(Topic ID: 297299)

Solved: Gottlieb System 80 Sound & Speech - intermittent groan on power up

By sparky672

84 days ago


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There are 176 posts in this topic. You are on page 2 of 4.
#51 55 days ago
Quoted from frenchmarky:

Wondering if it was related to R1 or R2, how/why could it only cause the weird noise problem right after booting, but then as soon as the game is caused to make a legitimate sound or speech call, the problem completely goes away? If one or both chips were the issue, why wouldn't they cause problems all the time?

Exactly my thought. It’s behaving perfectly normal after first speech sound happens.

The issue seems to have been improved both when I re-pinned the connector and changed the C1 capacitor. But it’s still there. Happened about 25% of the time yesterday and today not at all. I’ll get something put in for C22 and give it more time to see if it’s going to come back.

As far as the circuit, I was reading a lot on pinwiki. Apparently pins 15 & 16 on speech chip are like a toggle. The phoneme inputs are there but supposed to be ignored until these pins come on. So maybe a 5 V spike is coming through the clock and activating the chip, where C22 is not there to clamp it. Just my latest working theory.

#52 55 days ago

Have you tried contacting Ed at GPE and asking him if he has any ideas?
He has helped me out in the past and he has knowlegde of the comoonents on that board as well as early SS Gottliebs.
He is on this forum or you could email him at Great Plains Electronics.

#53 55 days ago

Well I ain't no electronics whiz but ya gotta make a bet sooner or later, so... based on what you got there and what you read up on, I bet putting C22 back in there fixes it or I'll be a monkey's uncle. Those disc capacitors almost never fail, and it's supposed to be there and why anybody would pull it out for whatever the reason was and just leave it like that is beyond me.

#54 54 days ago

C22 on a clock line at this point does two things -- introduce slight delay (larger the cap, longer the delay) and filters out glitches on clock.
Never looked at this circuit before so my best guess would be the introduction of a delay.

As Frenchmarky - these rarely fail. BUT they can easily break off if manhandled.
Use a ceramic multilayer cap to replace. Most ceramic disc style caps are becoming obsolete and being replaced by better ceramic multilayer caps.

#55 54 days ago

Following

#56 54 days ago

UPDATE:

I flipped the A6 board over for another closer inspection. All solder appears factory except for my new electrolytics, DIP switch bank, and U16 (74LS04).

I installed my 320 pF equivalent (220 + 100 pF in parallel) ceramic capacitor in C22. What a weird turn of events. It made a strange oscillating or pulsating sound, very quietly, on power up. When adding a credit and starting a game, the game sound was barely audible and it was not even close to normal. Hard to describe, but the sound was way more screwy than simply pitch and volume.

Removing the C22 put the sound back to normal. Now we know why C22 was originally removed... but obviously, this was/is not the correct "fix".

#57 54 days ago

Maybe needs the freq, amplitude and two volume pots readjusted? Who knows if whoever removed the cap messed with them especially after he removed the cap. Gotta be some kinda genius that guy, "hmm the sound is totally screwed up so if I simply remove this one tiny cap here it will work perfectly except right after boot-up". What happens when you try adjusting the volume pots?

How about the speech? What do you get when you hit the speech board test button?

I cleaned the two volume pots on my BH awhile back and then the speech was kaput but found out the main volume pot on the speech board was toast, resistive trace inside had virtually dissolved away except for both ends.

#58 53 days ago
Quoted from frenchmarky:

Maybe needs the freq, amplitude and two volume pots readjusted?

I'm hesitant to mess with these. It did not simply sound like the frequency was low... it was like a super quiet pulsating sound that ramps upward in frequency and then holds. If it sounded anything like a normal distorted sound, I would try adjustments.

Quoted from frenchmarky:

Who knows if whoever removed the cap messed with them especially after he removed the cap. Gotta be some kinda genius that guy, "hmm the sound is totally screwed up so if I simply remove this one tiny cap here it will work perfectly except right after boot-up".

Exactly!

Quoted from frenchmarky:

What happens when you try adjusting the volume pots?

