I have a Gottlieb Volcano (system 80). EDIT: The Sound & Speech board was replaced sometime in the past with a B-20887-3 from a system 80A model PV810 (Caveman)

Ground modifications done. New electrolytic caps on most of the boards including the sound board. The big orange capacitor was replaced in the past.

95% of the time the game boots fine. For the other 5%, there are booting issues and the consensus seems to be that I need to do the CPU reset circuit modification. Parts on the way. EDIT: Reset modification successful and MPU booting issues resolved. This sound issue remains.

Meanwhile, sometimes I get a random sound from the sound board on the switch click for power up (and power down). Sometimes it's a groaning sound as you can hear for yourself in the YouTube video. Other times, it's just a hiss barely audible to louder. Whatever it is, it's never louder than the master volume setting.

When I add credits, start a game, or attract mode kicks in, the groaning or hiss immediately stops and I get the normal game sounds. The problem never occurs after the initial power-up.

The sound & speech board passes all the self-tests.

Could this be something flaking out on the driver board? Like Z3 or Z13? EDIT: Problem still occurs with driver board unplugged, effectively eliminating the MPU and Driver as the cause.

The power supply for this game's sound board is down in the main cabinet under the playfield. I have not seen anything about mandatory fixes, updates, etc. in Pinwiki or Clay's guides for this other sound board power supply.

I am open to any suggestions about how to fix this.

Thank you!

EDIT: This particular post seems to be a red herring. Problem occurs with Driver board unplugged.

I checked all sound outputs with logic probe on Z13, both after booting normally and during the buzzing. All outputs are the same under both conditions.

After checking further, problem somehow seems to be related to "Sound 16" output which goes through an extra connector.

Following the Volcano schematics for "Sound 16":

Z3 pin 7 output on Driver board
-> A3-J2 pin 9 leaving Driver board
-> A7-J3/P3 pin 6 Molex connector with 0.093" pins in head
-> A6-J1 pin 2 input on Sound card

After unplugging and plugging in the A7-J3/P3 Molex connector, the problem became less frequent. EDIT: Problem still occurs without driver board connected, which means A7-J3/P3 is not even in the circuit during this case.

What is "Sound 16" and why is it routed differently through the A7 connector when it simply ends up at the Sound board like the other 4 sound triggers? Can anyone explain this?

Thank you for the explanation.

The ground mod is correct and ground is solid, but I still had my doubts about all the connections and connectors for the signal wires. So I bypassed around each of them with jumpers. No improvement.

Then I looked down inside the cabinet. The power supply for the sound board has another Molex connector so I jumped the grounds off the sound board power supply over to the ground bus. Again, no improvement.

Finally, I noticed how the 110 VAC cord was routed...

110 VAC routed with DC signals

It's tied tightly to a bundle of low voltage signal wires that go up to the head! You should never route the AC supply voltage in close proximity and parallel with low voltage DC signal wires. It was obvious that when somebody replaced the original cord, they tied it off here with orange zip ties. If I'm wrong and all the Gottlieb system 80 games routed the 110 VAC bundled with the signal wires, please let me know... and then maybe add this to the list of modifications.

Fixing it as such...

110 VAC re-routed

Where it's unavoidable and the 110 VAC needs to be near the DC signals, it's ok to cross them over each other perpendicularly.

Since the cord was routed so poorly, I decided to check the hot and neutral wiring... again wrong. In the US, in a 110 VAC plug/outlet, the neutral side is the wide blade and the hot side is the narrow blade. If the wires are color coded, neutral is white, hot may be black or red, and ground is green. This cord is not color coded and the person who replaced it had swapped the hot & neutral. Thankfully, this machine does not bond the neutral to ground.

Swapping hot & neutral can be a huge issue in many circumstance. In this machine, this mistake means:

• the main fuse was on the neutral side so if the 110 VAC was accidentally shorted out, the fuse might never blow depending on return path
• plugging a tool with a metal case into the service outlet might give you a surprise
• the power switch was only disconnecting the neutral side so...
• the main transformers would ALWAYS have 110 VAC on one primary leg even when machine is off
• numerous random hazards, etc.

Anyway, I re-routed the 110 VAC and wired the hot & neutral correctly. The sound issue has improved tremendously. I think it may have happened one time before I found the hot/neutral issue, but time will tell if it's fixed for good. I may look at replacing the AC filter or installing some kind of internal surge protection as it's obvious now this sound issue is being triggered by AC noise on power up. I also plan on looking closer at the capacitors on the sound & speech power supply.

