Conion Recording Woes

Bloodhound

Bloodhound

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Nov 5, 2019
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Not sure if it's us or the machine.

Here's an idea of what we're experiencing. After completing our mechanical restoration of his Conion C-100F my son and I decided to put deck 1 through it's paces. When recording from a crystal clear aux source to a regular type 1 tape we have no problems. The recording sounds clear, evenly balanced and distortion free.

When recording to a chrome tape with the setting on chrome the left channel is non responsive or dead during playback. Left VU reflects this.

Tonight we tried recording on a new metal tape for the first time. With Tape 1 set to metal the sound quality during playback sucks. Sounds muffled and unclear. There will be a 3-4 second stretch where it sounds great here and there and then it goes right back to crap. When playing a metal tape on the normal setting it sounds much stronger but is still muffled with distortion.

We've always left the rec level button set on auto. Have never tried manual as I'm not sure what the numbers on the rec level knob indicate or how it should be set.

Checked the basic stuff like the felt pads on the tapes and cleaned and demagnetized the heads and capstan again with no improvement.

Any tips, help or suggestions is most welcome!
 
Transistorized

Transistorized

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Jun 19, 2012
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Since the recording is okay with Type I tape I am wondering if the issue may be with the tape selector switch, Have you tried to record onto a chrome tape but keeping the tape type switch on Normal bias setting to confirm?

Also, I am wondering if there are VR trim pots for bias control on any of the boards for the different formula types? Anyone able to confirm this?
 
Bloodhound

Bloodhound

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Nov 5, 2019
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Transistorized said:
Since the recording is okay with Type I tape I am wondering if the issue may be with the tape selector switch, Have you tried to record onto a chrome tape but keeping the tape type switch on Normal bias setting to confirm?

Also, I am wondering if there are VR trim pots for bias control on any of the boards for the different formula types? Anyone able to confirm this?
Click to expand...
Gave it a try (chrome and metal tapes on normal bias setting) and they were both much worse. Sounds very weak during playback which I assume would be normal without the increased bias...

We don't seem to be having the same issue with the weak left channel when recording on chrome tapes. As of this morning we're getting the same results with chrome or metal..

After recording on both types on their corresponding tape type setting the recordings sound great for 2-3 seconds and then fade out to a weak muffled sound for 2-3 seconds and this repeats non stop. It's as if the correct bias setting can't sustain itself for more than those 2-3 seconds, dies out then comes back over and over and over again... Best way to describe it is like when playing music you turn the volume down for 2-3 seconds, then up for 2-3, then down 2-3 seconds and so on. This repeating pattern is now non-stop.

Very frustrating!
 
Transistorized

Transistorized

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When playing a pre-recorded cassette how does the player perform?

If it plays okay with nice clean crisp treble on both left and right channels we can rule out head alignment.
If playback on pre-recorded factory cassettes is muffled with dropouts etc. we can start to suspect the head may be failing, worn, magnetized or require adjustment.

You mentioned that recording onto Type I tape performed well previously. This is interesting. Since the other formulas are not recording well we have to look at what the variable is and try to draw a conclusion. So what has changed? As you have mentioned, the biasing and recording current needed. This is represented by the position of the selector switch (normal/Cr02/Metal) which sets the bias current. Type I ferric-oxide tape does not require as much current/signal to erase and record onto as chrome and metal. A weak signal will respond better on those tapes than on II and IV formulas.

Have you gone back to try and record onto Type I again to see if maybe a bad connection may have introduced itself into the equation? Sometimes a dirty record bar can work okay a few times then drop out with a bad connection internally. If all the sudden Type I is now not recording well then we have a bad connection.

My gut feeling "assuming playback is okay on pre-recorded cassettes and no one has previously tweaked or damaged any VRs on the lower deck logic board" is the record bar and/or dirty Rec Mode selector switches and finally the head itself. Any of these could limit the biasing current to the tape. Check all connections on the lower cassette board and hose down the record bar on it with DeOxit. Check and clean the Record Mode switches on the front. Try recording in manual mode with the mode selector switch pressed in and manually adjusting the record volume with the record level knob until the meters are just touching the yellow areas. Whether in Auto or Manual record mode, those meters reference the signal being pushed to the cassette. If they are both equal and moving then we know the signal is making its way to the record bar but that doesn't guarantee all of that signal is passing through the record bar to the head or from the head itself to the tape. I am inclined to not feel that the head is worn out if playback is excellent but this may not always be the case. I have seen heads that start to fade (level comes and goes) when they warm up. Weird issues for sure.

I would like to add a note on head demagnetizing. I have researched tons of threads on the subject and most experts agree that it is totally unnecessary unless the player has come into contact with a heavy magnet in storage or has been demagnetized incorrectly in the past. The slight magnetic field on the tape is not enough to magnetize any of the player components to cause concern on its own. Also the AC bias fed to the playback/record head during recording should remove any slight magnetizing that may be present on it (if any).
Should you decide to demagnetize the deck, if you do not do it properly, you can actually extremely magnetize the deck to where it ruins every tape fed through the machine and make things much worse or create an issue that otherwise wasn't there to begin with.

