[Restoration] Gran Trak 10 - the first EVER driving game

[Superully]

back to this one! i went to my mother's place to examine the board a little bit closer (and look for that test switch which is supposed to be there somewhere). let's examine the only switch on the board in detail: as i've already said you can read 1/p and 2/p next to the switch, but GT10 is a single player game. what could the function (if any) of that switch be?



up next, i examined the time potentiometer closer and realized that it is broken - literally!



however, all of the contacts seem to be good, so if i'm not mistaken it should work, but nothing changes at all when i turn being turned!



on the back of the board i found some burn traces ...



... coming from those little bastards ! what type of component are they?



conclusion: i didn't find the famous test switch, so here's a complete shot of the GT10 pcb - some kind of hidden picture puzzle! where's the test switch?



a close-up shot of the interesting board side (not just chips and circuit tracks i mean)



suggestions?

[level42]

Sure. Buy some glasses my friend.....

Look again at this pic:


I see the word "TEST" and 6 solder islands in two rows. MMMMmmmmm, maybe they "forgot" to solder in the test switch ?

AND I see a wire bridge across two solder islands. This is probably there to "fake" the normal play setting of the test-switch. I see some more stuff on the other row but can't really see it.
Anyway, if this bridge is still intact it is still strange that it doesn't work as it should. I mean this seems to be a permanent "setting" for the "switch"....if it had broken, that would explain it. Maybe there is supposed to be a 2nd wire on the other row and that is broken ?

Need a macro-shot of that spot.....

[level42]

Those are all diodes. The one's on the left are old-fashioned style one's, the two on the right modern style.

You can also see they printed the diode symbol ( |>| ) on the PCB on those locations (including the direction. )

[level42]

Looks like a 1 player/ 2 player switch. Remember there was also a Gran Track 20 which was 2 player and probably they simply used the same board.

[Superully]

Sure. Buy some glasses my friend.....

thanks, andré, just did that and guess what, the word TEST is printed on the pcb!!! stupid me, i was looking for a switch all along ...

I see the word "TEST" and 6 solder islands in two rows. MMMMmmmmm, maybe they "forgot" to solder in the test switch ?
Need a macro-shot of that spot.....

coming up tomorrow! can you tell from the manual how this was supposed to work / be wired?

[Superully]

Those are all diodes. The one's on the left are old-fashioned style one's, the two on the right modern style.
You can also see they printed the diode symbol ( |>| ) on the PCB on those locations (including the direction. )

would you replace those because of the burn marks underneath?

[Etienne MacGyver]

would you replace those because of the burn marks underneath?

Use the DVM in diode mode (beep)  to see if they work, if they do, no need to replace.
http://www.youtube.com/watch?v=fbSi_X7Ew3Y

Here a vid of how a diode works...  
http://www.youtube.com/watch?v=eJdGYtU7OZc&feature=related

back to this one! i went to my mother's place to examine the board a little bit closer (and look for that test switch which is supposed to be there somewhere). let's examine the only switch on the board in detail: as i've already said you can read 1/p and 2/p next to the switch, but GT10 is a single player game. what could the function (if any) of that switch be? suggestions?

RTFM  

up next, i examined the time potentiometer closer and realized that it is broken - literally!



however, all of the contacts seem to be good, so if i'm not mistaken it should work, but nothing changes at all when i turn being turned!



suggestions?

Yes you are mistaken    the pot is using the contact on the wheel that is completely cut off.

the 3 connections dont have any contact with eachother so the connection is "open"

Replace the pot and try to crash again (withing the time that also will work again i think after replacing the pot)

coming up tomorrow! can you tell from the manual how this was supposed to work / be wired?

when i see those solderpads, i think there should be the same switch on that board as the P1 - P2  switch.

This is a switch that connects pin 1 to pin 2 and pin 4 to pin 5 in the "test" position (see my blue lines)  and for normal  position it connects pin 2 to 3 and pin 5 to 6 (see my red lines)

be sure to remove that "fake switch" if you want to try the test switch, otherwise it will not work, and i dont know what the consequences are when they are all connected by that.. (i mean pin 1, 2 and 3 will be all connected, and pin 4, 5 and 6 also)

I would start with the pot, my guess is that that is the source of your problem.

Goodluck !

[level42]

Dont bother measuring the diodes, they are fine because else your board wouldnt be working and/or the fuses would be blowing.... In these early arcade days, they thought it was a good idea to convert the AC Supply voltage into DC on th game board itself. All manufacturers did it. Later they moved the AC to DC conversion to seperate boards or PSUs.
One of the reasons why you see here. Heat. I wouldnt call that a burning, its just a matter of these diodes getting very hot during use. Atari already knew that, that is why they installed the diodes so high above the PCB so they have more airflow around them to dissipate th heat.

What I WOULD do is renew those solderings. They look pretty dull and I think I can even see some circles which indicate a bad soldering. Again the cause is heat, the heat is slowy "desoldering" the part itself....
So suck away the old solder (add a bit of new tin to get it flowing) completely and make a new solderering on both legs of all thiose four diodes. Also check any big resistors as they can show the same issue.

Definitly replace the pot like Etienne says ! Can never work this way.....

[Etienne MacGyver]

Definitly replace the pot like Etienne says ! Can never work this way.....

oh and in case you still did not RTFM, its a 1M ohm pot 

[Muerto]

[off topic mode ON]
i just looove those macro soots!!!!!
[off topic mode OFF]

[Q*ris]

[off topic mode ON]
i just looove those macro soots!!!!!
[off topic mode OFF]

+1
Now I shut up and learn.

[Etienne MacGyver]

[off topic mode ON]
i just looove those macro soots!!!!!
[off topic mode OFF]

+1
Now I shut up and learn.

LOL ! 

[Superully]

oh and in case you still did not RTFM, its a 1M ohm pot 

believe it or not, ripley, i was able to deduct that information from the schematics myself, but thanks for confirming, it's always good to know that i got one thing right .

anyway, will that potentiometer work? it's smaller than the original one, but at least it looks almost identical (and it's one megaohm in value)!

[level42]

Youll have to check if it will fit physically. My first hunch is that this one is smaller.
Check the datsheet for the sizes between the legs and compare with the one on the PCB.

[simplesi]

I love this thread... the cab design is beautiful.