Topic: I think I killed my Apogee mini-mp. Any help would be appreciated.

[tenesejedd]

So I was making a 6 volt power supply to power this thing in the field. And as I was testing it, it was working, there was a slight buzz, but it was on. Then I shut it off and tried to turn it back on, and now nothing.  I tried the wallwart, and it still is not doing anything. I opened it up, and there is no burnt smell or visual signs of anything blown. Below is a picture of the power input on the inside. right where the power comes in, there is a white chip which appears to be some sort of voltage regulator. It has "2A 125V"  and "IE 460" on it. Is there a chance that I blew this.

Perhaps someone with some electronics expertise can offer some advice.....

[bluegrass_brad]

If you accidently reversed polarity on it then you may have fried it.  Unfortunately Apogee doesnt use reverse polarity protection like alot of companies (the Edirol UA5 for example).  reverse the polarity and *poof*. Here's hoping for the best for you.

[poorlyconditioned]

That white box is a fuse.  Maybe that popped.  Check with an ohmmeter/continuity tester.

Try putting the power in (proper polarity) and measuring the voltage after this box.  See if there is any juice.  If so, follow it along and see where the volts are.  Standard practice, at least to track the power supply.

Oh yeah, would you mind taking some pictures of this thing for me?  I'm curious what the mic input stage is, transistors probably, followed by some opamps.  I'd like to know details though.

Thanks and good luck,
  Richard

[poorlyconditioned]

Hey, that first capacitor (470uF) looks a bit dented (on the silver side).  Maybe that blew?  If so, you can replace pretty easily.

I think an electronics technician could easily trace and fix this.

  Richard

[Brennan]

It does look a bit depressed, could be your source of trouble..

Here's hoping it's just a fuse! Good luck with it..

[tenesejedd]

That white box is a fuse.  Maybe that popped.  Check with an ohmmeter/continuity tester.

Try putting the power in (proper polarity) and measuring the voltage after this box.  See if there is any juice.  If so, follow it along and see where the volts are.  Standard practice, at least to track the power supply.

Oh yeah, would you mind taking some pictures of this thing for me?  I'm curious what the mic input stage is, transistors probably, followed by some opamps.  I'd like to know details though.

Thanks and good luck,
  Richard

I'll give it a shot in the morning (just got back from taping Hot Buttered Rum, which was supposed to be my first night out with my new pre). I have never used the ohm/continuity testin functions of my digital voltmeter. What exactly should I be looking for?  If i'm not getting any juice from the lean on the right side of the fuse, then that is probably blown, but show should i test it for ohm/continuity? 

If it is this, where would be a good place to get a new one?

Hey, that first capacitor (470uF) looks a bit dented (on the silver side).  Maybe that blew?  If so, you can replace pretty easily.

is there a way to test with a voltmeter if this cap is blown? If so, where could i get  a new one.  If necessary, I could take it to Deltronics here in Chicago, but if I can fix it on my own, i would like to try it.

thanks for your help guys!

[Nick's Picks]

ugh...
I hope you get this fixed.  the MMP is the finest sounding commercial two chan preamp i've ever used. 

[Church-Audio]

That white box is a fuse.  Maybe that popped.  Check with an ohmmeter/continuity tester.

Try putting the power in (proper polarity) and measuring the voltage after this box.  See if there is any juice.  If so, follow it along and see where the volts are.  Standard practice, at least to track the power supply.

Oh yeah, would you mind taking some pictures of this thing for me?  I'm curious what the mic input stage is, transistors probably, followed by some opamps.  I'd like to know details though.

Thanks and good luck,
  Richard

I'll give it a shot in the morning (just got back from taping Hot Buttered Rum, which was supposed to be my first night out with my new pre). I have never used the ohm/continuity testin functions of my digital voltmeter. What exactly should I be looking for?  If i'm not getting any juice from the lean on the right side of the fuse, then that is probably blown, but show should i test it for ohm/continuity? 

If it is this, where would be a good place to get a new one?

Hey, that first capacitor (470uF) looks a bit dented (on the silver side).  Maybe that blew?  If so, you can replace pretty easily.

is there a way to test with a voltmeter if this cap is blown? If so, where could i get  a new one.  If necessary, I could take it to Deltronics here in Chicago, but if I can fix it on my own, i would like to try it.

thanks for your help guys!

I agree with Richard the white thing is a fuse measure the voltage from its output put one probe on ground and the other on the output of the fuse. If you have voltage then you know your fuse is ok. Then you have to do more tracing. If that Cap is blown up it will short out the fuse and it will be blown. Thus no workie... Right after the Cap is your reverse polarity protection... The diode. measure after that as well if you get no voltage then your diode is fried but if that is fried I would say the voltage regulator or that little Pump charge chip is fried.  It looks like after that stage your power go's into a step up transformer. The very worst case is that this part is fried.... But if it is thats actually a good thing because chances are nothing else after that got touched. A really good electronics tech can fix it but I would actually send it back to Apogee in the long run you might be better off getting them to fix it because if that transformer is pooched you will need them to get you the part anyway. I would say the fact that you did not smell anything tells me that its most likely the little fuse. They can be purchased from Digikey.

