Hydra scart switch – no signal for virtually all systems

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This topic contains 5 replies, has 3 voices, and was last updated by  paulb_nl 3 months, 1 week ago.

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    I have just retired 4 old Joytech scart switch boxes that ran to a Sony PVM in favour of a 16 port W-Hydra and OSSC combination to a Dell Ultrasharp 1920×1200 panel.

    However, I’m starting to pull my hair out with the Hydra – it’s so particular about what it will and won’t sync to. So far I’ve tried the following (all known-good, previously working):

    System / Hydra Sync? / OSSC Direct Sync?
    BBC No Yes (no active components)
    Jaguar No Yes (no active components)
    SNES No Yes (sync on luma cable)
    SMS No No
    MD No No
    Saturn No Yes (original Sega RGB scart cable)
    Gamecube Yes Yes
    Atari STE Yes Yes
    MSX2+ No Yes
    ZX Spectrum +3 No Yes

    Only the PAL Gamecube and the Atari STE work so far, I was surprised with the MD and SMS not working even to the OSSC directly, but I’ll give a new cable a shot with those two; but everything else works great when I skip the connection to the Hydra and go direct to the OSSC AV1 input.

    I still have an Amiga 500, 1200, NeoGeo AES and CPC 464 to try (waiting on replacement PSU’s for the latter), but I’m not holding out much hope based on the current results.

    Surely people are not having this much trouble with ‘fancy’ scart cables? I spent a fortune on this thing. Can anyone point me to a supplier of known-working scart cables that are being used with those above consoles and the Hydra?…. oh, and that don’t cost £30 each…. I can’t justify spending more than the cost of the switch on cables alone.




    I’ve not used my Hydra in a while, but I think there were some firmware updates for it, did you get it direct from Lotharek or second hand?



    It’s brand new from Lotharek about 6 weeks ago.

    Just bought two new csync type cables from for the MD1 and the SMS1 and now the OSSC is happy with those, though still nothing when they’re connected through the Hydra, and those cables definitely seem to be in-spec; they have the resister and capacitor on the sync line to bring it down from TTL levels (which supposedly the Hydra doesn’t cope with).

    Also managed to test my Amiga 500 and 1200 – the 500 works but the 1200 doesn’t, thought I haven’t had the time to see if there is any physical difference between the two scart cables.

    I’m now sitting here with a full 16 port wide-Hydra switch and I’ve got less than 6 devices of my original 16 that will work through it.



    So following some advice from Lotharek I’ve opened up the scart connectors of several of the above consoles (MD1, SMS1, SNES) and measured the voltage of the sync line (scart pin 20), some worrying results:

    MD1 (fitted with 220uF cap and 470Ohm resistor – and my multimeter confirms as such) : 3.22v!!!
    SMS1 (as above) : 1.13v
    SNES (wired as sync-on-luma) : 2.02v

    Since the lotharek states the Hydra follows the scart spec of a 1v max sync signal these are all out of spec.



    Yeah Retro Computer Shack aren’t known for making very high quality cables.



    You need to measure the voltages with a 75Ohm load so for example while connected to the OSSC.

    SNES sync on luma should drop to 1v with a 75Ohm load (0.3v sync+0.7v video)

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