Both pots work properly. The volume pot for the speech is maxed out.

Quoted from frenchmarky:

How about the speech? What do you get when you hit the speech board test button?

That was never a problem. Board passes all tests... it's just this speech phoneme getting triggered on power-up. I've proven to myself this groaning sound is coming from speech circuit because it only responds to speech volume pot, and not the sound volume pot.

Quoted from frenchmarky:

I cleaned the two volume pots on my BH awhile back and then the speech was kaput but found out the main volume pot on the speech board was toast, resistive trace inside had virtually dissolved away except for both ends.

Both volume pots work... I turned up speech a bit, which is max, and put the background sound down a little. They seem to work/sound good when I turn them up/down.

I'm actually looking at U16 chip, which has been changed at some point. It's the 74LS04 inverter where these sound triggers come into the board. Keeping in mind that the problem also occurs when the driver is unplugged, I'm wondering if this chip is flaking out and passing noise internally from 5 volts to an output... of course that doesn't explain the issue that happens when I put C22 back into circuit.

#59 53 days ago

Don't know how typical it is on these to have the speech maxed out but mine is about in the middle (after I replaced the bad one) and I balanced the other pot with it. Plus if I turn the other 'sound' pot up too high it starts to sound overloaded, and the main vol pot in the cabinet would even get warm to the touch.

#60 52 days ago
Quoted from frenchmarky:

Wondering if it was related to R1 or R2, how/why could it only cause the weird noise problem right after booting, but then as soon as the game is caused to make a legitimate sound or speech call, the problem completely goes away? If one or both chips were the issue, why wouldn't they cause problems all the time?

Exactly my thoughts. I don't think it's RP1 or RP2, especially since the solder is untouched and original. Like you said, once it's powered up, everything works correctly. If I set the DIP switches to turn off attract mode, then flip game on/off quickly enough, I can trigger the problem and it should continue groaning indefinitely as long as I don't start a game. However, I'll need a new troubleshooting strategy first.

I'll be working 12-hour days at the county fair until Sunday so I will just pop in here occasionally to see what's posted. Otherwise, I will not be working on my machine until next week. Which sucks for me, because I finally got my Docent kit for the double-edge connectors. (This sound issue happens when Driver board is completely unplugged, so it's not any of those connections. And the connector for the sound board has already been re-pinned.)

Quoted from frenchmarky:

Don't know how typical it is on these to have the speech maxed out but mine is about in the middle (after I replaced the bad one) and I balanced the other pot with it. Plus if I turn the other 'sound' pot up too high it starts to sound overloaded, and the main vol pot in the cabinet would even get warm to the touch.

My settings were close to where they are now, before I touched them. Maybe ⅛ turn down on sound and ⅛ turn up on speech before it maxed out. The main cabinet pot is set on the low end, otherwise everything is too loud... and the amp hums on that high end... assumed that was normal.

#61 46 days ago
Quoted from frenchmarky:

Well I ain't no electronics whiz but ya gotta make a bet sooner or later, so... based on what you got there and what you read up on, I bet putting C22 back in there fixes it or I'll be a monkey's uncle.

I agree and made that bet too.

Today I incrementally added capacitance to C22... first 100 pF and I had to turn up frequency of speech circuit on R6 by ¾ turn cw. Added another 220 pF for a total of 320 pF and had to turn R6 cw another few turns. So now with ~300 pF on C22 as specified on schematic, the sound & speech is sounding normal again.

That's not the end of the story. After powering up 20+ times without issue, I was going to post moderate success here, but decided to give it a little more time. Well, the problem came back... brand new Molex edge finger pins, brand new cabinet caps, brand new sound board caps, brand new caps on S & S power supply, and a cap in place for the missing C22...

... what could possibly be next? Out of ideas again.

#62 46 days ago

Are the pots original?

#63 46 days ago
Quoted from PinballAir:

Are the pots original?

Yes.

All pots on the speech circuit are working though. They adjust what they are supposed to adjust and hold their setting.

#64 46 days ago

Decided to get this board under 10x magnification especially since my eyes don't work like they used to.

