Major Havoc PCB - Dedicated vs. Conversion

KillerKades

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I have a few MH boards that I am trying to test in a MH --> Tempest conversion. Of the boards, 2 have the quad pokey eliminator and 1 does not. This brings up the question:

1. Is there a difference between a Dedicated MH PCB and a Conversion PCB? (not talking about the conversion board, just the main board itself) And maybe electrically speaking -- I'll get to this later.

2. Does the presense of the quad pokey eliminator mean it is for a dedicated cabinet. Or is it something else? Or does it even matter?

If there is a difference,

3. Can a dedicated board plug into a conversion board and be used in a conversion cabinet (i.e. Tempest)?

So hypothetically speaking, :D if one were to plug the board with the quad pokey eliminator in a conversion board and Tempest cabinet and say F4 & F5 blow on the power brick, is this a sign of different boards -- dedicated vs. conversion or more of a board issue.

Not sure what the fuses control just yet but with F4 & F5 blown, the spot killer comes on.

So, any answers, ideas, smacks across the face?
 
I have a few MH boards that I am trying to test in a MH --> Tempest conversion. Of the boards, 2 have the quad pokey eliminator and 1 does not. This brings up the question:

1. Is there a difference between a Dedicated MH PCB and a Conversion PCB? (not talking about the conversion board, just the main board itself) And maybe electrically speaking -- I'll get to this later.

2. Does the presense of the quad pokey eliminator mean it is for a dedicated cabinet. Or is it something else? Or does it even matter?

If there is a difference,

3. Can a dedicated board plug into a conversion board and be used in a conversion cabinet (i.e. Tempest)?

So hypothetically speaking, :D if one were to plug the board with the quad pokey eliminator in a conversion board and Tempest cabinet and say F4 & F5 blow on the power brick, is this a sign of different boards -- dedicated vs. conversion or more of a board issue.

Not sure what the fuses control just yet but with F4 & F5 blown, the spot killer comes on.

So, any answers, ideas, smacks across the face?

Dedicated's came with a quad pokey and conversions came with the quad pokey eliminator board, but that doesn't matter, you can substitute one for the other. The only difference I know of is the crystal speed. But as far as I know, you can plug either a dedicated or conversion board into either cabinet and it should be ok and not cause damage. The board itself may have a problem and blow fuses and such, but it won't be a problem just because it is dedicated or a conversion. Check the serial number stickers if they are still on the board. That will tell you if it's a conversion or dedicated. There are some letters before the number and that will tell you (I don't recall the letters right now, but post them and someone will verify).
 
The letters in front of the serial numbers either start with CB or CK. I'm not in front of the boards to say which series have the quad pokey eliminator.

Funny thing is the board with the quad pokey works fine with the conversion board. So if your statement is true, a dedicated board works just fine. One with the eliminator board is giving me the issues with the fuses blowing. Haven't really tried the other with the eliminator until I get more information.
 
Conversion boards will have a CK part number and will have the MC1495(?) pincushion circuit jumpered over w/ long wire wrap wires, since the correction circuit on the board is for amplifones, and the kits had a separate correction circuit on the harness adapter board.
 
The letters in front of the serial numbers either start with CB or CK. I'm not in front of the boards to say which series have the quad pokey eliminator.

Funny thing is the board with the quad pokey works fine with the conversion board. So if your statement is true, a dedicated board works just fine. One with the eliminator board is giving me the issues with the fuses blowing. Haven't really tried the other with the eliminator until I get more information.

CB = Conversion Board, CK = Conversion Kit, either way, they are not dedicated boards, which I think have UR (UpRight) as the letters.

You can definitely swap the quad pokey and the quad pokey eliminator boards and test, you won't hurt anything by just doing that. It sounds like your problem is elsewhere than the pokey's. I've never heard of a bad pokey blowing fuses.
 
I was checking out this old thread and I am a bit confused on the different board types. I just bought a Major Havoc PCB off of Ebay. When I paid via Paypal I noticed the seller's name was Scott Evans and the Ebay listing was in Roseville, CA (AtariScott). Knowing he has a dedicated Major Havoc and that the board was listed as untested as well as what was discussed here I ask him why he couldn't test it in his cab. The listing also stated with quad pokey, but it definitely wasn't the eliminator board as could be seen from the picture. Therefore according to this thread it would be the dedicated versioin, unless maybe someone switched the eliminator with dedicated version pokeys? Other than the fact that his machine is 130 miles from his home, Scott said he couldn't test it because it was the conversion kit board and does not plug directly into the dedicated machine. So does anybody really know what the correct information is? These information pieces are at odds with each other and I would like to know for moving ahead with collecting parts for my future Major Havoc project?
 

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A MH board from a dedicated machine will have:
serial number starting with "UR"
12MHz crystal at Y1, 10MHz crystal at Y2

A MH board from a conversion will have:
serial number starting with "CK"
10MHz crystal at Y1, 8.9MHz crystal at Y2
M & N on J19 will be cut from their traces, and there will be two small jumper wires running to them

If you plug a dedicated MH board into the adapter board in a MH conversion cabinet, you won't get any video. (The monitor will get a Y signal, but not X.)
I'd have to ponder whether or not you could test a conversion board in a dedicated cabinet.

Whether you have an actual quad pokey or a quad pokey eliminator board doesn't determine the board type.
 
A MH board from a dedicated machine will have:
serial number starting with "UR"
12MHz crystal at Y1, 10MHz crystal at Y2

A MH board from a conversion will have:
serial number starting with "CK"
10MHz crystal at Y1, 8.9MHz crystal at Y2
M & N on J19 will be cut from their traces, and there will be two small jumper wires running to them

If you plug a dedicated MH board into the adapter board in a MH conversion cabinet, you won't get any video. (The monitor will get a Y signal, but not X.)
I'd have to ponder whether or not you could test a conversion board in a dedicated cabinet.

Whether you have an actual quad pokey or a quad pokey eliminator board doesn't determine the board type.

And...please confirm...the CK / conversion boards are for running on Wells Gardner monitors. The dedicated versions are for running on Amplifones....correct?
 
Great info! Thank you! So if you take a dedicated board and change the crystals to the conversion cab crystals and then do the J19 modification you could play the dedicated board in a conversion cab with the adapter board. Not that I would necessarily do this, but I am attempting to understand this info.

A MH board from a dedicated machine will have:
serial number starting with "UR"
12MHz crystal at Y1, 10MHz crystal at Y2

A MH board from a conversion will have:
serial number starting with "CK"
10MHz crystal at Y1, 8.9MHz crystal at Y2
M & N on J19 will be cut from their traces, and there will be two small jumper wires running to them

If you plug a dedicated MH board into the adapter board in a MH conversion cabinet, you won't get any video. (The monitor will get a Y signal, but not X.)
I'd have to ponder whether or not you could test a conversion board in a dedicated cabinet.

Whether you have an actual quad pokey or a quad pokey eliminator board doesn't determine the board type.
 
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