eqt with low output voltage - 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 31st December 2006, 03:33 PM   #1
marko is offline marko  United Kingdom
diyAudio Member
 
Join Date: May 2004
Location: donnyuk
Default eqt with low output voltage

i have 3 eqt's but one struggles to make 5v output whilst the other 2 are well over the rates 9v. any idea why this might be? i did notice the transformer gets a little hot too...
  Reply With Quote
Old 1st January 2007, 06:46 AM   #2
diyAudio Member
 
Join Date: Dec 2005
Location: Northern California
Check you B+ voltages and your + - rail voltages feeding the chips in the EQT.
I have seen power transformer failure, and or OP-amp chip failure cause voltage drops like you have.

Happy New Year ! Good Luck
  Reply With Quote
Old 1st January 2007, 01:32 PM   #3
marko is offline marko  United Kingdom
diyAudio Member
 
Join Date: May 2004
Location: donnyuk
think this may be above me! only reason i wanted to fix it is because it's from a matching pair, the 3rd one has a green board in it and most likely made in the far east....as you can tell that tranny has been replaced at some time!
Attached Images
File Type: jpg dscn1916.jpg (48.8 KB, 49 views)
  Reply With Quote
Old 1st January 2007, 01:36 PM   #4
marko is offline marko  United Kingdom
diyAudio Member
 
Join Date: May 2004
Location: donnyuk
and the good one with the green board...
Attached Images
File Type: jpg dscn1917.jpg (46.9 KB, 41 views)
  Reply With Quote
Old 1st January 2007, 07:09 PM   #5
diyAudio Member
 
Join Date: Dec 2005
Location: Northern California
Nice Pics, Thx.
The LTC power device does fail from time to time, But be forewarned that this is typically a sign that the transformer is shorted on itself. The LTC is fairly cheap to come by here locally, but you will have to contact Audio Control for the transformer.

If your out to just save that board, then you could just swap parts to do the rescue/repair, or just order the LTC1070 I think it is from just about any source and try and replace it first, in hopes that will solve the issues.

try this to find your parts: http://www.findchips.com/avail

The transformers should just exchange across. It would be nice to read the rail voltages at the chips, referenced to ground of the RCA shield.
The voltage test points for those 14 pin op-amps are numbers 4 & 11.

These two pins have the rails on them. You might have a bad op-amp chip in one of the filter bands causing the excessive load on the power supply. A single blown eq band will cause this sometimes. The power supply in these EQT's were not intended for a very large load, so any chip failure would result is voltage drop.

The fact its trying to work tends to indicate that it might just be a power supply issue, possible the transformer, or the LTC1070 device, But it could be a op-amp or two that went south on you.

On another note, Audio Control might have flat rate repairs at their facility listed below:
http://www.mobileaudiocontrol.com/contact.asp


Good Luck, and Happy New Year
  Reply With Quote
Old 1st January 2007, 09:10 PM   #6
marko is offline marko  United Kingdom
diyAudio Member
 
Join Date: May 2004
Location: donnyuk
thanks for the detailed responce as usual!! you helped me resurect my 0.5 on sb not so long ago..

as for the cost of fixing, will have to look into it but for what they go for these days on ebay it might be just as cheap to buy a single unit off ebay!
  Reply With Quote
Old 2nd January 2007, 12:19 AM   #7
diyAudio Member
 
Join Date: Dec 2005
Location: Northern California
Yeah I remember Marko. Hows that doing so far? Well I hope. Have you tried Phoenixphorum yet ? if not here ya go

http://phoenixphorum.com

I hang around there alot nowadays. Anyway, always glad to help

Cheers !
  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
DC Voltage on RCA Output baxtr Parts 7 16th January 2009 10:37 PM
Can An Output Transformer Change A Voltage Amp's Output Impedance From 0.1 To 47 Ohms kelticwizard Everything Else 11 25th March 2007 05:17 AM
use D1 I/V with voltage output dac poolorpond Pass Labs 6 11th June 2006 07:47 PM
DC voltage on output durxter Chip Amps 20 6th March 2005 06:25 PM
P27 Output Voltage rayban68 Solid State 0 6th October 2004 06:19 PM


New To Site? Need Help?

All times are GMT. The time now is 10:14 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