Memphis missing FET's? - diyAudio
Go Back   Home > Forums > General Interest > Car Audio

Please consider donating to help us continue to serve you.

Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving
Reply
 
Thread Tools Search this Thread
Old 19th November 2007, 02:26 AM   #1
Itsme is offline Itsme  United States
diyAudio Member
 
Join Date: Oct 2007
Location: Nixa, Mo.
Default Memphis missing FET's?

I just opened a Memphis ST-1500d and it looks like somebody removed 2 FET's without removing the hold down bracket because the tamper proof glue is still on the screws. Is this possible? Or was yhis done on the assembly line? 2 pictures one left side bar removed and the right side not removed. Has anybody seen this before?
Attached Images
File Type: jpg memphis st-1500d-r.jpg (86.4 KB, 125 views)
  Reply With Quote
Old 19th November 2007, 02:27 AM   #2
Itsme is offline Itsme  United States
diyAudio Member
 
Join Date: Oct 2007
Location: Nixa, Mo.
other side.
Attached Images
File Type: jpg memphis st-1500d-l.jpg (96.0 KB, 126 views)
  Reply With Quote
Old 19th November 2007, 02:55 AM   #3
diyAudio Member
 
Join Date: Nov 2003
Location: Louisiana
Someone removed them. They probably loosened the screw enough to release the transistor, cut the legs (or pulled hard enough to break the legs) and pulled it out. It's also possible that the screw was removed but the thread-locking compound remained on the clamp.

If the screws have never been completely removed, you may want to place a drop of acetone on each screw to soften the thread-locking compound. It will make removing the screws much easier. The heads of these screws are easily stripped so be careful.

The transistors that have their 3rd legs tied to the missing one are the same part number as the missing one.
  Reply With Quote
Old 19th November 2007, 03:53 AM   #4
Itsme is offline Itsme  United States
diyAudio Member
 
Join Date: Oct 2007
Location: Nixa, Mo.
Perry... I just went to Ampguts and looked at the pics of another Memphis 16-ST1500d and they are missing on that one too. ??? So I guess it was built like that? Weird!

Anyway I have 3 - 200volt 20uf and 2- 10uf capacitor's with the top bulging, What should I look for causing this?
Attached Images
File Type: jpg memphis bulging caps.jpg (86.0 KB, 105 views)
  Reply With Quote
Old 19th November 2007, 03:58 AM   #5
Itsme is offline Itsme  United States
diyAudio Member
 
Join Date: Oct 2007
Location: Nixa, Mo.
Also here is a picture of another capacitor I think? But it is disfigured not really bulging but looks like it was heated a little?
Attached Images
File Type: jpg memphis amp.jpg (99.1 KB, 110 views)
  Reply With Quote
Old 19th November 2007, 04:26 AM   #6
diyAudio Member
 
Join Date: Nov 2003
Location: Louisiana
The transistors were definitely on the sink at one time. You can see the outline of the transistor in the grease.

The caps that vented are definitely defective. It's unlikly that you'll be able to get them from Memphis.

The caps probably failed from too much ripple current. This could have been from too low of an ohm load or a defective inductor.

I can't really tell anything from the second photo. If you remove it and it's not shorted, it's probably OK. When you touch your leads across the cap (meter set to ohms), it should initially show low resistance, then go to OL. It will only do this once. To do it a second time, you'll have to reverse the position of the leads on the cap.
  Reply With Quote
Old 19th November 2007, 04:43 AM   #7
ppia600 is offline ppia600  United States
diyAudio Member
 
Join Date: Jun 2007
Location: Louis y ana
If the transistors are also missing on the ampguts site, its probably a common problem area on the amp. They were obviously there if the compound still has an imprint. Perry, I think he's talking about the little red cap next to the transfomer and the large resistor. You can see its a little dark from doing its job.
__________________
Don't worry... you can always turn the gain down!
  Reply With Quote
Old 19th November 2007, 04:56 AM   #8
Itsme is offline Itsme  United States
diyAudio Member
 
Join Date: Oct 2007
Location: Nixa, Mo.
Yea, I just can't figure it out. On the FET hold down bar it has a peice of thin cardboard an it has the imprint of every FET but the one that is missing. If it wasn't for the indention in the paist I would be almost positive the FET didn't belong there. Very Strange.
Here is the ampguts link.

http://ampguts.realmofexcursion.com/...0D/inside4.jpg
  Reply With Quote
Old 19th November 2007, 05:12 AM   #9
diyAudio Member
 
Join Date: Nov 2003
Location: Louisiana
ppia600:
I think the red cap is simply dark from poor lighting but I could be wrong. When I zoom in on it, I can see what looks like a dark spot near its center but the low resolution makes it difficult to determine if it's really a defect or an artifact in the photo. I thought he was talking about the 2.2uf 250v cap near the inductor.

Itsme:
It's possible that they received the assembled amps and found that there was a problem (too much drive current causng drivers to fail, a problem with the circuit board layout...). If that's the case, they may have disassembled the amps, removed the transistors and reassembled them with new clamps.
  Reply With Quote
Old 19th November 2007, 05:30 AM   #10
Itsme is offline Itsme  United States
diyAudio Member
 
Join Date: Oct 2007
Location: Nixa, Mo.
Actually I was talking about the blue cap. It say's 225K250 on the top of it. It is a little warped on the end nearest the inductor. Perry's right.
  Reply With Quote

Reply


Hide this!Advertise here!
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Missing OUT Fets Memphis 16-mcd2500 amc32 Car Audio 2 3rd December 2008 07:00 PM
memphis 16-ST500D frt96 Car Audio 2 9th May 2008 08:16 AM
Memphis...? hooverjr10 Subwoofers 0 14th December 2007 04:16 AM
Kicker Vs. Memphis irokpierce Car Audio 1 23rd August 2005 04:12 PM
memphis car amp accept Car Audio 0 20th July 2003 06:36 PM


New To Site? Need Help?

All times are GMT. The time now is 11:40 AM.


vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2014 DragonByte Technologies Ltd.
Copyright 1999-2014 diyAudio

Content Relevant URLs by vBSEO 3.3.2