Found some mystery corrosion on two of the legs of the test button. It's weird... the only corrosion on entire board, but I'm fairly certain the test button has nothing to do with the issue...

test buttontest button

Overall, the board looks pretty good. Ignore C22; it's working but it's temporary until I order a new one.

A6 frontA6 rear

But on closer inspection, you can see that U12, U16, and U17 have all been changed. It looks like solder flow to the top traces of the board are not that great... either not enough solder or the joints have cracked.

U12U12U16U16U17U17

U12 feeds signals directly into the speech chip, and U16/17 take the triggers straight into the board and over to the processor. They all need to get fixed, but would like to know which one is causing the issue... I'll probably fix one at a time just to see when it resolves.

The question now is to reflow solder or remove & socket? Leaning towards reflow - less risky and presumably none of these chips need changing.

schematic

EDIT: U12 reflowed top and bottom... wait & see.

#65 45 days ago

As stated in previous post, U12 was reflowed front and back. The problem came back but at a higher pitch.

So then I reflowed U16 & U17, which should cover everything identified with cracked or missing solder.

No good. Problem is still there... back to same tone and pitch as originally posted. Problem goes away and stays away during normal game play and attract mode. Nothing has changed.

#66 45 days ago

The 7407 may have been changed as you say but it is dated 1980 which would make the swap very early in its life.

#67 45 days ago
Quoted from PinballAir:

The 7407 may have been changed as you say but it is dated 1980 which would make the swap very early in its life.

Yes, good point. But is there any specific reason to change it again? It would have to be intermittently creating/sending a signal only during power-up, and work perfectly fine during all other times. I'd like to be able to troubleshoot ideas somehow since I don't have any 7407 chips on hand.

#68 45 days ago

What value cap did you jump across the 5v that changed the power-up noise? Have you recapped the main power supply board in the head including C4 470uf which also goes across the 5v? Does adjusting the 5v pot a little up or down have any similar effect on the sound? Just wondering since jumping that cap on the 5V did at least have an effect on the noise.

#69 45 days ago
Quoted from frenchmarky:

What value cap did you jump across the 5v that changed the power-up noise?

If you're talking about what I did a couple weeks ago, honestly, I've done so many things I cannot remember... it was probably 47 or 470 µF

Quoted from frenchmarky:

Have you recapped the main power supply board in the head including C4 470uf which also goes across the 5v?

Yes. There are literally no electrolytic caps left to change in this machine. Not to mention the addition of electrolytics across the slingshot coils as per Gottlieb service bulletin.

We have beaten the capacitor issue to death... like stated previously, I think if caused by a capacitor the issue would be more common. But I've been wrong before.

Quoted from frenchmarky:

Does adjusting the 5v pot a little up or down have any similar effect on the sound? Just wondering since jumping that cap on the 5V did at least have an effect on the noise.

No. While troubleshooting an unrelated issue the other night, I noticed my 5 volts had drifted down from 5.1 to something slightly under ~5. I have a new pot on the power supply and it took quite a few turns to get it back up to 5.1 so that was slightly concerning - although I may have previously had it set to 5.05 volts... I don't recall.

But no, the voltage has absolutely no effect on speech sound. Whenever the problem occurs, it's the same tone as per the YouTube video in the first post. So my guess is the spike, transient, or errant signal is always coming in on the same chip pin. I wonder if there's a way to manually trip each line on the speech chip to see if i can duplicate the same erroneous phoneme.

#70 45 days ago

I’ve watch your video and this is a long shot. Try and remove all flasher lamps from the top box, the sound is syncronised with the flashes.

#71 45 days ago
Quoted from Mach1:

I’ve watch your video and this is a long shot. Try and remove all flasher lamps from the top box, the sound is syncronised with the flashes.

Hmmm... there are white bulbs that flash randomly and those are the flasher type light bulbs. There are also plain red bulbs that flash sequentially like a marquee in the outer box that are driven by a small flasher board. Which ones are you referring to?

I went back and watched my video again. I think the sound dropping out is just something with the video's audio. In person, it's that same sound but it's steady.

