(Topic ID: 132940)

squawk talk occasional garbled voice problem-> a solution


By Skateball

4 years ago



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#1 4 years ago

I have for quite some time been trying to get my FG Squawk & Talk board (AS-2518-61A) to talk properly and finally, it works! I thought I’d put my findings here. Maybe someone will find this useful.

The S&T board produced occasional garbled phrases or words. It could happen at the beginning, middle or end of the phrase or a complete phrase was just rubbish. It happened maybe 10% of the time. The rest of the time the voice was loud and clear.

I searched the web extensively in the hope of finding a solution, but did not find anything. The closest I got was this topic on pinside: “squawk talk occasional garbled voice problem”.
It describes the same problem that I had. Unfortunately there is no final conclusion in that thread.

Well, to cut it short, after having gone through the entire board, new caps, test with all new ICs (PROM, PIA, CPU, TMS5200NL) etc. the problem was still there. As a last try, I checked the resistor R9. According to the schematic and the color codes on the resistor, it should have been 130 kOhm, but when measured it was 150 kOhm!

After replacing the (faulty) resistor with a good one (measured to be 133 kOhm), my FG now talks very clear!

Some technical background info:
====================
Before finding the faulty resistor, I tried replacing the U8 (TMS5200NL) with a new device borrowed from a friend. After this replacement the board worked very well, so I thought the problem was solved. I therefore ordered a new U8.

After getting the new U8, I installed it and expected everything to be singing and dancing, well at least talking ... Great disappointment! There were more garbled phrases than ever before!

So, the conclusion of this must be that there is a spread in some internal parameters between each U8 device causing a slightly different behavior. In fact, the speech synthesizer U8 (TMS5200NL) uses an external resistor (R9) to set/trim the internal clock frequency of the device. This allows to compensate for slight variations in the parameters between different TMS5200NL devices.

I should probably from the very beginning have measured the frequency at TP11 (TMS5200 clock). This clock should have a frequency of 160 kHz (for a speech sample rate of 8 kHz). If this frequency is not correct, there are only two possibilities, either the TMS5200NL is bad or the (real) value of R9 is not matched to the actual TMS5200NL device used.

Considering the huge price difference between a resistor and a new TMS5200NL, checking and trimming the value of R9 to get a good clock frequency out of U8 should probably be the first thing to do whenever the S&T board produces any kind of strange speech.

Even though 130 kOhm might have been a good value of R9 in the early 80’s, the parameters of the still existing TMS5200NL might have drifted over the past 30-35 years, so also another value can possibly give better performance.

#2 4 years ago

Good info

Every single TMS5200 sounds different. Some are slow (darth vader), some are fast(chipmunks), some are medium. The pitches are even different besides the speed of speech. The differences between them can vary quite wildly

Fiddling with the speech clock resistor can get you different results as you found. You cant get a darth vader 5200 to sound like a chipmunk one with just changing the resistor though. There is some limits.

#3 4 years ago

Interesting. I've been fighting with my S&T for about a year for the same problem. Mine is garbled always in the same place though. Swapped ROMS, various ICs, can't figure it out.

#4 4 years ago

I have this problem with my Elektra, 10% of the time garbled speech. Thanks!

#5 4 years ago

Another thing to consider about these speech chips is the plating on the IC legs. Texas Instruments really eff'd up in the later 70s early 80s. You will notice all there ICs legs corrode out really bad with black stuff on them. Fairchild for a while has this problem too. This causes problems in the single wipe RN sockets typically used in all squawk and talk boards (and with fairchild 68xx stuff in bally MPUs). Random poor speech could be a bad connection on the speech socket.

Considering how obsolete and expensive these 5200 speech chips are it is tough to recommend pulling them from the IC socket and trying to clean the legs. I have lost a few legs trying to wire brush the black shit off of the speech chips and had to improvise a new leg on. Normally i would just bin a chip if it loses a leg, but these things are rare.

Dual wipe socket is really recommended considering how the TI legs of this era corrode and have continuity problems .

#6 4 years ago
Quoted from barakandl:

I have lost a few legs trying to wire brush the black shit off of the speech chips and had to improvise a new leg on. Normally i would just bin a chip if it loses a leg, but these things are rare.

