Betamax recording

[Clansman1968]

Hi have linked a dvd player up to betamax and set to camera dvd plays through it on to TV sound and picture but when try to record it on betamax on play back I'm getting picture but no sound any thoughts a pre recorded betamax tape plays with sound any help please.

[gallowfields]

presume you are using one of them scart to 6 phono leads . if so try using the other two audio leads .dont think you are are feeding in any audio.

[Vintage Engr]

Just be aware that some scart leads have their identification marking tags the wrong way round! i.e. 'audio out' doesn't necessarily mean that; it can mean the opposite...
I have some that are like that, which totally goes against convention, where the markings are usually WRT the source machine.

David.

[Clansman1968]

Thanks for replies swopped audio leads over but still no sound on recording and also swooping lost sound on TV. Not a big worry just wanted to put couple of dvds onto betamax.

[John123]

Check the machine's audio options to make sure it isn't set to receive audio from simulcast/ radio record/ microphone/ PCM/ audio dub, etc, etc..

[Clansman1968]

There's no audio options what can't understand is if when playing dvd through betamax to TV I'm getting sound and picture but when record onto betamax I get pic but no sound .

[patrickgnl]

I see the audio in/out is a DIN socket, are you sure that lead is OK and you haven’t connected the audio out from the SCART on the DVD player to the audio out within the DIN plug, instead of the audio in…. ?

That type of DIN socket normally has 5 pins plus the metal surround.. you can find the pin layout here https://www.electronics2000.co.uk/pin-out/dincon.php

Ie red and blue here…

Patrick

[Clansman1968]

Thanks will look when get in later.

[simpsons]

Good morning Portsmouth.

To narrow down the problem, which make and model Betamax recorder are you using?

Also, please confirm that you are using the RF output from the recorder to feed your TV.

Last but not least, I assume that you don't have any pre recorded tapes to try?

Chris

[Clansman1968]

Hi it's a sanyo VTC 9300PN yes using the RF output prerecorded tape works fine just found out there is sound if turn TV up to maximum but it's very muffled barely audible.

[patrickgnl]

According to this post https://www.vintage-radio.net/forum/...d.php?t=131818 this is an Australian model - so if you are connecting to the Tv via RF/Aerial cable, the machine will output Pal B (ie 7 mhz channel vhf/uhf depending upon the vcrs modulator), so the sound carrier is 5.5mhz. If you are using a UK Single standard TV it will be Pal I so a 6mhz sound carrier. So that is most likely it, also why you can hear the sound although very faintly..

If you have a modern LCD Tv most have a multistandard analogue tuner, so it should be possible to adjust standard B/G…

But then again… this will only affect RF playback, have you also got it connected to the TV via SCART or phono leads?

Patrick

[simpsons]

As the recording is direct and not via RF, as said, why would the sound carrier frequency matter and just as important, it has been said that a pre recorded tape plays back fine. This means that the internal RF modulator is correct for the UK. Red herrings, who would have them!

Now back to the real issue.

To undertake any fault finding, the service manual must be downloaded. This is available FOC and includes component layout, how to get at the parts, adjustments and the circuit diagram all of which will be necessary to enable fault finding.

A quick glance shows that a relay is used to switch between record and playback of the audio channel.

To see if it is operating, the bottom cover removed and circuit board will need
to be viewed. The recorder then switched between record and playback. This would be my starting point.

So, Clansman, how confident do you feel about unscrewing the recorder to get at the components and do you have a basic knowledge of schematics?

Over to you.

Chris

[Clansman1968]

Think I'll pass on that lol it's actually connected to a analogue colour TV which I can view TV by using a set top box and a RF modulator, the betamax is connected straight to TV using the aerial connection, think I'll stick to prerecorded tapes thanks guys for all your input .

[Clansman1968]

Just one more question lol if plug main aerial into betamax which will be a digital signal then areial wire out to digital TV will TV pick up signal sorry if it's a obvious answer.

[Snarf81]

Try it and find out

[agardiner]

Originally Posted by Clansman1968

There's no audio options what can't understand is if when playing dvd through betamax to TV I'm getting sound and picture but when record onto betamax I get pic but no sound .

OK - lots of suggestions have been given, but you mention that you have sound if you are playing the DVD through the betamax to the TV. Also, pre-recorded tapes are fine, and I presume that you using the same set up with the video recorder and TV.

Therefore, this would actually indicate a recording problem, further enforced by the fact that you can hear muffled audio on the recording when turning up the TV to max. It sounds like you have a fault in the audio input stages of the betamax machine.

[Clansman1968]

Yeah I think that's were the problem lies. I have tapes that were recorded when the machine was last used which had recorded and played ok.

[simpsons]

Re: Digital TV viewing.

The answer to this question is nuanced as follows.

In the pre digital age, when a video recorder is in standby or record mode then you are able to view the TV programme either on the broadcast channel or the "Video" channel, often CH36, which you choose when playing a tape.

For all video recorders, the broadcast channel is unaffected by the internal circuits of the video recorder. Hence when viewing a digital broadcast through the video recorder, all is well.

Choose the "Video" channel on your TV then for all recorders everything changes. The TV signal is then routed through circuits which, similar to a TV, select the channel you wish to record. The signal is then demodulated (converted) into video and sound.

Depending on the recorder, the demodulated signals (sound & vision) are either re-broadcast to the viewer on the Video Channel before any further circuits or, after they are modified to suit the recording limitation of the format and then re-broadcast.

Staying in the pre digital age, if re-broadcast before modification, then you will not notice any picture degradation. If after, then the picture becomes "soft" and looses detail.

In the latter case, the video bandwidth has been severely reduced and whilst I haven't tried to, I suspect, as with teletext, digital TV reception will not occur.

When the video is rebroadcast before bandwidth reduction, then, I don't see why it wouldn't work. Very much in the same way as a cable TV company receiver would work? Again I haven't tried this and so should you have the inclination to, let us know.

Those with a better understanding of signal processing might wish to either add their two penneth or demolish my logic.

Chris

[Clansman1968]

Gonna have a look at connections etc tomorrow see if I can come up with anything as said not a major problem if can't sort it thanks again guys.not sure when it was last used for recording 80s I expect I got it from the son of the owner who brought it from new and he can remember it recording ok.

[agardiner]

I think this is a case of a fault in the machine. I would start by looking at the audio bias oscillator. I really don't think there is an issue with digital vs analogue TV; it sounds like you have connected everything correctly.