My trouble with the Vari Mu & S.E.A. Germany

It all started a few months back whenI bought a second hand vari mu from a guy who owned it the last 10 years.
It is a model from the early 90ies with the 6386 tube and older (yellow) meters. It worked fine altough i heard little distortion on one channel so i decided to let it check by the official manley partner here in germany called S.E.A. (www.sea-vertrieb.de).  They immediately saw which parts had to be replaced and i sent them the unit.
Well, after some time they recapped the unit, replaced the tubes with new old stock and months later sent it back to me. Fully calibrated like they said and functioning fine.

This was the first tour..

To my bitter disappointment the unit arrived with broken tubes as the top lid was squeezed a little into the case. So i decided to tell them what i saw and they accepted to take the unit back for another repair. They ran a lot of tests, made the calibration and some weeks later i was sent back the unit again with working tubes (now with placeholderes from top to bottom lid..  )

Second tour..

However, now i noticed some weird behaviour of the VU meters. The left meter occasionally moved from 0 GR completely to the left and stayed there. After some time (mostly after restarting the unit) it went back on zero. This was the first time i experienced that behaviour, before the repair the meters were functioning without problems. So i called the responsble guy again, described the situation and asked for help. At first he wasn't willing to take it back but after some talking he offered to give it another shot.
They ran a lot of tests, contacted manley labs in USA and tried to reproduce what i saw but they weren't able to make out the problem. He offered to replace the meters at my cost but i wasn't willing to pay for something i wasn't responsible for. So it took several months until they finally replaced the meters with new ones from manley. They didn't see any problems with the meter. They even tried to place the device in different angles on the rack (i have mine slightly lifted in the rack, not flat)

Third tour..

As i got back the unit, the first hours everything was fine, until now when i had to see the exact same thing happen again...
I found out that when i slightly tap on the meter or touch the case of the unit or some switches, it immediatley pops up to zero. But unly so far, until it goes back to the left again... I am so clueless at the moment !

I'm really not a fussy or petty person but i just expected my unit to be completely fine after spending several hundreds of euros on a full service! I know it is an older device but still, can it be so hard for an official manley service shop ??

I didn't dare to call them a fourth time. I thought i'd try asking you guys first about what i should do or try..  ??? ??? ??? ???


Ansgar

It could be a static problem with the meters, I've seen that before.

radardoug said:

It could be a static problem with the meters, I've seen that before.

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Hi, radardoug!
Interesting. Would you care to elaborate? The meters are completely new btw.

The plastic front picks up static in an E field, and then acts on the needle. If you run your hand over the front, and the needle follows your hand, thats the problem.

I say cracked wire. You have eyes? Get a bright light, look at all the wiring from meter to whatever, wiggle all the connections.

radardoug said:

The plastic front picks up static in an E field, and then acts on the needle. If you run your hand over the front, and the needle follows your hand, thats the problem.

Click to expand...

nope, that's not it! It also moves when i just touch the chassis or a switch not even close to the meter. and its only the left meter..

PRR said:

I say cracked wire. You have eyes? Get a bright light, look at all the wiring from meter to whatever, wiggle all the connections.

Click to expand...

Yeah, i got eyes, but there's no cracked wire. everything has been checked by the service people and even after replacing the meter the problem persists..
Paul from Manley assumes it somehow happened during transportation and because the age of the device..  but in my opinion this is some grounding / voltage leaking problem ???

I´ve had a VariMu on the bench with the same problem. Since the owner didn´t care about the meter problem I didn´t care about it either. But I found that if the meter is pulled a bit out then the needle would behave normal. If you push it in then it gets stuck again. The unit had a lot of other problems, though. For a piece of gear in that price league it has quite some interesting design problems. It´s sounds nice, though, if it works properly.

jensenmann said:

I´ve had a VariMu on the bench with the same problem. Since the owner didn´t care about the meter problem I didn´t care about it either. But I found that if the meter is pulled a bit out then the needle would behave normal. If you push it in then it gets stuck again. The unit had a lot of other problems, though. For a piece of gear in that price league it has quite some interesting design problems. It´s sounds nice, though, if it works properly.

Click to expand...

I know the problem you talk about as well. But in this case it is no mechanical issue. It also wouldn't bug me if i didn't had to pay for the repair but yeah, maybe i'll just have to live with it..

I have seen the static problem also, and I have also seen some meters in the supply chain that somehow have their signal to the motor on a structural internal screw that finds a presence on the back of the meter and can short out to the faceplate when it it surface mounted like on all Variable Mu's and older ELOPs. Try removing the meter from the facia and see if there is a chance that there is a short there and if so, get some insulating electrical tape sandwiched between the offending screw and the facia. Note: this wasn't a problem with original Sifam meters made in UK in the 1990's but might be a problem with whatever meters we are using now...

The other issues, tall tubes getting hit by the top cover etc... that problem only was learned by experience, yes many years ago. The PCB is dropped low as it can go in the chassis, shortest 9-pin sockets are used, and sometimes shorter tubes are used! I remember also punching round clearing holes in the top covers over the output tubes. In production these days, there are also protective spacers installed near the output tubes so their heads don't get smashed with flexing top cover during shipping.

Anyway, I saw that Paul in my service department is actively helping you with this unit, so I'll let you guys carry on....

thanx for the input

JR

Thank you very much Eve for the instant support and your explanations.
I will try what you suggested.

Ansgar