Trident
Stern Electronics, 1979I picked up a stern trident in a trade this weekend. The games will go through the boot sequence and enter attract and then instantly begin going through the boot up sequence again. It will just do this over and over. The guy I got it from told me it did this however it started and played a few games at his place before I loaded it.
Any of you guys familiar with this and care to point me in the right direction. I appreciate it.
Put a logic probe (or meter) on U9 pin 40 and see if it pulses LO when it reboots.
Also probe MPU TP5. It should be HI or +5VDC. See if it pulses LO at reboot.
Another possibility to check - with the power off and unplugged, pull all the fuses on the rectifier board and inspect the fuse holders. If one is cracked it will cause this exact problem.
Quoted from Mk1Mod0:Another possibility to check - with the power off and unplugged, pull all the fuses on the rectifier board and inspect the fuse holders. If one is cracked it will cause this exact problem.
I'm going to check that now.
Quoted from cody_chunn:It may be time to replace the filter cap on the solenoid/regulator board.
It was tried with a solenoid board out of a working Galaxy and it still reset. I probably will end up recapping most of the boards anyway though.
Quoted from Mk1Mod0:Another possibility to check - with the power off and unplugged, pull all the fuses on the rectifier board and inspect the fuse holders. If one is cracked it will cause this exact problem.
I visually inspected the fuse clips and they appeared to be ok. I did not pull the board though. I suppose maybe there could be some cold solder on the back side of those fuse clips.
Quoted from jmountjoy111:maybe there could be some cold solder on the back side of those fuse clips.
Possible, but not likely. Another thought is loose wires in the plugs. Are there any visibly burned connectors? Corroded connectors? Not trying to be hit and miss here, just trying to eliminate the easy fixes.
Measure the voltages on the Power Rectifier board and the Solenoid Driver board against those in the manual to confirm if they're within spec.
Also, pull out the playfield solenoid fuse to disable the playfield solenoids, just incase the current surge from the attract mode Drop Target/Saucer reset activation is causing a power fluctuation issue.
Is the reset repetition exactly the same each time? Can you shoot a short video of the backbox and playfield as it resets a few times in a row?
I am interested to learn what makes the MPU reset when the /Reset signal stays @ 5VDC.
Interesting...
Quoted from cody_chunn:Is the reset repetition exactly the same each time? Can you shoot a short video of the backbox and playfield as it resets a few times in a row?
I am interested to learn what makes the MPU reset when the /Reset signal stays @ 5VDC.
Interesting...
I will try to get a quick video up later this evening after my little boys baseball practice.
It goes through the seven flashes, puts zeros on the displays and credits on the credit display. It starts the insert lights into feature then stops and starts the start up flash sequence again.
Quoted from Quench:Measure the voltages on the Power Rectifier board and the Solenoid Driver board against those in the manual to confirm if they're within spec.
Also, pull out the playfield solenoid fuse to disable the playfield solenoids, just incase the current surge from the attract mode Drop Target/Saucer reset activation is causing a power fluctuation issue.
I will test this out this evening as well and report back what happens.
You might want to try disconnecting all MPU connectors except J4, and as suggested above pull all solenoid outputs from SD board and see if the MPU LED repeats the blink cycle.
I reset all of the connectors on the mpu and the game works. I pulled all but j4 like mentioned and added to it one at a time. The game is booting and playing now so maybe it was a bad connection. I'm not sure it's completely out of the woods just yet but I am going to throw some games on it and see how it holds up
I put about 15-20 games on it last night and cleaned it up a bit. There are still some issues with the game such as strings of GI being out, Some displays not working, etc. I believe they might all be due to some connection issues. I noticed some green slime on some connectors but no burnt ones so I will re-pin a lot of those tonight and begin fixing the rest of the issues one at a time.
I had never seen a game reset over and over due to a bad connection. You learn something new everyday.
I appreciate all the help guys. I'm marking this one down as solved.
Actually, bad connectors on the CPU that sends power to the +5V circuit is a very common reset culprit. You reseated the connectors and the reset went away...temporarily. It's not 'solved' but rather identified. I'll guarantee you that eventually the resets will cone back. Replace the header and connectors and you'll be good to go.
Quoted from schudel5:Actually, bad connectors on the CPU that sends power to the +5V circuit is a very common reset culprit. You reseated the connectors and the reset went away...temporarily. It's not 'solved' but rather identified. I'll guarantee you that eventually the resets will cone back. Replace the header and connectors and you'll be good to go.
Agreed. Also replace J3, both of these get hit hard by corrosion.
...but...but...
"Both tp5 and the leg of u9 hold constant during reset
Tp5 stays over 5vdc."
How can that be with a connector continuity failure? Some kind of current loss without loss of voltage potential??
Quoted from cody_chunn:...but...but...
"Both tp5 and the leg of u9 hold constant during reset
Tp5 stays over 5vdc."
How can that be with a connector continuity failure? Some kind of current loss without loss of voltage potential??
Could there be something else other than the 5vdc that would cause a reset that would fall more inline with continuity issues? I don't know enough about it to say I just don't want to have to open a new thread about it next week lol
Quoted from schudel5:Actually, bad connectors on the CPU that sends power to the +5V circuit is a very common reset culprit. You reseated the connectors and the reset went away...temporarily. It's not 'solved' but rather identified. I'll guarantee you that eventually the resets will cone back. Replace the header and connectors and you'll be good to go.
I will do this for sure.
it's really hard to see voltage drops during resets unless you're using a scope with a digital recall. Trying to do that with a multimeter is pretty difficult if not impossible. might work with non-auto ranging meter, but it would be tough to see. really tough. an analogue meter might show it, but who has that any more?
A logic probe would catch a blip, I'd imagine. That's why I asked if the reset was uniform repeatedly. You could just monitor the chip leg and look for a blip when the predicted reset happened.
Doesn't really matter much now. I have three old "swing meters". I know one's a tTtriplet, then maybe two more Triplets, or Simpsons, or one of each. All three need to be reworked at an instrumentation shop...or I need to learn how to do it and fix 'em up myself. You can still buy cheap little swing meters...but who knows how to use them any more? 
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Williamsburg, KY