Question about Mission M5AS Subwoofer

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Mission M5 as

I'm a skilled technician and I've repaired several amplifiers but I*ve absolutely no plan of this amp.Symptom is the relays doesn't click and so you can't here a sound. But the fuse hasn't blown up and the transformer delivers ye,bl,ye 24,2 V AC and after the rectifier + - 32,3 V DC and red,white,red 44,9 V AC and rectified + - 61 V. So this seems to be o.k. Then I've looked for the power transistors. On the bigger plate there are two 2SC3519 and two 2SA1386 .They have no internal conduction and I can measure ~ 0.6 V Ube. This should also be good. But on the little plate the is also a pair of these power-transistors and there i can't measure a Ube.
So i will solder them out. But i don''t understand how the amp really works.
A there 3 quasi paralel Complementary power stages (push pull ),
What i need is at least a schematic diagram or a service manual . I even don't know the correct idle current. I would be very happy if you could help me With kind regards M.Reinhardt

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  • hoshimi Dec 04, 2008

    Not sure if I have the same problem, but my unit seems dead. I would like to have the schematics to do the failure analysis from. Can you help me ?

  • Anonymous Mar 09, 2009

    i have a similar problem, the amp just stays in stand by mode. i replaced the power transistors because they were shorted but it doesn't seem to want to fire up.

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5 Suggested Answers

  • 4 Answers

SOURCE: Mission speakers...i think i've blown one of them...

I'm guessing you mean one of the bass drivers (as standmount or floorstanding speakers don't have subs as such). Place your hand lightly against the driver when playing some music at normal volume, there should be some vibration (this increases the louder you play). If there's no vibration, you're probably right.

Contact Mission, who can send you a new driver, contact a Mission dealer to see how much it'll cost to go through the dealer network. I'd recommend going down the latter route if you are unsure of what to do yourself.

Just noticed you posted this in March, in which case, I hope you got it fixed (or are enjoying your new pair instead!).

Posted on Dec 04, 2008

  • 10 Answers

SOURCE: blown fuse in mission 700as subwoofer

if you have access to a multimeter, you should test you impedance (ohms) Ω, check to make sure the speakers reads higher than the amplifier needs; this will result in less strain on your amp and diminishement of sound...For example: if you connect two 4Ω
speakers in series it results an 8Ω circuit (least strain). and if you'd take the same two speakers and connect them in parralelle it would result in a 2Ω circuit (most strain).

Posted on Jul 24, 2009

Icebassman 5
  • 57 Answers

SOURCE: Mission 780s (from early 1990s) tweeter gone?

Hi there.
Do you have the make and number on the back of the magnet?
Check if the tweeter is at all available on the net!
To have it repaired is also an option.
Iceman.

Posted on Nov 05, 2009

dunnbiker
  • 8546 Answers

SOURCE: I've just been given a

Leave the brass plates in place and make sure they are TIGHT. They're for separating the internal drivers so one could power them with separate amplifier sources - bi-amping.

Connect the plus and minus speaker cables traditionally, one to either pole.

Removing the plates would silence whichever speaker is NOT amplifier-driven.


Posted on Feb 13, 2011

dunnbiker
  • 8546 Answers

SOURCE: I have this mission 782 for many years! It happen

It's bi-wireable (BUY-wire). Did it occur to you that may be a factor if you're using it that way? The jumpers (or lack thereof) on the back allow or disallow the amp(s) to affect all the drivers. You can tie any amp to one or the other pair of binding posts to test them.

Posted on Sep 20, 2011

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