Sony cassette puzzler

[Alexander69]

Hello, can anyone help me with a clue to solving a very frustrating problem?

I'm trying to record cassettes on my Sony Scala system with its TC-s1 cassette deck, and getting nowhere...

1) It plays back fine
2) with the in/out leads correctly set up there is no signal being received when recording (as judged by the little led meters)
3) mis-match the leads (ie out to in etc) and there is signal being received judging by the led meters (!?) but still all that's being recorded is hiss.
4) it will wipe cassettes

I've swapped around cables, tried different sources to be recorded and different amps, with no joy, cleaned the heads, checked that the cassette had its tabs...

It looks like it's the cassette deck itself is causing the problem, but I'm all out of ideas.

any next-step pointers gratefully received.

thanks, Alex

[camtechman]

Circa 1998 may be a bit too modern for some of us "oldies" on here.

[Studio263]

Check the recording level control if the meters show nothing.

[julie_m]

Well, you've got playback (so the record / playback head windings must be OK), and you've got erase (so the bias oscillator must be running). Next few things to check:

• Have you got the recording level controls turned up enough?
• Microphone socket switch contacts. Any dirt here will prevent the line-level signal from getting through. (Have you tried feeding a signal in from a microphone? Even a pair of headphones plugged in one of the mic sockets will give out some sort of a signal.)
• Switch off Dolby, so as to eliminate the encoder IC from the equation.

There is a service manual available here: http://www.fixdevice.com/smanuals/file/8850.html

You probably will need an oscilloscope; or failing that, a crystal earphone, to trace the signal through the circuit.

[Alexander69]

thanks for the replies chaps, and the manual link.

1) Recording level - I've tried max and halfway.
2) There is no microphone socket
3) I've tried dolby on and off

I don't understand why mis-connecting the cables makes a difference - is this a clue?


"When I die, please don't let my Wife sell my collection for the amount I told her it cost me!"

[ben]

Try connecting some other sound source to its Line In, and try again.

[DragonForce]

It's hard top say without knowing how you have things set up.

What is your input source? If an amplifier, it's maybe not going to send a signal TO the tape deck if the input selector on the amp is already set to tape (if that makes sense).

If by mis-connecting the inter-connects to mean plugging the input and outputs together, then you probably WILL record hiss - since the tape deck is in REC mode and the input to it is from the playback amp, hiss (background amplifier noise) is all that is going to be available.

I'd suggest to try another input source as Ben suggested, only you say you've tried that already.

Have you put a continuity tester through your interconnects?

A photograph and details of exactly how you are wiring the system up would be handy about now.

[julie_m]

Feeding a signal into the outputs makes the meters move because the meters are connected to the output sockets, measuring the signal there whether it is coming from within the tape deck or from outside. That tells us the meters are working.

When you feed a signal straight into the tape deck inputs and set it in record, do you see that signal, adjustable with the recording level controls, at the outputs? (Connect thus: CD player -> tape deck inputs; tape deck outputs -> amplifier). Never mind if it makes an impression on the tape or not right now, does it get from input to output?

[Alexander69]

thanks for the replies.

AJS, I tried connecting the CD directly as you suggest, no joy I'm afraid.

I've taken a few pics. It's all colour coded, so I'm confident I'm connecting it up right. Apologies for the general 1990s ugliness of this item (it hides in a cupboard) - I bought it mainly for the speakers which have snazzy electrostatic tweeters, and usually run the CD, tape and my phono through a Yamaha CR800, which is much easier on the eye.

I swapped out the Yam at an early stage of trying to solve this recording problem.

The Sony amp is a pre-amp only (the speakers are powered) if that has any bearing?

(btw The speakers have been connected during tests, but I've unplugged them in the pics in order to turn the unit round easily)

http://i185.photobucket.com/albums/x...s/DSCN4422.jpg

http://i185.photobucket.com/albums/x...s/DSCN4420.jpg

http://i185.photobucket.com/albums/x...s/DSCN4419.jpg

http://i185.photobucket.com/albums/x...s/DSCN4418.jpg

http://i185.photobucket.com/albums/x...s/DSCN4421.jpg

[julie_m]

So in video terminology, we have no E-E; and it is on both channels. Hmm.