Problem still randomly happening.

On the Sound & Speech Power Supply, the 3 diodes, 2 resistors, and 2 capacitors checked out good.

I remounted the transistor and voltage regulator with fresh heat sink compound.

Sound and Speech Power Supply

I think the power supply is fine and all the voltages are within spec...

+24 VDC
-12 VDC
+12 VDC
+30 VDC

I also verified these same voltages at the Sound & Speech card to make sure the connections are good.

I'm going to get a new line filter just to eliminate any additional interference on power up. Does anyone have the Gottlieb part number for this? It's the very first device the 110 VAC power cord is connected to.

Line Filter

I don't even know how that's possible. As stated, the problem still occurs even when all connectors are bypassed and additional grounds in place.

When I have the driver board removed from the machine, the noise is still randomly happening on boot and only on boot. Grounds are jumpered and the only connectors in play are at the sound card and power supply for voltages and speakers.

With no driver connected, there cannot be any MPU triggered sounds. This problem only randomly occurs on boot and NEVER happens during play. IMO, bad connections are always bad connections and should also manifest at other times besides boot. It’s like something is only spiking on power up. For only $10 I’ll try a new line filter while I continue to troubleshoot.

Meanwhile whatever the issue, I can reproduce while the sound & speech board is completely isolated to nothing but the sound & speech power supply and speakers. To me it sounds like one of the speech patterns gets triggered and stuck at the moment power (spike?) is switched on. Is there any other clever way to troubleshoot or isolate?

I installed a new line filter from PBR today. I don't regret as the 40-yr-old filter was probably not doing anything.

Although it's happening more infrequently, this did not eliminate the issue.

So now what to look for? Again, it also happens while the driver board is unplugged, so that eliminates the MPU logic and triggers.

The four voltages from the sound & speech power supply are correct. Maybe the DC isn't smooth enough and I need new capacitors on the S & S power supply? However, the big cap on the S & S power supply looks the same vintage as the main cap on the machine, which is not the original. I just don't have enough experience with this, but it seems like a power issue since the problem only ever happens when clicking on the main power switch and it's immediate.

It's almost like the sound board needs its own anti-thunk reset modification to keep it from activating until after the power settles down.

Finally got around to re-pinning the connector on the sound & speech board. This seems to have cleared it up for good. Since problem was happening with driver unplugged, ruling out the sound triggers, it had to be a loose power connection causing an intermittent spike on power up. I powered it up about 20 or 30 times in a row without one single sound being triggered.

Spoke too soon! This issue came back today.

• Fixed 110 VAC hot & neutral swapped
• New line filter
• All new Molex edge connector pins on A6-J1
• Solid ground verified
• Tested components on Sound & Speech power supply in lower cabinet
• Tested all voltages on Sound & Speech power supply at A6-J1 connector
• Replaced all electrolytic caps on Sound & Speech board

Still happens with Driver board unplugged (rules out Driver and MPU). Sound & Speech board passes the test routines without issue.

This issue only ever happens on power up. Never happens while machine in attract mode or during a game.

Anyone with any more ideas, things to double-check, anything?

Please anyone?

Board was re-capped just prior to posting this thread - maybe 3 or 4 weeks ago tops. I purchased these (Changxin) from Marco Pinball. Just to note, it's the same issue both before and after changing these caps.

Changxin cap from Marco

I also replaced the C33 capacitor that was only rated for 25 volts, in the 30 volt part of the circuit, with a 50 volt version.

Oh boy... so the capacitors I recently got on Amazon were factory-reject Chinese junk... sent back. I figured I could trust Marco. The caps I got from Big Daddy are JNC brand, which are also Chinese. The fuses I got from PBR looked like they were previously used in a machine (PBR blamed Chinese manufacturing). Does anyone manufacture caps outside of China these days? EDIT: Rubycon from Japan

Capacitor brand aside, any clue how I can narrow the troubleshooting down? I assume there's something on the board that is being extra sensitive to a spike on power-up. Or the sound & speech power supply itself is due for new caps?

Yes, thank you. I realized this after my last post.

Any idea how I can troubleshoot this further rather than just throwing more capacitors at it?

