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 Post subject: Re: Firefox Sync Issue?
PostPosted: Sat Jan 21, 2017 2:10 pm 
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GOOD NEWS!

I installed what is now my 4th board-set try and it works!

I need to balance the voltages between the boards and then comes the task of dialing in the display, setting the video outputs from the PCB.

I am just happy that everything works.....

Thanks for all the help and once I get this displaying correctly (color-wise), I'll make a video and post the link here.

Thank you everybody again, your help is much appreciated!

Jeff


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 Post subject: Re: Firefox Sync Issue?
PostPosted: Sat Jan 21, 2017 9:18 pm 
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jetusenet wrote:
GOOD NEWS!

I installed what is now my 4th board-set try and it works!

I need to balance the voltages between the boards and then comes the task of dialing in the display, setting the video outputs from the PCB.

I am just happy that everything works.....

Thanks for all the help and once I get this displaying correctly (color-wise), I'll make a video and post the link here.

Thank you everybody again, your help is much appreciated!

Jeff


woohoo!

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 Post subject: Unbelieveable............
PostPosted: Sat Feb 04, 2017 4:41 am 
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This is getting to be a real PITA!

I played a few games to be sure the boards were working properly and then put it on the back burner as midterms came around and I needed to study with the family, well..........

I went back to play in peace and the sync started to go, as in, every once in a while the image would "skip" up or I would get that black bar slowly rising up the display. I did not think too much of it but it then, over a period of days, got worse and worse and now I have basically lost the sync!

LINK:
2017-01-28 New board : https://youtu.be/luBF23o5h6Q

The boards as properly strapped and the voltages are correct on all three PCBs...........

What the heck is going on???? Is this cab cursed????

Maybe a capacitor is going out of spec on the PCB????

Any and all suggestions would be greatly appreciated.


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 Post subject: Re: Firefox Sync Issue?
PostPosted: Sat Feb 04, 2017 5:39 pm 
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Well, the "good" news is that this isn't the same problem you were having before... Previously, it was losing horizontal sync whenever the laserdisc player was busy. Now it's losing vertical sync, somewhat sporadically.

It might be that the vertical hold control on the monitor is near the end of the range where it will lock on, so it occasionally loses sync. Try tweaking it a bit to see if it helps.

One other thing to try as an experiment is to disconnect Dexter, so it's working entirely on the internally-generated sync. I'm not sure exactly what this will tell us, but it's another data point to consider.

Good luck!

-Warren.


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 Post subject: Re: Firefox Sync Issue?
PostPosted: Sat Feb 04, 2017 6:47 pm 
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Warren,
Thank you very much for the help, I try those suggestions and post the results.
Jeff


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 Post subject: Update
PostPosted: Sun Feb 05, 2017 12:35 pm 
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OK, I attempted to resolve the issue adjusting the vertical hold to no avail. No matter how extreme I set the vert. in anticipation of the roll, it just happens no matter what.

I disconnected the Dexter and the game plays fine, although with some color issues, (AFAIK).

https://youtu.be/BDm9ABJIuP4

Since this is the second "working" PCB to have an issue, could there be some incompatibilities with this Dexter?

Thanks again for your help.

Jeff


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 Post subject: Re: Firefox Sync Issue?
PostPosted: Sun Feb 05, 2017 3:25 pm 
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jetusenet wrote:
BTW, this is a sitdown boardset that I converted to an upright w/ switcher P/S, (standard 15A Happ).
I have W1 and W2 cut with the 15ohm 10w resistor installed at R205 on the NTSC PCB and SP1 jumpered and SP2 cut on the main PCB...........


I forgot to ask... If you're using a standard switcher, what are you doing for the +22/-22V? Or is the switcher only powering the main 5V rail?

My best theory right now is that the NTSC board is producing sync that is too far out of spec for the monitor. (Sync timing is set using resistors/capacitors on U3, U4 and U5, with U3 being the one used for vertical sync.) Can you try a different NTSC board?

I can't say definitively that Dexter is not the cause of the problem, but I can't think of a failure mode that would cause these symptoms.

Good luck!


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 Post subject: Re: Firefox Sync Issue?
PostPosted: Sun Feb 05, 2017 6:08 pm 
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Warren,
Yes, you are correct, the switcher is only powering the +5vdc, the two rebuilt (partially) A/R II's are supplying the +/- 22vdc. There was a voltage issue between the boards but a carefully installed jumper wire then balanced the voltage to ~ +5.04vdc on all three boards.

The boards are strapped properly for the linear power supply.

What is funny (confusing) is that the board seemed to work fine, with the exception of the color issues and after about eight games, started to loose sync and now it is all the time.........

Is there an adjustment that I can "tweak" and try to get this working properly?

If all else fails, I'll try swapping NTSC boards.

Thank you again for taking the time to help me.

Jeff


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 Post subject: Re: Firefox Sync Issue?
PostPosted: Mon Feb 06, 2017 3:36 am 
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jetusenet wrote:
Is there an adjustment that I can "tweak" and try to get this working properly?


I looked through the schematics earlier, and I didn't see any adjustments that would help with vertical sync. I suspect C14 on U3 in the "Sync Logic" section might be out of spec, so the vsync pulses aren't the right length, but I would try another NTSC board first, and poke around with a scope a bit before replacing things...


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 Post subject: Re: Firefox Sync Issue?
PostPosted: Mon Feb 06, 2017 5:30 am 
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Thank you for giving me the heads up on what component "might" be giving me the hard time......

I will take your advice and try other NTSC boards first and if all else fails, I will then start the repair attempt.

Again, many thanks for your time and help.

Jeff


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