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Outrun monitor missing colour?

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sfoster417360 View Drop Down
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    Posted: 23 Nov 2021 at 1:44pm
Hi,

I have an outrun standard upright and colours are not right on the crt test screen. Someone said on fb looks like blue is missing. So if thats the case i want to check what is at fault and if its the pcb, chassis or tube first of all.

Im thinking of plugging in a 60 in 1 check pattern generator first of all to test the monitor and tube to rule out the outrun pcb.

So far:
Adjust flyback, neckboard pots, contrast / brightness.
Flyback and caps on chassis have been recently replaced


https://www.dropbox.com/s/bm488mbhxb0yi2h/20211121_201146.jpg?dl=0


Regards,

Stephen

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Chopper79 View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Chopper79 Quote  Post ReplyReply Direct Link To This Post Posted: 23 Nov 2021 at 1:59pm
Was it ok before, or has this just happened? Doubtful it's a fly back issue. Maybe someone can test the board for you, to rule it out. What chassis does it have?

Check the RGB cables from the pcb to the chassis. Wires can break in sockets, or poor contact on pins.

Edited by Chopper79 - 23 Nov 2021 at 2:02pm
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sfoster417360 View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote sfoster417360 Quote  Post ReplyReply Direct Link To This Post Posted: 23 Nov 2021 at 8:35pm
Checked continuity of RGB ground, sync from pcb to monitor chassis and all ok.

Was like it when i bought and told prob just neck board. Only had it for a week.

Ive tried changing all neck pots while on and its definately the blue channel not doing anything at all.

Will hook up another known good gameboard to to monitor via the rgb and sync inputs and see to rule out the game pcb.

Any other suggestion let me know. See if i can take some pics.



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smarty View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote smarty Quote  Post ReplyReply Direct Link To This Post Posted: 23 Nov 2021 at 8:52pm
Yes do have all three colours getting to the monitor, you wouldn’t see any white if a colour was missing.

I’ve taken a snip from MAME to show how the pattern should look.

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Post Options Post Options   Thanks (0) Thanks(0)   Quote big10p Quote  Post ReplyReply Direct Link To This Post Posted: 23 Nov 2021 at 9:32pm
Yes, the colours just look wrong, rather than anything missing. Board fault?
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Post Options Post Options   Thanks (0) Thanks(0)   Quote gunblade Quote  Post ReplyReply Direct Link To This Post Posted: 23 Nov 2021 at 9:37pm
either tube is buggered or game board is the issue
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Retroman839 Quote  Post ReplyReply Direct Link To This Post Posted: 24 Nov 2021 at 11:42am
colour pallet roms receiving bad logic

was watching a punch out repair last night

bad pallet …

bad data      you would need the schimatics
and probe the pcb from cpu through to the
colour video out section
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Post Options Post Options   Thanks (0) Thanks(0)   Quote sfoster417360 Quote  Post ReplyReply Direct Link To This Post Posted: 25 Nov 2021 at 7:45pm
Hi,

Thanks for all your suggestions. I am making a testing kit for game board that i can connect to a known good flat monitor / scart and a test signal generator to plug into monitor chassis. Ideas ive seen from RGP and retro clinic videos.

Also just wondered if anyone can confirm the chassis from the pic, i thinks its a WG k7000.




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Post Options Post Options   Thanks (0) Thanks(0)   Quote tb2000 Quote  Post ReplyReply Direct Link To This Post Posted: 25 Nov 2021 at 8:30pm
Yeah it's a k7000 with 8 pin minineck crt. Probably a Philips or WG's own labelled crt (I think the WG labelled ones were made by Orion).
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Post Options Post Options   Thanks (0) Thanks(0)   Quote sfoster417360 Quote  Post ReplyReply Direct Link To This Post Posted: 25 Nov 2021 at 10:38pm
Thanks for confirming, its a philips tube. Will be doing some testing over weekend to see whats causing colour issues.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote sfoster417360 Quote  Post ReplyReply Direct Link To This Post Posted: 28 Nov 2021 at 9:25pm
Ok so i've rigged up a test pattern generator to the k7000 chassis of the outrun and blue is definately out or very low. Adjusring the blue pot on the back of the neck makes no difference to the picture. Red and green adjust all ok.

So its now the chassis or the tube. Is there a quick test to check the tube, i heard grounding the inputs for a few secs??? here is pic of test pattern.

