Weird Cassette deck issue

[Transistorized]

My friend has C100 that has a weird issue. It plays cassettes just fine in the lower deck however, after playing a cassette tape it introduces a slight clicking noise that's actually RECORDED onto the tape. It's barely noticeable and only between tracks and on the left channel. The first time the tape is played you hear nothing on the first pass. After that the offending player will start to pick up on the background clicks on the previous pass as it introduces more clicks to the background of the tape with each pass. Eventually the background of the tape starts sounding like an old 45 between songs on the left channel.

What the heck? How can a deck play a tape and at the same time, introduce a clicking noise onto the tape?

Now I know a few may say that the head may be magnetized but the high frequencies are excellent and the clicking sound is only on the left channel. Plus on tapeheads.net most of the major players there believe magnetized heads are a myth so IDK. Even if the head was magnetized, I would think it would just dull the sound of the tape, not record a slight click on just the left channel during playback. The record bar inside works great and is not particularly stuck or dirty.

Anyone have this happen? I tried a Google search and couldn't find a thing on this type of issue.

 

[floyd]

The closest I had to that symptom was when the backing plate on the deck was not on straight and the main flywheel would grind on a certain spot , I'm not saying that's the problem but its worth looking into if you have opened up.

 

[Transistorized]

Thanks JVC Floyd. I'll definitely check. I do hear a slight mechanical noise. It's worth the research on that end.

What's got me is the click/pop is actually being recorded onto the tape when being played. When you play the cassette on another deck you can hear the clicks its putting on the recording in the background on the quiet parts of the prerecorded tape.

Weird..

 

[floyd]

I know this sounds stupid but you might want to think about investing in a mechanic's stethoscope because basically they hold it up to the mechanism to see where they can hear any noise coming from.

 

[Transistorized]

I might as well Floyd. I tell you. I've been playing Dr on these things. Might as well start getting the proper tools

 

[caution]

The record head doesn't work unless the record bar is engaged, so the energy is coming from another source. Maybe the play head needs to be demagnetized?

 

[Transistorized]

Thanks Caution. I need to invest in a demagnetizer. I've seen the ones that come in cassette form and I've seen the ones that come in wand form.

I imagine the wand is probably better.

I know my repair tech has one. Probably could have it demagnetized fairly cheap.

I'll try this. Couldn't hurt.

 

[Transistorized]

Ok. Well this is the first I've experienced this but the click/pop issue is resolved.

When you research decks being magnetized and such, the most common form of this phenomenon is stripping the crisp highs off your tapes leaving them dull and lifeless. Also, playback can be lacking the crisp details but Azimuth adjustment is more likely the cause for muffled playback. However, a magnetized head can do this as well.

Researching this further amongst Pros at tapeheads.net I discovered that the playback head can sometimes pick up a slight magnetic charge over time however, the minor magnetic field it may develop is possible but rarely ever gets to the point of ruining a cassette recording to where it is noticeable.....but is possible. Usually if someone has attempted to demagnetize the deck and did so incorrectly resulting in a stronger field than it would have ever obtained from normal playback. For normal situations where the head has picked up a minor field over time, if the deck is able to record, pressing record and feeding an AC bias into the head will (in itself) correct a typical slightly magnetized head.

That being said, the capstan area is also likely to be magnetized over time or from an incorrect demagnetize attempt. This can introduce a pop/click onto type I cassettes because their sensitivity to recording are higher than metal bias tapes which require a stronger signal to introduce interference onto the tape.

This made perfect sense to me because the first pass with a clean blank tape plays silently with no clicks or pops. Only the typical hiss noise at louder volumes. I always felt that if it was a circuit in the box or the head itself putting the noise onto the tape during playback, you would hear the pop or click during the first pass playback of a clean tape. You only hear the click/pop after you rewind and play the tape again for the second pass. Then the playback head sees this signal.

This told me that the noise was being added to the tape AFTER the head. Since this is a 2 head machine the only thing after the playback/record head is the capstan. I took the machine to my tech, removed the door and had him demagnetize the capstan post.

BINGO. Noise gone. The one post I read on tapeheads.net said that a partial capstan field could introduce pops/click and he was right.

The issue is gone. You will read all day long about how a magnetized deck will destroy the crisp highs on your tapes however, it must be more uncommon but a magnetized capstan can introduce a click and pop at even intervals of the tape. Who'd have thought. Wierd.

Oh well. My friend can stop ruining his tape collection now

 

[Fatdog]

Wow! Glad you were able to get that sorted. I had never heard of, or experienced, anything like that.

 

[MyOhMy]

^ ^ ^ ^ ^ Same-same here.

I use a cassette style demagnetiser which has always done the job nicely but, from what I've read in you post, would it be right to suggest a demagnetising wand would also be needed to demagnetise the capstan?

 

[Transistorized]

Wow! Glad you were able to get that sorted. I had never heard of, or experienced, anything like that.

Thanks Fatdog. Yes sir. This had me going for a bit. And because I am such a good friend with internet and the equipment to do it, I took all of his factory cassettes that suffered from use in that machine and remastered the original cassettes in their factory shells by taping up the erase holes, biasing, leveling them and then digitally remastering them using Dolby B (like they originally were) along with HX-Pro. They actually sound better than when new now. Gotta love a 3-Head Sony with dual capstan closed loop system. It can restore a factory cassette to better than normal.

So I basically ServPro'd him.....like it never happened. Plus I adjusted his tape motor while I was poking around in there. That's what good buddies are for. Maybe one day I'll need a favor so it all works out in the end.

I use a cassette style demagnetiser which has always done the job nicely but, from what I've read in you post, would it be right to suggest a demagnetising wand would also be needed to demagnetise the capstan?

A wand is great for when you have plenty of room and want to take care of all the components in the deck. As long as your machine isn't destroying your cassettes I would keep doing what your doing

 

[MyOhMy]

A wand is great for when you have plenty of room and want to take care of all the components in the deck. As long as your machine isn't destroying your cassettes I would keep doing what your doing

Many thanks, I appreciate the help and advice.