Mephisto MMII Board Dilemma ....

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Scally
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Mephisto MMII Board Dilemma ....

Post by Scally »

Hi Guys,

I've been trying out all my Mephisto Program & Book modules in my 2 Exclusive Boards and my Modular board.

Although I don't own an Exclusive S board, one of my Exclusive boards only has 2 active sockets, the left socket has no connections.

Here is my Dilemma.

As all my Programs Moduls work in my Exclusive & Modular Boards except my MMII Modul. This only works in the Exclusive Board with the 2 active sockets meaning I cannot use my EG240 Book Modul with it.

Is there any reason why this shouldn't work in my other Exclusive Board or my Modular Board?

Thanks in advance..

Al.
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Scally
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Post by Scally »

Hmm, ok I got that wrong ....

Both Exclusive Boards do have 3 active sockets, so I can use the MMII and EG240 book and display in one of my Exclusive boards, but not the other Exclusive Board or the Modular Board.

The Exclusive Board it works in has a pull out rail at the back for batteries, whereas my other Exclusive Board the back is stapled closed.

Any ideas please?

Al.
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Scally
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Post by Scally »

Hmm, ok I got that wrong ....

Both Exclusive Boards do have 3 active sockets, so I can use the MMII and EG240 book and display in one of my Exclusive boards, but not the other Exclusive Board or the Modular Board.

The Exclusive Board it works in has a pull out rail at the back for batteries, whereas my other Exclusive Board the back is stapled closed.

Any ideas please?

Al.
xchessg
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Post by xchessg »

Scally wrote:Hmm, ok I got that wrong ....

Both Exclusive Boards do have 3 active sockets, so I can use the MMII and EG240 book and display in one of my Exclusive boards, but not the other Exclusive Board or the Modular Board.

The Exclusive Board it works in has a pull out rail at the back for batteries, whereas my other Exclusive Board the back is stapled closed.

Any ideas please?

Al.
Hi,

Difficult to tell from within the EU :roll: ... But I'm guessing that the exclusive that runs the MMII is regulated on 6V, whereas the others put 5v on the modules. Which would mean that the board that accepts the MMII, puts too much volts on the other modules...

Buy a Voltmeter and get wiser.

Regards

Xavier
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Scally
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Post by Scally »

Hi Xavier, thanks for your reply.

I have a voltmeter but wouldn't know where to start.

I'm confused as why all my Moduls work in all 3 boards except the MMII Modul which only works on one Board?

Are you saying that only this board is regulated for the correct voltage for the MMII Modul, yet the rest of the Moduls work on different voltages?

The Moduls that work on all boards are:

MMIV, MMV, Rebel Portorose, Mirage, Senator & Polgar (some have their own book and display Moduls)

All three of the power supplies are 9v and also work on all 3 boards.


Cheers

Al.
xchessg
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Post by xchessg »

Scally wrote:Hi Xavier, thanks for your reply.

I have a voltmeter but wouldn't know where to start.

I'm confused as why all my Moduls work in all 3 boards except the MMII Modul which only works on one Board?

Are you saying that only this board is regulated for the correct voltage for the MMII Modul, yet the rest of the Moduls work on different voltages?

The Moduls that work on all boards are:

MMIV, MMV, Rebel Portorose, Mirage, Senator & Polgar (some have their own book and display Moduls)

All three of the power supplies are 9v and also work on all 3 boards.


Cheers

Al.
Hi,

Well you can start messuring the voltage in Modular, that is simple to open. Check the V where on the coils that give current to the board. If you feel you're ready for an exclusive after that, you would need to unscrew things a bit to get to the coils.

About the MMII: That one was build when the Mephisto boards were regulated on 6V. If you open the Module, you will find a diode that takes about 0,7 V from the 6V to get to "about" 5V for which the eletronics are build to work on.

After this first batch of boards (all models btw), Mephisto switched to 5V regulated boards, with the new 16/32 bits Modules. What happens when you put a MMII in such a 5V board: The diode still performs its task, taking 0,7 V from 5V this time and you end up with "about" 4V, which is simlpy not enough to let that MMII run.

You can do 2 things:

Send that Exclusive and the MMII to a repair man, have the exclusive regulated on 5V and have that diode in the MMII removed or circumvented. The safest option.

Or: Keep the Exclusive to play preferably with only the MMII, or only the cheaper 8 bit modules at most. NEVER use this 6V board for Phoenix or 16/32 bit modules! The Displays will be the first to shine bright and after that never again...

Hope this will help

Xavier
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Scally
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Post by Scally »

Hi Xavier,

Thanks, that makes perfect sense.

So only play the MMII with HG240 and it's display on the unregulated Exclusive board.

Play everything else on the regulated Exclusive & the regulated Modular boards.


Cheers,

Al.
Josef
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Post by Josef »

I measured a voltage of the Mephisto chess MM V and there was 5,9V on the printed connector of the electronic board. The power supply is unregulated and has 13V without a loading. For module Phoenix or other 5V modules, you have to disconnect the internal power supply and connect directly an external stable power supply 5V to the printed connector (+5V and ground wires).
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Post by Rhglomb »

Because i found it very complicated to measure the voltage on module side on the mephisto boards, i just build a very easy solution.
Works fine.

Voltage Modul for Mephisto

Image
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