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Post Options Post Options   Thanks (0) Thanks(0)   Quote ColinD Quote  Post ReplyReply Direct Link To This Post Posted: 29 Nov 2021 at 2:15pm
You could try temporarily swapping the blue with the red (or green) on the cable going to the neck board and use your test pattern again.

If the blue is still dim (when it should be displaying red of course) then its the neck board or the tube.

If you find instead that you now have a dim red (where the blue should be) and a nice blue (where the red should be), then the fault is on the chassis.




Edited by ColinD - 29 Nov 2021 at 2:16pm
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Post Options Post Options   Thanks (0) Thanks(0)   Quote big10p Quote  Post ReplyReply Direct Link To This Post Posted: 29 Nov 2021 at 2:31pm
Red, green and blue look washed out to me, so maybe the tube is just at end of life. No idea if a rejuvenator would help?

Edited by big10p - 29 Nov 2021 at 2:31pm
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Post Options Post Options   Thanks (0) Thanks(0)   Quote jinq-sea Quote  Post ReplyReply Direct Link To This Post Posted: 29 Nov 2021 at 4:24pm
Is the video ground connection missing on that video lead?
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Post Options Post Options   Thanks (0) Thanks(0)   Quote big10p Quote  Post ReplyReply Direct Link To This Post Posted: 29 Nov 2021 at 4:27pm
Originally posted by jinq-sea jinq-sea wrote:

Is the video ground connection missing on that video lead?
I assume the white and black wires are comp sync and ground?
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Post Options Post Options   Thanks (0) Thanks(0)   Quote sfoster417360 Quote  Post ReplyReply Direct Link To This Post Posted: 29 Nov 2021 at 8:25pm
Super appreciate everyone yrying to help.

Ok so i tried swapping the red and blue and same result on the screen. I also disconnected the blue and that also made no difference at all, same result on screen. So the blue line is having no impact at all weather its red, green, blue or no signal.

I double checked the video ground and h sync and all good (white and black)

I tried adjusting the neck board blue line cut off and drive and no difference at all in any configuration

Any ideas on next steps for further tube testing or what to measure?

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Post Options Post Options   Thanks (0) Thanks(0)   Quote BulkSlash Quote  Post ReplyReply Direct Link To This Post Posted: 29 Nov 2021 at 8:39pm
Originally posted by jinq-sea jinq-sea wrote:

Is the video ground connection missing on that video lead?


Yeah looking at the little diagram in the corner of the photo it looks like there should be three extra wires on that connector. 

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Post Options Post Options   Thanks (0) Thanks(0)   Quote ColinD Quote  Post ReplyReply Direct Link To This Post Posted: 29 Nov 2021 at 8:42pm
So you still had a dim blue where the red should be with the wires swapped ?

I'd have a look at the transistor on the blue using a Digital Volt Meter set to diode check.

You might have to remove it, but in situ you could do a very rough check from collector to emitter (the top and bottom connections shown below) - Measure both ways  and compare to the other two.

If still unsure... remove it and follow the instructions below...

https://vetco.net/blog/test-a-transistor-with-a-multimeter/2017-05-04-12-25-37-07

If still no luck.... Check the R209 and R212 also for starters.





Edited by ColinD - 29 Nov 2021 at 8:55pm
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Post Options Post Options   Thanks (0) Thanks(0)   Quote sfoster417360 Quote  Post ReplyReply Direct Link To This Post Posted: 29 Nov 2021 at 9:06pm
ColinD that is correct, pic below of wires red and blue swapped.



I will check neck board and test transistors on diode test and check resistors while im at it.

Ok will get back to you guys, thanks again.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote ColinD Quote  Post ReplyReply Direct Link To This Post Posted: 29 Nov 2021 at 9:38pm
That's great.... Thanks for posting the new photo.  This was with the wires swapped around going FROM the chassis TO the neck board to double / triple check - right ?  (Edit - Possibly silly question as you have already eliminated the game board using another video source - sorry !)

Not everyone understands what they should see with the wires swapped, so this is a good example. (the Red signal FROM the Chassis is now driving the Blue circuitry on the neck and tube)

It's a crude test, but at least we can say the main chassis is mostly ok and we are now a little closer.

Do you have any colour brightness / gradient tests available ?  - That might help a little for further diagnosis.

EDIT2.... Also....  You might consider swapping the red and blue transistors around on the neck board if you are unable to test them and you are confident that you can do so without causing any damage - Let's not worry about that just yet though.



Edited by ColinD - 29 Nov 2021 at 9:57pm
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