#72 45 days ago

<<I wonder if there's a way to manually trip each line on the speech chip to see if i can duplicate the same erroneous phoneme.>>

Okay but even if you could do that, you're getting a phenome sometimes, sometimes you got a hiss or a different noise, and the phenome changed when you stuck a filtering cap to the 5V. So sure don't sound like it is a glitch pertaining to one particular phenome.

Some interesting stuff in here, http://www.bitsavers.org/pdf/federalScrewWorks/Votrax_SC-01_Phoneme_Speech_Synthesizer_Data_Sheet_1980.pdf like a note where they say an "initial strobe is supplied to insure power up reset of the Acknowledge/Request output" and how the 5V should come up after the 12v does. Maybe it's not so much a spike, but something wrong on the speech board itself where the initial power up is not properly resetting the SC-01. Then attract starts and seems to finally 'reset' the sound board even though the start of attract mode normally doesn't do a sound effect. Experts - Is the MPU indeed supposed to do an initial reset of the sound board when attract starts?

You have to be an SC-01 expert I guess... with no sound line inputs, what could cause the SC-01 to not only say a phenome, but to where it is literally stuck on and continuously repeats it?

Those resistor packs are incorrect no matter what schems and boards were dug up, and by over 100% value difference, still suspicious about those, might they be involved in the speech resetting properly at power up(?) Or some other component involved with power up resetting it correctly?

#73 45 days ago
Quoted from frenchmarky:

<<I wonder if there's a way to manually trip each line on the speech chip to see if i can duplicate the same erroneous phoneme.>>
Okay but even if you could do that, you're getting a phenome sometimes, sometimes you got a hiss or a different noise, and the phenome changed when you stuck a filtering cap to the 5V. So sure don't sound like it is a glitch pertaining to one particular phenome.

Yes, all true... but the vast majority of incidents 99%+ are the same phoneme. Rarely a hiss, and I actually have not heard the hiss in a long time. Changing the phoneme required a capacitance change, which also affected the clock frequency. To me it seems like if it's one phenome, then it may be a defective logic chip that is passing a transient on power up. Again, I'm grasping.

Quoted from frenchmarky:

Some interesting stuff in here, http://www.bitsavers.org/pdf/federalScrewWorks/Votrax_SC-01_Phoneme_Speech_Synthesizer_Data_Sheet_1980.pdf like a note where they say an "initial strobe is supplied to insure power up reset of the Acknowledge/Request output" and how the 5V should come up after the 12v does. Maybe it's not so much a spike, but something wrong on the speech board itself where the initial power up is not properly resetting the SC-01.

This is good stuff... going to go read it now.

Quoted from frenchmarky:

Then attract starts and seems to finally 'reset' the sound board even though the start of attract mode normally doesn't do a sound effect. Experts - Is the MPU indeed supposed to do an initial reset of the sound board when attract starts?

Attract mode on this game is all from the speech side, AFAIK. Since setting attract to 10 seconds, I constantly hear "throw me a sacrifice", etc. The "add credit" sound also resets and removes the errant phoneme, but not sure if credit tone is from the sound or speech side.

Quoted from frenchmarky:

You have to be an SC-01 expert I guess... with no sound line inputs, what could cause the SC-01 to not only say a phenome, but to where it is literally stuck on and continuously repeats it?

Not really sure if it's considered a repeat or simply stuck on. My understanding is that a combination of triggers creates the speech, but do those triggers pulse on for the same length of time or do the pulses stay on to cause the corresponding phoneme to stay on?

Quoted from frenchmarky:

Those resistor packs are incorrect no matter what schems and boards were dug up, and by over 100% value difference...

For sure, and since closely examining the board's solder yesterday, am convinced they're factory original, which is super-weird.

Quoted from frenchmarky:

... still suspicious about those, might they be involved in the speech resetting properly at power up(?) Or some other component involved with power up resetting it correctly?

All great questions. Need a strategy to proceed.

