Sony DVW-A510 Digibeta playback audio cuts in / out?

[mark_in]

Hi everyone,

I have a Sony DVW-A510 Digibeta playback VTR that plays back digibeta cassettes where the audio pops in and out every second. No popping, just coming on and off every second. I take that same tape (only tested 2 so far), and both tapes elicit the same behavior.

I work in a good shop, just signed on. I ran through an alignment (auto alignment with the zr alignment tapes) and manually adjusted A19 and A010 in the maintenance menu with the Sony maintenance manual and an oscilloscope, and cleaned the video and audio heads, and tape path with a tex wipe and alcohol but the issue still exists. Also reseated all the boards. both VTRs are on standalone carts, for QC playback, without a sync gen.

I'm brushing off the cobwebs here, since I haven't aligned a digibeta in quite some time. Has anyone come across a similar issue with playback of digibeta on a DVW-A510? These are old film transfers, done correctly I'm assuming. Thanks in advance, if anyone can point me in the right direction. I already swapped a few boards with working spares but no change in playback behavior.

[lordsmurf]

Welcome.

Audio dropouts/distortion is often I/O. With external connections, it's obvious, check/replace the wires, check the port soldering.

But this is Digital Betacam, so what does your workflow look like?

With video, never assumes anything. Just yesterday, I had a "professionally produced video" that had more jitter than not, color bleeding (chroma offset), and just generally sucked. Age also messes with videotapes in odd ways at times. I see strange things all the time.

[latreche34]

I would pull the RF and audio boards and look to see any damage or corrosion of traces or leaky capacitors, Those microwave size beasts are hard to troubleshoot, I got the desktop version about 3/4 the size of a consumer VCR, the Sony J3-SDI, I knew those big boys are prone to failure, haven't had a problem with mine so far.

[mark_in]

Quote:

Originally Posted by lordsmurf

Welcome.

Audio dropouts/distortion is often I/O. With external connections, it's obvious, check/replace the wires, check the port soldering.

But this is Digital Betacam, so what does your workflow look like?

With video, never assumes anything. Just yesterday, I had a "professionally produced video" that had more jitter than not, color bleeding (chroma offset), and just generally sucked. Age also messes with videotapes in odd ways at times. I see strange things all the time.

Thanks LordSmurf.

The workflow for this VTR is to QC tapes, it sits in a Producer's office. so it's just the DVW-A510 or DVW-A500 to an AJA Hi5 Plus, then to an OLED monitor and speakers.

I pulled the DVW-A510 because digibeta tapes play video out fine, but the audio plays out every second, cutting in and out, where the same tape in the DVW-A500 plays video and audio out fine (same tapes). Both VTRs have been serviced regularly, and professionally. I am going to check the alignment / azimuth of the TC, CTL and audio heads today, perhaps they got out of alignment or don't have locktite on the screws.

Quote:

Originally Posted by latreche34

I would pull the RF and audio boards and look to see any damage or corrosion of traces or leaky capacitors, Those microwave size beasts are hard to troubleshoot, I got the desktop version about 3/4 the size of a consumer VCR, the Sony J3-SDI, I knew those big boys are prone to failure, haven't had a problem with mine so far.

I have already done that, but I will do again. I also swapped out the boards I found spares for. Thanks

-- merged --

I am looking at the A510 now, and I just enabled the 1khz internal audio signal. The signal pulses every second, just like the audio playback from a digibeta. The VU meters on the front of the vtr show the audio pulsing as heard in the audio monitors. I'm going to try swapping a few boards again, then check the ctl, audio and tc heads.

-- merged --

Update: It's the VPR-1 board, not sure what IC may be causing this but ebay also sells the VPR-1 board for $169.00. Thanks all for the help.

[latreche34]

The VPR-1 I believe is the TBC board, Correct? If you can recap it , it is better to do so because any board you buy now would be in the exact condition age wise, But if $170 is worth the gamble for you, why not?

[lordsmurf]

$170 is generally more than I want to spend on "extra parts in a drawer" that may never even be needed, but that's because I've done it many times, and rarely needed the parts.

I'm not familiar with this deck, but if a TBC board is causing audio, isn't that weird? TBC boards do not process audio, and pass it at most. If it does pass, sounds like another bad deck engineering design to me.

In the end, I hope you found the issue now, and can fix it.

[mark_in]

Quote:

Originally Posted by latreche34

The VPR-1 I believe is the TBC board, Correct? If you can recap it , it is better to do so because any board you buy now would be in the exact condition age wise, But if $170 is worth the gamble for you, why not?

VPR-1 is the video processing board. It also has the TBC, audio sync, and other chips for A/D and D/A processing. A lot is packed into these workhorse machines from the '90s. Since this also happens with a 1khz sinewave internal audio signal, I believe it is one of those ICs within this board. Some of them are pretty big with over 40 soldered contacts. I may find like you said that it winds up to be one or more caps that need replacement, but I may not have the time to dedicate to troubleshooting further.

I'm going to see if my shop has any non-working decks with spares first.

[latreche34]

Quote:

Originally Posted by lordsmurf

I'm not familiar with this deck, but if a TBC board is causing audio, isn't that weird? TBC boards do not process audio, and pass it at most. If it does pass, sounds like another bad deck engineering design to me.

In the broadcast world that's how TBCs work, not only do video timing but audio synchronization as well, SDI contains both video and audio.

[lordsmurf]

Quote:

Originally Posted by latreche34

In the broadcast world that's how TBCs work, not only do video timing but audio synchronization as well, SDI contains both video and audio.

Yeah, I forgot about the audio until his last post. I've not had any real interaction with that format since my studio days, which are now over a decade past.

When you don't use knowledge, you lose/forget it.