Noise flowing up the screen..

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  • #40713
    Michael Dawes
    Participant

    I get a horizontal band of noise that flows up the screen from the bottom. (I’m using the OSSC on my amiga, and other than this it’s a totally solid display) It’s hard to explain, it’s like a heat haze almost, just a jiggly band.

    I can’t figure out what setting, if any could help lessen it. I’m running line 3x .. it basically looks like what the entire display does if I turn down (to higher values, so maybe turning “up!”) the low pass filter.. is there any way i can turn it up higher than 9mhz?

    #40714
    Fnnrqwin
    Participant

    I get this exact same thing. Pretty sure it’s a power issue.

    #40722
    BuckoA51
    Keymaster

    If it’s an A1200 or CD32 I’d definitely get the system recapped. On my CD32 I had to get the machine recapped, swap the PSU and install a RGB mod (don’t use the RGB from something like a SX32 or terriblefire) to get rid of all the noise.

    #40734
    Fnnrqwin
    Participant

    I actually have this same thing happening on all my systems, although it’s much more noticeable on 240p systems. I’ve used two OSSCs, an official pre-HDMI one and a knockoff HDMI one. Both have the same issue. Used the power supplies that came with each and swapped them too. I’ve bypassed my SCART switch and I got the same issue, so that’s not the part of the chain. Running everything through power conditioners.

    Systems tested:
    – NES
    – SNES
    – N64
    – Gamecube
    – Wii
    – PS1
    – PS2
    – Genesis
    – Dreamcast

    I don’t want to start blaming the design of the OSSC because I haven’t heard of this being a widespread issue, it’s just weird I’d have it with two different models. Any ideas?

    #40735
    BuckoA51
    Keymaster

    What PSUs do you use with your consoles?

    #40742
    Michael Dawes
    Participant

    Ah interesting, thanks both 🙂 My Amiga is using a new PSU and a new RGB Scart cable (plugged into the amiga’s standard 23 pin connector) – But the Amiga’s the only thing I’ve really tried on the OSSC and I guess I could try the Wii on it and see if I get the noise with that too. In the long term I plan on getting the A1200 recapped anyway, so maybe that’ll help as well.

    #40744
    Fnnrqwin
    Participant

    All stock power supplies. NTSC only.

    #40918
    Michael Dawes
    Participant

    All PAL here, but the noise is also apparent if I switch to NTSC screen modes. I can’t see the noise with the Wii plugged in using Component cables so it seems like an Amiga issue here.

    I tried a different SCART cable on the amiga and the noise was much, much worse.. Which makes me think if there was a premium, shielded SCART cable for the amiga i might be able to mitigate or remove the noise entirely. Anyone know where I can buy one of those though? I’m only finding pretty flimsy looking ones like my two. :/

    #47498
    MrClump
    Participant

    I’m curious if you ever resolved this issue?

    I was having exactly the same issue with my A1200 (recapped with a modern PSU). I’ve spent weeks messing with the OSSC, but no amount of phase adjustments would get rid of the shimmering. While messing around trying to found other sources, when I disconnected the USB power supply to my Plipbox the hazy shimmering stopped! Powering the Plipbox from a battery and there is no noise. Now to figure out how to power more permanently as the battery is only a temporary solution.

    #47500
    Michael Dawes
    Participant

    It doesn’t happen anymore but I’m not certain which thing fixed it. I got things recapped, I also am not using the same USB power adapter on my Plipbox that I was once using, plugged into a much nicer plugboard.. And I bought a shielded SCART cable.. One of those things seems to have stopped it. 🙂 I also run the A1200 without the RF shielding now as I was adding so many little things to the mainboard that it was just inconvenient keeping it on.. So it’s not RF interference coming from inside the Amiga causing it, I guess? (i thought it might be at one point) Sorry I can’t be more specific, I’d forgotten it had been such an annoying issue! Now the picture seems rock solid.

