Why is sound missing on some 8mm-Hi8 playback but not all?

[Ohank]

I picked up a Sony CCD-TR805E to archive PAL tapes. I recorded them with a Sony tr2200 many years ago. Many of the tapes have a clear picture but absolutely no sound. Actually just one of the ten I tried has any sound at all. I cleaned the main head but no change. It's not as if there are fragments of sound or intermittent. None at all. It could well have been that I used an external mic on the one that has sound. I can't remember but I did that pretty often but not all the time. Maybe 50-50. I certainly have heard sound from the other tapes before (years ago). There is a switch saying hi-fi sound. I found that on the one tape that played sound fine if I put the switch in position 2 it made it best. Position 1 nothing and the top a scratchy weak but consistent sound. Changing this switch did nothing for the tapes I couldn't hear. I'm not that sophisticated in knowing all the ins and out of these camera's but wonder if there's more that I can do in terms of a setting on the camera or physically making an adjustment? I tried both the audio out and headphones with the same results. Thanks.

[Ohank]

Oops. Forgot to click "upload" on those attachments. btw, the original was a tr2200e.

[timtape]

These camcorders are well known to have failed capacitors, often many. This may be the problem. Replacing the caps is difficult and specialist work unfortunately.

[latreche34]

Could the original camcorder had the digital PCM audio capability? Not a lot of consumer camcorders did have PCM but maybe worth checking the manual.

[Ohank]

Quote:

Originally Posted by latreche34

Could the original camcorder had the digital PCM audio capability? Not a lot of consumer camcorders did have PCM but maybe worth checking the manual.

Thanks for the reply. The manual for the original (2200e) only mentions pcm briefly. It says ...
"When bars (– –:––:––) appear
An index signal is marked, the RC time code is
written, or PCM after recording is made on the
tape>"
I don't find pcm mentioned (online search) for the one I have now. TR805e.

[Ohank]

Quote:

Originally Posted by timtape

These camcorders are well known to have failed capacitors, often many. This may be the problem. Replacing the caps is difficult and specialist work unfortunately.

If there were bad caps would it play some tapes fine and not others? Thanks

[latreche34]

No, If the camcorder is bad it will affect all tapes.

[Ohank]

Don't know if this sheds light but the one tape whose sound played OK with the TR805 had these characteristics in the capture.
Initial Audio Stream
Format: mp2
Bitrate: 192 kbps
Rate: 48000 Hz
Channels: 2
Selected codec: mp2
Audio Streams
Track 0
ID: 1

Format: mp2
Bitrate: 192 kbps
Rate: 48000 Hz
Channels: 2
Selected codec: mp2

[latreche34]

Those are the captured file parameters, The parameter you capture software set to capture at, it has nothing to do with what is on the tape.

[Ohank]

Aha. I hoped it would give a hint. Thanks