Zapco Z400C4-SL... Not Again! - 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 23rd August 2012, 10:20 PM   #1
diyAudio Member
 
90scaraudio's Avatar
 
Join Date: Aug 2012
Location: ILLINOIS
Arrow Zapco Z400C4-SL... Not Again!

Hi All...
Picked up my second broken Zapco! Must be a glutton for punishment...Anyway... first thing I did was to look at the mess that those 4 caps make when they leak. Well, only one leaked, the far left side. Want to say it's channel one, or left front channel. Pulled all 4 caps then started to clean. When I was brushing around the leak area, one SMD res and semi came off. That's corrosion at work! I replaced the caps and some other 10uf caps, put it back together and tested it. (I think I was the first one to take the amp apart since factory). When it turns on, the idle current is about 1.75amps, good so far. The rear input clip light stays on with no other lights on except the green on light. Then after about 4 second it goes into protect mode and starts the process over. There is negligible dc voltage at the speaker outputs, could be my meter, guess I should have a look at it with a scope, and the front end semis and finals look nice with no shorts.
My Question is does anyone know if the input clip circuit is after the op-amps and after the front end, before the finals? The Soundstream amps have it before the front end boards, after the op-amps.
Guess I could half split it and I haven't ruled out that NAND gate. I'll play some more and write what I find.
BTW. this is scott-leanne that did the post on one of these years ago and I cant remember the password or email address I used the last time I posted.

OK... I replaced the 10uf cap next to the NAND gate pins 12 and 13 with a 100uf for now until I can order some new gates. Next I wanted to see any dc voltage on the spk outputs with a scope. I turn the system on and the rear input clip light comes on along with the power on green light, Idle current still good, then it goes into protect and stays there. It does not try to restart, that tells me the NAND gate is flakey. I think I found one possible problem with the scope.
When the system is on for 4 seconds, the dc voltage on ether rear channels is about .3 volts or less. While its going into protect, the left rear spk output goes to about 5vdc. None of the other channels do this. Am I on to something? Guess I need to pull the finals out of circuit and check them or should I dissect the front end and possibly op-amps for this channel?
Any body??? Suggestions???


Last edited by 90scaraudio; 24th August 2012 at 12:51 AM.
  Reply With Quote
Old 24th August 2012, 01:00 AM   #2
diyAudio Member
 
90scaraudio's Avatar
 
Join Date: Aug 2012
Location: ILLINOIS
Here is what the old SS reference clip circuit looks like...
Attached Images
File Type: jpg clip.jpg (233.7 KB, 125 views)
  Reply With Quote
Old 24th August 2012, 10:33 AM   #3
diyAudio Member
 
Join Date: Apr 2011
Location: Anchorage AK
if i have learned anything about old school soundstream is their individuality and weakness/strength is all one in the same. unless someone has verified similarities in this amp, i would look at more similar amps. however, in a soundstream, it monitors the voltage differential between the rail and output. speaking soundstream, if outputs are okay, then the first place to look would be the feb connections (with a meter probe, not just naked eye)
however, this is zapco..... what is the voltage to/from the drivers giving 5v? ".3 or less" is fine by me, but 5v is substantial, and certainly a/the problem. you have the board in fromt of you and 3 good channels to compare...
  Reply With Quote
Old 24th August 2012, 07:02 PM   #4
diyAudio Member
 
90scaraudio's Avatar
 
Join Date: Aug 2012
Location: ILLINOIS
When the system is on for 4 seconds, the dc voltage on ether rear channels is about .3 volts or less. While its going into protect, the left rear spk output goes to about 5vdc just for a split second. None of the other channels do this.
Should have added this..

The last one of these I mest with, none of the finals were bad and its not too fun pulling them out. I will post more on what I find. I'm going to start on the op-amp/pre-amp area first.
  Reply With Quote
Old 24th August 2012, 10:02 PM   #5
diyAudio Member
 
Join Date: Apr 2011
Location: Anchorage AK
does your amp have the delayed turn-on, utilizing a source mute? i don't know the circuit of your amp, but there could be a bad capacitor in that channel, allowing a normally harmless dc signal to pass, and initiate protect.
  Reply With Quote
Old 25th August 2012, 12:52 AM   #6
diyAudio Member
 
90scaraudio's Avatar
 
Join Date: Aug 2012
Location: ILLINOIS
It has some caps on the balanced input section. It does have delay turn on. I hope it's one of the op amps. Its hard to catch the DC because it only stays on for 3 or 4 seconds. I'll post what I tried and what I found.
  Reply With Quote
Old 25th August 2012, 02:14 AM   #7
diyAudio Member
 
Join Date: Apr 2011
Location: Anchorage AK
i suppose it kills rail voltage, and thus the pre-amp power when in protect, making it hard to find the dc source. i would venture to say it should be present in the 4 seconds if before the mute circuit, and show up if after. it may be possible to keep mute active to test further.
  Reply With Quote
Old 25th August 2012, 02:23 AM   #8
diyAudio Member
 
90scaraudio's Avatar
 
Join Date: Aug 2012
Location: ILLINOIS
Correct... Sometimes its faster to just replace than to TS. Have you seen the inside of these?
The last one I did is on an old post with pics under the user name; scott-leanne. Have a look.
  Reply With Quote
Old 25th August 2012, 12:05 PM   #9
diyAudio Member
 
Join Date: Apr 2011
Location: Anchorage AK
looks as bad as x-taint and J-gaLo amps to work on. anyways... what;s up with the soundstreams, 'ole buddy, 'ole pal?
  Reply With Quote
Old 25th August 2012, 12:18 PM   #10
diyAudio Member
 
90scaraudio's Avatar
 
Join Date: Aug 2012
Location: ILLINOIS
Don't have a problem with Soundstreams... Fixed quite a few....
Attached Images
File Type: jpg 100_1768.jpg (467.8 KB, 107 views)
  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
Zapco Z400C4-SL noisegate jumperboard? gisewhcs Car Audio 1 6th January 2012 07:04 PM
Zapco Z400C4-SL missing it's fan gisewhcs Car Audio 4 10th May 2011 04:28 PM
Zapco Z400c4-SL no power supply fongman Car Audio 36 15th March 2010 06:00 PM
Zapco z400c4-vx problem shallowfu Car Audio 17 4th November 2006 04:14 PM
Zapco Z400C4-SL scott-leanne Car Audio 23 13th May 2006 07:44 PM


New To Site? Need Help?

All times are GMT. The time now is 06:52 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