digitalFAQ.com Forum - VHS capture with AG1980

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MX50A seems to be made in 1998. I opened it up. It is a lot easier to open up the MX50A than the AG1980 and it is also the boards are more accessible. There are a lot of capacitors way more than the AG1980. It will take some time to recap it. I have to figure out why the color correction is not working. T bar is also not working. It is semi working as you can see in my 2nd sample. Have to figure out why audio is not going through the machine either. Maybe cap issue there? Any suggestions?

Quote:

Originally Posted by dpalomaki (Post 70665)

As implied above, it is not unheard of to use, for example, a 10-bit A/D converter chip, and just ignore the two least significant bits essentially using it as an 8-bit A/D. Or more significantly used 8-bit converters for luma and chroma, but only used 6-bits for the chroma. (Reduced memory cost back in the days when ram was not cheap and did not waste limited available processing power on detail that might be below the noise floor). It worked for the typical material that was being recorded and the limited quality displays used for home video back then. It is not up to today's quality standards.

Some devices may be 10-bit for input and internal processing, but only output 8-bit.

The WJ-MX50A sold new from something over $4000 back in the late 1990s. THe MX50 adn MX50A date to the 1990 and they may well suffer from the SMD capacitor problem that plagued the AG-1980s from that era. If the mixer does not provide an improvement in the video I would not use it in the signal path.

It is mainly the SMD caps that were a problem, at least with the AG-1980.

As too audio, check for broken connections at jacks. If it was a cap there would likely be some kind of audio coming out, probably rather ratty audio or noise.

Moving contacts, e.g., pots, sliders, switches, and t-bars, might have dirt on the contacts. Electronic contact cleaner might help.

The service manual is available on line but there might be some cost. IT appears that the service manual for the WJ-MX50A is mainly the updates to the WJ-MX50 manual.

Luckily I just found the full service manual. One site gave it for free. My AG 1980 had 1-2 near bad capacitors also. I will check according to your suggestions when I find the time. The audio seems like it is not inputting as I don't see the audio level light turning on at all no matter what I try.

Quote:

Originally Posted by dpalomaki (Post 70667)

I have a WJ-AWE55 here which also seems to have some dodgy SMD caps (got random noise and flicker on video input.), so maybe that's common. Seemed to be able to work as a TBC to an extent, but I haven't gotten around to test it much yet.

If audio is not working, it's usually not an issue to connect audio directly instead of via the mixer and alternatively compensate for Audio/video offset in post if it occurs. I don't know if the audio is buffered in the mixer or not.

That is what I did regarding Audio but it kind of bugs me that it is not working. I saw no delay as far as I noticed when I connected the audio directly. But audio is secondary. My main concern is the color correction (stuck in reddish tint when turned on), chroma setting, and other manual settings not working.

Quote:

Originally Posted by hodgey (Post 70671)

Quote:

Originally Posted by RS456 (Post 70621)

Can anyone see a difference between the two clips? Is the 2nd one an improvement?

It's hard to tell which differences were caused by hardware and which were caused by lossy compressing to AVC. But one that stands out is the picture in "WJ-MX50A-mywtc1" is shifted to the right and several columns of pixels are cropped from the right side.

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