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(Topic ID: 237281)

Stern Meteor ROM Issue - Bugfix, Sound Issues, NVRAM Discussion

By acebathound

1 year ago

Topic Stats

  • 89 posts
  • 11 Pinsiders participating
  • Latest reply 1 year ago by I_P_D_B
  • Topic is favorited by 13 Pinsiders


Linked Games

  • Meteor Stern Electronics, 1979

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#2 1 year ago

I encountered this on my Dad's Meteor. It was working fine with a matched pair of 5101 SRAM and coin battery. This was an early MPU200 board with four masked ROMs. When installing NVRAM one audit would not save correctly and always revert to the same junk value. Also the spinner sound among a few other sound effects was wrong. This is the identical issue that comes up when you use two 5101s of a mismatched speed... IE a U8 is 150ns rated and U13 250ns.

The fix for my Dad's meteor was to change the MPU from four masked roms to two M2732A EPROMs the issue resolved itself. Other people have told me changing to 2732 ROMs also fixed this issue that can happen after installing NVRAM.

I think the problem relates to this

which was fixed on later boards with a blue jumper on top side and then later on the PCB was fixed (i think?).

My replacement MPU using the same FM16W08 chip is fine in meteor. It is triggered a little differently tho.

#4 1 year ago
Quoted from acebathound:

Did you use the bugfix code on the new EPROMs or was that the original code?
See what's standing out to me is the report of the Alltek having the same problem with a Zeropower RAM, but also running the original code. Not saying it may not be related to jumper issue you linked from Pinwiki, but it looks like it's either code or hardware. If we can get some people who own Meteor machines and have had sound issues to work things out here, maybe we can nip it once and for all.

It was the stock ROM but it shouldn't matter if using the bug fix rom as they are different issues that are not related as far as I know.

The "bug fix" is a software issue for the when the bonus multiplier value is allowed to roll backwards from zero to 255 in resulting in a 255x bonus countdown which feels like forever.

The sound issue is feels more like a hardware problem of the 5101 not being accessed properly that I speculate is related pinwiki fix link in my first reply. Stuff related to the sound must get written in the NVRAM. I say this because if you can take a NVRAM module. Write junk data to it, like leave the neoloch test pattern on it. Put that NVRAM module into a MPU200 game. Go into test mode BEFORE starting a game. The sound test is "funny" and not the normal tones. Once you start a game. THEN go into test mode. Sound test is back to normal. So when the game begins for the first time it must make up some data for the sound board that is saved in the (NV)RAM.

#8 1 year ago
Quoted from kbliznick:

Ran into this issue last month. Customer's meteor produced drastically wrong sound effects when using any NVRAM in any of the positions. Initially had installed the 2-in-1 NVRAM. Tried it with 2 individual NVRAM as well as 1 stock RAM and 1 NVRAM in both possible combinations. All produced the sound error. Ended up putting the stock RAM and battery holder back in and went back to normal. Have not tried again.

Four masked ROMs? If so it should work with two EPROMs instead. Also could try the VUA vs VUA-Q2 differences that is in the triggering of the NVRAM chip select.

Maybe I will find some time and grab my dad's meteor board and tinker with it. I bet if I go back to four masked PROMs the sound issue comes back... I also think if I change the NVRAM CS triggering to be like later boards it will also fix it.

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#10 1 year ago
Quoted from acebathound:

So your references to triggering of the NVRAM chip select are to the U17/U19 modifications mentioned on Pinwiki below right?
In other words, very early MPU-200 boards had an issue & modifications were done to some of the boards leaving the factory at some point. Then the MPU-200 board was revised to include those modifications. Do I have that correct?

It seems like there's several possibilities of what's causing the issue with sound with NVRAM..

4x Factory Masked ROMs Being Used (possible solution - try 2x 2732 eproms instead, with board jumpered appropriately)
Very early MPU-200 board being used, *without* the modifications mentioned in the Pinwiki link above.
Code issue in the early masked ROMs and/or possibly related to what the bug fix rom fixes.
State of the NVRAM/memory when first plugged into the board (ie. Alltek "system clear" had fixed the issue?)

This is why I created the thread, to try to get to the root of the problem via people's experiences installing NVRAM on Meteor. If we can get an idea of what ROMs or version of the MPU is being used on games the sound issue was experienced on, we might be able to flush out the actual cause.
It's interesting to hear a "system clear" on an Alltek cleared things up.

The four masked PROMs had the same code on them as the two m2732a EPROMs so I don't think its a software issue. Using four masked PROMs vs two 2732 changes the some of the triggering. Perhaps it is a timing issue since the same effect of bad spinner sound can be achieved by using two different speeds of 5101 RAMs. Also seems kind of strange the 5101s need to be the fast type for relatively slow clock speed. Perhaps the propagation through all the 4000 series requires the fast 5101s.