#74 45 days ago

>>Attract mode on this game is all from the speech side, AFAIK. Since setting attract to 10 seconds, I constantly hear "throw me a sacrifice", etc. The "add credit" sound also resets and removes the errant phoneme, but not sure if credit tone is from the sound or speech side.>>

But the noise also disappears at the moment boot up is complete, i.e. start of attract, before and without any sound effects or speech being generated at all by the attract speech kicking in or coin switches, correct?

There is a note in the description of their Speech Pac application of the chip of how if certain things don't happen when they should the SC01 can remain 'stuck' on one phenome. 'Remains stuck' seems to imply it keeps repeating it.

#75 45 days ago
Quoted from frenchmarky:

But the noise also disappears at the moment boot up is complete, i.e. start of attract, before and without any sound effects or speech being generated at all by the attract speech kicking in or coin switches, correct?

When this problem occurs, these are the only things that will stop it...

attract mode kicks in, if attract enabled
• add a credit
• start a game
• turn off the machine

If I were to disable attract mode, then this errant phoneme would continue indefinitely or until one of the other actions take place. When attract mode is set to 2 minutes, the errant phoneme continues for 2 minutes. When attract mode is set to 10 seconds, the phoneme continues for 10 seconds... it continues until the attract sounds start. EDIT: attract mode was ignored today... I had to start a game to get it to stop.

At one point a month or two ago, I don't remember what I did or was doing, but the errant phoneme was stopping all by itself fairly quickly after it started. This was temporary, like only for one day it was like that.

Quoted from frenchmarky:

There is a note in the description of their Speech Pac application of the chip of how if certain things don't happen when they should the SC01 can remain 'stuck' on one phenome. 'Remains stuck' seems to imply it keeps repeating it.

It's the only thing in the document that mentions a "stuck" phoneme. After reading about how this chip generates 64 different phonemes, it's really curious how mine is always triggering or getting stuck on one.

I need to absorb this information to understand better...

Screen Shot 2021-09-01 at 2.15.46 PM (resized).png

Screen Shot 2021-09-01 at 2.15.31 PM (resized).png

So confusing... the quoted section is talking about the SPEECH-PAC™ "Load Line" ... it's entirely unclear how we go from the SC-01 chip data-sheet to a complete stand alone circuit called Speech-Pac in this document. And since the A6 only uses the SC-01 chip, I'm not sure how relevant the pages dealing with Speech-Pac are to this.

Page 11 talks about a "figure 2" schematic but the circuits on page 10 are labeled figures 6, 7, 8, and 9 and contain a SC-01A, which is a totally different chip. The description mentions edge connector J1, which is not shown on any of the circuits. I think this PDF was cobbled together from various bits and pieces, and it's missing something critical.

The "stuck phoneme" is a huge clue but without the relevant information about Speech-Pac back to SC-01, not SC-01A, I don't know what to make of it.
I found another PDF online for the SC-01 and it's the same but stops on page 9 - only contains SC-01 data-sheet and nothing about Speech-Pac.

#76 45 days ago

So confusing... the quoted section is talking about the SPEECH-PAC™ "Load Line" ... it's entirely unclear how we go from the SC-01 chip data-sheet to a complete stand alone circuit called Speech-Pac in this document. And since the A6 only uses the SC-01 chip, I'm not sure how relevant the pages dealing with Speech-Pac are to this.

Page 11 talks about a "figure 2" schematic but the circuits on page 10 are labeled figures 6, 7, 8, and 9 and contain a SC-01A, which is a totally different chip. The description mentions edge connector J1, which is not shown on any of the circuits. I think this PDF was cobbled together from various bits and pieces, and it's missing something critical.

The "stuck phoneme" is a huge clue but without the relevant information about Speech-Pac back to SC-01, not SC-01A, I don't know what to make of it.

I found another PDF online for the SC-01 and it's the same but stops on page 9 - only contains SC-01 data-sheet and nothing about Speech-Pac.

#77 45 days ago
Quoted from sparky672:

Hmmm... there are white bulbs that flash randomly and those are the flasher type light bulbs. There are also plain red bulbs that flash sequentially like a marquee in the outer box that are driven by a small flasher board. Which ones are you referring to?

