Otari mtr90 tension and other mechanicals

[pucho812]

This otari mtr90 will be the death of me.

out of nowhere the machine reel card was all over the map.
Following alignment as per chapter 5 in the manual
I now have the following.
If I lock the reels and then hit the stop button to go from locked into the ready position, they bypass that and go directly into the unloaded position.
I assume this is purely a reel control card alignment as the mechanicals under the deck plate seem to be ok and match the manual pretty well. Any adjustment seems to change things by a lot and I am stumped…
Any ideas?

 

[pucho812]

notes to the rescue....

if any first you don't succeed try again. IN the file cabinet I found this gem.... Now I just gotta follow it and get it to be as listed.

I am posting this In case anyone needs shorthand notes that are written right to the point with voltage reedings vs adjust trim pot so speed on the reel is half As listed in the manual

 

[Brian Roth]

Is that a MK II or MK III there? I have this for the III (attached). Same guy wrote both. I used this one when maintaining a III in the early 1990's.

Bri

 

[pucho812]

Is that a MK II or MK III there? I have this for the III (attached). Same guy wrote both. I used this one when maintaining a III in the early 1990's.

Bri

It’s a mkII

 

[richiyobs]

This otari mtr90 will be the death of me.

out of nowhere the machine reel card was all over the map.
Following alignment as per chapter 5 in the manual
I now have the following.
If I lock the reels and then hit the stop button to go from locked into the ready position, they bypass that and go directly into the unloaded position.
I assume this is purely a reel control card alignment as the mechanicals under the deck plate seem to be ok and match the manual pretty well. Any adjustment seems to change things by a lot and I am stumped…
Any ideas?

Hi Pucho
I had quite same problem with my Mk1!
Solved moving the solenoid in the right position and tape tension spring.
I m still fighting with proper bias calibration cause I Don t own the Mrl...
Great machine but also a great nightmare to keep it alive for my knowledge!

 

[gyraf]

HA!

if you think that a mtr90 is a technical nightmare, you should really try fixing a dead DTR900 or it's cousins the Mitsubishi X-850 and the Sony PCM-3324

now THAT grows hair on your chest..

/Jakob E.

 

[richiyobs]

I m a newbie in this field...it s only 2 years I m reading about electronic ... Still have a lot to learn... It s just a miracle I can service my gears... And keep them alive
Best
Richi

 

[pucho812]

HA!

if you think that a mtr90 is a technical nightmare, you should really try fixing a dead DTR900 or it's cousins the Mitsubishi X-850 and the Sony PCM-3324

now THAT grows hair on your chest..

/Jakob E.

thankfully I only had to deal with the sony 3348 and 3348hr's. I started past mitsubishi days, but I know some guys who still have them for tape transfers.

 

[Big Valley Audio]

I feel for you!
I didn’t work on the MTR90’s much but did work on the MTR 100’s a lot and I think they are pretty similar.
You’ve probably done all this but I would always make sure any synchronizer wiring was removed as well as SSL transport control. I would even disconnect the remote.
Then extend the card and check all the signals are present. The closed loop system they use needs everything to be in order before it lets things proceed as you know.
Hopefully you don’t have something intermittent in the wiring harness off the back of the cards?

Thoughts and prayers!

 

[pucho812]

After a adjustment session, the machine is back to running tape like a champ.
springs were loose, well below the 460 gram standard as mention in the right up. Lot of other things were way off. The electronic adjustments were fine except for the supply reel take up pot found under the deck plate. Couldn’t get that to 0v. Closet was 1v. So we’ll see how it goes and take it from there. But was able to go from locked to ready with tape on and do the usual of play, rewind, stop and fast forward with it looking well.

 

[radardoug]

You do realise the pots are movable once you loosen the screws holding them? 1 volt off is a lot. You need to persevere and adjust to specification.

 

[gyraf]

..and please do NOT set tape tension high, even though it's tempting for getting good tape handling at high-output (slippery) tape types. Setting tension high wears heavily on heads and guides...

/Jakob E.

 

[pucho812]

You do realise the pots are movable once you loosen the screws holding them? 1 volt off is a lot. You need to persevere and adjust to specification.

Yes I do. We originally were measuring 3.XXV and after adjustments of the pot under the deck plate, best we could get it on the supply side was down to 1V. The take-up side measured a proper 0V at their respective test points. Everything else per the documents and manual was spot on

 

[pucho812]

..and please do NOT set tape tension high, even though it's tempting for getting good tape handling at high-output (slippery) tape types. Setting tension high wears heavily on heads and guides...

/Jakob E.

Tension is not high, the alignment guide says 460grams +/- 10 grams on the springs. this comes out to 1.xx pounds so we shot for 450 grams and are happy with test performance. Our only tape we use is ATR brand so should be good there.

 

[One F Sound]

Always worth giving the tape a pull on the reel to make sure there's no slack before lacing it up. Otherwise the transport can violently take up the slack and bend the tension arms. And IIRC the tension arms should be parallel with the front of the machine when in play. I think there was a mark on the deck plate too but it's been a while since I've worked on one. And if the rollers get a glazed look then a diamond spatular can take the sheen off although extreme caution is advised! All in all, great workhorse machines and aside from bending tension arms pretty indestructible.

 

[pucho812]

Always worth giving the tape a pull on the reel to make sure there's no slack before lacing it up. Otherwise the transport can violently take up the slack and bend the tension arms. And IIRC the tension arms should be parallel with the front of the machine when in play. I think there was a mark on the deck plate too but it's been a while since I've worked on one. And if the rollers get a glazed look then a diamond spatular can take the sheen off although extreme caution is advised! All in all, great workhorse machines and aside from bending tension arms pretty indestructible.

Yes. correct.

 

[musiklab]

Hi all otari users From my days ( 87- 95) of servicing and repairing MTR90 ´s, I have a good capstan motor and other mechanical and electric parts, power transformer, audio and drive cards, some capstan and reel drive transistors etc. for sale. & other otari model parts too. If any one needs let me know. musiklab.dk