Willing to buy MTH Proto-Sound 1 Boards (Working or Dead) + Identifying Board Components

The sounds are all contained in the PLCC chip on the top board.  However, that part is programmed and then read-locked, so I'm not sure if you're going to easily extract the sounds.

We’re actually switching plans now with that in mind. We will now attempt to make an analog recording of the sounds by figuring out which pins are for transformer input and speaker output, then hooking the speaker output to a computer and the input to a transformer. Because of this plan change, we request only WORKING boards. We will also attempt to e-mail QSI and see if they still have the sounds.

@GameBreaker64 posted:

We’re actually switching plans now with that in mind. We will now attempt to make an analog recording of the sounds by figuring out which pins are for transformer input and speaker output, then hooking the speaker output to a computer and the input to a transformer. Because of this plan change, we request only WORKING boards. We will also attempt to e-mail QSI and see if they still have the sounds.

Do you have an email to respond to?

You realize you only need a version or two of the board set, and just buy chips for the sounds.  This is kind of like saying you want a rotary dial on your smart phone though.  G

Click on image to enlarge.

GameBreaker64 Maybe you now have no need, but I do have one that came from a BL2.  If interested please send me an email using the address that is in my profile.

@GGG The problem is, finding the chips alone is actually harder than finding the board set. It's easy to find reset chips, but I don't know what sound data those contain.

@Sid's Trains I sent an email via the QSIndustries contact form. I haven't got a response yet.

@GameBreaker64 posted:

@GGG The problem is, finding the chips alone is actually harder than finding the board set. It's easy to find reset chips, but I don't know what sound data those contain.

@Sid's Trains I sent an email via the QSIndustries contact form. I haven't got a response yet.

I never got it.

I’ll try sending via their “new” address.

Just sent an Inquiry

@GameBreaker64 posted:

@GGG The problem is, finding the chips alone is actually harder than finding the board set. It's easy to find reset chips, but I don't know what sound data those contain.

@Sid's Trains I sent an email via the QSIndustries contact form. I haven't got a response yet.

You can still buy the chips from MTH, just give them the catalog number of the locomotive you want.

I'd still have to buy a board to make a recording

I've debated posting a reply because lack of time and I'm not sure I want to reveal all of my secrets. My knowledge comes partially from the MTH ASC class but mostly from personal research and effort. I'll try to post more information over the coming weeks and months as time permits.  The below answers some questions in this and the linked PS1 thread.

My ultimate goal is to build a collection of all PS1 ROMs which is almost identical to GameBreaker64’s wish.  As I collect engines and I perform repairs, I copy the PS1 ROM and add it to my ROM folder.  The ROMs are for my personal use only and are considered as a backup to the original.  I’m also concerned MTH may one day lose the ability to create new ROMs.  A ROM is just a computer file and if not properly backed-up in multiple locations on different types of media, could disappear forever.  There is also the concern current custodians of the PS1 ROMs will simply stop selling them; which could be a business discussion or the business doesn’t exist anymore.  This will leave the community with no way to repair a bad sound chip.

I currently have about 10 good chip ROMs with a few more “DESELECTED” and corrupted ROMs.  I also have the special Make, Fix 1011, Force 10, and Force 11 chips.

Request 1:  I would like to get an estimate from the community as to how many PS1 ROM variants exist.  My guess is between 100 and 500.  There are standard sound file libraries that are reused within a class of engine (diesel/SD-40 for example).  For an individual engine, engine specific processor code is applied to control the functions implemented (diesel and steam have different lighting characteristics even though they use the same PS1 light plug).  I assume there is also a standard library of processor code.  The number of combinations between the two sets can quickly become a big deal (any equation with n factorial, n!, can get out of hand quickly), but many combinations are invalid.  I make another assumption that several engines reuse identical ROMs but slap a different label on them.  There are likely multiple revisions or variants for some models.  This could be due to bug fixes, feature tweaks, early verses late production runs, or post-production changes.

