LP-2020A+ mod thread - Page 23 - diyAudio
Go Back   Home > Forums > Amplifiers > Class D

Class D Switching Power Amplifiers and Power D/A conversion

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 29th April 2013, 12:51 AM   #221
diyAudio Member
 
THUMP LUMP's Avatar
 
Join Date: Aug 2007
45 day "No Hassle Returns" for PE my ***. I have to call them for a RA number for a pathetic little $20.00 amp. On the other hand, I'm temped to diagnose and repair the problem myself just so I don't have to mess with PE at all.
  Reply With Quote
Old 29th April 2013, 03:18 PM   #222
diyAudio Member
 
tamasic1's Avatar
 
Join Date: Dec 2006
Default Cigar box

Sorry your amp showed up bad. If you plan to diagnose it yourself, you might want to look at that output relay first. It keeps the speakers cut off for a few seconds at power on. You could try bypassing it.

Finished this yesterday. I took Tylerís advice and just used metal film PE caps. All were pulled from a large pcb I had in my parts bin. Large power cap is from same. If a smaller cap was used, this would have easily fit back in the case but I really like the looks of it in the cigar box. I didn't get fancy with gold connectors or toroid inductors. I plan to gift this to a family member along with a set of 2-way Dayton speakers.
.
.
Attached Images
File Type: jpg Cigarbox1.jpg (98.6 KB, 263 views)
__________________
Tube Amp builders - Getter Done!
  Reply With Quote
Old 29th April 2013, 04:44 PM   #223
diyAudio Member
 
THUMP LUMP's Avatar
 
Join Date: Aug 2007
OK....PE have redeemed themselves. I called for the RA number and when "Stacy" realized it was just a small $20.00 amp, he said not to bother returning it and would ship out another today. I guess it's setup within their system that if it's an "electronic" item (as opposed to "electrical"), a RA number is required.

The up side is that I can play a good bit more with this first one a try to diagnose what is wrong with it. I'm still what I consider an "electronics noob" so this will help me learn a bit.
  Reply With Quote
Old 29th April 2013, 09:09 PM   #224
diyAudio Member
 
tamasic1's Avatar
 
Join Date: Dec 2006
Default schematics

Download the TA2020-20 datasheet from the web. Combine the test circuit from the datasheet and Tyler's schematic from his op and you have the Lepai's layout.

Several people have commented that they would power up the unit and have no sound but if they let it sit for a period of time, 10~15mins or so, the sound would finally come through. (not just this version but older ones too) They would ether bypass or replace the relay.

Take the 4 screws off the front and slide the board out. Connect the power cable and switch it on. Do you hear a click from the relay? You should hear one within a secord or so after engaging the power switch. Very audible, you don't have to put your ear to it.
__________________
Tube Amp builders - Getter Done!

Last edited by tamasic1; 29th April 2013 at 09:11 PM.
  Reply With Quote
Old 30th April 2013, 12:09 AM   #225
diyAudio Member
 
THUMP LUMP's Avatar
 
Join Date: Aug 2007
I have had the datasheet for awhile. The relays on mine are just that, two separate ones on their own PCB soldered to the main PCB. I have not heard any clicking from them at all. I checked VCC at pins 22, 25, 27, 29 and that was all good. I believe the chip is bad because I didn't get any voltage coming out from pins 21, 23, 24, 26. Looks like I will be getting a new TA2020-020 chip from MCM unless anyone has anything else to check first. I need to order a compression driver from them anyway for a TalkBox I am building.
  Reply With Quote
Old 30th April 2013, 02:48 AM   #226
diyAudio Member
 
THUMP LUMP's Avatar
 
Join Date: Aug 2007
I got tracing the relays and it looks like they are used to break the speaker grounds from the rest of the circuit until power is turned on. Could someone else confirm this?
  Reply With Quote
Old 1st May 2013, 07:17 PM   #227
diyAudio Member
 
THUMP LUMP's Avatar
 
Join Date: Aug 2007
Got the replacement Lepai in today. Bone stock, right out of the box, I have to say, it lives up to the hype. That is, not bad at all for a $20.00 amp.

I am going to leave this one stock for the time being and mod/repair the first one probably beyond recognition (almost).

And I did answer my last question myself, after doing a bit more tracing to be sure. The relay does break the connection between the speaker neg. and the amp when the power is off. Regardless, I still do get a "thump", both turning it off and on.
  Reply With Quote
Old 1st May 2013, 07:29 PM   #228
diyAudio Member
 
Join Date: May 2013
Hi! im new here, saw this thread googling and think maybe any of you can help me, i've got this lepai and it's semi-broken now. When i turn it on, the right speaker do a weird thing and does not sound. It is not a problem of the speaker cos i changed it with the left one and it works. Here is a video of the problem, hoping if anyone know what happen and if i "mod" (change the capacitors) it will work again? Finally, i oppened it and everithing seems in good conditions.

(sorry for the yells, was football day)
Problema altavoces y ampli - YouTube

Thank you very much!
  Reply With Quote
Old 2nd May 2013, 03:23 AM   #229
diyAudio Member
 
THUMP LUMP's Avatar
 
Join Date: Aug 2007
alejandrop89...Not sure what your problem may be other than it looks like your getting DC current to your speaker.
  Reply With Quote
Old 2nd May 2013, 03:26 AM   #230
diyAudio Member
 
THUMP LUMP's Avatar
 
Join Date: Aug 2007
Managed to get the first one that was DOA stripped down today. I still need to get a TA2020 chip from MCM though. I did leave in all the output side components until later. This one will go into a custom enclosure.
Attached Images
File Type: jpg TA2020 stripped.JPG (591.3 KB, 227 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
TA2024 SA-36 or LP-2020A Terrymm Class D 3 28th September 2012 04:34 PM
Help with Lepai LP-2020a+ ChrisChris Class D 5 14th September 2012 03:24 PM
Lepai LP-2020A+ Balance Problem Nightcry7 Class D 3 14th September 2012 03:16 PM
Lepai LP-2020 mod to include sub out rziebro Class D 1 12th February 2011 03:01 PM
X-LP Mod Journey pjpoes Analogue Source 2 11th March 2007 07:35 AM


New To Site? Need Help?

All times are GMT. The time now is 01:32 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