Lanzar MXA 242 - Page 2 - 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 4th April 2013, 01:59 AM   #11
diyAudio Member
 
Deadly Sones's Avatar
 
Join Date: Feb 2011
Location: Windsor, Ontario
Awww, ok... was gonna say I didn't switch probe positions as I went across them but that is likely the case (board layout/position). I'll order up the replacements in the morning. thx vm

One thing I did notice was that 3 of them emitter resistors kept a solid reading and #4 varied between .025vdc and .035vdc... could this be a sign of the "leaky" transistor?

Last edited by Deadly Sones; 4th April 2013 at 02:01 AM.
  Reply With Quote
Old 9th April 2013, 11:54 PM   #12
diyAudio Member
 
Deadly Sones's Avatar
 
Join Date: Feb 2011
Location: Windsor, Ontario
The outputs in this amp are A1941 and C5198 and I can't seem to find any without buying 50 or 1000. Can they be subbed with 35/36C's? or is there a better sub?

Can I use 3watt dale resistors for these? Or are these ones (please see pic) 5watt? These are the largest output resistors I've seen in an amp.
Attached Images
File Type: jpg IMG_0618.jpg (484.6 KB, 28 views)
  Reply With Quote
Old 10th April 2013, 01:12 AM   #13
diyAudio Member
 
Join Date: Nov 2003
Location: Louisiana
I use the FJA4313 and FJA4213 as subs for all transistors in this style case.

Are they defective?

The TIP transistors often require modification to the bias circuit to prevent thermal avalanche.

If the resistors are within tolerance, there's no point in replacing them.

They appear to be 5w.
  Reply With Quote
Old 23rd April 2013, 06:54 PM   #14
diyAudio Member
 
Deadly Sones's Avatar
 
Join Date: Feb 2011
Location: Windsor, Ontario
I replaced all outputs with the FJA4213/4313 subs. I removed the gate resistors and they seemed to read the same as the new ones I bought... 0.1- .2 bouncing to .4 even though they should be 0.15ohm. The 5w wire wound ones I bought are much smaller than the ones in the amp so I reinstalled the old ones in case the wattage is higher.

Now, its no longer in protect, but is pulling a lot of current (current limiter gets hot fast) and the output is extremely distorted. It is audible but sounds terrible. I have over 1.5vdc on the outputs bridging terminals and when checking across each gate resistor now 3 of the 4 banks have DC where as before it was only one channel (2 banks).

I'm going to try the 5w resistors I bought tomorrow (have to get to work right now) just to see if they are the issue... could the problem be driver oriented?
  Reply With Quote
Old 24th April 2013, 04:55 PM   #15
diyAudio Member
 
Deadly Sones's Avatar
 
Join Date: Feb 2011
Location: Windsor, Ontario
Wow, I really need to learn to be more attentive when reading posts. Perry the driver transistors are 2SA1358 & 2SC3421's. What are good subs for these?
  Reply With Quote
Old 24th April 2013, 06:49 PM   #16
diyAudio Member
 
seankane's Avatar
 
Join Date: May 2010
Location: Washington State
I have had very good luck subbing the BD139 and BD140 for most any application I have come across.

You may want a second opinion but I have subbed them in probably 15 or 20 amps with no issues.
__________________
Pyramid 52 Amp Power Supply----Fluke 787 Processmeter----Tektronix 465 Scope----Velleman HPS40 Scope----Soldering Iron----Desoldering Iron----Hejet HJ 500-S Heatgun----DM4070 Digital LCR Meter----Propane Torch
  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
DH-220 Clone (SMART TA-242) WAY too high bias current issue? beady Solid State 10 27th January 2013 07:50 PM
Lanzar MXA 282 S Merlington Car Audio 48 5th January 2013 06:47 AM
DH-220 Clone (SMART TA-242) can't adjust DC offset using offset bias pot? beady Solid State 6 17th March 2011 11:53 AM
FS Hadcock 242 Super Silver mab Swap Meet 3 24th July 2007 02:42 AM


New To Site? Need Help?

All times are GMT. The time now is 02:30 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