I have had success with a rectangular pink rubber eraser. I support the legs on one side, and run the eraser along the other side, then switch. I do both sides of each row of pins. The eraser doesn't catch on the pins at all. Using this method, I haven't bent or broken any pins so far (unless the pins were already questionable to begin with and ready to come off anyway).

#7 4 years ago

TI used silver plating in select IC's back then. This is what was jump starting the oxidation so badly. Unfortunately, with RoHS - a lot of components have again going back to silver plating.
Best way to fix this without risking damaging IC legs - use Tarnex. Dip in Tarnex and then rinse with water. If there are any stubborn spots - rub Tarnex into legs very lightly with finger tips and rinse.

#8 4 years ago

That is a cool tip about the Tarnex. Seems so obvious yet I'd never think of it.

Wish my FG wasn't folded up in storage at the moment, this thread has me wanting to mess with it again.

#9 4 years ago
Quoted from G-P-E:

TI used silver plating in select IC's back then. This is what was jump starting the oxidation so badly. Unfortunately, with RoHS - a lot of components have again going back to silver plating.
Best way to fix this without risking damaging IC legs - use Tarnex. Dip in Tarnex and then rinse with water. If there are any stubborn spots - rub Tarnex into legs very lightly with finger tips and rinse.

I will have to grab some Tarnex to try. I had better luck with a wire brush than an eraser on delicate stuff. I would try and be gentle with the eraser but i would break pins. The fine brush i use does not apply much force on each pin, but the abrasion knocks off the black stuff. Some times they corrode so much they legs just fall off. I have had some where you try and pull the IC out of the socket and nearly all the legs just crumble. Sad face.

#10 4 years ago

Thanks for your reactions. I am completely new on Pinside and this is my very first topic here so its extra fun to follow the discussions.

I have been fighting with the S&T the last several months and it would be great to be able to focus on something else again..... but before moving on, I would indeed also be very interested to know if the trick with the R9 solves the problem also for any of you, including the case where always the same phrase is garbled.

#11 4 years ago
Quoted from barakandl:

Some times they corrode so much they legs just fall off. I have had some where you try and pull the IC out of the socket and nearly all the legs just crumble. Sad face.

Yeah, if they get to that point, there is nothing that is going to be 'gentle' on these ones. Just hold your breath and hope for the best.

#12 4 years ago
Quoted from Skateball:

I have for quite some time been trying to get my FG Squawk & Talk board (AS-2518-61A) to talk properly and finally, it works! I thought I’d put my findings here. Maybe someone will find this useful.
The S&T board produced occasional garbled phrases or words. It could happen at the beginning, middle or end of the phrase or a complete phrase was just rubbish. It happened maybe 10% of the time. The rest of the time the voice was loud and clear.
I searched the web extensively in the hope of finding a solution, but did not find anything. The closest I got was this topic on pinside: “squawk talk occasional garbled voice problem”.
It describes the same problem that I had. Unfortunately there is no final conclusion in that thread.
Well, to cut it short, after having gone through the entire board, new caps, test with all new ICs (PROM, PIA, CPU, TMS5200NL) etc. the problem was still there. As a last try, I checked the resistor R9. According to the schematic and the color codes on the resistor, it should have been 130 kOhm, but when measured it was 150 kOhm!
After replacing the (faulty) resistor with a good one (measured to be 133 kOhm), my FG now talks very clear!

Hi

Thanks for the post. Interesting findings. I'm producing my own design Squawk & talk sound board See here - https://pinside.com/pinball/forum/topic/mypinballs-squawk-talk-sound-board-gordons-alive I have also experienced various issues with the TMS5200 ics and i am using NOS parts with a brand new board and all new components !!

My view is that the chips themselves have not always survived the 30/35 years in storage well. I have had new chips that sound totally different in a brand new board. Some too low, some too high. I use various sound roms from games that i know well during my board testing to check the TMS chips is correct and working ok! It can be expensive though, as the chips themselves were over £10 each to me and sometimes are no good.