As far as the 5101/nvram triggering I think the original mpu200 design had the error which in most cases did not cause a problem with 5101 SRAMs. Stern identified there was a problem and started adding the blue jumper wire to boards during or sometime after or during meteor. Past that the MPU board was changed per the pinwiki picture. Users that do not have a sound problem in meteor with NVRAM probably have the fixed MPU200 board either with the blue jumper wire or a PCB where the layout was changed for the fix.

#11 1 year ago

Here is a mpu200 made in 1980. This board has continuity where the factory blue wire fix normally is so should be a later mpu200 with the fix.

I looked and couldn't find any early mpu200 around my place. Can anyone post the same area of a meteor pcb that acts up with nvram to see what is different? Next time I am at my dad's house I will look at that early meteor board.

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#13 1 year ago

I just dug up some facebook communication I had with someone that fixes boards.


Him: Any thought on a Stern mpu200 with a SB300 sound board not liking NVRam? Someone said you may have posted on this in the past

Me: Yeah. I have ran into it once with a meteor. 5101 sram worked fine. With nvram, the sound effects where off. Quite similar to the effect of using two different speeds of 5101 srams. It is a timing issue of some sort. In my case, changing from four masked roms to two 2732 eproms solved it.

Him: Interesting. Same game. I'll try changing it to 2732s.
Him: That fixed it. Thanks

3 months later
#25 1 year ago

Also keep in mind you can replicate the identical issue with NVRAM in meteor by using slow 5101s or mis matching speeds of a 5101s. Same sound problem and same audit problems.

Small changes in the CPU clock speed seem to effect the sound board sounds. You can sit two identical MPU200 games with the same hardware in each next to each other and they usually sound a little different than each other. Years back i bought some soviet cloned 6800 CM601P chips and noticed they even made pitch changes to the sound board when swapped in versus a moto 6800.

If its a timing thing I wonder if all the 4000 series gates and maybe the earliest MPUs used slow 74L which has a 3x longer gate delay than 74LS. The boards I make is all HC(T) logic chips for the most part. For my MPU the chip select the for RAM more like the Bally MPU with VUA+Q2 instead of just VUA at U17C

#27 1 year ago
Quoted from slochar:

On a tangential note, do you ever run into issues with people using your -35 to -200 upgrade kit with the sound? Might provide a clue there.

No problems with the -35 to mpu200 kit that has been reported to me. Its not a very popular item tho. I tried it in at least four games myself and never any trouble. I am pretty sure I tested it OK in a Meteor as well. Maybe slight differences in pitch of sound effects vs the original MPU200 board that was replaced, but within the normal range expected by original and aftermarket boards and not like Meteor where it is wrong sounds entirely.

Phillips 5101s where pretty good to me. I think they where 150ns. I bought big lot of used pulls of them maybe 6-8 years back and never had much trouble with them. When I was fixing original boards dead 5101s in general was really really common.... even beyond the corrosion thing.

2 weeks later
#47 1 year ago

VUA-Q2 has a 150ohm (wow thats stiff) pullup. Wouldnt that pull the data bits up to 4.4v or so with the series diode voltage drop? I never fully understood what they where trying to accomplish with that vs just pulling up all eight data to 5v.

With a FM16W08 the system works fine with all the data bits pulled up to 5v. The 5101s are also powered by a circuit that drops the 12v down to around 5v. As the 82ohm resistor drifts the voltage to the 5101s rams will change which may effect timing? The replacement MPU powers the fm16w08 right off of the 5v.

VMA to the 6840 will actually lock up some MPUs. I think its a fail mode of the 6840 chip itself but appears somewhat common as I ran into it numerous times back when I used to repair original boards. I'd fix a MPU200 that worked fine for me but is locked up in another game. Using a 32pin ribbon cable or lifting the VMA pin out of the 6840's socket resolved it and the sound board and MPU work fine.

1 month later
#48 1 year ago

I just had a message from someone using the aftermarket MPU in meteor that was having the sound problem with the free play version and divide by ten versions. When he switched the software the factory bonus x underflow bug fix rom the sound problem cleared.

Testing around various things when the NVRAM chip is blank I can use any meteor software version and the sound is fine. If I boot a Bally game first, then go to Meteor, the spinner sound and other sounds is wrong. I can always use the factory bug fix rom no matter the RAM contents and the sound works fine.

Something saved in the RAM chip seems to be able to cause the sound problem in certain cases. That makes it seem like a software bug but why on original MPUs does mixing the speed of the RAM chips do the same thing???? Odd issue but using the "factory bug fix" ROM seems like a solution.

#50 1 year ago
Quoted from slochar:

That kind of mirrors what's going on with mine, although of course the software I'm using doesn't exist any where else yet, but it is based around the original non-factory bugfix software.