If original I would replace without hesitation, but as mentioned previously, they're not. They were replaced when big orange main cap was done. So it would just be another part$ guess. I’m looking for some analytical troubleshooting help. Even if I borrow a scope, I’d need data to compare. Thank you!!

With all the system 80 games out there, and all their old caps, isn’t it odd that nobody else has been here on Pinside reporting a similar problem? Especially since rebuilding this particular S&S power supply is not covered in the PinWiki, this should be a very common issue if caused by aging caps. Just thinking out loud. Appreciate the help.

I did a little more troubleshooting...

I confirmed the noise being generated is from the "speech" section of the board. The two trimmers on the board control the volumes separately...

•  R15 is the "sounds" volume
•  R16 is the "speech" volume

While the problem is happening, the volume of the tone can only be changed by R16. The sound from the YouTube video as well as the quieter hissing... both controllable only by speech volume.

So I overlooked C36... going to change it right now. Not sure how I missed it... a big electrolytic... 470 µF, 35 volts. I don't think it will solve this issue because it's on the output side of the amplifier, while this sound problem is coming from somewhere in the speech circuit.

I also toggled all of the S&S DIP switches several times to clean as suggested in Clay's guide. Not sure if this did any good yet.

It seems that both PinWiki and the other guide focus on problems such as missing sounds, missing speech, no amp, triggers from the MPU/driver, or no sound at all. There's really no information in there about troubleshooting spontaneous speech sounds and false triggers when the driver is unplugged.

As predicted, changing the C36 capacitor made no difference, nor did "cleaning" the DIP switches. Nor did tinning the bare copper on the edge connector.

Really hoping there's somebody who has seen this problem before and can shed some light on this.

Thinking it's a spike or noise on power up, I methodically jumped a 4700 µF cap to each voltage on the sound & speech power supply... one side to ground and the other to power... and this made no difference. Same sound.

Then I visually inspected the big caps in the cabinet. Besides the "big orange" on the 38 VDC (which is not orange - had already been replaced at one point), there is another called C1 on the 12 VDC rectifier. This one has definitely been replaced at some point, but it looks pretty old. It was too big for the original mounting clip so you know it's probably something even older that somebody pulled off a shelf or recycled it from who knows where. This is the 12 VDC that goes into the main PS in the lightbox... the same 12 VDC that is used to generate 5 VDC for logic and processors including the sound & speech board circuits. EDIT: As per PinWiki, the 12 VDC capacitor is a.k.a. "big orange". I was confused because my C1 is not in same position on the board as the PinWiki photo.

As a test, I jumped in a cap from 5 VDC to ground and I still have the issue, but now it's changed into a completely different sound. Remove the cap and the next time it happens, it's back to the original problem sound.

I think I'm finally on the right track and here's my latest working theory:

I already know the sound is being generated from the speech circuit. The 12 VDC that powers the SC01 voice chip is coming from the sound & speech power supply - ruled that out. The 5 VDC, however is coming from the main PS, which is generating it from the 12 VDC that is being conditioned by questionable C1 in the lower cabinet. This is the same 5 VDC that is used to generate the various spoken words. I don't think it can be coming in through the U13 logic chip since the processor hasn't fully booted, this spike must be coming straight through the RP1 DIP resistor package and the SC01 voice chip is converting it straight into speech - which actually sounds like a long deep groan. Ironic. LOL.

Again, once powered up, sound & speech operates perfectly fine, so another reason to rule out any of the logic chips.

speech circuit

For sure I am going to replace C1 in the cabinet and probably the other two or three caps just to be sure.

Like I said before, what I don't understand is why this wouldn't be a more common issue with all of the sound & speech machines before these capacitors are replaced.

EDIT: As per Clay's Guide:

This is where the designer of this board was seriously off his face. It’s really quite clever but unnecessarily complex compared to what modern machines use.

This circuit all revolves around the now defunct SC01A chip (U14). This chip produces phonemes (I had to look this word up)- basic units of speech. Vary the clock frequency to it (Pins 15 & 16) and it speaks- Wow! It can also produce sound effects the same way.

See the diagram where I’ve outlined the sections of the board and look at the speech output section. Basically two latches (7475 – U11 and U18- controlled by U10) receive data from the MPU , pass it through a DAC (U19) which converts the signal into a proportional current. This then passes through a frequency adjust LM741 (U21), a couple of transistors (Q1 and Q2) then into the speech chip (U14) at pins 15,16. This is the variable clock signal for the speech chip. The pot R16 controls the speech volume. The R6 is a "frequency adjust" pot, and R13 is an "amplitude adjust" pot.

