No Signal (possibly related to sync issues?) – SOLVED!

[Morpheus_79]

I’ve replaced the EP4CE15E22 and C60 too (cause under the microscope the ceramic capacitor looked kind of chipped… even though its measurements indicated otherwise) – with no luck at all. The OSSC boots up as always… but the sync signal is as unstable as it was before. Well… not entirely: when my laptop is plugged into the VGA input, the LEDs indicate a stable sync for the VGA signal… but it wont pass any output signal to my TV. I tried different resolutions on the laptop (from 800×600 up to 720p), but my TV always says “No Signal”.

The grey test pattern still works though (and the audio addon board seems to work too, since i get an audio signal with the test pattern)… but nothing else does. After replacing both ICs i never ever had a proper output signal again (apart from the test pattern). I even replaced C13 (for the second time) and R3 (for the first time) – but since the measurements for these parts are all fine, replacing them didn’t do anything.

So now it’s official: i’m too stupid to find the culprit. And i don’t know where else to look. If it were a heat related problem, shouldn’t the OSSC work at least when powering it up after a cool down phase??? But this was never the case. It worked randomly without changing any extraneous influence, just by powering it up multiple times. Such random behavior could be the case, if there’s a cold solder joint or a broken trace. But all the sync related parts and traces seem to be fine. I could try to resolder EVERY part… but if that wont work: then what?

I’m frustrated cause i’ve obviously build one expensive night light.

[paulb_nl]

Are you sure the power supply is good? Have you tried removing the audio board? Also do you have sync with component or composite in the green component input?

[Morpheus_79]

Thanks for answering. I bought this HNP06-050 power supply just for the OSSC:

http://www.hnec.de/pdf/hnp06.pdf

According to its specs it seems to be a pretty decent one. But… of course: just because it is brandnew, doesn’t mean it arrived in perfect working condition. It may be a flaky one… i don’t know. I previously had the idea it may be the power supply – but after going through all my other power supplys, i just found an old unregulated one for my 5V ethernet switch. And i didn’t trust it enough to test it with the OSSC. But since i need a new 5V power supply with an USB plug, i’ll buy a good one… and a USB adapter cable to power up my OSSC. Maybe it will help…

Removing the audio board was the first thing i tried. I even flashed the non-audio firmware to… tried different (older) firmware versions… without success.

I don’t have any device with component output… so i plugged my old VCR via composite cable into the green component input of my OSSC. But like with my SNES: the OSSC display shows resolution and refresh rate for this input signal… yet the red LED stays on, indicating no stable sync.

[Morpheus_79]

Yesterday (with a new USB power supply on its way and nothing else to test) i resoldered every(!) single(!) part(!) under the microscope at work – just to rule out a cold solder joint. Yet again: with no luck. So i took the time to measure all resistors… but they seemed to be fine. I would’ve loved to measure all capacitors too… but just having a multimeter and a cheap diode tester from China at hand, it was impossible to get viable in-circuit capacitance readings.

Kind of depressed and angry i pressed my finger on some of the soldered parts, while the OSSC was still running. Suddenly i noticed the OSSC saying ‘NO SYNC’ while having my finger on one of the capacitors. At first i thought, it may be a cold solder joint i overlooked while resoldering. But then i realized, that the conductivity of my skin may messes things up. So i came up with the strange idea of touching all ceramic capacitors around the TVP7002 and replacing just the ones, where touching them messes with the sync signaling.

So i replaced C11, C13, C16, C19 & C20, testing the OSSC every single time afterwards. And (who would have thought?) after replacing C20 i got a stable sync less than one second after switching to AV1… and sure enough: a picture on my TV.

Till now i got no sync issues at all. So it seems like C20 was kind of flaky or even broken, resulting in this strange behavior. It’s such a relieve, since not being able to solve this issue drove me crazy.

However – there now is another tiny problem…

[Harrumph]

What a thriller! Glad it finally worked out for you!! 🙂

[paulb_nl]

Great that you found the issue! What a relief it must be.

[Morpheus_79]

It surely is – you have no idea. That unpredictable behavior of my OSSC was frustrating as hell. But now it works like a treat.

[Ruud85]

I also have a problem with my 60hz modded 1chip pal snes
No signal on 60hz only on 50hz
Picture and sound on 50hz is great
Only I realy want to play my snes on 60hz Specialy smw rom hacks
Can someone plz tell me what to do so I can play 60hz snes with the ossc

[Morpheus_79]

Does your OSSC recognize the signal (while your TV won’t show anything) or does your OSSC complain about ‘NO SIGNAL’ or ‘NO SYNC’ in the first place?

[Ruud85]

My ossc displays av1 rgbs 262p
15.74khz 60.08hz when the snes is in 60hz mode
But TV shows black screen
(Philips 55pus8503 4k tv)
If I can’t play my snes on 60hz with the ossc what other choice do I have then?
Buying a framemeister?

Sorry for my English I’m from Holland 🙂

[Morpheus_79]

Maybe your TV has some compatibility issues with this particular resolution/refresh rate combination!? What TV do you have? Did you try to switch through all the pixel multiplication modes (Line2x -> Line5x) to see if one or more modes work for your TV?

[Ruud85]

I’m using a philips 55pus8503 4k TV

Linemult mode 1 to 5 all work on 50hz
But switching my snes to 60hz 1 to 5 doesn’t work
TV has no signal

[Ruud85]

Only line5x mode 256 x 240 optim works just a bit on 60hz but the image is realy blurry and the screen flickers to black every few seconds

on 320 x 240 looks a bit better but screen flickers al the time

PLEASE HELP ME

[Morpheus_79]

Afaik most (if not all) Philips 4K TVs have bad scaling and very poor vsync tolerance:

http://junkerhq.net/xrgb/index.php?title=OSSC_Display_Compatibility

Since you have a modded PAL SNES it could be the (slightly off spec) refresh rate which your TV can’t tolerate.

[paulb_nl]

60Hz Modded 1-CHIP PAL SNES get an additional crystal so they have the same refresh rate as NTSC consoles.

Most likely he needs the de-jitter mod. https://videogameperfection.com/forums/topic/nes-snes-240p-audio-video-stability-issues-read-before-posting/

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