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  Questions to repair a conchess
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   Author  Topic: Questions to repair a conchess  (Read 1120 times)
bobosse
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Re:Questions to repair a conchess
« on: March 9, 2009, 03:11PM »
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Some news:
First of all thank you to all, you helped me a lot.

Some information:
- these 2 pages helped me a lot
http://www.ismenio.com/chess_conchess_ambassador.html
http://www.chesscomputeruk.com/html/conchess.html
So thank You Ismenio and Mike.

The explanations from Mike around Reed Switch Corrosion are right. Fixing such problem is a step by step approach because some Reed Switch are not stable - they are just temporary working after a test with a good magnet. And changing the 64 reed switches is efficient but very expensive.  So after some time and several replacements, it seems ok now but I will test it again and again each week during some time to be sure that it's stable.

The diodes:
Thank you Arno Kreuzberg, Mychess and TerryG, These are common diodes 1N4148 but I used 1N914 as proposed by TerryG/Mychess and it works very well. To identify the faulty diodes, I used the multimeter test of TerryG and it helps a lot.

Leds: Leds have often bad contacts. Moving them using a pen is usually enough to get them work again. Of course, it's better to use a soldering iron to make a better contact.

I also had the control button problem described by Mike. But using a contact cleaner spray alone was not enough. I also used a small screwdriver to scratch the contact under the thin metal plate without unmounting the control button. Now it works very well.

Now, I have 2 Conchess Monarch working. I will follow them carefully during some weeks to identify the remaining unstable reed switches.

Thank you again, this is a great forum 

JB
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hondo
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Re:Questions to repair a conchess
« Reply #1 on: February 25, 2009, 11:48AM »
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Hi....might I make a minor suggestion with reference to checking the diodes. In order to get a meaningful reading most times it's necessary to at least remove one end from the circuit board. This would prevent getting a false reading.  Regards  Hondo
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TerryG
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Re:Questions to repair a conchess
« Reply #2 on: February 25, 2009, 09:48AM »
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  Bobosse,
                    I agree with Mychess that the diode is most likely 1N914 / or 1N4148 common switching diode used on many applications to block reverse current to another part of the circuit.
If you have a multimeter (digital, preferably) measure across one of the other diodes (they are usually oriented the same way, like on your photograph one end has a black band). Then measure your suspected diode, in one direction you will get about 600 - 900 ohms, when you reverse the meter leads there should be no measurement, not even on the highest scale(over Megohm).
If you suspect a faulty diode then again measuring across a replacement and soldering it in place so that it is in the same orientation again. The replacement may not have the same colour bands but virtually any high speed switching diode will do the job.
Note it will not be a zener diode as they are used for power regulation circuits and they are connected in a reverse direction, as they only conduct when the voltage approaches its breakdown value.
It's a fairly simple job to replace diode or indeed LED or reed (usualy far easier than getting to it!!), but if you are of a 'certain age' like me seeing up close can be a bit tricky without a magnifying glass. It's also a good idea to make sure if any other components need changing like LED's, as occasionally they can get a bit dull.
                        Terry
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TerryG
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Re:Questions to repair a conchess
« Reply #3 on: February 25, 2009, 12:17AM »
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Hello,

This is probably switching diode type 1N4148 low current (JEDEC code yellow-brown-yellow-gray). May  be replaced with a 1N914 diode.
Max peak voltage : 75 V
Max power : 500 mW
Max current : 450 mA
mean current : 150-200 mA.

Price: 0.50 euro for 10 units , 3 euros for 100 units.

Mychess.

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hondo
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Re:Questions to repair a conchess
« Reply #4 on: February 24, 2009, 02:16PM »
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Ok....I have taken a look at your circuit pic. for what thats worth. First here is a disclaimer...  LOL...  I cant fix or diagnose or even see for sure what your problem is so what I am about to tell you to do may be worthless !!! With that said I also want you to know that if you choose to do this you do it at your own risk and expense and I dont recommend you do it with out knowing for sure whats wrong or what part to use.

Now... the diode may very well be a low voltage zener at approx. 2.7 volts or so as many game IC'S function at approx. 5 volts. This is just a guess...read GUESS... Radio shack does carry an assorment of low voltage assorted packages of diodes. Many are approx. around the 2 to 3 volt range....maybe ...just maybe you could get lucky...  You do this at your own peril and risk...  LOL...good luck....    Hondo
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mychess
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Re:Questions to repair a conchess
« Reply #5 on: February 24, 2009, 02:02PM »
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Bonsoir

http://www.chesscomputeruk.com/html/conchess.html

Bonsoir!

Mychess
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hondo
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Re:Questions to repair a conchess
« Reply #6 on: February 24, 2009, 01:57PM »
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If you are absolutely sure thats the problem(without checking!) then I would look for identifying numbers or letters on any of the existing diodes that are in the same placement as your "bad" one. Remember that you need to put/place the diode with the "bar" in the same position as it's in now. Placement of the diode is critical to how it functions in circuit. You could also take it out of circuit and bring it to a local radio TV repair shop and ask them if they could help to identify what type etc. so you can order one. I would do this rather than go to a "radio shack" kind of parts store where the employees may know 0 about what you need.  Hondo
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bobosse
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Re:Questions to repair a conchess
« Reply #7 on: February 24, 2009, 01:43PM »
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Some answers are here:
http://www.ismenio.com/chess_conchess_ambassador.html

Each square has a diode, a LED and a reed switch. It's a very simple electronic on the board.

