Repairing a Mirage PS-12-90 Powered Subwoofer amp (info needed)

[Pioneer621]

Hello everybody!

Hope I'm in the right forum with these questions.

I had a powered subwoofer come to me for repair & hope I can get a little info on a part or two.

It is a Mirage, model: PS-12-90

As soon as I started looking at it I pulled the amp / power supply off of the back of the unit to inspect it before powering it on. I can tell someone else did some repairs in there before as they did not do a very good job, they did not even install / replace the negative regulator which I will assume is a 79L15 as there is nothing in its place, and the positive regulator that is in there is a 78L15 & the datasheet of the two parts match up to the pin connection on the board. They burnt several pads while soldering as well & did not bolt the main power amplifier I.C to the heat-sink properly, maybe they replaced it & the leads were not as long as the original, I don’t know, but it don’t look like a reliable connection for thermal transfer.

My main question, however, is one of the small 16-pin I.C chips on the board (pc board designation UD) (I'll have pictures at the bottom of this post of the amp / I.C chip in question); the part number was sanded off the I.C so I am not sure what it is, & it looks like it will need replaced as PIN-11 appears to have broken off of the I.C & they tried to solder a small jumper to it & it looks like a very bad connection. From what I can tell, PIN-11 is the Vcc(+) pin & PIN-6 appears to be the Vcc(-) pin on this chip. If someone has a schematic for the PS-12-90 that should be all I need, but since the number is sanded off I am guessing the schematics are not available for this amp.

It looks like all the other part numbers are still on the components; just this one I.C has been sanded off.

Hopefully someone can give me some info on this part as I am not sure what it is.

I greatly appreciate any help on this matter! Thank you all for taking the time to view this post. Take care.

Pioneer621


Here are the pictures of the amp & I.C with sanded numbers:

Here is a picture of the back of the amp for reference:



Here is an overview picture of the main board in this amp (look how someone mounted the main power amp I.C ):



Here is an overview of the sanded I.C chip:



Here is a side view of the sanded I.C chip where they soldered PIN-11:

[Pioneer621]

Update:

I don’t know why I did not contact the Mirage Company first as I usually always contact any companies first when I need info, then ask for help later if they won’t or can’t help.

I went ahead and contacted the company that makes the Mirage PS-12-90 subwoofer & asked them for the schematics as they would help with my repair; they replied within a couple days with the attached schematics of the unit!

After reviewing the schematic I found that the sanded off I.C chip is an LM13700AN.

I should not have any problems repairing it now, but if I do I may post back for help.

Ok, just figured I would post an update.

Take care!

Pioneer621

[mroberts]

I have a ps-12-90 that needs repaired (makes a white noise sporadically). I just sent it to a Mirage-approved service center in Indiana. They contacted Mirage support, but were not able to get a schematic.

Is it possible for you to email me the schematic so I can pass it along? I wil have a better chance of a successful repair.

Thanks,
Mike

[mirage1]

Did you ever get a schematic? I have a Mirage PS12 90 in need of repair but it would be great if you could send me a copy of the schematic.
Thanks
Jim

[quaddo1]

Any help regarding the thread below is most welcome:

Mirage PS-12-180 subwoofer

[Pioneer621]

Hello!

I do not post real often & hardly ever check my email, so any threads I am not posting in that are recent to me, I may not see right away.

I do have the schematics for the Mirage PS-12-90; I found out there are two different versions, one based on a chip-amp like this one, & one using a MOSFET based output stage. I have both copies; one thanks to Mirage, & the other thanks to a fellow member that acquired from Mirage if I am not mistaken as well.

I will gladly email anyone the schematics if they need them, however, since I do not check my email very often & may not see a request for them, my best suggestion would be to email the Mirage company & request the schematic for your particular unit (they were pretty quick to send it to me), you probably want to check yours to see if it uses the chip-amp output stage or is MOSFET based, so you can get the correct schematic sent to you. They were real helpful for me, so I think that would be the best idea as I may be kind of slow in reply. If all else fails send me a PM with your email address you want me to send the schematic to & which one you need & I will send it as soon as I see your message.

Take care everybody!

[quaddo1]

Pioneer621, thank you for your replies to both this thread and mine.

I'm interested in any documents related to the PS-12-180, and since the PS-12-90 is its "little brother", I'm interested in any docs you may have for that model.


Thanks in advance.

[rgrayoh]

I have a Mirage PS-12-90 subwoofer. It went out and I took it to a certified repairman. He said the the Amp Moduel is out but he cannot find parts. Does anyone know where I can get the Amp Moduel for the PS-12-90?

[Arnb]

I have a Mirage PS-12-180 with a hum. Contacted Klipsh, the current trademark owner who state they have nothing available in the way of parts or schematics for this unit. if anyone has the schematic the this unit, (it uses the same board as the PS-12-90) contact me here or at Arnb.Org Contact Form
Thank You