I am using the original spec 130k resistor for the timing. It would be interesting to experiment with other values as you mention to see what could be done with them, though i like the board bom to be standard. (Will note a possible change to a pot for future revisions)

One other idea for this chip i have is working out how to create an emulation of it using the pinmame source and an embedded controller. I think this is the only way going forward

Final thought is that its a real shame the TMS5220 ics isn't fully functional compatible as it is pin compatible and does work in my boards, but unfortunately the speech pitch isn't quite right and some parts are sometimes garbled. I wonder if a different resistor value here may help to??

#13 4 years ago

There is probably space to put a variable resistor in there. Something like 500k or 250k would be interesting to play with.

#14 4 years ago
Quoted from barakandl:

Another thing to consider about these speech chips is the plating on the IC legs. Texas Instruments really eff'd up in the later 70s early 80s. You will notice all there ICs legs corrode out really bad with black stuff on them. Fairchild for a while has this problem too. This causes problems in the single wipe RN sockets typically used in all squawk and talk boards (and with fairchild 68xx stuff in bally MPUs). Random poor speech could be a bad connection on the speech socket.
Considering how obsolete and expensive these 5200 speech chips are it is tough to recommend pulling them from the IC socket and trying to clean the legs. I have lost a few legs trying to wire brush the black shit off of the speech chips and had to improvise a new leg on. Normally i would just bin a chip if it loses a leg, but these things are rare.
Dual wipe socket is really recommended considering how the TI legs of this era corrode and have continuity problems .

Yes using silver for pin legs was a big mistake!! I guess we are lucky they realised soon and ditched that idea. The TMS5220 ic uses tin legs to. Damn those TEXAS bods

#15 4 years ago

So how the hell is a resistor used to affect timing anyway?

Is it used to change how long it takes for a capacitor to charge or something?

#16 4 years ago
Quoted from radium:

So how the hell is a resistor used to affect timing anyway?
Is it used to change how long it takes for a capacitor to charge or something?

Yes, the resistor along with C51 form the oscillator for the 5220.

If subbing with a trim pot, I would use a 100K resistor in series with a 50K trim pot. That should give you enough variance around the original 130K without going too far out of range of the oscillator. It could actually be the value of C51 that has drifted out of spec as it is only 10 pfd.

#17 4 years ago

Next squawk and talk i get in for repair i will install a pot and play with its value and see what i come up with as far as a good range of resistors to use.

#18 4 years ago
Quoted from CactusJack:

Yes, the resistor along with C51 form the oscillator for the 5220.

Thanks, that's really cool. I ended up reading all about RC oscillator circuits.

So this thread got me curious, and I went and pulled my S&T board out of my FG in storage. I'm at work and don't have a meter, but I'm going to test R9 as soon as I get home.

What I did notice is my R9 shows signs of physical damage.

IMG_4690.JPG

#19 4 years ago

Thanks for all your reactions!

Quoted from radium:

So how the hell is a resistor used to affect timing anyway?
Is it used to change how long it takes for a capacitor to charge or something?

Yes, the internal operating frequency of the TMS5200 is defined by the value of R9. The input pin of the TMS where R9 is connected has a very high impedance, which makes it very sensitive to noise. I believe thats the reason for capacitor C51 across R9, i.e. to filter out stray noise. The actual frequency of the TMS is thus probably entirely defined by the TMS parameters for a given resistor value. This could explain the fact that different TMS devices talk differently. If the value of R9 is kept the same, dropping in different TMS devices will cause each device to be running at slightly different frequencies.

Quoted from barakandl:

Next squawk and talk i get in for repair i will install a pot and play with its value and see what i come up with as far as a good range of resistors to use.

In order to achieve an operating frequency of 160kHz, the value of R9 could be between 120kOhm and up to 200kOhm! There is thus a very large spread in the parameters.

I just measured the clock at TP11 and got 6.6us clock period (using R9=133kOhm). Just to see the effect, I then temporarily added 1.8MOhm in parallel to that which gives an R9=124 kOhm. With that value I got almost spot on a clock period of 6.25us (which is exactly what the TMS5200 is expecting). Will probably replace the 133kOhm I have now with a 124kOhm.

Originally in the 80's I think that indeed the parameter spread of the TMS devices was less pronounced and Bally probably bought a whole bunch of parts manufactured roughly at the same time. For Bally it was thus good enough to fix R9 to 130 kOhm. After all it does not matter too much if different games talk slightly different as long as the oscillator frequency is sufficiently good to avoid the garbling.