Here is the RMA procedure for Apogee

How to arrange for repair of your unit

In the event that your unit needs to be repaired, contact your dealer or distributor in the first instance. Many dealers can repair Apogee units at their own location, saving you the time and hassle of having to send it to California. Your dealer will advise you if you need to contact us directly to arrange for repair at Apogee.
If you need to return the unit to Apogee, you must contact us (by one of the means listed) and obtain a Return Materials Authorization (RMA) number. You will be asked for your unit model and serial number, plus a description of the problem and some other relevant details.
Package your unit securely in its original packaging if possible. Be sure that shipping is pre-paid and insured:

Apogee will not accept returns which do not have an RMA number or are not insured and pre-paid.
CALL: 310 584-9394
Tech Support assistance is available weekdays from 9 A.M. - 6 P.M. P.S.T.

[bluegrass_brad]

Right after the Cap is your reverse polarity protection... The diode.

According to Apogee tech support the mini-me wasnt polarity reversed protected.  I didnt think the mini-mp was either?

> Also note that the Mini-Me is not reverse polarity and must be center
> positive. So if someone reversed the polarity on their battery by mistake
> this can cause it to fail.
> In regards to Voltage requirements. The Mini-Me rev A units can only use a
> minimum of 8 Volts whereas the Mini-Me rev C units can go down to 6 Volts.
> The reason for this is due to special requests that we got from many
> resellers and customers. At that point we also decided to add in the gain
> changing feature.
> Basically any unit that a dealer has just received is indeed a Rev C board.
> Units in the serial range of 85-118 are Rev A.
> Rumors are rumors and there truly is nothing we can do about people
> spreading them.
> I hope this helps understand or answer any of your questions
> Regards,
> Gary Brenner
> Apogee  Digital
> Technical Support

[tenesejedd]

So I am getting voltage across the fuse. With my digital volt meter set to "DC V 20" i'm getting 12 volts, which is what the wallwart puts out. Now, when I test the little black chip between the fuse and the capacitor, I'm not getting much. The volt meter is only showing like .10, and same with the cap next to it.  I'm not sure what this little black chip is. It has two lines of text. the first line has a backwards C ::344. The second line says B140B on it.  Any thoughts?

Also, the capacitor doesn't have a dent on it. It has an imprint in the shape of a 'T' and there is another larger capacitor elsewhere on the board with that same 'T' imprinted on it.

I am hoping I wouldn't have to send it in, but if I have to, then so be it. I have WSP coming up in two weeks and hope to have it up and running by then.  According to Apogee's website, Sweetwater is the closest repair facility that would possibly work on this for me. Anyone have any experience with repairs with them?

thanks guys!

EDIT TO ADD

OK, now i'm a little confused. I think I may have tested this wrong. I was putting one lead of my volt meter on the left (in) site of the fuse and the other lead on the right side (out) i was getting a 12volt reading. Then I realized that when I had my one lead on the left side of the fuse and I touched anyting metal with the other lead, I was still getting a 12 volt reading.  Now correct me if i'm wrong but, for further testing, I should be able to put my volt meter lead on the right (out) side of the fuse and still be getting the 12 volt reading. For example, I should get a 12 volt reading if one lead is on the right side of the fuse and the other on one of the leads of the black chip right next to it (again, correct me if i'm wrong). When I put my volt meter on the right side of the fuse, and then on the top tab of the black chip, i'm only getting a reading of .02. and if i switch it to the bottom tab of the black chip, i get nothing.

This sounds to me like the fuse might be blown. If so, then i should be able to replace this on my own. What do you guys think? I have never used the OHM functions on my volt meter so I don't know how to test it or what to look for.


Lastly,
Richard, I will take some pictures of this thing now that it is all taken apart. I'll end up posting it in Rig Pics at some point over the weekend. There seems to be a lot of wasted realestate on this thing, I think they could easily cut the size down by 2-2.5 inches.

[Church-Audio]

So I am getting voltage across the fuse. With my digital volt meter set to "DC V 20" i'm getting 12 volts, which is what the wallwart puts out. Now, when I test the little black chip between the fuse and the capacitor, I'm not getting much. The volt meter is only showing like .10, and same with the cap next to it.  I'm not sure what this little black chip is. It has two lines of text. the first line has a backwards C ::344. The second line says B140B on it.  Any thoughts?

Also, the capacitor doesn't have a dent on it. It has an imprint in the shape of a 'T' and there is another larger capacitor elsewhere on the board with that same 'T' imprinted on it.

I am hoping I wouldn't have to send it in, but if I have to, then so be it. I have WSP coming up in two weeks and hope to have it up and running by then.  According to Apogee's website, Sweetwater is the closest repair facility that would possibly work on this for me. Anyone have any experience with repairs with them?

thanks guys!

