Hifonics Problem - 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 December 2006, 07:16 PM   #1
diyAudio Member
 
Join Date: Jan 2005
Location: The Great Lakes
Default Hifonics Problem

I have a hifonics that had the protection light on. I Fixed this problem, Now when the protection light goes off the amp doesn't turn on. Here's my quick question, it uses the Ka7500bd smps controller can i use a tl494 as a replacement. The amp is a zx7500.
  Reply With Quote
Old 7th December 2006, 09:12 AM   #2
diyAudio Member
 
Join Date: Nov 2003
Location: Louisiana
I think the 7500 is the same as the TLx94 but I'd suggest using the 594 instead of the 494. The 594 has always been a good replacement for the 494 but the 494 was not always a good replacement for the 594. I don't think this is a problem in the newer amp designs but it was in some of the older designs so I always use the 594 because I know it's not going to cause any unforeseen problems.
  Reply With Quote
Old 2nd April 2007, 12:37 AM   #3
diyAudio Member
 
Join Date: Jan 2005
Location: The Great Lakes
I finally changed the pwm chip, thinking this is my problem, I ordered 594's but first i wanted to see if it worked with the 494. It works, but I'm not having nice square waves on the inputs, and pin 9 and 10 are only 1.8v. I find that a little low, I'm guessing 5v is the norm on this amp. Also the outputs have 21volts on one side and only 17volts on the other. Then i put in the 594 to see maybe the chip is not strong enough to run 4 drive transistors, the 594 is even worse i get only 17 and 11 volts on the outputs and the light is barely on.

p.s. I learned with the original chip the ka7600bd, the supply would start up then shut down.


Here are voltages on the chip


p1 :1.2mv
p2 :5v
p3 :62mv
p4 :186mv
p5 :1.71v
p6 :3.94v
p7 :gnd 0v
p8 :11.28v p.s.
p9 :1.789v
p10 :1.799v
p11 :11.28v
p12 :10.64v
p13-14-15 :5v
p15:.872v
  Reply With Quote
Old 2nd April 2007, 01:39 AM   #4
diyAudio Member
 
Join Date: Nov 2003
Location: Louisiana
This is very strange. With only 186mv of deadtime, you should be very near full duty cycle.

I breadboarded a chip and set the deadtime to ~190mv and the output was ~4.5v.

Have you measured a square wave gate drive before with that meter? Do you know if it will read ~1/2 B+ with a 50% duty cycle square wave?
  Reply With Quote
Old 2nd April 2007, 03:28 PM   #5
diyAudio Member
 
Join Date: Jan 2005
Location: The Great Lakes
Here's what it looks coming from pin 9 and 10



the 5volts/div
and 5uS/div

I should be seeing around 20uS, it seem very compact.Also the chip runs very warm.

Sorry perry, i don't understand what you mean.

Click the image to open in full size.
  Reply With Quote
Old 2nd April 2007, 03:49 PM   #6
diyAudio Member
 
Join Date: Nov 2003
Location: Louisiana
If that's 5us/div, the operating frequency is too high. The timing capacitor is likely the cause but you should also check the timing resistor.

Ct and Rt are connected to pins 5 and 6 of the 594.
  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
Sub for Gen VII HiFonics Morts Car Audio 0 26th May 2009 04:29 PM
Hifonics BX1000D Dobermann Car Audio 2 26th September 2008 04:27 PM
Hifonics Boltar VIII Problem vypr Car Audio 22 19th February 2008 03:46 AM
Hifonics Zeus VII redimp Car Audio 1 20th December 2006 10:47 PM
Hifonics pluto amp deriver23 Car Audio 1 27th September 2006 06:09 AM


New To Site? Need Help?

All times are GMT. The time now is 01:00 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