Quoted from radium:

Interesting. I've been fighting with my S&T for about a year for the same problem. Mine is garbled always in the same place though. Swapped ROMS, various ICs, can't figure it out.

Would be really interesting to see if both the occasional and consistent garbling can be recreated/resolved by the trimming operation.

Quoted from applejuice:

Hi
Thanks for the post. Interesting findings. I'm producing my own design Squawk & talk sound board See here - https://pinside.com/pinball/forum/topic/mypinballs-squawk-talk-sound-board-gordons-alive I have also experienced various issues with the TMS5200 ics and i am using NOS parts with a brand new board and all new components !!
My view is that the chips themselves have not always survived the 30/35 years in storage well. I have had new chips that sound totally different in a brand new board. Some too low, some too high. I use various sound roms from games that i know well during my board testing to check the TMS chips is correct and working ok! It can be expensive though, as the chips themselves were over £10 each to me and sometimes are no good.
I am using the original spec 130k resistor for the timing. It would be interesting to experiment with other values as you mention to see what could be done with them, though i like the board bom to be standard. (Will note a possible change to a pot for future revisions)
One other idea for this chip i have is working out how to create an emulation of it using the pinmame source and an embedded controller. I think this is the only way going forward
Final thought is that its a real shame the TMS5220 ics isn't fully functional compatible as it is pin compatible and does work in my boards, but unfortunately the speech pitch isn't quite right and some parts are sometimes garbled. I wonder if a different resistor value here may help to??

I believe the TMS is a purely digital device with digital filtering etc internally and the only analogue parts are the oscillator and the digital to analogue converter at the output. There could be internal (digital) failures due to the age of the devices but I would expect them to be rare. Analogue parameters are a different story. I would think they can easily drift a lot over 30 years and could impact a lot the resulting clock frequency.

Although I have not made extensive research, I would in fact expect that it should be possible to get different devices to talk reasonably similar by means of trimming R9.

If you have TMS5220 devices available, I would do the same test I did today. Try trimming the clock period to 6.25us. I think there is a good chance you will get it talking properly unless there is a difference in the internal coding tables between the TMS5200 and the 5220.

==========
Considering the problem with the occasionally garbled phrases, my hypothesis is as follows:
* In my case the value of R9 was too high => clock frequency too low. This was also clear from the pitch and speed of the speech which was lower.
* As a consequence of the (too) low clock frequency, the TMS device runs slower overall. Normally, the TMS expects that the CPU waits 10us after a write before the next write occurs. If the TMS runs slower, this could also imply that the TMS will expect also a longer wait time from the CPU.
* If the CPU then occasionally violates this longer wait time, the effect could be an occasional lost byte of speech data.

This is pure speculation so far from my side so I could be completely wrong. I might try to check if this theory fits sometime in the future. Any feedback would be much appreciated!

#20 4 years ago
Quoted from radium:

Thanks, that's really cool. I ended up reading all about RC oscillator circuits.
So this thread got me curious, and I went and pulled my S&T board out of my FG in storage. I'm at work and don't have a meter, but I'm going to test R9 as soon as I get home.
What I did notice is my R9 shows signs of physical damage.
IMG_4690.JPG

Yes your R9 looks a bit worn.

Looking at your board, I believe you have the first generation S&T, AS-2518-61 with an R9 of 240kOhm (which is in line with the schematic I have here for that board). I have no clue why these early boards had 240kOhm but its quite different compared to the 130kOhm on the A version.

You also do not have the C51 that is present on the A version (but thats less of a concern I think). You can always add one later if that seems to be necessary (to reduce any noise).

If you have the possibility, hooking the board up and measure the current clock period or frequency at TP11 could also be very interesting.

Curious to see what you find!

#21 4 years ago

Something else interesting... my board (it is a -61) has an empty socket at U10.

Everything I've read says there should be a DAC there, but maybe that is only on some boards?

#22 4 years ago
Quoted from radium:

Something else interesting... my board (it is a -61) has an empty socket at U10.
Everything I've read says there should be a DAC there, but maybe that is only on some boards?

My spare, dusty board is a -61a and it also has an empty socket at U10 (just noticed that yesterday!). I just ordered a couple off ebay to populate my spare board.