EDIT TO ADD

OK, now i'm a little confused. I think I may have tested this wrong. I was putting one lead of my volt meter on the left (in) site of the fuse and the other lead on the right side (out) i was getting a 12volt reading. Then I realized that when I had my one lead on the left side of the fuse and I touched anything metal with the other lead, I was still getting a 12 volt reading.  Now correct me if I'm wrong but, for further testing, I should be able to put my volt meter lead on the right (out) side of the fuse and still be getting the 12 volt reading. For example, I should get a 12 volt reading if one lead is on the right side of the fuse and the other on one of the leads of the black chip right next to it (again, correct me if i'm wrong). When I put my volt meter on the right side of the fuse, and then on the top tab of the black chip, i'm only getting a reading of .02. and if i switch it to the bottom tab of the black chip, i get nothing.

This sounds to me like the fuse might be blown. If so, then i should be able to replace this on my own. What do you guys think? I have never used the OHM functions on my volt meter so I don't know how to test it or what to look for.


Lastly,
Richard, I will take some pictures of this thing now that it is all taken apart. I'll end up posting it in Rig Pics at some point over the weekend. There seems to be a lot of wasted realestate on this thing, I think they could easily cut the size down by 2-2.5 inches.

The black chip is your diode that blew because of the reverse polarity. That part is replaceable but At this point in time you should send it to someone. Although Apogee says that its not reverse polarity protection that diode is there to protect the circuit from reverse polarity, They do not call it reverse polarity protection because they dont want people sending the unit back saying Hey ! my apogee blew up because of reverse polarity I want this to get fixed for free! Very few products will have that type of protection and advertise it. But any company that is worth anything will at least have a diode in the power supply section. One of two things happened ether that diode "opened" when the high current was applied and did no damage to the rest of the circuit or it fused "close" and blew up the voltage regulator and maybe a few other goodies. So the fact that your not getting much on one side of the diode is a good thing. I would make sure that your measuring on the side that has the stripe that should be going to Positive. So with a probe on the positive side of the diode and a probe on ground you should see 12volts. If not measure on the other side of the diode if you see 12v then you can cross your fingers that is all you blew up. It really does depend on how long the battery was connected. Good luck Let me know how it works out.

Chris

[Church-Audio]

Right after the Cap is your reverse polarity protection... The diode.

According to Apogee tech support the mini-me wasnt polarity reversed protected.  I didnt think the mini-mp was either?

> Also note that the Mini-Me is not reverse polarity and must be center
> positive. So if someone reversed the polarity on their battery by mistake
> this can cause it to fail.
> In regards to Voltage requirements. The Mini-Me rev A units can only use a
> minimum of 8 Volts whereas the Mini-Me rev C units can go down to 6 Volts.
> The reason for this is due to special requests that we got from many
> resellers and customers. At that point we also decided to add in the gain
> changing feature.
> Basically any unit that a dealer has just received is indeed a Rev C board.
> Units in the serial range of 85-118 are Rev A.
> Rumors are rumors and there truly is nothing we can do about people
> spreading them.
> I hope this helps understand or answer any of your questions
> Regards,
> Gary Brenner
> Apogee  Digital
> Technical Support

Technically that's not true there is a diode in place to protect the circuit from "quick" mistakes. If you leave the battery or supply connected for a long time say maybe 30-60 seconds that diode will blow up. But again not to many companies would build a product with out some form of protection. They dont advertise it because they dont want your coming around and saying hey my apogee blew up and you guys said it was protected against reverse polarity so I want you to fix it. That's why they dont say it is. But the  fact that there is a diode in the circuit means that there is some form of reverse polarity protection.

[bluegrass_brad]

In this case I am talking about true reverse polarity protection.  The Edirol UA5 is a true polarity protected unit.  It will not power up under reverse polarity, but it doesnt blow anything or make any part of the unit fail.  When it is reconnected in the right polarity it powers right up.  Apogee units fail under reverse polarity, often requiring service.

[Church-Audio]

In this case I am talking about true reverse polarity protection.  The Edirol UA5 is a true polarity protected unit.  It will not power up under reverse polarity, but it doesnt blow anything or make any part of the unit fail.  When it is reconnected in the right polarity it powers right up.  Apogee units fail under reverse polarity, often requiring service.

Yes thats correct. But in electronics we refer to revers polarity protection as a diode even though all it takes to blow up the diode is more current then the diode can take. For example I use a diode rated at 1 amp for my small preamps because, there is no such thing as a regular 9 volt battery with 1000ma of current capability. So you can connect the battery to my preamp and now blow it. Its not like the UA-5 but its pretty hard to blow up my preamp with a regular battery.

[Daryan]

I actually plugged a reverse polarity batt. into a mini-mp, and all it fried was the fuse.  Easily replaced.  I wouldn't reccomend doing this on the mini-me, as it is boderline dangerous and you will smell smoke.  Why in the world apogee didn't integrate a fuse into the mini-me is beyond me.  EVERY other unit I have ever used had some.