I’ve never seen one but is there a generic PS1 steam or Diesel chip?  Lionel has generic Railsounds steam and diesel which can be very useful during a repair.  If there were a generic PS1 steam ROM then many repair problems would disappear.

Request 2:  Now this is a pie in the sky idea that has little chance of succeeding but I have to throw it out there anyway.  Maybe we can come up with a way of exchanging chips?  Don’t know how it would work but I would love to be contacted by a collector that has a bunch of PS1 engines willing to let me “examine” his or her collection.  Maybe I can swap out the battery for each engine in exchange.  I don’t drink beer but I’ll but you a cold one for each engine.

Observation 1:  Recording analog audio from a PS1 card might be the easiest but also the lowest quality option.  In order of difficulty and sound quality:

1)  Use a stand-alone tape recorder (do they even make those anymore) or equivalent.

2)  Put your computer microphone next to the speaker and hit the record button.

3)  Attach a professional mic to your computer and build a makeshift anechoic chamber out of a cardboard box and antistatic foam.

4)  Unsolder the PS1 speaker wire and record the audio directly from the analog to digital (A2D) converter via the LM386-1 audio amplifier IC.  Don’t go and solder a 3.5mm plug onto the speaker wires and plug it into your computer’s line in or mic port!  That will end badly with magic smoke filling the air and all sorts of other nasty side effects.  A computer’s sound card line in is typically rated at 1 volt root mean square (V_RMS) with an impedance of around 10k ohms.  The microphone input handles even smaller voltages of .01 V_RMS[i] [ii].

The PS1 speaker is 8 ohms.  The LM386-1 audio amp output voltage is one-half the supply voltage[iii] which I believe is 5 volts (will edit later if I hook-up my scope to find out).  Input and output impedances are designed to be different but the input is usually 100 to 600 ohms.

I just killed about two hours trying to find a way to convert the PS1 speaker signal to something a computer or other recorder could handle.  The best I could find is something called a “line level converter” which is used in car stereo systems to add a speaker to RCA pre-amp input.  This is getting well outside of my knowledge base but the take-away is, don’t do this unless you are really sure what you are doing.

5)  Convert original digital audio into modern audio format such as MP3 or flac.  This is the path I would take if presented with the challenge.  It is also beyond my current capabilities and knowledge.  I will get into the details in a later post but here are the highlights.  The microprocessor is an 8-bit NEC µPD78233[iv] from the 1990’s.  Audio formats used by microprocessors of that era were usually vendor specific and obscure even for the time.  The “file” (more specifically the ROM memory address block) also had to be insanely small.

Even if you have the raw sound file, decoding it may be easy or next to impossible.  A developer will likely need a 78K[v] compiler and development suite (I don’t have), add-on audio CODEC (don’t have or know if needed), in-circuit emulator (don’t have), lots of 78233 documentation (don’t have and Google hasn’t been very useful) and an assembly language reverse engineering tool (don’t have but currently but working on it).

This is all I have in me for the moment.  Next up I will start into the detailed description of chips on the PS1 top processor board.  Depending on response I will continue in this thread or start a new one.  I don’t have any completely dead PS1 boards to give away at the moment.  I can usually repair them 95% of the time.

[i] Line level - https://en.wikipedia.org/wiki/Line_level

[ii] Mic Level and Line Level -- What do they mean?, https://service.shure.com/s/ar...-mean?language=en_US

[iii] LM386 Low Voltage Audio Power Amplifier, https://www.ti.com/lit/ds/syml...ll-sf-df-ds-null-wwe

[iv] NEC Data Sheet MOS Integrated Circuit µPD78233, 78234, 78237, 78238, http://www1.futureelectronics....C/UPD78237GC-3B9.pdf

[v] 78K, https://en.wikipedia.org/wiki/78K

That's some heavy stuff posted above. How about just enjoying the trains.

@Freight Train Jim posted:

That's some heavy stuff posted above. How about just enjoying the trains.

I understand your concern for the complexity of this situation, but what we want is to enjoy our trains. Some of use still enjoy these older models and we don't want to lose the chance to have their sounds and functions. I think @tansqrx is onto something good and interesting.

