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  1. i just bought this Panasonic, the Audio was very noisy (can't understand voices/music) seems that the Audio amplification is out of range

    i cleaned the unit, heads, contacs, everything and mechanically the unit is very nice... video payback is correct and internal stabilization (some kind of panasonic TBCish) is working fine.

    here a sample:

    the audio recorded is linear.. i tried several tapes with amateur content taken from old vhs-c camcorders and also old vhs from 1980 and.. audio stilll like this one. (this is not the HIFI audio taken from the rotating head)

    maybe can be capacitors.. but why are affecting only the linear audio.?
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    Last edited by Bartoloni; 24th Aug 2024 at 10:10.
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  2. Just tried with an HIFI stereo tape.. and the issue is present also in HIFI .. this mean that is the amplifier? because preamplifiers i think are different.

    [EDIT] also tried the OPTICAL out.. and the noise is here also.
    Last edited by Bartoloni; 26th Aug 2024 at 07:58.
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  3. Recapped the power supply and still no changes.. BUT i found that audio from a recorded DVD is clean.
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  4. Capturing Memories dellsam34's Avatar
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    Check the audio pre-amp in the VCR section, DVD audio processing is separate from the VHS, They only take the same path to the audio jacks once they are processed and pre amplified by their own circuits. Remember one is coming from the RF heads/linear head and the other is coming from the MPEG-2/PCM optical pickup, they must be processed separately to a line level signal first.
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  5. very thank you for the suggestion dellsam .. i have the boack diagram from the service manual , but i'm not so good reading it.. i'm a laptop repair guy and block diagram is something "difficult" to follow...

    do you have any hint on what part of page is the section i need to check? the 18 diagram is about the VHS analog audio but not sure what part i need to check.
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  6. Capturing Memories dellsam34's Avatar
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    Everything is crammed in the main PCB, it's hard to tell but I would be looking around the AC head connector area as well as around the IC4501 audio processing chip, look for bad capacitors, dry solder joints, corrosion ... etc.
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  7. the condition of this unit is pristine, no moisture, no corrosion, no oxidation, checked the joints of the board, i remake (just to try) all those that seems worst (but nice joints compared to other units i have)
    checked all electrolytic capacitors near the IC... replaced 2.. but they was not bad...
    no changes....

    there is also a thing that yesterday i saw... the AV1 audio is highter compared to AV2... (But compared to other VCR both have lower volume)
    and on the AV2 there is some sort of echo. (???)
    the worst audio seems coming from the 2 RCA connectors near the 220V plug


    P.S. is possible to take audio directly from the head and use an external preamplifier?
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    Last edited by Bartoloni; 13th Nov 2024 at 12:14.
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  8. Capturing Memories dellsam34's Avatar
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    You could, but it is not the correct way, You would have to know the magnetic tape characteristics to get the right preamp tape equalization applied, So basically you have to design your own, none of the ones taken from audio tape players or the chinese sold online as kits are designed for a low speed VHS tape formulation, You also mentioned that HiFi audio is affected as well, so you would have to find the audio pins for that as well, I would just try to fix it or get another unit.
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  9. thank you for the infos Dellsam
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  10. Capturing Memories dellsam34's Avatar
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    No problem, but make sure that the fault is present when you hook it up to say a normal TV or an audio receiver, I just noticed that you said in an earlier thread that the optical out is affected as well, So this leads me to believe it could be a capture card driver issue or an OS issue.
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