LM4870 Noob mess up - Page 7 - diyAudio
Go Back   Home > Forums > Commercial Sector > Vendor Forums > Audio Sector

Audio Sector Kits & PC boards from AudioSector

Reply
 
Thread Tools Search this Thread
Old 20th February 2010, 08:44 PM   #61
diyAudio Member
 
Join Date: Nov 2009
Location: Lincolnshire UK
Ok rewired it up and tgis is how i've got it....

This is my transformer wiring diagram...

Technical notes: : Technical Information

I have got Red to AC1 nearest edge of board, Black AC1 Inner hole, Yellow AC2 Inner hole and Orange AC2 Edge of board.

Is this the right way?
  Reply With Quote
Old 20th February 2010, 09:37 PM   #62
diyAudio Member
 
Join Date: Nov 2009
Location: Lincolnshire UK
Got my simple bulb tester... negative and earth into block connector and live into bulb and out othr side of bulb.

Rewired transformer to amp and powered up... Light didnt light up or flicker at all. However when I put probes onto AC side the bulb is lighting up.

MMMmm I'm getting a bit !$*@%&$ angry now. Think I might call it a day and try again tomoro. Only upto rectifier, got the amps to go though yet.
  Reply With Quote
Old 20th February 2010, 09:52 PM   #63
jaycee is offline jaycee  United Kingdom
diyAudio Member
 
Join Date: Apr 2004
Location: Norwich, UK
The bulb should not light, or light only dimly... you may get a flash when everything is connected up and the capacitors charge. If the bulb lights up brightly and stays lit, it means something is trying to draw a lot of current, and the bulb takes the power instead. The beauty of it is that the bulb absorbs the power instead of whatever is shorted, saving the parts.

You were testing the diodes correctly - they should only conduct one way. It seems like they are OK.

The transformer wiring now sounds correct.

Start with a 60W bulb.
  Reply With Quote
Old 20th February 2010, 10:22 PM   #64
diyAudio Member
 
Join Date: Nov 2009
Location: Lincolnshire UK
Only managed to find a 40W bulb... Power up is fine, no light, bangs or flashes.

I set my multimeter to DC, place red probe on V+ and black probe on PG+... I get a spark which freaks me out to start with... Then bulb starts to glow. Should I leave probes on for a time to see if bulb fades or do I carry on freaking and jumping back 3 feet.
  Reply With Quote
Old 20th February 2010, 11:59 PM   #65
diyAudio Member
 
Join Date: Nov 2009
Location: Lincolnshire UK
Maybe I should see about getting 8 fresh MUR860's, a couple of caps and make another rectifier.

transformer is ok, so its either the wires going into rectifier thats wrong or I've done something during rectifier build thats not right. I have looked though a magnifying glass and cant see any solder that is shorting anywhere. everything is in right place and the right way round.

I just dont get it at all... I'm off to bed to sulk about it.
  Reply With Quote
Old 21st February 2010, 03:01 PM   #66
diyAudio Member
 
Peter Daniel's Avatar
 
Join Date: Jul 2002
Location: Toronto, Canada
Send a message via AIM to Peter Daniel
You checked the diodes and they seem to measure fine, I checked your pics and they are installed properly.

Forget about the bulb, it's good for testing complete amp, but you don't need it here yet.

See attached pic, this is how PS should be wired:

You have two sets of secondaries on the transformer, colors don't mean anything to us without manufacturer's diagram. Identify secondary pairs by measure AC voltages; connect one set to pads marked AC2-AC2, the other set to AC1-AC1 (the orientation of wires is not critical as long as two pairs are sorted out properly)

Now measure voltages between V- and PG- and between V+ and PG+, it should be approx 2x 34V DC. If LED doesn't light up, it may be installed incorrectly and you need to reverse it.

All those measurements should be done without PS connected to the amp boards.
Attached Images
File Type: jpg ps.jpg (93.3 KB, 145 views)
__________________
www.audiosector.com
“Do something really well. See how much time it takes. It might be a product, a work of art, who knows? Then give it away cheaply, just because you feel that it should not cost so much, even if it took a lot of time and expensive materials to make it.” - JC

Last edited by Peter Daniel; 21st February 2010 at 03:04 PM.
  Reply With Quote
Old 21st February 2010, 03:11 PM   #67
AndrewT is offline AndrewT  Scotland
diyAudio Member
 
Join Date: Jul 2004
Location: Scottish Borders
the purpose of the bulb tester is to prevent damage if any of the wiring is wrong and causes excessive power demand.
It is best used right from the start rather at the end of the building sequence.
__________________
regards Andrew T.
  Reply With Quote
Old 21st February 2010, 03:23 PM   #68
diyAudio Member
 
Peter Daniel's Avatar
 
Join Date: Jul 2002
Location: Toronto, Canada
Send a message via AIM to Peter Daniel
Well, I know that. But you can't make an error wiring a simple PS circuit, and I'm not completely sure if he did wire the bulb tester correctly, are you?
__________________
www.audiosector.com
“Do something really well. See how much time it takes. It might be a product, a work of art, who knows? Then give it away cheaply, just because you feel that it should not cost so much, even if it took a lot of time and expensive materials to make it.” - JC
  Reply With Quote
Old 21st February 2010, 04:56 PM   #69
diyAudio Member
 
Join Date: Nov 2009
Location: Lincolnshire UK
Ok guys please dont start fighting

My bulb tester is a monitor lead, cut in half.. Neutral and earth into block connector and the live in and out of bulb.

Its frustrating, but its my error somewhere. I'm sure it will be sorted soon.
  Reply With Quote
Old 21st February 2010, 08:01 PM   #70
jaycee is offline jaycee  United Kingdom
diyAudio Member
 
Join Date: Apr 2004
Location: Norwich, UK
if you are getting a spark trying to measure between -V and -PG, something is wrong. The bulb is lighting up because lots of current is being drawn - your multimeter will not do this!
  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
RB250 Rewiring - accidental mess up? InfiniteGain Analogue Source 5 30th January 2009 10:11 PM
LM4870 PCB Group Buy Wynand Chip Amps 4 10th January 2006 05:33 PM
Help Please Guitar Project Mess Trout Tubes / Valves 7 15th September 2005 03:45 AM
Classification Mess Up freedom Solid State 2 15th November 2004 04:32 PM


New To Site? Need Help?

All times are GMT. The time now is 03:30 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