Data is also sent to the speech chip from MPU to the Level Shift 74LS05 (U13), pulled up by a Dip resistor (RP1) and into pins 9 to 14 of the speech chip.

Voice and effects pitch is varied from the MPU by making Pin 13 of Latch 7475 (U9) high then transferring the data to U12 then onto Pins 2 & 3 of the speech chip(U14).

Yes, yes. As soon as anything triggers a sound the groaning noise stops.

• Adding a credit
• Starting a game
• Attract mode

Then it’s perfectly fine, no matter how long left on, until some random future power-up of the machine. (You can sometimes hear the same sound for a split second on power-down as well.)

It’s simultaneous with the mechanical action of the switch. I’ve also made it happen by plugging in 110 VAC power with switch left on. Definitely seems like a power spike.

EDIT: I have all five of the cabinet capacitors on order from Mouser... C1 through C5... that's C1, C4, and C5 on the main cabinet board and C2 and C3 on the sound & speech power supply. I've owned the game since 2012 and the person before me had it for more than a decade. I believe these caps were changed sometime before the previous owner got it... probably when it was pulled from the arcade... so maybe 20-25-30 years ago? As far as hours of time on the caps, that's impossible to know because I didn't use it at all 2013 through 2020. It's a worthy investment but just FYI on electrolytic caps... yes, they have a rated number of hours that seems low, however that lifespan rating is based on their max temp rating... 85°C (185°F) or 105°C (221°F)... there is NO WAY the cabinet air temp or the caps in this cabinet are ever going to see 185° let alone 221° F. And for every 10° C below the max temp rating that it runs, the rated number of hours doubles. Pulling out crappy caps from machines that spent years in arcades decades ago makes tons of sense.... pulling them out of a machine that already had all caps replaced after it came out of the arcade and then sat in a residence getting played occasionally... I'm not so sure. In my case, C1 looks really really old even though it's not original... and while I'm ordering one, might as well get all five for a few more bucks. They're all reputable brands that meet or exceed the specified voltage rating, have a case diameter that fits the existing metal clip, and have the same kind of electrical connection. Plus as per PinWiki, I upgraded C1 from a 6,800 µF to a 12,000 µF so it should be extra smooth and creamy.

I changed C1 today. That's the capacitor formerly known as "big orange". I upgraded to a 12,000 µF from Mouser. Not only selected for capacitance, voltage, and brand, I carefully selected one that also had the physical diameter to properly fit into the original holder clamp.

After testing C1, I went ahead and changed C2 through C5 as well... so that's all caps in main cabinet including the sound & speech power supply.

Seems to be working great, and so far, issue is gone. Time will tell.

Again, quite perplexed about why not more people with sound & speech are reporting this issue if caused by the famous orange capacitor.

Yes, that is a given. Or in my case, the cap was actually changed once before, so I blindly assumed it was fine... *shrug*

Thank you guys... I feel a lot better about it now.

Makes sense. DIP switch #5 is the toggle for background sound and #6 is the toggle for speech.

Which revision of the sound & speech board does yours have? Somehow mine ended up with the latest, B-20887-3 (revision 3). Does not match the Volcano manual... had to track down the correct A6 schematic from the "Gottlieb Star Series System 80 Service Manual"

Or another theory... because it wasn't the C1 capacitor causing the issue, or any capacitor apparently, since now I've changed all of the electrolytics, plus a few other kinds.

Unfortunately, the problem came back today! I don't know whether to laugh or cry, and I hate blindly throwing parts at a problem.

Or it's still the C1 capacitor because a 12,000 µF Nichicon just isn't good enough?... no idea. Maybe it's time to borrow a scope?

At some point in this game's life, somebody replaced the original sound & speech board with the latest revision: B-20887-3

This is revision 3 and it does not contain any components soldered to the back like the previous revisions.

Unfortunately, my Volcano manual only contains the revision 1 layout and schematic that came with the game. I obtained the B-20887-3 layout & schematic from the "Gottlieb Star Series 80 Service Manual".

Since this is the 3rd revision, some components have been moved around, added, or designed out such as C35. It's still shown in the bill of materials, but C35 is not in the schematic, and the holes are filled with factory solder. Also, RP1 DIP resistor bank is listed as a 222 (2,200 ohm) ... however, the actual component on the board is a 102 (1,000 ohm). So now I know not to completely trust the bill of materials or schematics.

