Rockford punch 250a2 dead - 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 26th June 2010, 01:27 AM   #1
diyAudio Member
 
Join Date: Jun 2002
Location: non
Default Rockford punch 250a2 dead

Having a power supply issue on this. it had blown channel along with both 50N06s shorted/blown. replaced all of that, and checked the driver transistors off the TL494 and they are good.

However i get NO action from the TL494 at all. checked all the voltages, and i have my 12V VCC sitting at the TL494, but no drive output. changed the TL494 and no change. Everything appears to be ok voltage wise, i had the reference 5V present at the IC. both error amplifiers and feedback pin are in the "false" meaning the IC should start up and run just fine without an error condition. I even scoped the oscillator, and had a clean 66khz ramp.

only thing that is odd, is the DTC is pinned kinda high. around 4V. maybe higher, i cant remember the exact value. but it seems high, as the fosgate 1200 i worked on, the DTC was near 0.

any ideas?
  Reply With Quote
Old 26th June 2010, 09:21 AM   #2
diyAudio Member
 
Join Date: Nov 2003
Location: Louisiana
Pin 4 must be near 0v. Post the voltages on the LM339.

IC#
Pin 1:
Pin 2:
Pin 3:
Pin 4:
Pin 5:
Pin 6:
Pin 7:
Pin 8:
Pin 9:
Pin 10:
Pin 11:
Pin 12:
Pin 13:
Pin 14:
  Reply With Quote
Old 27th June 2010, 03:15 AM   #3
diyAudio Member
 
Join Date: Jun 2002
Location: non
I swapped the LM339 as a potential failure point. But i will do the readings monday when i get back to the shop. I will have to repair a couple burned traces and replace a mosfet becuase my meter lead is too fat. it slipped and shorted 7/8 together momentarily which resulted in smoke, flames and heavily loaded 12v power supply. lol.
  Reply With Quote
Old 29th June 2010, 01:41 AM   #4
diyAudio Member
 
Join Date: Jun 2002
Location: non
I fixed it. rockford sent me the 250a2 schematic.

But i found a shorted thermistor. of ALL THINGs. the thermistor was shorted 0ohms. removed it, replaced it with another one from a scrapped amp. it fired right up. go figure. it worked fine though.
  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
Rockford 250a2 Won't turn on stusigpi Car Audio 15 12th May 2010 07:42 AM
Rockford Fosgate 250a2 mike49504 Car Audio 4 28th April 2010 02:38 AM
Selling a punch 250a2, old punch 75, and ppi epx 205 on EBAY ppia600 Swap Meet 0 23rd February 2008 01:17 AM
Hey I put an old punch 75, a 250a2, and an epx 205 up on ebay ppia600 Car Audio 0 23rd February 2008 01:13 AM
Repairing Rockford Fosgate 250a2 03Jeep Car Audio 6 18th January 2006 02:02 PM


New To Site? Need Help?

All times are GMT. The time now is 11:17 PM.


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