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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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#1 1 year ago

Recently had a customer ask about the incompatibility I list with the MPU-200 NVRAM when used with Meteor. Got me looking again at what info was out there for this game and to see if there were any updates on what AFAIK are isolated cases of people having issues with using NVRAM on these boards.

The Facts:
1. Some people (not all) have reported installing NVRAM on Meteor caused the sounds to be "noticeably different" (esp the spinner).
2. Upgrading the game to EPROMs fixes the issue for some people (not all).

I hadn't really thought of Meteor being *THE* first MPU-200 game (1979). At least according to IPDB, it's game #113 (for reference, game #112 was Hot Hand). This right here tipped me off of a possible code or hardware issue related to it being the first game using the new board.

Then I see these threads about a bugfix for MPU getting bogged down, loop of counting the bonus 255 times..

And finally, dothedoo even mentions a problem with Zeropower NVRAM on an Alltek causing issues with spinner sound... which seems to be the same type of issues being reported with the MPU-200 NVRAM (or individual 5101 NVRAM Modules used at U8/U13).

Seeing as how a spinner sound issue is mentioned with Alltek + Zeropower, it has me wondering if the bugfix rom IS THE FIX for the MPU-200 NVRAM "incompatibility".

Can those with a METEOR and experience with this whole sound issue and/or bugfix code chime in?

If you had a sound issue when using NVRAM, was it fixed using EPROMs & if so, did you use the newer bugfix code?

If this has been addressed anywhere, let me know. I just thought I'd throw together a full discussion on it and even if the bugfix ROM isn't the solution for MPU-200 NVRAM compatibility, maybe we can see how widespread sound issues are. I've heard some people have upgraded Meteor to NVRAM without a problem.

--- - "Pinball Inspired Technology"
NVRAM, Bally/Stern LED Displays & Mods for pinball machines

#3 1 year ago
Quoted from barakandl:

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.

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.

#9 1 year ago
Quoted from barakandl:

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.[quoted image]

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.

#12 1 year ago
Quoted from barakandl:

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.

Cool, thanks for posting what info you have & the pics. I know we discussed this *WAY BACK* some.. and I just went with calling Meteor "incompatible" with the MPU-200 NVRAM after having a few people contact me with the sound issue. One guy tried a new set of EPROMs and no luck.

Unfortunately without a Meteor to test this in myself, I'd have to setup some kind of bench test to first reproduce the problem and I haven't seen/heard it myself to know exactly what's different At least with this thread sitting out there, some people having the issues can post a picture of their MPU and mention if upgrading to the 2x 2732 eproms fixed things.

3 months later
#20 1 year ago

slochar it's nice to see someone trying to look into this deeper, from a code and eprom standpoint even.

Looks like the needle-in-the-haystack search continues. Thanks for your efforts and insight!

2 months later
#57 1 year ago
Quoted from barakandl:

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.

Awesome! Thanks for taking the time to look at this again Andrew! Nice to have some idea what was happening and a resolution / fix!

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