I can tell other games must save stuff in RAM related to sounds. Like in Big Game when I first time boot with a blank NVRAM and you add credits, the credit noise is wrong and sound test is wrong. Once you start a single game then the credit noise is normal and sound test goes to normal for big game. So something happens at game start that effects what the sounds are in Big Game.

Maybe compare what happens at game start in the factory bug fix version of meteor and the other versions.

#52 1 year ago

I also noticed a problem in Nine Ball with the background sound being different that is the same kind of issue as in Meteor.

#54 1 year ago
Quoted from Coyote:

I have been holding off saying anything, because I know that sometimes 'noise' can be bad and help get away from the real issue, but I thought I'd share something -
I was running v24 (the 7-digit OS) for over a year now. On original hardware (do not know if my MPU had that trace fix or not) - without any issues. No sound issues at all.
Then, at some point back in this past December or January, it started showing the sound issue. I went ahead and rebuilt my SB-300. A LOT of chips for replaced (almost all of them, except for the timer), and caps all got replaced. This did NOT fix the issue.
Then I went ahead and got @barakandl 's MPU board. (For two reasons - to have a good 'test' board to swap out if needed, and to see if it helped with this.) Setting the DIPs to the v24 on IT (not sure if code was identical), the issue did NOT go away.
I have NOT replaced the timer on my SB-300 yet. That is next.
However! Here's something interesting. Back in May, had guests over, and was playing multi-player games. Everything seemed to be fine - except for the audio. A couple weeks after they left, I turn the game on, and notice that my HSTD is .. corrupted. Displays read "5<space>438". I have yet to reset the board, but.. thought I'd mention it in case it was important.
Also - at some point between the start of v24 and now, I replaced the sound cable. My **original** cable was ALL pins. The replacement I got was only 32 pins. (Hey, @barakandl - remember I mentioned a long time ago to make a second adapter for the audio cable, allowing it to use a ribbon cable? So in case new sound boards are released, it'd be easier to hooke them up? And you said 'nnaaah' .. and now you made a sound board, even, and STILL can't use a ribbon cable. )

Adding a two row ribbon cable would be nice but the reason I don't switch to that is the the original boards where not designed that way. Not everyone is going to replace both the MPU and Sound board at the same time and they may mix aftermarket brands. Sure I could have both connectors but then assembly and BOM goes up... by a negligible amount but still. Then I would also get email questions about where the connectors go and why there is an extra one etc... I had China make new 16p 0.1" and individual wires which works fine for SB100 and SB300. They are reasonably priced even compared to ribbon cables so I will probably never change to two row ribbon. Go back in time and tell Stern to do 2x16 ribbon instead. =D

I can email you a ROM file that will clear out the RAM back to FF and that should fix the replacement and original MPUs having sound issues. I am going to start including RAM clear software in the combo ROM.

Not sure what to make about the memory corruption. If the game ever jumps out of the software for whatever reason it can write crap to the NVRAM chip. Best guess is something like that happened at some point. Unplugging the J5 plug while the MPU is running is one way to possibly do it.

#56 1 year ago

Meteor versions besides the factory bug fix one does not initialize the RAM like it should and corruption of certain areas of the memory will cause the sound problem.

To fix this problem you need to fill the (NV)RAM with 00. I have put software on my website that will fix Meteor sound problems. Burn the software onto an appropriate chip. Power on. Wait until the LED starts to blink. Then the RAM is filled with 00 and you can go back to Meteor and the sound will work.

Bottom of the page you can find a zip file with the ROMs in it.

THANK YOU to everyone who helped with information and resolution of this bug.

#59 1 year ago
Quoted from Coyote:

Ah, awesome! Thank YOU!
I have the source for v24, and would like to add it in. Or have it added in to that version, if we can work that out!

The memory clear is a separate ROM file from the meteor ROMs. You would remove the Meteor v24 rom. Boot up the mem clear rom. Wait for the LED to start blinking. Then the RAM is filled with 00 and you can switch back to your meteor ROM. The sound problem will then be fixed. Audits will also be cleared back to all 00.

#61 1 year ago
Quoted from Coyote:

Sorry, I was referring to this part, here:

Could we get it added to the v24 ROM? (Either sending me the code you have, or I send you the source for v24..)

I don't know how to modify the sound bugged Meteor ROMs but the theory for the fix would be to write zeros everywhere sound values are stored in memory at boot up.

The "factory modified" meteor ROM version does not have the sound bug, so Stern must have realized there was a problem and fixed it in that version. Maybe you can compare the two ROMs and transplant the all the sound code from the factory modified ROM into all the custom ROMs that are based on the sound bugged Meteor. That is out of my skill set. I am good with hardware... software not so much.

