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Noise over Audio during use - Printable Version

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Noise over Audio during use - Dave - 04-05-2017

Hello,

I was curious if there is a fix for what sounds like data noise when the wimodem is connected coming over the speakers. There was always a little noise that came from the C64 over the audio line. However, when the wimodem connects you get click, click, click, click constantly. Once you disconnect from a BBS the clicking continues until you turn the C64 off. Just curious if others have noticed this or have a solution to shield the noise??

Thanks,
..Dave


RE: Noise over Audio during use - Digital Man - 04-05-2017

(04-05-2017, 11:16 AM)Dave Wrote: Hello,

I was curious if there is a fix for what sounds like data noise when the wimodem is connected coming over the speakers. There was always a little noise that came from the C64 over the audio line. However, when the wimodem connects you get click, click, click, click constantly. Once you disconnect from a BBS the clicking continues until you turn the C64 off. Just curious if others have noticed this or have a solution to shield the noise??

Thanks,
..Dave

I'm experiencing similar interference on the C128.  I'm also seeing a flicking on the screen.  Both are ever so slight but noticeable and go away when i remove the Wimodem.


RE: Noise over Audio during use - Dave - 04-05-2017

(04-05-2017, 11:43 AM)Digital Man Wrote:
(04-05-2017, 11:16 AM)Dave Wrote: Hello,

I was curious if there is a fix for what sounds like data noise when the wimodem is connected coming over the speakers. There was always a little noise that came from the C64 over the audio line. However, when the wimodem connects you get click, click, click, click constantly. Once you disconnect from a BBS the clicking continues until you turn the C64 off. Just curious if others have noticed this or have a solution to shield the noise??

Thanks,
..Dave

I'm experiencing similar interference on the C128.  I'm also seeing a flicking on the screen.  Both are ever so slight but noticeable and go away when i remove the Wimodem.

I'm starting to think there's some grounding issue or the C64 needs a better shield internally????


RE: Noise over Audio during use - beamrider - 05-02-2017

I am also receiving a flickering screen on various (not all) C64s/Vic20s. Also it seems to disrupt the joystick port readings causing random menu selections etc.


RE: Noise over Audio during use - admin - 05-02-2017

That is a problem with your power supply then.


RE: Noise over Audio during use - beamrider - 05-03-2017

It only occurs when the WiModem is connected and manifests with multiple power supply/computer combinations. It even occurs with the expensive "Ray Carlsen" switch mode power supply (for Commodore computers) that delivers up to 5 amps. I also get random signals on the joystick ports when connected.


RE: Noise over Audio during use - admin - 05-03-2017

I am not sure what to tell you.  Nobody else has reported any joystick issue, and I have never seen this problem on any of my systems.  Bad 5v power can cause things like this though.  Measure 5v and see what yours shows.  Low 5v will cause the screen flicker (the VIC is very sensitive to voltage).   You could also try swapping the 6526 VIA chips in your C64 and see of the problem changes or goes away.  The VIAs are connected to the joystick port and user port.


RE: Noise over Audio during use - beamrider - 05-03-2017

Ok, thanks. Yes, I suspect that the WiModem is within spec but that it perhaps "stresses" the Vic-20 exposing any weaknesses in the system.  I'm assuming the Ray Carlsen PSU is good (it cost me over $100) but perhaps I also need to test that.


RE: Noise over Audio during use - beamrider - 05-07-2017

Discovered a couple of things..

the random joystick input seems to be down to a conflict with the mega-cart on the vic-20 [someone over on Denial has seen the same thing].

As for the flickering on the Vic-20 - I have discovered that it occurs on my CR Vic 20's with 5-pin power connectors, but not on the old 2-pin models. Strange...


RE: Noise over Audio during use - admin - 05-07-2017

Maybe there is a bad ground?

Did you check the 5v line inside of your VIC-20's to see what it really is?