This would be my limit of troubleshooting this issue but record bar cleaning, mode selector switches and finally the head itself would all be my suspicions. Coming and going every 2 or 3 seconds can certainly be a weak/failing head.
 
Bloodhound

Bloodhound

Member (SA)
Nov 5, 2019
95
23
8
Transistorized said:
When playing a pre-recorded cassette how does the player perform?

If it plays okay with nice clean crisp treble on both left and right channels we can rule out head alignment.
If playback on pre-recorded factory cassettes is muffled with dropouts etc. we can start to suspect the head may be failing, worn, magnetized or require adjustment.

You mentioned that recording onto Type I tape performed well previously. This is interesting. Since the other formulas are not recording well we have to look at what the variable is and try to draw a conclusion. So what has changed? As you have mentioned, the biasing and recording current needed. This is represented by the position of the selector switch (normal/Cr02/Metal) which sets the bias current. Type I ferric-oxide tape does not require as much current/signal to erase and record onto as chrome and metal. A weak signal will respond better on those tapes than on II and IV formulas.

Have you gone back to try and record onto Type I again to see if maybe a bad connection may have introduced itself into the equation? Sometimes a dirty record bar can work okay a few times then drop out with a bad connection internally. If all the sudden Type I is now not recording well then we have a bad connection.

My gut feeling "assuming playback is okay on pre-recorded cassettes and no one has previously tweaked or damaged any VRs on the lower deck logic board" is the record bar and/or dirty Rec Mode selector switches and finally the head itself. Any of these could limit the biasing current to the tape. Check all connections on the lower cassette board and hose down the record bar on it with DeOxit. Check and clean the Record Mode switches on the front. Try recording in manual mode with the mode selector switch pressed in and manually adjusting the record volume with the record level knob until the meters are just touching the yellow areas. Whether in Auto or Manual record mode, those meters reference the signal being pushed to the cassette. If they are both equal and moving then we know the signal is making its way to the record bar but that doesn't guarantee all of that signal is passing through the record bar to the head or from the head itself to the tape. I am inclined to not feel that the head is worn out if playback is excellent but this may not always be the case. I have seen heads that start to fade (level comes and goes) when they warm up. Weird issues for sure.

I would like to add a note on head demagnetizing. I have researched tons of threads on the subject and most experts agree that it is totally unnecessary unless the player has come into contact with a heavy magnet in storage or has been demagnetized incorrectly in the past. The slight magnetic field on the tape is not enough to magnetize any of the player components to cause concern on its own. Also the AC bias fed to the playback/record head during recording should remove any slight magnetizing that may be present on it (if any).
Should you decide to demagnetize the deck, if you do not do it properly, you can actually extremely magnetize the deck to where it ruins every tape fed through the machine and make things much worse or create an issue that otherwise wasn't there to begin with.

This would be my limit of troubleshooting this issue but record bar cleaning, mode selector switches and finally the head itself would all be my suspicions. Coming and going every 2 or 3 seconds can certainly be a weak/failing head.
Click to expand...
Hey transistorized! Thanks for chiming in!

Just tried recording on a type I cassette. The recording is crystal clear. Playback is 100% with nice clean crisp treble on both the left and right channels. Playback on pre-recorded factory cassettes is great as well. This goes for both Type I and Chrome.

I never cleaned the record bar... As a newbie I feel foolish. I 'll start there once I figure out what/where it is and how to clean it. I did deoxit the mode selector switch that denotes the tape type (Normal, CrO2, Metal) but did not clean the record mode dial or mode switch (Manual/Auto).

I'll try figuring out the record bar by searching some threads and also try and figure out how to clean the dial and manual/auto mode switch. Once I get that handled I'll test again and report back. Thank you for helping us with a starting point.

Wayne
 
Transistorized

Transistorized

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Anytime Wayne.

I'm not going to guarantee the record bar and Auto/Manual switch is the culprit but it certainly is a great place to start and can't hurt to Deoxit them. Once you deoxit the slide bar, work it back and forth a few times. If that doesn't clear up the issue then I would suspect the head or a biasing control somewhere...and I know it might sound weird but might even try another brand of Chrome tape to see if it might be the actual media. I have run into bad batches of NOS tapes that do not record properly. Unlikely....but possible.

At that point you will have ventured into the situation enough to rule out switches and contacts and will soon be traveling down the road of checking component values for which I am weaker in knowledge than some. I am usually fairly good at pinpointing where the issue lies mechanically. After cleaning the weakest links in the path of the recording signal it would be time to look at schematics and testing values.

The record bar is the slide switch that is operated by the spring on the arm of the cassette deck to the rear board. I'll see if I can find a photo on my machine from when I had mine apart.

20180909_163652.jpg
 
Bloodhound

Bloodhound

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Nov 5, 2019
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Thanks for pointing it out. I'll give it a shot and try a different chrome tape as well.

I'm confident the issue can be sorted provided it's something mechanical like you mentioned. Gonna keep our fingers crossed and report back asap!

Thanks again! :)
 
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