When troubleshooting the original issue further, I noticed that the space on the board for capacitor C22 is empty, the holes are not filled with solder, but yet it's showing on the rev 3 layout and schematic. It's listed as a 300 pF "CMD" (ceramic metal disc, I presume).

It's part of the clock circuit for the speech chip. I don't know if this missing capacitor is the root of my issue, but if it's supposed to be on my board, I'd like to install one there and rule it out.

Since I don't completely trust the schematic, can somebody with the same revision sound & speech board (B-20887-3) please confirm whether or not C22 exists on your board and if it's a 300 pF ceramic disc. Thank you!

C22 on sound and speech B-20887-3

clock circuit for speech chip

I would agree. Just trying to confirm the value listed in the documentation is correct.

The main problem with the PinWiki photo is the same as the schematics I obtained... both show part number the same version 3 board. However, the DIP resistors, RP1 on the PinWiki board is 2.2 kΩ, and the RP1 on mine is 1 kΩ ("102" = 1, 0, plus 2 more zeros)

RP1 = 2,200 Ω

RP1 = 1,000 Ω

I know... everything in documentation says 2.2 kΩ. Both RP1 and RP2 on mine are same chip... 1 kΩ

It sure looks original (see closeup photo of my RP1 and examine solder job). My sound board is really clean and looks the newest and cleanest out of all the boards in the machine. Until I changed the caps, all the solder looked original and untouched.

Notice the Bourns logo and part number on my chip: 16-2-102. This matches the Bourns numbering scheme as per their datasheet. The Gottlieb bill of materials also uses a Bourns style part number (4116R-002-222), but the PinWiki photo shows a DIP that is a different brand and numbering scheme. My guess is there's yet another version of the revision 3 board, and there may be even newer schematics out there in a specific game manual. How many Gottlieb games used these B-20887-3 sound & speech boards and what/when was the last one?

According to PinWiki "PV810" is Caveman... my board came from Caveman... since Caveman is system 80A, maybe that explains the discrepancy in certain parts?

serial number on A6

Issues now:

• How to verify C22 (I'll probably just try a 300 pF)?
• How to get proper schematics to match this version of board? Anyone have a Caveman manual?
• Does C22 have anything to do with this issue (try it and see)?

It's crazy. These resistor DIPs are a real mystery. Since my previous theory was a spike coming into the phoneme triggers from 5 VDC through these DIP resistors, maybe this is an important issue after all?

Regardless, I think getting C22 back onto the board would be a good idea. Maybe once I get my hands on the A6 schematic from Caveman, I need to carefully trace out my board and compare component by component.

I presume that's the issue. When I clip a capacitor onto the 5 volts, the groaning was still randomly triggered but it changed to a different phoneme.

I put the reset generator modification on the MPU and the Driver. This groaning issue was happening before. It also happens with the Driver board unplugged so that completely rules out any sound triggers from the MPU through the Driver. I also looked at the voltages coming from the sound & speech power supply and they are all testing good. Capacitors added to these voltages for filtering had no effect on the problem.

Yes, all pins measure 1,000 Ω

I will definitely have to investigate this idea... unfortunately, I cannot find the scope I knew I used to have.

The clock frequency adjust pot controls the pitch of the speech. When the speech started sounding like chipmunks, I touched this pot and got it slowed down a touch and it started sounding normal again. So not entirely sure that changing this frequency would let transient noise through. No idea though.

Maybe C22 is critical for this? I have to see if I have any 300 pF caps handy.

Thank you!

After reviewing the Caveman schematics, the RP1/2 mystery remains. The layout and schematics from the Caveman manual appear to be identical to those from the Star Series 80 service manual. Same value for C22 and also shows a 2.2 kΩ value on RP1/RP2.

C22 is listed as a ceramic metal disc, CMD, valued at 300 pF without giving a voltage rating. I dug through my stash... the closest I found were a 100 pF and a 220 pF. Wired in parallel, those would be equivalent to 320 pF. Less than 7% over 300, close enough I think, especially since there's zero farads there now. Lol.

I won't have a chance to get to this today. Then it's going to take a day or two to see if C22 had any effect.

No, RP1 and RP2 are original to this board and both testing fine.