It should be a diode zener (If I remember well the comments from the electronic shop) - but I am not an expert.
When the diode is out of order, you can see the following problem. I move one piece and several red leds of the area are switched on (instead of a single one). As it's not a reed switch problem and not a led problem and the electronic circuit looks nice, it can only be a diode problem.
« Last Edit: February 24, 2009, 01:51PM by bobosse » Report to moderator Logged
hondo
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Re:Questions to repair a conchess
« Reply #8 on: February 24, 2009, 01:19PM »
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Diodes serve and perform different functions in a circuit. It would be helpful before you pluck one out of the board to know first that it is bad. It would also help to know what KIND of diode it is...such as a ZENER diode and is it ACTING as a voltage limiting part or is it functioning in the protective part of the circuitry and preventing reverse polarity hookups? Some times, all that info will help to get you closer to an accurate part subsitution...  Good luck with your repair...  Hondo
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bobosse
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Re:Questions to repair a conchess
« Reply #9 on: February 24, 2009, 02:29AM »
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Quote from: hondo on February 23, 2009, 08:30AM   

Hi JB,
ok...by your response, or lack there of, I can see you most likely aren't aware of how to read or check diodes. Just briefly...diodes arent color coded ....for the most part they USUALLY have a numerical code ie. 1n914 etc...  with that said I think you might want to consider having someone with experience close to where you reside help you resolve this issue. One other thing to consider is what CAUSED the problem and that may help you find where the problem is and to further isolate the problem parts. Good luck and best regards    Hondo


Sorry for the color code mistake. I came to an experienced people locally in an electronic store and he said me: the black line indicates that it's a diode and I can not read the reference (I thought it was a color code but I was wrong). So this experienced electronic expert said me: please try to find the reference. That's why I posted the question here. I will send a mail to Arno. Maybe he has some electronic schemas.

The cause of the problem is not obvious. The game I got is probably coming from a repair shop. because there was here 8 different games - all out of orders. I just took 2 of them to be able to build one working (and I am not far now - I was able to play a game). But it's to bad not to try to repair the second one.
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hondo
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Re:Questions to repair a conchess
« Reply #10 on: February 23, 2009, 08:30AM »
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Hi JB,
ok...by your response, or lack there of, I can see you most likely aren't aware of how to read or check diodes. Just briefly...diodes arent color coded ....for the most part they USUALLY have a numerical code ie. 1n914 etc...  with that said I think you might want to consider having someone with experience close to where you reside help you resolve this issue. One other thing to consider is what CAUSED the problem and that may help you find where the problem is and to further isolate the problem parts. Good luck and best regards    Hondo
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bobosse
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Re:Questions to repair a conchess
« Reply #11 on: February 23, 2009, 04:47AM »
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Quote from: hondo on February 22, 2009, 03:49PM   

Hi JB.,
Maybe I can be of help to you so first let me get a cpl basic answers from you. Are you aware how to correctly check LED's and diodes... and are you aware that you may need to remove diodes from the circuit to check them correctly. With that said.... I have some parts distributors info. if you wish, however I dont know if you are in the US. Chess board circuitry tend to be repetitive ...What I mean by that is that if you find another diode approx. the same size etc. in maybe the same similiar area (assuming you dont have a schematic) you may be able to read the markings on that one and use it to replace the other one. So as not to tie up this thread with my ramblings you may contact me privately if you wish and maybe I might be of some help....    regards...    Hondo

I am not in the US. The diodes are very small and very old, so the color code is unreadable (except the black line that indicates it's a diode). Of course I also do not have the schematic
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Sargon
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Re:Questions to repair a conchess
« Reply #12 on: February 23, 2009, 12:00AM »
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Hello JB,

Mabey a mail to Arno Kreuzberg can help u
U can find him on schachcomputer.at by REPARATUREN
Good luck with it.

Kind Regards,Hans
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hondo
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Re:Questions to repair a conchess
« Reply #13 on: February 22, 2009, 03:49PM »
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Hi JB.,
Maybe I can be of help to you so first let me get a cpl basic answers from you. Are you aware how to correctly check LED's and diodes... and are you aware that you may need to remove diodes from the circuit to check them correctly. With that said.... I have some parts distributors info. if you wish, however I dont know if you are in the US. Chess board circuitry tend to be repetitive ...What I mean by that is that if you find another diode approx. the same size etc. in maybe the same similiar area (assuming you dont have a schematic) you may be able to read the markings on that one and use it to replace the other one. So as not to tie up this thread with my ramblings you may contact me privately if you wish and maybe I might be of some help....    regards...    Hondo
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bobosse
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Questions to repair a conchess
« Reply #14 on: February 22, 2009, 12:43PM »
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I am currently repairing 2 conchess ambassadors.

Of course, this page helps:
http://www.ismenio.com/chess_conchess_ambassador.html
However, one of my Conchess has some reed switch and some leds and some diodes damaged.

To find reed switch is quite easy and I already replaced them.

But I am looking for the electronic reference of the diode. I took one to the electronic store but the reference is unreadable. Anybody has this information ?

This is my main question. But as i also need to replace some leds, do you also have reference for leds ?

Thank you,
JB
« Last Edit: February 22, 2009, 12:43PM by bobosse » Report to moderator Logged
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