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sexy240
05-24-2002, 08:48 AM
I suck at electronics. but I do get adventerous from time to time. This months adventure... repair my sony xplod amplifier XM-1002HX. I took it apart and found a burnt piece it connects to the circuit board with three pins and one machine screw connects it to the heat sink and shell. between the heat sink and the part in question is a white grease. the part reads on its face

MT A3
0n06HD
J936 M

the last M is in a circle and looks like it could be the motorola symbol. I want to replace this part. I have looked everywhere and just am not sure exactly what I am looking for can anyone help Please?

jdurning
05-24-2002, 09:00 AM
Originally posted by sexy:
I suck at electronics. but I do get adventerous from time to time. This months adventure... repair my sony xplod amplifier XM-1002HX. I took it apart and found a burnt piece it connects to the circuit board with three pins and one machine screw connects it to the heat sink and shell. between the heat sink and the part in question is a white grease. the part reads on its face

MT A3
0n06HD
J936 M

the last M is in a circle and looks like it could be the motorola symbol. I want to replace this part. I have looked everywhere and just am not sure exactly what I am looking for can anyone help Please?<font size="2" face="Verdana, Arial[/img]I'm not an EE, but so have a bit of experience in the design of amps; that is probably a MOSFET transistor. It's job is to heat up and transfer the heat to the heat sink. The white goo is a thermal transer agent that provides a full "contact" area between the MOSFET and the heat sink. It would make sense as you said it was "burn" or shorted out. If you are getting adventerous, make sure that when you are unscrewing stuff you don't scratch the heatsink mating surface. I'm assuming it's pretty shiny and perhaps anodized. If the MOSFET is allowed to make a good electrical (not thermal) contact with the heat sink, the unit will short.

This is my two cents on the matter. Your milage may vary, use with caution.

--Joe

grinder
05-24-2002, 06:04 PM
use some arctic silver thermal interface material http://www.freshalloy.com/ i love dat shizzit on my superfly amd's that double as scrambled egg cookers.

AZ_Dave
05-24-2002, 06:13 PM
Well I'm a computer engineering major, which is close...
Your best bet is to lookup websites on ICs...try motorola, www.st.com (http://www.st.com) and www.ti.com (http://www.ti.com)

Do you have Fry's electronics where you live? They have most ICs and can help you.

FYI:
IC - Integrated Circuit (not intercooler)
MOSFET - Metal Oxide Semiconductor Field Effect Transistor

Dave

sexy240
05-24-2002, 07:12 PM
Ill do my best. so can to find the right part. could I just use any mosfet transistor, or should I be carfull to use the exact same one? frys is about 45min but I have plenty of radio shacks. I did brows at the shack and found things that looked like my IC but they had metal backs... the one that blew out looked like the back was graphite. I dont know what it was made of but it wasnt metal. when I solder this piece in am I supposed to make an effort not to let it make direct contact witht he heat sink thingy by adding my white grease?

jdurning
05-24-2002, 08:19 PM
Originally posted by sexy:
Ill do my best. so can to find the right part. could I just use any mosfet transistor, or should I be carfull to use the exact same one? frys is about 45min but I have plenty of radio shacks. I did brows at the shack and found things that looked like my IC but they had metal backs... the one that blew out looked like the back was graphite. I dont know what it was made of but it wasnt metal. when I solder this piece in am I supposed to make an effort not to let it make direct contact witht he heat sink thingy by adding my white grease?<font size="2" face="Verdana, Arial[/img]If you can find the "performance" spec's of the piece you have, you should be able to replace it with a like unit if you cannot find an exact replacement.

By all means, you must use the white grease when you re-assemble the amp. As I stated before... If the IC and the heatsink are allowed to meet metal to metal, they will short.

Good luck.

--Joe

**DONOTDELETE**
05-24-2002, 10:37 PM
Just an off the wall question, shouldn't you ask something like that at a geeks'r'us forum? I'm a geek yes but your asking at a car forum, which luckly has a few electronicish people running around.

AZ_Dave
05-24-2002, 10:44 PM
by all means use the same IC !! Frys has a much larger selection. Mind you, they could have changed the name/number of the chip...so like what jdurning said, see the performance specs...that way you can still match it up.

I can understand why he's ask this question here, there are alot of engineers, plus this way you don't have to go through the whole registration process in a new forum http://www.freshalloy.com/

Dave

**DONOTDELETE**
05-24-2002, 10:46 PM
Oh... right. I was going to think that next. http://www.freshalloy.com/

sexy240
05-25-2002, 12:49 AM
I tried motorola a week ago and couldnt find a site with valuble info. anyway I could only find one electrical engineering forum and i posted there but with no luck. it was mostly people posting question, and asking for scematics, not many people answering. if anyone is interested it is http://www.rlocman.com.ru/en/forum.htm?board=4&fs=0 anyway if you know of a better site for me to ask on please tell me. I cant seem to find the ratings on that MOSFET where can I turn? any one got schematics for a sony explode?

