RE: Leppai 2020A+ Modd Help! got issues
This is what I have done and in the order I did it. My problem is hopefully easily diagnosed. I re caped the amp in stages using the parts and method described by XtremeRevolution however some of the caps and the basic board layout for a couple of the caps was different than his amp, so I replaced only the caps that were the same. I first replaced the input cap 1X (yellow in photo) and the six output caps (Red in photo) Tested great. Next the rest that were the same(Green). this is where the issues started, I should have done one at a time and test but live and learn.
Symptons as follows.
1. amp played great for approx 10 min. started to pop loudly! and do bad things, amp volume had no control over this, then loss of all amplification, dead except for power light.
2. I unplugged it and turned it on unplugged to drain power from it power light slowly goes out, I let it set approx 30 min re powered and it plays great for approx 2 minutes then amplification slowly fades to nothing.
3. The preamp signal can sometimes be heard but the amp controls have no effect on the volume, it just passes thru the amp unaffected, but the volume on the preamp doe's make a difference.
4. unpluged and drained of power it will function for a short time then fade away to nothing but the preamp signal. (sometimes).
Thanks for your thoughts, Less Opinion
This is what I have done and in the order I did it. My problem is hopefully easily diagnosed. I re caped the amp in stages using the parts and method described by XtremeRevolution however some of the caps and the basic board layout for a couple of the caps was different than his amp, so I replaced only the caps that were the same. I first replaced the input cap 1X (yellow in photo) and the six output caps (Red in photo) Tested great. Next the rest that were the same(Green). this is where the issues started, I should have done one at a time and test but live and learn.
Symptons as follows.
1. amp played great for approx 10 min. started to pop loudly! and do bad things, amp volume had no control over this, then loss of all amplification, dead except for power light.
2. I unplugged it and turned it on unplugged to drain power from it power light slowly goes out, I let it set approx 30 min re powered and it plays great for approx 2 minutes then amplification slowly fades to nothing.
3. The preamp signal can sometimes be heard but the amp controls have no effect on the volume, it just passes thru the amp unaffected, but the volume on the preamp doe's make a difference.
4. unpluged and drained of power it will function for a short time then fade away to nothing but the preamp signal. (sometimes).
Thanks for your thoughts, Less Opinion
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There should never be a need to swap out good capacitors.
The capacitors that may need to be changed are dying electrolytic capacitors.
Put all the others back in the way they were.
BTW, there are probably no coupling capacitors in there and the few that might be this duty will not need to be replaced.
The capacitors that may need to be changed are dying electrolytic capacitors.
Put all the others back in the way they were.
BTW, there are probably no coupling capacitors in there and the few that might be this duty will not need to be replaced.
RE: Results Lepai 2020A modd
Bad solder on one of my caps, My lack of experience made me damage the trace on the board at the hole, I couldn't see the bad contact but suspected that might be the issue so I re soldered. These are very cheap boards they will stand for very little abuse. Problem solved and quite pleased with the results.
The new style boards don't leave much room for the larger output caps so a little improvisation was in order, two caps were mounted from the backside of the board. In retrospect the caps can be laid down and the board will fit back into the housing if the leads are left longer when soldered in place. Much improved performance, better base response and sound reinforcement over the entire frequency spectrum. Using the tone control circuit before the mod would have a pronounced effect on the volume and sound quality, after the modds there is no effect on the output and the tone controls are now a fully functional addition to the amp. Well worth the $7.00 US invested.
Bad solder on one of my caps, My lack of experience made me damage the trace on the board at the hole, I couldn't see the bad contact but suspected that might be the issue so I re soldered. These are very cheap boards they will stand for very little abuse. Problem solved and quite pleased with the results.
The new style boards don't leave much room for the larger output caps so a little improvisation was in order, two caps were mounted from the backside of the board. In retrospect the caps can be laid down and the board will fit back into the housing if the leads are left longer when soldered in place. Much improved performance, better base response and sound reinforcement over the entire frequency spectrum. Using the tone control circuit before the mod would have a pronounced effect on the volume and sound quality, after the modds there is no effect on the output and the tone controls are now a fully functional addition to the amp. Well worth the $7.00 US invested.
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