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Other Pc Engine Duo-R graphic glitch

earthshaker

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Nov 18, 2019
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earthshaker
Here I am with another Pc Engine duo..
I got the machine around two weeks ago for my collection and it was working fine, then I decided to install the RGB as I had some rgb boards with 7314 on it at home.
Unfortunately something went wrong as I broke 2 solder pads (n.60 and 58) of the board where the HUC6260 is soldered ... :cry:
I checked the schematic of the HUC6260 and that legs are labeled as "TEST". However I decided to finish to mod the console and check the results but unfortunately the console doesnt work properly. As I made even the rgb cable I thought that way be the problem, but even by the "old" composite cable the image glitches.
The glitch is not stable.. its more similar to an intereference with kinda of greenish stripes that appears on screen. Sometimes everything seems normal...
I double checked with multimeter everywhere, I tried another 7314, i rewired the rgb cable, tried different games, without game, connected and disconnected the c.sync.... but same result.
I want to reconnect the legs, but I dunno where... I got another pc engine duo from a friend to check where that legs go.. but I cannot find it!! :unsure:
I am not a novice in soldering and I really feel stupid for what I have done there.. can't forgive me. ?
Hope you can help me guys
Here some picture of the board.



Video:
 

truemaster

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either my eyes are deceiveing me. or those 2 pads are not conected anywhere. clean with isopropyl alcohol those legs i can still see flux.(some are contuctive) also maybe a wire is exposed and bridging at near pads
 
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earthshaker

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Nov 18, 2019
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either my eyes are deceiveing me. or those 2 pads are not conected anywhere. clean with isopropyl alcohol those legs i can still see flux.(some are contuctive) also maybe a wire is exposed and bridging at near pads
First of all thank you for you comment.
The pads under the legs are missing (coz on me).. I was "refreshing" the soldering of the chip and I found the 2 pads on my solder tip :eek:
However I cleaned and tested the legs with a multimeter and there isn't any bridge..
The main problem is the interference it is not always there, I mean, sometimes everthing seems ok but after some minutes the problem come back. In particular with composite cable the image is quite normal.
Do you have any schematic for a proper pc engine scart RGB cable? Or shall I buy it from retrogamingcables.co.uk (I am located in Europe)?
I used this:
 
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truemaster

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no i dont have anything like that. when i say the legs are not conected anywhere (propably) is because theres no line going there. all the pins are solder in pads but not all pads are conected to something. and those not conected pads are more easy to come off the pcb
 
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earthshaker

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Nov 18, 2019
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no i dont have anything like that. when i say the legs are not conected anywhere (propably) is because theres no line going there. all the pins are solder in pads but not all pads are conected to something. and those not conected pads are more easy to come off the pcb
Yep, that's what I guess too. However I checked with multimeter other legs of the chip which don't seem connected anywhere, instead are connected to some close solder points.. The only "positive" thing is that up to the schematic it those legs are labeled "test", then it shouldn't be used.
 

earthshaker

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a quick update.. the composite works fine now (dunno why). I tested with many games and for long time. The RGB instead works for the first 5 minutes and then the glitches appear.. :unsure:
Then I guess the problem is the board (but I tried 3 boards and I got the same results), the cable (a custom one that I made) or.. I dunno XD
 

truemaster

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yeah from the look of it the broken pads has nothing to do with any issue. theres a green pcb that takes the rgb wires after this ic and before the output jack try a different one. its the main suspect to me
 
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Ergot

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What power supply are you using? Also could be a grounding issue with the scart cable you made.
 

earthshaker

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Nov 18, 2019
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yeah from the look of it the broken pads has nothing to do with any issue. theres a green pcb that takes the rgb wires after this ic and before the output jack try a different one. its the main suspect to me
that pcb was a brand new one.. I had two and both give the same problem.
What power supply are you using? Also could be a grounding issue with the scart cable you made.
It's a 9v positive pin power supply. I tested it with multimeter and it's fine.
I will double check the ground of my cable, however I wired together scart pin ground (pin 21, 18, 17, 14, 13, 9, 5, 4) with the socket gorund (pin 2 + outern socket shield). I tried disconnectying the outern shield or other ground pins, but the result was the same exapt for a little more disturbed image.
 

earthshaker

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Nov 18, 2019
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Hi guys, just want to inform you that the problem was the sync wire! I disconnected it and now finally the console works fine.
Yesterday I got other two pce duo that need to be repaired, but that's another story... XD
Thank you very much for your help!
by the eay do you use caps or resistors into your pce rgb scart cable on the RGB signal? coz the image is slightly dark
 

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