I figure this is off topic and people can ask questions like whats better crunchy or smooth penut butter. ohh gotta go I just got a great Idea for a new topic!!!

AZ_Dave
05-28-2002, 06:48 AM
I highly doubt you could find schematics, cuz then other companies would steal their design.

I'll look in some of my old digital sytems books, and let you know what i find...

sexy240
05-28-2002, 09:34 AM
thanks

jdurning
05-29-2002, 09:30 AM
I was just thinking about something... You said that you were going to try to "repair" the amp, so you pulled it apart and found this IC with "burnt" wires. My new question to you is what was or was not your amp doing before you tried to fix it? (how was that for poor english!)

My reasoning being, that I don't know if the shorted IC would cause any problems. It's purpose as I said before was to transfer energy (heat) to the heat sink for disipation. Unless the IC is a part of the integral circuit (and it may be) it won't cause the amp to stop working. ie. the IC may not be a one point failure. It may be the end result of a large problem, for example a short somewhere else that burnt the IC.

I guess what I'm getting at is that as long as the burnt IC you have is not a failure point of the entire IC circuit (heat sink), you may be able to get by without it. It is a fairly straighforward calculation to figure how much energy you need to get rid of for the amp to work properly. Any good design would be redundant and excessive to a certain extent. Not knowing what Sony would design their amp to, you may be able to calculate that just hardwiring the IC circuit closed would still allow for operation of the amp.

I don't have any of my old lab notebooks so I wouldn't be as much help, but here's something else to chew on.

I'd check for a larger problem though and if there is nothing, perhaps you just had a faulty component, you may be able to find a way around re-installing the IC.

Let me know if I made no sense.

--Joe

sexy240
05-31-2002, 05:02 PM
the amp wasnt working. all the malfunction lights where lit. saying overload or something.

I would try and close the circuit but there are three terminals. witch two of the three do i conect?

**DONOTDELETE**
05-31-2002, 06:19 PM
jdurning has a good point. A lot of times when a chip gets fried it is because something else went bad. Did you look the whole board over looking for black spots or broken traces? Any wires that are missing insulation? Do you have a multimeter so you can test some traces? I would look for a bad voltage regulator just for the heck of it. You can pick up the thermal goo at radioshack for cheap. Check www.digikey.com (http://www.digikey.com) or www.mpja.com (http://www.mpja.com) to see if you can find any parts.

Also i would ask this question to audio fanatics as well. Despite what people think not all EE's are big on circuit theory. A lot of EE's today specialize in comm theory which is more electromagnetics and statistics than plain circuit theory. Not saying they wouldn't know, but your average audiophile has a better chance of knowing exactly what part you might need. Mostly due to the fact that they probably have had to replace a few. http://www.freshalloy.com/

chris@speedalliance.com
06-06-2002, 06:15 PM
hello...
the piece you speak of is probably a voltage regulator module.
the M you speak of is probably a company called Maxim.

VRM's tend to heat up.

I hve never seen a FET bolted down to the board. Besides that...transistors are usually pretty small.

Hope this helps.
Chris

jdurning
06-07-2002, 11:42 PM
Originally posted by chris@speedalliance.com:
hello...
the piece you speak of is probably a voltage regulator module.
the M you speak of is probably a company called Maxim.

VRM's tend to heat up.

I hve never seen a FET bolted down to the board. Besides that...transistors are usually pretty small.

Hope this helps.
Chris<font size="2" face="Verdana, Arial[/img]Nope. I think you're confused. It was stated that there are 3 wires and one screw mounting it to the heat sink with a white grease. The MOSFET's used in the common car amp are actually a pretty good size (about an inch square plus or minus from what I remember).

--Joe

chris@speedalliance.com
06-08-2002, 07:05 AM
The best thing to do would be to look at the silkscreen laid down on the PCB. Find out what the part designation is. Transistors are usually labeled as Qx, where x = some consecutive number. VRM's ... hmmmm...i forgot what they are designated as.

but if it's a "Q" part...then yeah you got a transisitor.

Chris

sexy240
06-09-2002, 01:10 AM
Originally posted by chris@speedalliance.com:
The best thing to do would be to look at the silkscreen laid down on the PCB. Find out what the part designation is. Transistors are usually labeled as Qx, where x = some consecutive number. VRM's ... hmmmm...i forgot what they are designated as.

but if it's a "Q" part...then yeah you got a transisitor.

Chris<font size="2" face="Verdana, Arial[/img]Ill take a look tommorow.

as far as the size goes. well, it is closer to a square 1/4 inch than a square inch. OR a little smaller than a button on your keyboard. and there where 8 of them. I did not spot any other burn marks on the board.