TEAC 80-8 Troubleshooting suggestion on distortion issue

lassoharp

lassoharp

New member
Hello Everyone,




've recently started getting some jagged sounding distortion from Track 5 on my 80-8. I've ran through some basic troubleshooting by doing the following:

1) swapped rec/rep cards (twice with different channels)

2) spray cleaned and reseated cards for each swap

3) ruled out input and output cables on the snake

4) made sure all heads were super clean

5) compared output of recorded track on sync and rep head

So after all this the distortion is still there and everything is pointing to something specific to track 5. The distortion is being printed. I considered a failing headstack but there looks to be nothing close to a visible gap on bias or sync head. I have a small gap showing on a failing track 1 sync head for visual comparison.

Anyone have any suggestions as to where to look next?


Thanks
 
Sounds like something happening with the heads during the record process for sure, if a new recording is printing after cards are swapped and you're sure about no issues with mixer or source through cabling. Next thing to try is to test the erase head. Record as usual but manually lift the tape away from the record head while keeping tape contact with the erase head.

You can use a couple round pens or pencils for a 60 second test or so. If the erase head looks ok we're checking to see if perhaps a capacitor or something has opened up and this hum is being laid down from the erase head. However, if you do have one track opening up on your record head that's not a good sign for the head in general. The record and replay heads are the same on the 80-8 so if you narrow it down to the record head you can swap them if the repro head looks better. You can look for new heads, but Jinks! They’re expensive from TEAC!
 
Thanks Beck, I'll give this a try later today.

I'm also going to check the PS rail voltages for that channel. I noticed yesterday that the rec ready lights for each channel were doing something strange - I had 6 tracks enabled and when I hit the either Play or Rew the lights sort of flashed quickly in unison at a different (lower) intensity. Never seen that before but it was like engaging the transport was somehow triggering the behavior. I have no idea if they're related but it's the first time I've seen either problem so maybe.
 
That is unusual to have the unstable LED. It could be a coincidence, but tracking down these little gremlins can be tricky. It could be a clue to unstable voltage. I’ve looked through my old 80-8 resources, common failures and fixes, and haven’t seen that one. There are members that know a lot more about the 80-series than I do. Hope someone will chime in. Best of luck.
 
lassoharp said:
Hello Everyone,




've recently started getting some jagged sounding distortion from Track 5 on my 80-8. I've ran through some basic troubleshooting by doing the following:

1) swapped rec/rep cards (twice with different channels)

2) spray cleaned and reseated cards for each swap

3) ruled out input and output cables on the snake

4) made sure all heads were super clean

5) compared output of recorded track on sync and rep head

So after all this the distortion is still there and everything is pointing to something specific to track 5. The distortion is being printed. I considered a failing headstack but there looks to be nothing close to a visible gap on bias or sync head. I have a small gap showing on a failing track 1 sync head for visual comparison.

Anyone have any suggestions as to where to look next?


Thanks
Click to expand...

Do you get the same distortion when monitoring off the r/p head?
 
Do you get the same distortion when monitoring off the r/p head?
Click to expand...

Yes.


I was able to try recording tones while physically lifting tape off of the sync head and there was no hum or sub noise being laid down there.

I also checked one of the 24V rails and got good voltage there. Will have to disassemble from the back to get the other measurements. During one power up I was able to get distortion free recording from track 5, so it may be an intermittent issue and hopefully not a blown head. Up until then the distortion had been consistent over about 6 different attempts so it seemed like something had permanently gone bad. The blinking LED issue was absent when I got dist free recording so it may be PS related. Seems like there was a voltage regulator issue common with these machines.

I may go ahead with swapping the rep and sync heads anyway since track 1 is already gone to the point of permanent hi freq loss. Does anyone know of a good tech guide for swapping the heads? It would be the first time for me and I want to try to avoid making any serious mistakes.
 
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