With the simplified setup I suggested above, and while a CD is playing, disconnect the plugs from the tape deck's IN L and IN R sockets, leaving the right-hand channel connections in place so there is a continuous earth path.

1. Holding the plug that came from the "out" socket by the plastic insulation, touch the inner pin with your finger. What happens?
2. Touch the inner pins of the two plugs together. What happens?
3. Reconnect the left-hand plugs whence they came, and try the same procedure with the right-hand plugs. What happens?

Do you have, or can you borrow, a multimeter? Ditto an oscilloscope?

[Alexander69]

is that a typo and you meant IN left and OUT left? followed by IN right and OUT right?

I do have a multimeter, and I'm not afraid to use it!

I'll give it a go tomorrow, thanks for the help.

[julie_m]

Oops yes, what you said. IN L and OUT L, then IN R and OUT R.

[Alexander69]

just tried that test series.

1) With everything plugged in, cd playing, tape recording, amp set to tape; then amp set to CD:

no playback sound, no movement of recording meters

2) Left hand centre-pin tests

no playback sound, no movement of recording meters, no pops or crackles

3) Right hand centre-pin tests

no playback sound, no movement of recording meters, no pops or crackles

I've dusted off the multi-meter - other than continuity in the leads is there anything I can test from outside the boxes?

[julie_m]

The test results above suggest either no signal is coming from the CD player, or the amplifier is not amplifying. Otherwise, touching the inner pins with a finger would have produced a burst of power hum; and when the plugs were touched together, audio (possibly crackling in sympathy with contact being made and broken) would have appeared in one speaker. The other leads, still plugged into the tape deck, maintain earth continuity throughout.

To prove it, connect the CD player outputs straight to the amplifier inputs.

Next, test all leads for continuity.

[camtechman]

An "off the wall" suggestion; is the lead you're using to connect it an original unmodified one?

The reason for asking is that, some years ago, I had a customer supply leads with an audio system he was having problems with and which he bought off a 'mate'. One of the leads he supplied, although it looked identical to the rest, wasn't for audio use and someone had wired in a resistor/capacitor/diode configuration and didn't work on the unit.

[Alexander69]

AJS, cd output to amplifier input is the normal state of affairs unless I'm misunderstanding you - and there's playback.
continuity in all leads too.

The problem seems to be getting input into the tape deck from any source, and by a process of elimination the blame rests on the deck, specifically the point from the input plug inwards.

....or I'm doing something REALLY stupid!!

[julie_m]

If you touched the plug that used to go to the input to the plug that used to go to the output, you should have got signal going through. If you didn't, that's a sign something is wrong. No impression on the tape on the channel still connected either, suggests the source not working.

[Alexander69]

I swapped out the sony deck, and the replacement playback and records fine.

So by my reckoning that's narrowed it down to two things:

1) a problem with the input circuit inside the sony deck
2) a problem with the recording head inside the sony deck

It's a shame because the playback is lovely, and there's all sorts of Dolby including S!!

I'm keeping it in the system for playback, and will use the other for recording (I've got Tape A and Tape B on the Yam luckily).

Thanks for all your help guys, particularly AJS for your perseverance - I've got a result of sorts, but my guess is that short of getting inside the unit I've reached the end of the road now.

Alex

[julie_m]

This deck is only a 2-head type; the same head is used for both recording and playback. So that isn't the fault.

It's just vaguely possible that a duff electrolytic capacitor could be the culprit. There are IC analogue switches in the circuit, which might well not let a signal through if any power supply rail is missing. And there are several power rails. If you do decide to open the unit up, look to the power supply section first; and replace any bulging or otherwise suspect caps with good quality ones.