Problem with MM V
 

Hello all,

I purchased a MM V module with integrated HG550 plus the display module.
It does not work on my Exclusive (latest china model) All I get is flickering lights and random junk on the display.

They are inserted properly and I swapped the sockets many times. I am looking at my Exclusive power adapter which is 9v 300mA.
I suspect the MM V may need a higher Amp but I don't want to risk damaging my Exclusive mother board so I am not trying.
The board works fine with the original Senator module and display.

Any advice on how to get this module to work is appreciated.

Thank you

Murat

AW: Problem with MM V
 

I would try a stabilized power supply with 9 volts and 500mA or higher. However, I suspect that the MMV module is not compatible or defective.

AW: Problem with MM V
 

Hello Murat,

I hope, that my english knowledges are sufficent to give you an understandable answer.
I am not sure, that your power adapter which is 9v 300mA ist the same configuration i know (MM modules are also designed for 9 volt input and 6 volt internal), i have learned, that every universal adapter works better than an original adapter. So probably you should order an appropriate universal adapter for your board and try 9 volt Input or 7,5 Volt Input, but nothing above 9 volt.

Many greetings
Marco

Re: Problem with MM V
 

Thank you Marco and Udo for responding.

I did try 9v 500mA and 9v 800mA adapters. Module still won't work. I did test the voltage internally from the socket without the modules. It shows 5.12v.

If the MM V requires 6 volts it looks like my Exclusive board which came with the Senator module (5v) can not handle it.

The ebay seller has no return policy so it looks like I am stuck with items I cant use.

All the best
Murat

AW: Problem with MM V
 

Exactly that is the explanation. The saitek boards did not need the 6v stuff. Magellan, senator etc. Use only 5v.

Therefore the new saitek boards only for those modules that run with 5V.

Re: Problem with MM V
 

Thank you Mclane.

I was looking at another auction today for a Mephisto Modular plastic board but the seller told me it is 5 volts.

Is there a way of knowing which boards are 6 volts and compatible with the MM V?

All the best
Murat

AW: Problem with MM V
 

MM V should work with 5 V too.

300 mA are sufficient.

"integrated HG550" means: somebody has modified the module.

We don't know what exactly has been modified.

Possibly the module has be tuned to 10 MHz?

It's difficult to decide whether a board is 5 V or 6 V without opening it.

Best way would be to buy a board from somebody who can open it and thus guarantee for 6 V.

Anyway, it could be, the module is damaged and the problem has nothing to do with board, voltage and current...

Cheers
Andreas

Re: Problem with MM V
 

Hello Andreas,

The module has the HG550 in a single eprom. Because it had a nice label I thought it was an original Mephisto product which now I know it does not exist.

It is not tuned to 10MHz.
He has no returns policy. This is my first experience with ebay seller. I don't know what to do since I can not test it on a 6V board.

here is his initial response to my inquiry.
==================================
New message from: nord_strahl (179TURQUOISE_STAR Star)

Hallo,
das Senator-Modul läuft mit 5V Schachbrettern.
Das MM V-Modul mit 6V Schachbrettern.
Wahrscheinlich liegt an ihrem Schachbrett nur 5V am Ausgang an.
Mit freundlichen Grüßen
Norbert
==================================

All the best

Murat

AW: Problem with MM V
 

Hi Murat,

I have just tested a MMV Modul with 10 Mhz and integrated HG550 with 2 Modular and 2 Exlusive Boards both one with 5V and one with 6V.
The Modul works in all 4 Boards.

best regards
Markus

Re: Problem with MM V
 

Thank you Markus.

Although he has no returns policy I politely asked for one.
Stating the information I got from the members here.

Hoping for the best.

Murat

AW: Problem with MM V
 

If there is no way to send it back... we can try to find out what the problem is.

I have a suspicion...

Please, open the MM V Module, take pictures. Show the pictures here.

Some of the "chips" on the circuit board (PCB) are placed in an IC-socket (CPU, Eprom, RAM, ...). Maybe on shipment something happened and this causes contact problems... You can try to loose the chips slighlty and then press in correct position again.

Good luck!