The randomly flashing ones, not the marquee.

#78 45 days ago
Quoted from Mach1:

The randomly flashing ones, not the marquee.

It's a steady and constant phoneme tone. The random flashers have no audible effect.

#79 45 days ago

>>Page 11 talks about "figure 2" schematic but they are labeled 6, 7, 8, and 9. The description is for edge connector J1, which is not shown on any of the drawings. I think this PDF was cobbled together from various bits and pieces, and it's missing some pages.>>

Fig. 2 is on the final page, it's their version of a board that would include the SC-01 and the ROMs that would load the speech data into it etc.

#80 45 days ago

This Pinwiki diagram shows a 'power on reset' signal from the MPU to the sound board but I can't really see where/how that is accomplished on the schematics. Maybe it only applies to the sound-only boards? And maybe the speech board is supposed to just be sent a 'no sound' signal from the mpu when boot up is complete? Anyway it wouldn't help you unless it's supposed to send this reset signal immediately upon power up.

Sys80b_IO_lines (resized).png

#81 45 days ago
Quoted from frenchmarky:

Fig. 2 is on the final page, it's their version of a board that would include the SC-01 and the ROMs that would load the speech data into it etc.

I see it now.

To make sense of their "stuck phoneme" scenario, we'd have to compare Speech-Pac to the A6 schematic... it's more tedious than my brain can handle today... I will have to revisit. Thank you.

#82 45 days ago
Quoted from frenchmarky:

This Pinwiki diagram shows a 'power up reset' signal from the MPU to the sound board but I can't really see where/how that is accomplished on the schematics. Maybe it only applies to the sound-only boards? And maybe the speech board is supposed to just be sent a 'no sound' signal from the mpu when boot up is complete? Anyway it wouldn't help you unless it's supposed to send this reset signal immediately upon power up.

And how that all works with the driver board unplugged? The issue also occurs with the driver board unplugged. In other words, unplugging the driver board does not cause this issue, nor prevent this issue... it seems to be isolated to the sound board, unless it needs a signal from the MPU that never gets there. But nothing like that is connected...

A6-P1

1: +12 VDC
2: S16
3: -12 VDC
4: S32
5: +5 VDC
6: Gnd
7: Audio Out
8: S1
9: S2
10: +30 VDC
11: S4
12: S8

#83 44 days ago

But if the MPU really is supposed to perform a "power up reset" on the speech board when the boot is done, at least you'd only have to live with that awful sound for 5 seconds. *IF* that reset would kill the noise just like the first triggering of a speech or sound effect does

Anybody know where that reset line labeled #1 is on the mpu board? It's one of a lot of other "#"s on that diagram that seem like they are supposed to be referring to some other document that ain't there.

#84 44 days ago
Quoted from frenchmarky:

Anybody know where that reset line labeled #1 is on the mpu board? It's one of a lot of other "#"s on that diagram that seem like they are supposed to be referring to some other document that ain't there.

If it exists, it somehow has to be part of S1-S32. Otherwise, I don't know where... the other pins are just various voltages. Where on MPU drawing are you seeing this?

BTW, the attract mode did NOT kill the sound today. I don't know if this has to do with attract being set to 10 seconds or what, but back when attract was 2-minutes, for a fact attract mode was killing it.

Here's a video from today...

My finger is interfering with the audio output signal.... then I'm checking for hot chips... none.

#85 44 days ago
Quoted from frenchmarky:

This Pinwiki diagram shows a 'power on reset' signal from the MPU to the sound board but I can't really see where/how that is accomplished on the schematics....

Screen Shot 2021-09-01 at 4.54.05 PM (resized).png

That does not look right at all... based on the title lacking an "A" and the reset going through display boards ... I think this is strictly 80B. For 80B, the S & S board was completely different than S & S boards in 80 (Volcano) and 80A (Caveman) games.

#86 44 days ago

Are you still stuck at where you were before where everything was much worse with C22 installed, so you currently do not have a cap there?

#87 44 days ago
Quoted from frenchmarky:

Are you still stuck at where you were before where everything was much worse with C22 installed, so you currently do not have a cap there?

