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STTNG LH canon Opto not working

Freespawn

Freespawn

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Jun 1, 2018
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Southampton
Hi all a bit stumped with this one.
The LH canon has allways moved on startup and was working when I got the machine but it started not to find home so I orderd the new looms and new Opto boards and have replaced both and the Opto’s still won’t work, I have swapped the connection for the the right canon Opto to test the opto’s on the the left and it registered in switch test. So I’m thinking something is up with the Opto control board under the playfield ? Have reflowed solder on all its connectors but still no good 😖

Any suggestions greatly appreciated :)
 
Hi, you said the LH canon can't find home. The home switch is a normal switch under the playfield and not an opto. The opto switch is in the canon where the ball sits prior to being fired from the canon.
When in switch tests the canon optos are easy to test by putting a ball in there or just your finger.
If you lift the playfield you can see the switches underneath the canon where the cam moves round and activates the home and mark switches. If you go into the gun test (T14?) you can see the gun go through it's full routine and see the switches operate. If the home switch doesn't activate then maybe a wire has come off or its got out of correct alignment or maybe the switch arm has come off.
Hope that helps
Garry
 
The home switch is on the cam as Garry says, however if the opto beam is blocked the cannon won't find home. My game had a sticking plunger when it arrived and cannon would just keep sweeping until the plunger was tapped back, then it would find home and work normally. STTNG is a strange beast..
 
Max said:
The home switch is on the cam as Garry says, however if the opto beam is blocked the cannon won't find home. My game had a sticking plunger when it arrived and cannon would just keep sweeping until the plunger was tapped back, then it would find home and work normally. STTNG is a strange beast..
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Thanks for the reply.
The switches underneath work fine and both register when at home position.
The opto’s don’t work on the left cannon
There is nothing wrong with the opto’s as I have tested them plugged into the right guns connector and they register when the beam is broken.
So I’m thinking something is up with the Opto board under the playfield.
But not sure how to test that without replacing the lm399 chips ?
 
Sounds like you're on the right track. Is it possible to switch the working board onto the left loom, if that works at least it would isolate the board as being at fault and not something upstream?

edit: I don't have my machine to check, I'm guessing it's a single board for both.. ignore
 
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Max said:
Sounds like you're on the right track. Is it possible to switch the working board onto the left loom, if that works at least it would isolate the board as being at fault and not something upstream?

edit: I don't have my machine to check, I'm guessing it's a single board for both.. ignore
Click to expand...
Yep single board for both annoyingly :)
 
Having tested everything else now the only thing left is the 339’s will socket and replace and see how it goes :) just have to wait for the parts to arrive :)
 
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Right have socketed and replaced all the 339’s and still no joy :(
But doing further tests it would appear some other switches are not working.
Neutral zone /Borg entry/ left delta ramp entry/right neutral zone target

Can’t see any acid damage on cpu board
Bit stumped 🤔
Can anyone see anything out of the ordinary on the switch test ?
 

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Would appear I have somehow killed the u20 chip 😖 testing with jumper cable and no response on the test, will order and replace hope there isn’t something else hiding causing the issue
 
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Ignore previous
Was testing on wrong pins 😖😖
But good news u20 not fried 😊
And switches test fine at cpu connectors
So back under the playfield I went
And found this loose wire…….
Re solder back together and working again ! :)
Shame I have just ordered several more parts 😂 oh well spares for the future :)
 

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