Help needed from a reel tape technician ...

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gilwe

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Thanks in advance .

I own a Fostex M-80 eight track reel-to-reel recorder.

All channels play and record just fine, except for channel 8.

The channel plays fine (I checked older recordings),
but recording is done on an extremely low level. When I plug an input the channel meter shows the correct signal but the actual recording is done on the lowest level (between -20db and -15db).

I know some electronics and if someone will give me some directions of what to check I'll be thankful.

BTW - if it was a worn head so the channel would also play at low levels ? Is this correct ?
 
Had a recording today using the 8th track ...

Well, it still isn't fixed yet -
the sound is not "stable". What I mean is that the recorded track sounds like the frequencies change in waves -

last time I was trying to fix the problem, I cleaned the head thoroughly so that might have brought the 8th track to life but as I said it still not good ...

Any other ides ReelPerson ?
 
Well,...

Clean the head again, and keep cleaning it periodically.

Second, just for grins, on a test tape, run the test signals onto all 8 tracks, and notice how and where the track #8 problem shows up, which I assume it will,... intermittently.

Then, turn the tape over, and notice if the flaky channel remains at #8 or switches to track #1. This might indicate a bad tape.

Oh yeah, forgot to mention, try a brand new tape, or a second brand new tape, if necessary,... just to be sure. See if the channel #8 dropout is consistent on all 3 tapes. Try reversing these tapes also, as I've described above.

I've found that on certain reels of 1/4" Quantegy 499, I was getting dropouts on channel 8, which were definitely from a flaw on the tape. Now, I don't use 499, because I'm concerned about dropout issues on 499, which I read another user had posted about also, quite some time ago.

Good luck.;)
 
Wow.

I touhgt the Quantegy are the best 1/4" reel makers (?)
at least from what I've been told...

Anyway,

after checking it once again I found that there is no frquency changes (or "modulation"), but I do hear a kind of "drop" of the sound from time to time when playing the track - it's like it is missing few miliseconds of the signal every few seconds.

Was this what you mean when you said "dropouts" ?

I'm definately gonna check again on a new tape.

BTW, if the Quantegy is no good, what other tape is recommended for the machine ? What are you using ?
 
I'm not gonna say Quantegy 499 is no good.

I'm saying I read a post about 499 dropouts, and then I experienced a track 8 dropout on 499, and therefore I don't use it.

I have a large variety of tape stock, considering how little I record, but I'm currently using 3M-226. I have many reels of 3M-226, and Ampex 457, which is the 1800'/7" reel of 456-bias-compatible tape. [456 only comes in 1200'/7"]. I also have several reels of Ampex 456.

[I have more Ampex than Quantegy, and they're the same manufacturer, but Ampex reels are older that Quantegy reels].

I've never experienced dropouts, except on 499.

I'm not gonna say Quantegy 499 is no good. Most of the posts I've read, except one, only say good things about 499.

I experienced dropouts on 499, and stopped using it immediately, and have had no such problems on any other reels.

Sorry, I guess I'm reapeating myself.

What you're describing does sound like a typical tape-type dropout, and I'd definitely recommend verifying the problem with a couple new tapes.

Remember to keep the heads clean, and also try to flip the tape, and see if the problem relocates itself to track 1. If the problem recording changes to track 1, then it's definitely pointing to the tape, not the machine.

Good luck.;)
 
Played the tape on reverse and found that the dropouts are heard on track 1 (=8)

Not only that , dropouts can be heard also on track 7 as well !
 
Ok, so the dropouts seem to be on the tape,...

but to make absolutely sure, do this verification by RECORDing on the tape in the flipped-over orientation.

[you weren't specific, so I can't tell], but it's safe to assume that your first original tests were record/playback tests, and that dropout occurred on track 8.

If you then reverse the tape, and do PLAYBACK only, then it's safe to assume the dropout will show up on track 1, which was previously track 8. This, in itself, does not prove whether that's a flaw in the tape, or an inconsistency in the record signal that was printed to tape.

Then, by doing test RECORDING again, with the tape in this flipped over orientation, if the dropouts occur again on track 1, then it'sdefinitely the tape, but if the dropouts occur again on track 8, then it could be the machine causing the problem.

The track 7 issue is just another factor that needs to be verified.

========

It's a simple procedure of record/playback verification, then flipping the tape, and doing record/playback verification again, and comparing the results.

I hope with this explanation I did not confuse things.

Regardless of my explanation, confusing or not, it's a simple principle of troubleshooting to verify either the tape or the machine causing this problem, and I have faith in your troubleshooting skills.

========

Without assuming too much, it does seem like the tape is causing the dropouts, but it stands to be verified thoroughly, with both record and playback, and with the tape in the forward and reverse orientation, before you can be absolutely sure.

Having a second or third test tape would go miles toward verifying this issue.

==========

Sorry, it's simple troubleshooting concepts that can sometimes be difficult to explain clearly. Good luck & report back when you have definitive results.

==========

I'm still not gonna say 499 is no good, but...

Never mind. Haha.;)
 
456 has an excellent sound, except for these dropout it's a great tape !

But how do I know if the new tape I buy will have these dropout ?....

anyway, solved the "8 track not being heard" just by slightly adjusting the head, tuning it vertlically... just a very slight change with the head screw ...
 
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