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  Repair a Conchess Ambassador
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   Author  Topic: Repair a Conchess Ambassador  (Read 1980 times)
altomcat
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Re:Repair a Conchess Ambassador
« on: October 16, 2010, 02:53AM »
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Quote from: Kostea on October 15, 2010, 09:48PM   

I also read where you attempted to read the ROMs, and it didn't work.
You said that you soldered wires to the ROM pins, but you didn't mention where the other end of the wires went (or maybe I missed that detail because of translation).
Did you use a device programmer of some sort?


As you bring some interest for my work, you can find below a picture of my own tools



Yes i made my own eeprom reader and i use a device programmer from my job but i did not talk much about it on my article.
I use the USB for power supply and a serial to usb adapter to retrieve the data from the eeprom to the computer. By reading every memory cells more than one time, i can check if the component is faulty. I also reports CRC checksum as a real programmer will do.

At the bottom of the picture, you can see the first eeprom of the module. At first, i tried to dump it directly from the PCB but it's a bit complicated to explain here how i have done this ... Then i cut every component leads with a special wire cutters (take a look here)and i tried to dump through the test clip but it did not work well.
The best solution was to solder the eeprom again on a DIP socket and dump the content with the reader.
I hope it sounds clear to you

Best regards, Arnaud.




« Last Edit: October 16, 2010, 02:55AM by altomcat » Report to moderator Logged
altomcat
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Re:Repair a Conchess Ambassador
« Reply #1 on: October 16, 2010, 02:09AM »
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Quote from: Alain Zanchetta on October 15, 2010, 09:52PM   

congratulations for the great work !


Many thanks Alain
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Alain Zanchetta
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Re:Repair a Conchess Ambassador
« Reply #2 on: October 15, 2010, 09:52PM »
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Hi Arnaud,

congratulations for the great work !

best regards,
Alain
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Kostea
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Re:Repair a Conchess Ambassador
« Reply #3 on: October 15, 2010, 09:48PM »
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Hi Arnaud,


That's great news! You fixed it really fast! No real challenge for you, right?

I read your webpage, interesting projects you have there.

I also read where you attempted to read the ROMs, and it didn't work.
You said that you soldered wires to the ROM pins, but you didn't mention where the other end of the wires went (or maybe I missed that detail because of translation).
Did you use a device programmer of some sort?


Keep up the good work,
Kostea
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altomcat
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Re:Repair a Conchess Ambassador
« Reply #4 on: October 15, 2010, 10:46AM »
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Hello guys,

Many thanks for your help and your support. I can tell you today that i have succeeded in repaired this chessboard (from last week). I wrote a little story about it on my blog but i'm sorry, it's in french. As Kostea suggested me, i did not give up since last month. Moreover, i have done a little retro-engineering to draw the schematics. You can have a look to this little work and download the pdf from my site.
It was a bit painless but the result worths the overall work.

At first, i thought the eeproms were damaged. The behavior of the chessboard was very strange and the processor talked to only one eeprom and one ram chip.  The previous owner told me he had changed the cpu but in fact, it was bad.
There was many other defective electronic parts like the buzzer, the column decoder, leds & reed switches that i changed.

Finally, i've already lost and won some games. It's an happy end, isn't it ?
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hondo
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Re:Repair a Conchess Ambassador
« Reply #5 on: October 15, 2010, 12:45AM »
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Hi Arnaud... I am not sure how much help I can be but I do have a cpl. questions first. I see where you bypassed the power supply input and went directly to the input leg of the voltage regulator and ground. Why didnt you just use the power supply that comes with the game? Next...  are you sure you are using the correct input voltage and have you checked the regulator output voltage? I am assuming you have some electronics background by the way you wired the lead to the regulator... have you checked the filter cap. and the diodes in the circuit just for starters? Have you checked all solder joints? Again to rule out issues have you checked the ribbon cable and the PC board real carefully for bad soldering etc.? I looked the best I could and didn't see where there were parts that were obviously swapped out but that doesnt mean they weren't. If you are sure they were ... I would try to figure out why they were replaced and what function they served. Most people wont try to replace IC's unless they know what they are doing so if they were replaced they may be functional. I would start with the basics and trace voltages to IC inputs and then check the outputs to see if they are close. A scope would be helpful if you have one. The fact that you get an instant chirp on and then nothing may be a cap. shorting to ground but thats a guess... I would go through the power supply circuit real carefully as that would be my first place to start. Hope I have been of some help.  Regards    Hondo
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Kostea
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Re:Repair a Conchess Ambassador
« Reply #6 on: October 14, 2010, 01:52PM »
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Hi Arnaud,