There are three sources for sound on the S&T. One is through the AY-3-8912 Programmable Sound Generator (PSG), This where simple tone and white noise related sounds as well as music can be produced (Think Early 80's Video Games). The TMS5200 for speech. And the DAC for complex noises/SFX.

FWIW, the board was from a Flash Gordon and the Date code on the TMS5200 is 8048. I have not tested the board yet (waiting for the AD558).

#23 4 years ago
Quoted from radium:

Something else interesting... my board (it is a -61) has an empty socket at U10.
Everything I've read says there should be a DAC there, but maybe that is only on some boards?

The dac is used on all boards. the ay-3-8912 (psg) is only used on some. If the psg is installed then it does the background sounds. I've always wondered why bally didn't make use of the ay-3-8912's music abilities on this era of board. If you look at gottlieb system 80b sound boards, they used 2 of these to make some really great 80s music

The ay-3-8912 are actually 3 channel themselves to, so the board is in theory 5 channel

#24 4 years ago
Quoted from Skateball:

In order to achieve an operating frequency of 160kHz, the value of R9 could be between 120kOhm and up to 200kOhm! There is thus a very large spread in the parameters.

Exactly what i was going to add. It seems quite a wide range and this is written in the data sheet!! How come such a large range can be ok? It almost seems like you had to buy your chips from texas in the same batch then work out what the correct frequency of them was??

#25 4 years ago
Quoted from applejuice:

The dac is used on all boards.

Hmm... I'm confused. My Flash Gordon seemed to have working sound except for the garbled speech (after I enable background sounds in settings of course). I wonder if that DAC is not utilized for all games? Or maybe there are additional sounds I just didn't know I was missing. I'll check some YouTube videos and see if I notice anything.

#26 4 years ago

Also, I tested R9 on my -61 and got 237k ohms. This seems close to 240k ohms to me.

I still think my "garbled speech in the same place every time" problem is most likely an incomplete read from the ROM somewhere. I have not been able to track that down. I am really not qualified to troubleshoot this in the first place though.

I find S&T interesting for some reason... cool thread and I appreciate the info being posted.

#27 4 years ago
Quoted from radium:

Hmm... I'm confused. My Flash Gordon seemed to have working sound except for the garbled speech (after I enable background sounds in settings of course). I wonder if that DAC is not utilized for all games? Or maybe there are additional sounds I just didn't know I was missing. I'll check some YouTube videos and see if I notice anything.

Interesting. It is possible that the DAC isn't used for Flash Gordon although populated as specced by the schematics. Flash gorgon was the first game to use the s&t board, so maybe Bally already had all the sound effects done for use with the PSG chip (like the earlier sound board) and so hadn't started using the newer DAC idea. The DAC isn't part of any boot up test either (not sure it could be) so the board will boot without it on any game. Of course games that do use it will have all the sfx missing. The psg is part of the boot up and the board will not boot if this chip is used and missing.

To me it seems like the idea was to move away from the PSG entirely and do all sounds through the DAC. Probably cheaper at the time, but i still want to know why they didn't add music capability to the boards. That would have really blown every other manufacturer at the time out of the water, and the board already is the best example for the time

Not sure why this rev board has a 240k speech timing resistor either. My boards with 130k in, 10pf shunt and flash gordon roms sound correct.

#28 4 years ago

I believe the dac is only for sounds made by the PIA. Sounds made by the sound generator do not use it. I would have to look again at the schematic.

#29 4 years ago
Quoted from barakandl:

I believe the dac is only for sounds made by the PIA. Sounds made by the sound generator do not use it. I would have to look again at the schematic.

Yes that is correct. The interesting thing here is Flash Gordon being the first game to use the s&t board may not actually need the DAC, as all sounds are possibly made still using the PSG (like the earlier sound board does).

#30 4 years ago
Quoted from applejuice:

Yes that is correct. The interesting thing here is Flash Gordon being the first game to use the s&t board may not actually need the DAC, as all sounds are possibly made still using the PSG (like the earlier sound board does).

Credit and a chime effects i think are done by the PIA on at least a good bit of games if not all.