Yes, stuck. Everything pretty much the same where it started, except I have a 320 pF cap in C22. As recommended by you, I had to make some big adjustments. I cranked frequency way up about 4 turns to accommodate having C22 in place.

• All electrolytic caps on entire machine changed, including new 12,000 µF for C1
• 320 pF ceramic cap in C22 (and cranked freq up to normal sound to accommodate)
• New molex finger pins on A6 edge connector
• U12, U16, and U17 are not original and I reflowed missing/cracked solder front and back
• New 110 VAC line filter in cabinet

The problem is the same but for the attract mode not making it stop now. Same tone (phoneme) as before.

I suspect maybe U12, U16, or U17 but don't want to replace unless I can verify somehow.

#88 44 days ago

I admire your tenacity.
By now i would have shot gunned this board with every part i could find.
I once replaced every component on a stern sb-100 to make it work correctly.

#89 44 days ago
Quoted from PinballAir:

I admire your tenacity.
By now i would have shot gunned this board with every part i could find.
I once replaced every component on a stern sb-100 to make it work correctly.

Thank you... the game is playable although this last issue is very annoying. Eventually, I'll figure it out and we'll all learn something.

I discovered the chip is a SC-01A, which I thought was not exactly the same as SC-01; maybe I am mistaken. I popped it out of U14 socket and cleaned the pins. Made no difference although the errant phoneme tone changed into something else this time.

From the Caveman manual, no idea what "not used" is supposed to mean! LOL ...

A6 Caveman

#90 44 days ago

I'm now also using this thread to poke around and try to learn the rudimetaries of digital electronics...

Since it's strictly a power-up issue, could the RC circuit that keeps the speech board's 6502 reset line low for a bit upon power up have anything to do with it? You did change that cap too it sounds like, but...

Since triggering a sound clears it up, wondering if grounding that pin to low for a split second while the sound is happening would do it too.
656565656 (resized).jpg

#91 44 days ago
Quoted from frenchmarky:

Since it's strictly a power-up issue, could the RC circuit that keeps the speech board's 6502 reset line low for a bit upon power up have anything to do with it? You did change that cap too it sounds like

Maybe. The resistor is measuring at 3.25 kΩ (within 2%) and the C3 cap was already changed (Chineseum from Marco). Wondering how close the timing is on that and if cap is slightly out of whack. Then again, I had the same issue with the old cap in place too.

I'd have to remove diode to test it properly since resistor is shorted across it. What's weird is that I was not expecting to read same resistance across resistor swapping the leads since a diode is shorted across it. 3.25 kΩ in both directions. So then I used diode mode to measure CR1 and see 0.59 in one direction and 0.89 in the other... so CR1 is probably ok.

Quoted from frenchmarky:

but...
Since triggering a sound clears it up, wondering if grounding that pin to low for a split second while the sound is happening would do it too.

Exactly. I tried that and it works. Everything goes silent when I hit pin 40 on U3 to ground, and then normal attract sounds start up.

So maybe time to look closer at U1 since it's also part of this reset circuit.

#92 44 days ago

Looking at U1 (7414) and doing the DMM diode test mode with red lead on pin 7 (Gnd), and ignoring pin 14 (+5 V)...

I get about 0.65 - 0.67 on every pin except 1 and 8.
Pin 1 is 0.78 and pin 8 is 0.55

Pin 1 is an input of a gate in the reset circuit.

Not entirely sure if this is significant or if the chip needs to be removed to be tested more properly.

#93 44 days ago

For the issue with the SC-01A the issue is probably on the speech/sound board itself. I would take another look at the reset circuitry on the sound card but honestly I think the issue is going to be with the strobe line (pin 7 on the SC-01A) which I haven't heard that you looked at yet.

The signals present on P0-P5 (phoneme data) and I1-I2 (Inflection) are irrelevant until the strobe line latches the data. If that strobe line tells the chip to latch the data when it isn't supposed to then it may tell it to make a sound>

I would check C17 (.002uf) R10 1.5K, U12 7407 and their connections for any opens, etc. You could also check U10B 74LS02.

