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Vintage Tape (Audio), Cassette, Wire and Magnetic Disc Recorders and Players Open-reel tape recorders, cassette recorders, 8-track players etc.

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Old 19th Apr 2017, 7:54 pm   #1
Nickuk99
Triode
 
Join Date: Mar 2017
Location: Reading, Berks, UK.
Posts: 23
Default Otari MTR10 expert here? help needed please

I have an MTR-10 (11) CT (rev D) model, C = Console with meter overbridge, The 'T' indicating it is the timecode model factory fitted with the "ZA-55H TIME CODE KIT", the time code card is the PB-47RA. Butterfly heads. All the red power LED's are alight and fine, the green LED on the Master CPU is green (after a few seconds)... and the Capstan LED is red until tape is loaded, then green as it should be, no errors showing..

The issue I have is that when entering "play" mode, the audio is muted!!!

I can however hear the playback audio (both left and right) in, 'cue', 'fast forward' and 'rewind' mode (as the tape lifters are defeated, so the tape is in contact with the playback head, I can also hear the audio (again on both channels) in 'reverse play mode' (plays slowly in this mode, which I believe is normal), however when entering 'play' mode the machine always totally mutes the audio output!!!

Also when exiting 'play' mode, by pressing the 'stop' button.. I do hear the playback audio for a split second as the muting is cancelled and the tape comes to a halt...

According to the manual, when in 'cue', 'fast forward' and 'rewind' modes the audio output is muted by -6db to protect the monitoring equipment. . and that is what I'm hearing.

The transport seems to operate okay apart from the reels on a full 'rewind' or 'fast forward', the brakes do not seem very effective. .. It takes a very long time to stop with the tape leader thrashing around... could this be causing a mute to the audio?


The tape lifters do not function (which is correct), as having read the manual for the timecode card I discovered that the PB-47RA timecode card has a 'lifter defeat' dip switch (7-2) which 'defeats' (switches off the tape lifters), and the factory default setting of this dip switch is 'off'..

http://lcweb2.loc.gov/master/mbrs/re...Code%20Kit.pdf

I removed the timecode card and turned the dip switch to 'on', thus turning off the 'defeat', I then re-fitted the timecode card and tape lifters operated perfectly in all modes, however with this dip switch set to 'on', I had no playback audio at all from the machine at all in any operating mode, so the audio was muted in all modes... cue, rewind, ff, play etc..

I presume that the tape lifter 'defeat' switch being defaulted to 'defeating' the tape lifters is so they don't operate, and so the timecode head (KH-41W) will always be in contact with the timecode on the tape.

Now that I understand why the tape lifters are not working (factory set to 'off' by the timecode card), I have the anomaly where if I set the tape lifters to operate. .They do operate perfectly but I have total muting of all audio in all modes, and when the tape lifter 'defeat' dip switch is set to the factory default (tape lifters defeat 'on', so they are switched off) I get muted audio at -6db in all modes except when I enter play mode. . When then the audio is totally muted..

I have read in the May 1989 release of the MTR10 manual that the later master CPU card PB-4GEA has a dip switch (switch 2-3) 'output muting on entering play' which of course the factory default is set to 'off'.

This is what seems to be what is happening with my machine.

My MTR -10 is fitted with the PCB PB-46T(C) master CPU (an IC on the CPU is dated March 1987), and I can't find any info in the manual or dip switches on this CPU that would explain why the audio is being muted when entering 'play' mode.

Does anyone have any idea where this muting on entering "play" is coming from??. I'm wondering if it is somewhere on the timecode card? as when I switch off the tape lifter defeat dip switch (so they operate) I get total muting of all audio in all modes.. when I switch it back on again to 'defeat', I get muted audio at -6db and totally muted audio when entering 'play' mode.

Any suggestions or referrals to an Otari MTR guru??

Any help or advice here very gratefully received. ...

Last edited by Nickuk99; 19th Apr 2017 at 8:01 pm.
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Old 22nd Apr 2017, 10:57 am   #2
Lodgesound
Retired Dormant Member
 
Join Date: Jun 2009
Location: Surrey, UK.
Posts: 66
Default Re: Otari MTR10 expert here? help needed please

Have you tried unplugging the timecode card and then running the machine?

Most timecode equipped machines that I encountered in post production including the Sony and Nagra ones I own now will mute their outputs in play mode UNLESS they are locked and stable to a source of incoming timecode whilst running in chase mode.

I wonder if your machine is in chase mode hence it's muting due to what it perhaps "sees" as an incoming timecode absence or error.

Also maybe try feeding clean timecode to the card's input. It may need some kind of reference.
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Old 23rd Apr 2017, 11:22 am   #3
Nickuk99
Triode
 
Join Date: Mar 2017
Location: Reading, Berks, UK.
Posts: 23
Default Re: Otari MTR10 expert here? help needed please

Thanks for this suggestion. . I have removed the time card and ran the machine.. It was exactly the same.. I replaced the card and put it in safe mode and set the lower switch to repro. .. The machine is only muting the audio output .. but I can't see where to switch this off. . I don't know if it is the time code card or in the master CPU that is responsible for muting the audio. I am thinking to remove the card, the pcb mother board, and the loom where it attaches to the main board (so it doesn't know it has the time code 'kit' fitted).. but I don't know if the time code model came with a differs master CPU pcb. .. mine is circa April 1987 and has the PCB PB-46T master CPU board fitted... I am wondering if this is a standard master CPU... or one fitted specifically for the time code model...
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Old 23rd Apr 2017, 11:54 am   #4
Lodgesound
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Join Date: Jun 2009
Location: Surrey, UK.
Posts: 66
Default Re: Otari MTR10 expert here? help needed please

https://mpe.berklee.edu/documents/st...ri%20MTR10.pdf

Think this may be your problem - go to page 6-14 in the PDF above and have a read.

If this mod or the like has been done then the machine will VERY likely mute in replay when a synchroniser unit is NOT plugged in to the machine (as I assume it is not in your case).
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