Basically use the Factory Modified ROM if possible. If you really want the free /divide by 10/ home ROM / version 1 you must do a run of the memory clear software if you have bugged out sound. Then as long as you keep the MPU set for meteor the sound bug should never come back.

2 weeks later
#64 1 year ago
Quoted from Coyote:

Well, update on my machine -
The pinball gods hate me, sadly.
Reset NVRAM using the ROM above - turned game on, went through audits and reset everything. Played game, still had sound issues. I thought, 'Hey, maybe one of the new audits in the v24 is affecting it!' So I put the RAM clear ROM back in, power game up. Got static out of the sound board, and lights would randomly flicker. Took ROM out, checked to make sure (idiot me) didn't bend a pin - nope. Reinsert ROM, this time get the expected flash. Remove ROM, turn game back on and play withOUT resetting audits. Still messed up sound.
Next step for me? Replacing the chip on the sound board.

What sounds are wrong? When the bug is happening the credit noise will be wrong(i think its a beep instead of explosion) and the spinner sound is missing or just a click that silences all other sounds.

After running the RAM clear software did you notice that the audits all got reset back to 00?

#66 1 year ago
Quoted from RC_like_the_cola:

I'm having this issue where the sound for my spinner is basically just a rapid click. Guess I've been under a rock about this issue lol. My MPU is one of your earlier versions that had no option to choose the game. I had to pick the game upon ordering and I can't change it now. Will the roms on your site work with my older version? I have a friend who can burn the chip.

The RAM clear should fix you up but your best option is to upgrade to the non bugged version of meteor as long as you do not require free play, divide by ten or etc..

Bottom of the page there is a zip file containing the RAM clear software.

If your board has a single chip at U2. Use the memclear_v2_U2.764 file onto a 2764 EPROM. Power up. Wait until the LED starts to blink. Then go back to your meteor ROM.

If you want the bug fixed version of meteor software I can email you that ROM file. If you mail the entire PCB back to me I will take care of it that way too.


#67 1 year ago
Quoted from Coyote:

Well, update on my machine -
The pinball gods hate me, sadly.
Reset NVRAM using the ROM above - turned game on, went through audits and reset everything. Played game, still had sound issues. I thought, 'Hey, maybe one of the new audits in the v24 is affecting it!' So I put the RAM clear ROM back in, power game up. Got static out of the sound board, and lights would randomly flicker. Took ROM out, checked to make sure (idiot me) didn't bend a pin - nope. Reinsert ROM, this time get the expected flash. Remove ROM, turn game back on and play withOUT resetting audits. Still messed up sound.
Next step for me? Replacing the chip on the sound board.

another idea is to try the bug fixed version of meteor as the sound bug does not exist in that version no matter the ram contents. if the sound is still wrong there is some other issue going on.

#70 1 year ago
Quoted from Coyote:

(1) - Yes, that is correct - the background noise is wrong, the spinner silences everything, and other (seemingly) random noises are cut off or distorted. (Like the explosion.)
(2) - No, everything got reset to either "blank" or "0000". In this state, I CAN play a game - no display in the credits window, but it'll start games. After manually resetting all audits to "00", then I have to add credits before starting.
I'm not TOO worried - at least, not until I get a new timer chip for the soundboard. It's been completely rebuilt, including bypass caps (and audio caps), and there's only two chips that have NOT been replaced on it.

Ah, good point! No wonder you get paid the big bucks. I didn't think of this; will give it a try tonight.

(2) the audits should all show 00 after the memory clear so it did not reset the ram properly. If you push the NMI button while the LED is blinking it makes the ram clear software it do a FF fill where the bug will still exist and most audits will be blank or show 0000. Boot memory clear, wait for led to blink, and then power down. Don't push the NMI. Then the audits should all show 00 and the sound bug goes away. If you used the 27512 sized file run it from U1 expanded ROM spot, if you used the 2764 sized file run from U2.

4 weeks later
#83 1 year ago
Quoted from slochar:

Yeah I don't think the silence is normal. I'll play around on my large supply of OEM boards with and without NVram as well as probably every revision of Andrew's boards. Probably send you a test version once I determine what's different (probably a timer somewhere.....)
First things first is I have to remove the non-working background sound quash that doesn't work... like, at all. I'd always assumed it did from RGP years ago but I guess no one (including me) ever tested it until v27. I don't WANT to remove the bg sound, people that get meteor, get it, and all other people that don't like it.... tough

BG sound dip switch selection?

I have no problem with BG sound until it gets to the 2nd octave and its like a dog whistle.... then i'd rather have it turned off.

#85 1 year ago

err.. big game sounds great i think... its meteor's background sound. i meant to say dip switch control for meteor's background sound would be nice if easily possible.

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