I do not own a Conchess Ambassador, and I cannot help with any pictures of the electronics.

From what I read on forums and Internet, I have never heard of anyone having repair manuals for any brand of chess computers.

It sounds like whoever tried to fix the chess computer simply 'threw parts at it' hoping that by pure luck a defective component will be replaced. Not a very scientific approach but on occasion it happens to work.

Did the seller mention how the Conchess became defective? Sometimes this particular info gives a valuable hint for an area to focus on troubleshooting.

I hope that you supplied between 4.5 - 5.5 volts to the electronics when you tested them with the lab power supply, otherwise you may have toasted some chips.

Are you somewhat familiar with how these old computers work? I'm talking about CPU connection to RAM/ROM, memory address decoders, inputs/outputs, etc? You don't have to be an expert on the 6502 CPU, but if you know some general rules, and with the help of datasheets for the electronic parts (they can be easily found on Internet) you would be able to figure things out.

The good thing is that, looking at the pictures, all parts are standard, easy to find info about or purchase, there is nothing special here.
The bad thing, is if any of the ROM chips are bad, you're screwed. Yes they can be found to buy but they will be blank/empty when brand new. Finding the data files to burn them can be a hassle. Someone has to lend you the ROMs or computer to copy them. Who's going to give you a working Conchess to mess with?

If you have any questions, please feel free to ask. I'll try to answer them to the best of my knowledge, as it is difficult to troubleshoot digital electronics from a distance.

I realize that after reading my post, you won't be a step closer to repairing the Conchess.
I want to encourage you to not give up. Fixing something could be a fun thing. You'll better yourself overcoming all odds. Some people are trying to save endangered species from extinction, we should do the same about the good old chess computers.

Good luck,

Kostea
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altomcat
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Re:Repair a Conchess Ambassador
« Reply #7 on: September 11, 2010, 04:12AM »
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Thank for the link  Bryan. I know this page but this does not answer my problem.

What is the behavior of this chessboard when you switch it on ? what about sound and led lighting ?

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Mephisto
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Re:Repair a Conchess Ambassador
« Reply #8 on: September 9, 2010, 05:10AM »
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Hi Arnaud
Have a look at the following Conchess Repair Page by Mike Watters, I'm sure it will help you.
http://www.chesscomputeruk.com/html/conchess.html
Regards
Bryan
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altomcat
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Repair a Conchess Ambassador
« Reply #9 on: September 9, 2010, 12:09AM »
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Hello,

I'm a french owner of a Conchess chessboard i bought on ebay few days ago.
It's completely broken and i'm trying to repair it.

About the failure, there is no light, a "very very" short sound from the board when i switch it on and off. Nothing more ...

Many electronics parts have been changed on the chess module and on the interface board before i got it. It would be great if someone could send to me a close-up picture of the interface board and the module board to see the references of all electronic parts.

EDIT: here are my pics

Two wires connected to a lab power supply for testing purpose


The chess module cartdrige


The ribbon cable between chessboard and interface board.

Another question, where can i find the service manual if it exists ?

Thanks for help, Arnaud.
« Last Edit: September 9, 2010, 10:14AM by altomcat » Report to moderator Logged
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