Re: Problem with MM V
 

Hi,
Drahti is right.
As I've already written, once it's flashing, a lot of things are working (in particular the microprocessor, partial access to the roms and rams needed to make these I/Os, the flashing diodes and part of the LCD).
One (if more than one, there's little chance of the program working and continuing) bad contact with a ROM pin can generate errors when checking the hardware when the device is powered up (checking the pieces on the chessboard, for example).
The RAMS are soldered, so only the ROMs need to be removed and replaced in their socket.
With a medium-sized flathead screwdriver inserted between the IC and its socket, rotate the screwdriver through 15-30°, then to the opposite side, and repeat until it is completely extracted. The aim is to avoid bending the pins. Of course, pay attention to the direction of the circuit when reinserting it.
In any case, this type of 8-bit hardware is repairable (no comparison with the GALs on my Risc 2500).

Cordially.

2878FE54DE3E6571AB155EEFA1F81C0E751173F0

AW: Problem with MM V
 

I mean that the modular boards, at least the first ones, ran at 6 volts. I can't say whether this was also the case with the first Exclusive boards.

Re: Problem with MM V
 

Hello everyone

The seller was super nice about the refund.

Not only he did a full refund and he asked me to keep the modules in case in the future I get access to a 6volt board.

I promised him to compensate for his kindness if I can get it to work.

I did remove the CPU and the eprom from the sockets and used contact cleaner spray plus air to dry. After carefully reinserting the
chips the same issue persists. Random lights flashing on the board and module. And garbage characters on display.

I am going to try to purchase a CPU from ebay and if possible a replacement programmed eprom from a member here if any one is able to sell me one.

I feel bad for the seller to be honest.

I will try to post pictures here.

Thanks for looking in to this for me all.

Murat

Re: Problem with MM V
 

Hello Andreas.

Here are the pictures you requested.

https://www.schachcomputer.info/foru...pictureid=3865

https://www.schachcomputer.info/foru...pictureid=3866

I did clean the sockets and re inserted the chips. Did not see any
broken solder points.

Thanks again

Murat

AW: Problem with MM V
 

This looks a bit strange.

Re: Problem with MM V
 

You are right Udo,

there is some damage done by soldering there but I was
thinking it is part of the modification to use a bigger eprom
for the integrated HG 550. perhaps I am wrong.

I am adding a close up for that area.

https://www.schachcomputer.info/foru...pictureid=3868

https://www.schachcomputer.info/foru...pictureid=3867

maybe we got something

Murat

AW: Problem with MM V
 

Thank you for pictures.

CPU is rated at 3 MHz, so in MM V it is overclocked by approx. 65 %... Not unusual for devices designed by H&G. And not likely to cause the problem.

Yes, some solder eyes look odd.

Ideas:
Incompatibilty with your modular board. Try another one if possible.
Eprom could be corrupted.

Do you have other modules oder chess computers with 65c02 inside? If you buy a CPU on ebay... you don't know whether it is working or faulty.

I would try:
another modular board
new Eprom
another CPU

In this order.

AW: Problem with MM V
 

The "problem zone" with corrosion (!) has nothing to do with HG550 modification.

Some part of modification you can see in the upper-left corner of the first picture. There is a region of three solderpads. The connection of middle and right pad is opened and left to middle one has been soldered.

AW: Problem with MM V
 

That would probably have to be measured. :gruebel:

I know something about it, but I'm not an electronics engineer.

AW: Problem with MM V
 

Ich würde das Teil wenn möglich zurückschicken.

I would send the part back if possible.

Re: Problem with MM V
 

Sadly I do not have another modular board to try.

These 2 points on the board have a hairline connection. Do they have to be connected nor not in your experience?

https://www.schachcomputer.info/foru...pictureid=3869

Eprom corruption is possible because when I first opened the module, one side of the Eprom was slightly raised but of course I had already tried to run it.

If any member in the forum is willing to help me with a
pre programmed eprom, I will gladly pay for it.

If I purchase a new 65C02 from ebay, does it matter
if the speed is higher then 3MHz or try to get the same speed.

Thanks again everyone.

Murat

AW: Problem with MM V
 

You should clean everything a little and then rework the critical soldering points with a soldering station, not with a normal soldering iron at mains voltage! Static Overvoltage possible.
However, the right of return would then expire.

Re: Problem with MM V
 

Hi Udo,

the seller issued a full refund and asked me to keep the module.

I don't own a hot air soldering station. Perhaps I should get one.

I like to get this module working. I will order a cpu first then
I will try to get a pre programmed eprom from a member here if anyone is able to help with it.

All the best
Murat

AW: Problem with MM V
 

Then everything is fine. I didn't mean a hot air station, but a normal soldering station.

https://www.netzvergleiche.de/loetstation/