Pioneer GMX-962 - 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 6th April 2011, 12:11 AM   #1
NauTech is offline NauTech  Canada
diyAudio Member
 
Join Date: Apr 2011
Location: montreal
Default Pioneer GMX-962

I got this amp who stopped working
when i opened it there was the trace from the ground terminal that was wide open on the board it shorted hard exactly between where the trace split in half.. the 2 fuses had blown also

I repaired the trace and replaced 2 P55NE06 that were shorted but i dont want to power the amp cause when i measure between the B+ and GND there is a resistance around 8K and i am not shure those 2 P55NE could have exploded that trace like that... it must have been a real hard short to blow away the trace from the board ...
what do you think about it



Click the image to open in full size.

Last edited by NauTech; 6th April 2011 at 12:16 AM.
  Reply With Quote
Old 6th April 2011, 01:04 AM   #2
diyAudio Member
 
Join Date: Nov 2003
Location: Louisiana
You should have replaced all 6 of the power supply FETs. I'd suggest removing all 6 of them and checking them for leakage from the gate to the other legs of each transistor.
  Reply With Quote
Old 6th April 2011, 01:19 AM   #3
NauTech is offline NauTech  Canada
diyAudio Member
 
Join Date: Apr 2011
Location: montreal
yeah thats what i will do i bought 8 anyways
the problem is that they sent me STP55NE06 instead of FP with a TO-220 non insulated casing ... so i wanted to use little mika's and screw insulators to isolate them from the heatsink... would it be ok ? they are rated at 55A instead of 30A
I wanted to check if the amp was working before changing them all..
I already checked the others are not leaking.. but i will change them all since they are all in parrallel and i have enough to replace them all...

is the 4K-10K resistance between the B+ and GND terminal normal ??
depending on wich sides i put my probes it reads around 10k or 4k
do you think the 2 blown FETs could have busted the track on the circuit and that only problem could be it ?
  Reply With Quote
Old 6th April 2011, 01:24 AM   #4
diyAudio Member
 
Join Date: Nov 2003
Location: Louisiana
The trace was likely burned when 12v contacted the heatsink.

While you have the FETs out of the board, power up the amp and measure the DC voltage on the gate pads for the FETs. They should all read about 5v.

I wouldn't expect to read anything as low as 4k across the B+ and ground terminals but can't say it's not normal for this amp because that's not something I normally check.

With the FETs out of the board, what's the resistance across the B+ and ground terminals?
  Reply With Quote
Old 6th April 2011, 01:34 AM   #5
NauTech is offline NauTech  Canada
diyAudio Member
 
Join Date: Apr 2011
Location: montreal
the resistance i am measuring is always rising or lowering slowly

now when i measure the B+ and ground terminal (with the FETs still on the board ill remove them after this message) i read 2k then going down slowly to almost 0 and then rising slowly up to 20K.. then i remove the probes and rechecked after moving the board closer to me ... and remeasured with the com probe on ground and V probe on B+ i measure 180K resistance and if i reverse them i measure 40K resistance...
what am i measuring exactly ?
am i charging something with the DMM .. the amp as been siting on a shelf for 6 months and the capacitors are discharged...
  Reply With Quote
Old 6th April 2011, 01:42 AM   #6
diyAudio Member
 
Join Date: Nov 2003
Location: Louisiana
You didn't say that the resistance was changing. If the value is changing, you're charging/discharging the capacitors.
  Reply With Quote
Old 6th April 2011, 01:48 AM   #7
NauTech is offline NauTech  Canada
diyAudio Member
 
Join Date: Apr 2011
Location: montreal
ok okay thats what i tought
so this is normal... allright

for the STP55NE06FP
is STP55NE06 a suitable replacement if i use insulator pads and tabs ? dont know if the thermal transfer will be as good... at least the STP55NE06 are rated higher...

do you have a part number or a name for those mika pads and screw shoulders? i dont know how they are called
  Reply With Quote
Old 6th April 2011, 01:52 AM   #8
diyAudio Member
 
Join Date: Nov 2003
Location: Louisiana
Charging/discharging is normal. Constant resistance is not, for most amps.

The thermal transfer will be about the same but the clamping pressure probably won't be nearly as good because most of the washers are too soft.

I don't have numbers for Allied.
  Reply With Quote
Old 6th April 2011, 01:58 AM   #9
NauTech is offline NauTech  Canada
diyAudio Member
 
Join Date: Apr 2011
Location: montreal
I will have to try it out since i dont have the FP's
ill check to see if the clamping looks good after screwing them on the heatsink

for the washers/pads
whatever the company digikey or newark will be just fine ... it would help me a lot ill know the name/specs and everything needed to find it on Allied cause i dont know if they are called mika pads or shoulder tabs .. etc

its just cause i dont know the name for them i had 2 or 3 lying around at the job but now i need more obviously
  Reply With Quote
Old 6th April 2011, 02:01 AM   #10
diyAudio Member
 
Join Date: Nov 2003
Location: Louisiana
At least try to find them on Mouser. Mica and Shoulder washers.
  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
Behringer GMX microphonic inputs screamersusa Instruments and Amps 4 7th July 2009 01:03 PM
Need Help With GMX Klipsch System DontWannaName Multi-Way 0 5th December 2008 10:44 AM
Klipsch Promedia GMX A-2.1 + Decware Taboo gni Tubes / Valves 0 7th February 2008 03:11 PM
needed pioneer gmx-944 manual zerohead_ak47 Solid State 0 24th June 2007 11:44 AM
Logitech Z-5300 versus Klipsch ProMedia GMX jack_soltysik Multi-Way 10 14th August 2004 06:01 PM


New To Site? Need Help?

All times are GMT. The time now is 06:56 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