Thank you so much for the information @tansqrx! The thing I'd probably want to do as well is extract the raw digital audio data from the locomotives. Unfortunately, the PROM chip that contains the sounds is programmed. If we read from the chip, the audio data would be in a proprietary format which would be very difficult to convert to MP3. You'd end up having to find pointers to the sound data in a hex editor and go from there.

You could buy system and data from MTH.  Pretty sure it was almost offered to me once.  I think all the PS-1 parts were up for sale or being considered for sale.  Here is your problem.  The chip that is used is obsolete.  So even if you had the program and data what do you put the new data on?  Same reason PS-2 5V and later 3V became obsolete.  The old service manager was doing last buys of the chip.  So what MTH has in stock is all there is.

So have you actually wrote to a chip one of your stored ROMs and produced your own new chip for use?  Are you going to invest in some sort of adapter board to make some new type of memory work with 1980s tech?

I still do PS-1 repairs, but each year less.  But still plenty of upgrades especially Premier Steam.  While I am sure there are unique sounds like Gas Turbine and some other passenger effects.  The diesel stuff was pretty generic and the freight even more so.  There are tons of this stuff out there still.  QSI was for sale too. 

Lastly, I think I can count on one hand the times I had to replace a chip.  And I have done hundreds of PS-1 repairs.  Physically breaking the chip or a leg, and the extremely rare chip failure.  All most all repairs are board or software related.  And those tech chips from MTH don't resolve all those issue.  My secrets from doing this.   G

The main point of this project is not to reverse engineer and/or duplicate the chips. While that would be nice, my goal is to extract the sound data from them so it can be played back on modern software.

1)  Yes, I can both read and write to the EPROM chips.  I’ve only been in the hobby and performing repairs for a few years so I don’t know what the supply chain looked like years ago.  As of this moment chips are available by the 1000’s on Digikey and Mouser.  The downside is they are ridiculously expensive for 512k (4Mbit) of memory; about $5.00 each.

On Digikey go to Product Index > Integrated Circuits (ICs) > Memory.  Search for In Stock=yes, Technology=”EPROM - OTP”, Memory Interface=”Parallel”, Memory Size=”4Mb (512Kx8)” Supplier Device Package=”32-PLCC (11.43x13.97), 32-PLCC (13.97x11.43)”.  I don’t think Access Time matters but I erred on the safe side and went with 70ns.

My last order was:

AT27C040-70JU,

Digi-Key Part Number AT27C040-70JU-ND

EPROM - OTP Memory IC 4Mb (512K x 8) Parallel 70ns 32-PLCC (13.97x11.43)

https://www.digikey.com/short/z98w38

2)  I haven’t created my own ROM code, yet.  My starting point will be a comparison between an L&N F-3 ROM on the deselect list verses the fixed version.  Attached is the first part of said ROM.

3)  I’m very interested taking over some or all of the chip data from MTH if the price is right.

4)  I’ve had to replace a few chips so far.  I think the best use case is to use the backups as a diagnostic tool.  If a PS1 engine comes in with sound issues, burn a new chip from a known good backup, install, and rule out or confirm a chip issue.  I have seen two or three boards with corrupted EPROM chips and also a couple on the DESELECT list.

5)  Sorry for hijacking the thread.  I understand the intent is to get the sounds.  I think the only way to truly do that is to reverse engineer the system.  The PS1 system has the ability to mix two sounds together.  This means engine sounds AND the horn/whistle will play at the same time.  It will be hard to isolate each sound without the original code.

My continuation of this series will be posted in its own thread.

I had some time this weekend so I did more research on µPD78233 programming.  Resources and documentation are almost non-existent.  The most critical piece is the assembler program (MS-DOS based).  I can usually find anything on the Internet but this thing can’t be found.  If anyone did embedded programming during the 1990’s maybe you could check your old floppies and see what you can dig-up?  The assembler package is called “RA78K”.  I found the opcode listing but manually converting from binary to assembly would be like digging the Panama Canal with a spoon.