one sound?
Any Gottlieb experts know if the rest look okay or if I should check other chips? KenLayton ? ChrisHibler ?

Afternoon bump

Thanks Chris, I'll check it tonight.
Here's a crop of the Z13 schematics.

Driver Z13a (resized).jpg

I checked Z13 as you suggested & this is what I got.
L1=-045; L2=-319; L4=-247; L5=365; L6=-349; L8=-348; L9=-045; L10=-344; L12=-344
You can understand my confusion. I have no idea what these numbers mean. Mind you, I have a cheap DMM.

It's a Canadian Tire meter. Can't find it on the website, but my neighbour just bought one, so I'll get the model number tomorrow & try to find it. I think I paid about $30 CAD for it on sale, regular $50.
I'll see if anybody I know has a better one.
Side note: it has a signal insertion function. What's the purpose of that?
Thanks for your help!
Edit: I tried using the diode mode on the MPU chips, couldn't understand the readings & ended up shot-gunning it. I've read a lot the last year and a half & really want to diagnose this properly. It would be sooooo satisfying.
Edit #2: Should I be measuring with the power off? I measured with it on.

I'll try again tonight.
Thanks.

Chris, I checked it with the power off & this is what I got:
L1=600; L2=031; L3=599; L4=016; L5=599; L6=423; L8=424; L9=599; L10=582; L12=589
I'm assuming my DMM doesn't display the decimal point & 016 is 0.16
So, is the chip bad since L2 & L4 are so low?
Edit: Just saw that you had said power off. Duh.

No, the board wasn't removed. I'll pull it & test it tomorrow. Thanks.

I checked with those connectors unplugged & this is what I got.
L1=717; L2=578; L3=716; L4=015; L5=572; L6=574; L8=578; L9=711; L10=577; L12=586
So, I guess the chip's bad? There's a local place, NuTech, that does good board work, except they don't diagnose. I'll call them & have the chip socketed & replaced.
Interestingly, the sound came back on Friday. It started playing random sounds that didn't belong in the game & then started constantly playing the game play music. Haven't heard it in months. It stopped when I turned it off & on though. It had been resetting due to the power connector on the MPU & I had moved the wires around. I think it was coincidence though.

Yeah, I've done the ground mods, replaced the 5v pot, the transformer rectifiers & re-pinned a lot of the single sided connectors with no luck.

I'm pretty sure I did but it was a while ago. I'll check tonight.

Do you meant the 40-pin connector between the MPU & driver board?

Thanks Todd, I'll check it out!

Well, I had Z13 socketed & replaced. Still no sound. I'll check the driver board & then concentrate on the sound board. Unfortunately, I don't have access to an eeprom reader.
Plus, now the lower right sniper doesn't pop up. Too big a coincidence to be a coincidence. I'll figure out which solenoid it is & track it down. One has a jumper wire on the driver board instead of a diode so maybe that got dislodged. I'll start another thread for that if necessary.
Edit: On a good note, they had left the chip for me to install so instead of pushing the legs against the table, I used the inside jaws of my digital vernier to measure the width of the holes in the socket, zeroed it, then put the chip in the outside jaws & used the roller to squeeze the legs until it read zero. Worked like a charm.

Dothedoo, I did that a while back in answer to you were in my other thread. I grounded pins 1, 2, 3, 5, & 8 and got no sounds. I'll do that again tonight though.

I had an ah-ha moment.
I was reading about grounding pins to try to get sounds to happen & then grounding pins on Z13 on the driver board after testing the SB, but didn't understand the first part. Then I read someone's thread somewhere about A3 on the sound board, so I looked at the schematics & A3 is the chip just before the SB output & I figured out that that's where I should be grounding the pins to test the SB.
I grounded pins 4, 14, 8, 13, 17, 18 & 3 on A3 & got nothing. I also grounded pins 1 thru 8 (that were used) in the A6P1 connector & got nothing. Pin 9, the reset, produced the bing sound.
I checked voltages before pulling the SB, but forgot how to check the chips with my DMM, plus football came on. I'm at work so I'll read up on checking the ICs & study the schematics to try to work back from A3 to see what other ICs to check.
Thanks for the help & the patience.

I checked A3 with my DMM & leg 4 measured low, my meter read 058, so I checked B3 & got the same thing. I then checked E3 as a comparison & leg 1 was low, so I checked A2 & leg 1 was also low.
I rechecked them a couple times & got the same results, so I don't think I'm doing it wrong. When I first had sound problems I re-pinned A6P1, but in my newbness, I did it backwards & didn't realize it before I turned it on, so I may have fried the SB. At this point I'm thinking I should just get another SB. What do you guys think?

Rats.
I'll ask around & see if there's any one around here with one to sell. A tech came over a year or so ago & he said he thought he had one, but he'd had a break-in & wasn't sure. I'll give him a call first.

Fellow pinsider erak brought his friend's SB over on Saturday & it's definitely my SB. Bought the board & now it's working!
I guess what happened was I re-pinned the connector backwards, sent 12v somewhere & fried the board. I thought it was working as every now & then the gameplay music would play. I then proceeded to chase my tail.
Learned a lot along the way & would do it differently now.
Thanks for everybody's help!