#31 4 years ago
Quoted from barakandl:

There is probably space to put a variable resistor in there. Something like 500k or 250k would be interesting to play with.

You totally can. Installed a 500k and....

#32 4 years ago
Quoted from radium:

Also, I tested R9 on my -61 and got 237k ohms. This seems close to 240k ohms to me.
I still think my "garbled speech in the same place every time" problem is most likely an incomplete read from the ROM somewhere. I have not been able to track that down. I am really not qualified to troubleshoot this in the first place though.
I find S&T interesting for some reason... cool thread and I appreciate the info being posted.

Another interesting observation is that you have a newer TMS than I have, but an older -61 board. My date code is 8048 while yours is 8109.

An easy test to check if the value of R9 is part of the problem could be to add another resistor in parallel to the one on the board to bring the resulting value of R9 down to around 130kOhm which is on the lower end of the trimming scale (and in line with newer boards). Has to be done with care of course but no need to solder. I used two crocodile clips (or whatever they are called) to temporarily attach an additional resistor.

#33 4 years ago
Quoted from dothedoo:

You totally can. Installed a 500k and....
» YouTube video

Huh. I would have expected higher ohms to produce slower speech.

#34 4 years ago
Quoted from radium:

Huh. I would have expected higher ohms to produce slower speech.

I agree if it is running an R/C clock network. It might be used for a VCO (Voltage Controlled Oscillator).

But I am thinking he installed a 500K trim pot and turned it down quite a bit.

I am having a hard time understanding the 240K (early run) vs 130K (later run) aspect. It makes me think they really had to tune the boards to various batches of TI chips. I know we noticed subtle differences from game to game when they were brand new but never anything too far out of pitch, I seem to recall it being mentioned on RGP years ago that the chips currently on the market could be rejects that failed to meet TI's specs at the time. So, before discarding a newly purchased 5200 that seems dead, I would certainly try the trim pot thing to see if it will respond to other R9 values.

I fired up my spare FG S&T in my Centaur this morning. With the 8048 date code and 130K R9, it sounded just like Flash should. I just couldn't tell if there were sounds missing (still missing the AD558) by just batting the ball around a bit.

#35 4 years ago
Quoted from radium:

Huh. I would have expected higher ohms to produce slower speech.

I should have said a 500k pot. Full range adjustability to speed up or slow down speech.

#36 4 years ago
Quoted from CactusJack:

I am having a hard time understanding the 240K (early run) vs 130K (later run) aspect. It makes me think they really had to tune the boards to various batches of TI chips. I know we noticed subtle differences from game to game when they were brand new but never anything too far out of pitch, I seem to recall it being mentioned on RGP years ago that the chips currently on the market could be rejects that failed to meet TI's specs at the time. So, before discarding a newly purchased 5200 that seems dead, I would certainly try the trim pot thing to see if it will respond to other R9 values.

This is my thought to from seeing such as large range of resistor values specced in the data sheet. I am also wondering about the TMS5220 ic and if a different resistor value will cure the occasional garbling here to. The way the voice sounds i think will be slightly different (not the pitch) as the internal tables are slightly different, but they may be possible to get working in a much better fashion. The dac non install on fg still intrigues me, as i would have expected no sound effects if this was being used as per the other games. I don't think you can rules out the fact fg was the first game to use the new board and the older generation of sound boards were pure psg sound gen boards for sfx.

Really great thread to be discussing some top notch pinball tech from the old days.

#37 4 years ago
Quoted from applejuice:

I don't think you can rules out the fact fg was the first game to use the new board and the older generation of sound boards were pure psg sound gen boards for sfx.

Wasn't the Sounds Plus with Vocalizer in Xenon the first non-psg?

#38 4 years ago
Quoted from dothedoo:

Wasn't the Sounds Plus with Vocalizer in Xenon the first non-psg?

No, the sound plus board is the computer sound board with an extra interface for speech, all sound effects are psg generated. See my new version of the board that works for both eras here : https://pinside.com/pinball/forum/topic/mypinballs-sounds-plus-sound-board-in-development

#39 4 years ago

Interesting video of encoding a WAV file to an LPC stream (TMS5220 table) and playing it back thru a TI-99 emulator.

https://www.youtube.com/watch?gl=GB&hl=en-GB&v=wVDE-6TtmFQ

The compression ratio compared to quality of output is pretty amazing.