    #47509
    MrClump
    Participant

    Interesting that you also have a Plipbox, I noticed mine was the cause when plugging it in and the wavy lines immediately returned! To think I almost bought a Indivision as I wasn’t happy with the output, now it looks stunning.

    I’ve got a cable coming that will allow me to power the Plipbox from the floppy drive port, hopefully having both powered from the same power supply will avoid any interference. Until then I shall continue using my battery. 🙂

    #47520
    BuckoA51
    Keymaster

    USB can add insane amounts of noise just by having something plugged in with a bad power supply. For instance my JTAG programmer somehow manages to add noise when connected to my USB hub, just because it’s on the same power strip as the PS2 I was capturing.

    #47571
    MrClump
    Participant

    I guess if you’re using a cheap USB charger (like I was) which is primarily designed for charging batteries, noise doesn’t really matter! Hopefully powering my Plipbox from the Amiga floppy port will solve it, just waiting for the cable to arrive.

    #47609
    MrClump
    Participant

    I can confirm that powering the Plipbox from the Amiga’s floppy drive port does not lead to any shimmering, I now have a rock solid image without having to power it with a battery.

    It of course has the side benefit that the Plipbox is now powered on and off with the Amiga. 🙂

    #50485
    Reezo
    Participant

    Hello everyone!

    New user here, I’ve been reading this thread avidly <-fancy terms after noticing the exact same (quote) “..horizontal band of noise that flows up the screen from the bottom. It’s hard to explain, it’s like a heat haze almost, just a jiggly band.”

    This is the best explanation for what is happening to me, right now.

    My setup is:
    – Amiga 1200HD
    – Vampire V1200 v2
    – Original Commodore Amiga 500 PSU (tried an A600 PSU as well, but it smells as sh*t and will probably die soon :))
    – IDE-to-CF adapter plugged on the Vampire IDE
    – Ethernet adapter plugged on the Vampire IDE
    – MicroSD plugged into the MicroSD slot on the Vampire
    – RGB to SCART cable by AmigaStore (4m.. so coiled around because a bit longer than needed)
    – OSSC 1.6 with firmware v0.88
    – HDMI short cable from my OSSC to my Philips 60″ HDTV
    – HDMI cable from my Vampire board to the Philips 60″ HDTV

    I basically boot Workbench via the Vampire HDMI and then when loading something from WHDLoad, it switches to its RGB and goes through the OSSC.

    All the above is to give you context but it’s probably not related to the issue itself.. the image quality is stunning and the zero-latency feel (I had almost 500 ms when going from the Amiga RGB to SCART directly into my TV.. insane and unplayable).

    I remember something that might help go deep in this topic: weeks ago I tried a small, portable 15″ display (unknown Chinese brand, but pretty good-looking and good video quality) to use for the HDMI out of the Vampire board. It worked well but I noticed that the image from the RGB to SCART cable was incredibly noisy, with lots of interference. This portable display was powered only by an non-grounded “phone-charger-size” PSU, with a USB-C cable. As soon as I unplugged the power supply OR the HDMI cable connecting the Vampire to the little display.. the interference would go away completely.

    The PSU my Amiga is using is plugged into a multi-socket in which a lot of stuff is connected: lava lamps, a Synology NAS, a small BOSE portable speaker system, two small LED lamps etc. plus the TV, my FritzBox! router and a ROKU player. That’s A LOT of stuff. I am actually laughing now that I am writing this all down, realizing how much is going on, there.

    First and foremost, the RGB to SCART cable looks rather thin.. (sorry AmigaStore.. I love you but it is thin). I am sure a lot of interference could be picked from it, but also:

    – Interference from devices plugged to the same power line
    – RF interference
    – Amiga needs recapping

    are possible causes, for sure.

    It’s nothing horrible, but it’s ‘this close’ to being perfect and it’s a shame that it’s shimmering.

    Thanks enough for any info or help you might wanna give me, in the meantime I’ll keep this thread up with any further finding or experiment.

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