Also C27 and the zener diode CR2 1N5225B

I just fixed a Volcano sound board for someone. That one was a different issue and mainly reset related.

#94 44 days ago

Here is a link to the SC-01A datasheet:

https://www.redcedar.com/sc01/Poor10PageSc01.pdf

Here is an article I wrote almost 14 years ago on the SC-01A and it explains how I emulated it at the time. It will give you some insight on how the SC-01A is driven.

https://www.robotworkshop.com/robotweb/wp-content/uploads/servo200712_HERO_Speech_translator.pdf

#95 44 days ago
Quoted from Robotworkshop:

I would check ... U12 7407 and their connections for any opens, etc.

Quoted from Robotworkshop:

... but honestly I think the issue is going to be with the strobe line (pin 7 on the SC-01A) which I haven't heard that you looked at yet.

Pin 7 on SC-01 comes from U12 and that was mentioned yesterday as one of three chips with bad solder that I reflowed front and back.

I will check the other components you mention. Thank you.

#96 44 days ago
Quoted from Robotworkshop:

I would check C17 (.002uf)

I do not see C17 in the bill of materials or schematics. Remember, my Volcano is using a version 3 sound & speech board from a Caveman.

#97 44 days ago
Quoted from sparky672:

I do not see C17 in the bill of materials or schematics. Remember, my Volcano is using a version 3 sound & speech board from a Caveman.

I haven’t seen the whole schematic for the version 3 board but did see a clip you posted with the different U12 wiring. As long as you’re running the correct ROM chips and board is jumpered correctly it should work. Several games didn’t have the SC-01A chip installed as it was optional in the board. Haunted House didn’t have the speech chip installed but I added one on mine.

Checking the pull-up resistor would be good. If you have good de soldering equipment I’d remove U12, put in a socket, and try another chip.

#98 44 days ago
Quoted from Robotworkshop:

Checking the pull-up resistor would be good. If you have good de soldering equipment I’d remove U12, put in a socket, and try another chip.

Which pull-up resistor? On U12?

I'll have to get a 7407 chip first. Is there a simple test or a setup where I can verify this chip could be the root cause?

Thank you!

#99 44 days ago
Quoted from sparky672:

Which pull-up resistor? On U12?
I'll have to get a 7407 chip first. Is there a simple test or a setup where I can verify this chip could be the root cause?
Thank you!

The resistor is connected to pins 2, 10, and 12 of U12. I can't tell you the number since it is covered up by a red circle in your post and I don't have the schematics for that version of the board.

It is critical that resistor is ok and connected or you won't have any way to reliably drive that line high and it would sort of float and it would be anyone's guess when it could be triggered. The 7407 is an open collector meaning it can pull that line to ground but doesn't drive it to a high state. The pull up resistor does that.

As far as testing that chip I would unsolder it and see how it reads in my chip testers. If they say it's bad then it gets replaced. I've had some chips read ok but were partially bad so I would just swap it out to test and if no difference put hte original back in. You may not have chip testers or spare chips on hand. Since I do repairs on all sorts of boards I've stocked up on all sorts of parts and tools over the last 30+ years.

#100 44 days ago
Quoted from Robotworkshop:

The resistor is connected to pins 2, 10, and 12 of U12. I can't tell you the number since it is covered up by a red circle in your post and I don't have the schematics for that version of the board.

R10

Screen Shot 2021-09-02 at 12.07.36 PM (resized).png

Quoted from Robotworkshop:

It is critical that resistor is ok and connected or you won't have any way to reliably drive that line high and it would sort of float and it would be anyone's guess when it could be triggered. The 7407 is an open collector meaning it can pull that line to ground but doesn't drive it to a high state. The pull up resistor does that.
As far as testing that chip I would unsolder it and see how it reads in my chip testers. If they say it's bad then it gets replaced. I've had some chips read ok but were partially bad so I would just swap it out to test and if no difference put hte original back in.

Ok thanks. Solid advice. I will get some chips on hand and do that.

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