#40 4 years ago
Quoted from dothedoo:

You totally can. Installed a 500k and....

That backglass is such an improvement

#41 4 years ago
Quoted from CactusJack:

I am having a hard time understanding the 240K (early run) vs 130K (later run) aspect.

Was thinking about this more. Wouldn't different resistor value be used to accommodate a lower/higher sample frequency? Maybe the different resistor value is because of difference in the sample rate of the source data stored on the ROM for some games.

Kind of like a 45 RPM record versus a 78 RPM record. You can have the same song on both records but they only sound correct if played at the correct speed.

Just an uniformed guess though.

#42 4 years ago
Quoted from radium:

Was thinking about this more. Wouldn't different resistor value be used to accommodate a lower/higher sample frequency? Maybe the different resistor value is because of difference in the sample rate of the source data stored on the ROM for some games.
Kind of like a 45 RPM record versus a 78 RPM record. You can have the same song on both records but they only sound correct if played at the correct speed.
Just an uniformed guess though.

Makes Sense but if that were the case, it would be necessary to change the resistor when changing game roms as the sampling rate would reflect the data stored in the ROMs and being sent to the TI chip.

Is it documented anywhere if the 240K matches up with a particular title? My FG S&T uses the 130K as do my Centaur and Eight Ball Deluxe.

#43 4 years ago
Quoted from CactusJack:

My FG S&T uses the 130K as do my Centaur and Eight Ball Deluxe.

Oh I didn't realize that. I thought the older -61 board had the 240K resistor and the newer revision had the 130K.

#44 4 years ago

I suppose that is possible . However, my Spare S&T is a -61a and has an original EFG serial number sticker on it so I can't be sure about R9 on a straight -61 ( I can't find any reference to it on the net).

I wonder where games like Midnight Marauders (Midway Gun Game), and Discs of Tron fell in the R&D sequence for use of S&T sound? And the YouTube videos show MM stole a lot of sounds from Space Invaders Pin.

#45 4 years ago
Quoted from applejuice:

No, the sound plus board is the computer sound board with an extra interface for speech, all sound effects are psg generated. See my new version of the board that works for both eras here : https://pinside.com/pinball/forum/topic/mypinballs-sounds-plus-sound-board-in-development

So how was all of Suzanne Ciani's music generated? Stored in ROM and treated as speech calls?

#46 4 years ago

Here are some videos on my experiments with a 470K pot. I adjusted from around 100k upwards and back down again with the same new board, but swapping the speech chips over.

TMS5200 installed

TMS5220 installed

Kind of cool to be able to change the pitch on the fly, but it doesn't really help much with getting a 5220 chip to work better on s&t boards. Such a shame as it seems the coding tables internally are just that little bit too different for the speech to sound correct. Speech seems to be slightly scratchy and bait muffled. Would be a really great future solution to, as they use tin legs and are still much more readily available. Oh well guess its back to buying seriously expensive nos 5200 parts again with unknown storage histories...

Date code on 2 batches on nos TMS5200 i have currently are:

8236
8109

The 8109 ones are the only ones i have had issues with so far

The TMS5220 date codes are:

8340

#47 4 years ago
Quoted from CactusJack:

Is it documented anywhere if the 240K matches up with a particular title?

The Flash Gordon manual lists the part for R9 as "1/4W, 5%, 240K Ohm"

#48 4 years ago
Quoted from applejuice:

Here are some videos on my experiments with a 470K pot.

That's cool!

Where did you guys find a copy of the schematics for S&T anyway? Can't seem to find it.

#49 4 years ago
Quoted from radium:

Oh I didn't realize that. I thought the older -61 board had the 240K resistor and the newer revision had the 130K.

Yes, there was a change of R9 between -61 and -61A. The -61A is included in the Fathom schematic on IPDB. The change record says: "R9 was 240K". Pity that it does not say why!

#50 4 years ago

Have now installed R9=124 kOhm which is the matching R9 for my 5200 => TP11 clock period of 6.25 us.
Done a lot of self tests and triggered speech generation in various situations and played many games. The board seems to be rock solid now, no garbling at all. I just hope it stays like that...

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