Well, Yesterday I received the following parts from Conrad.nl:
Today I've got the new parts soldered in place (Yes, got the backsides of the FET's pre-soldered
) but not yet soldered to the MEHSA thermal management system.
I wanted to see if the beast would power up.. So I hooked it up to my trusty Delta Elekronika Power Supply E 030-3 (30V 3A both adjustable) without the remote connected. The amp doesn't draw any current so that's a good thing. But when I connect the Remote to B+ it shorts out (Amp draws the full 3A).
Here's a picture of the amp's board in current state:
Green arrow: Parts newly installed
Red arrow: Parts removed
What could be the problem? Is it because there are parts missing?
- IRF3205 (International Rectifier)
- IRF9640 (International Rectifier)
- IRF640 (STMicroelectronics)
Today I've got the new parts soldered in place (Yes, got the backsides of the FET's pre-soldered
) but not yet soldered to the MEHSA thermal management system.I wanted to see if the beast would power up.. So I hooked it up to my trusty Delta Elekronika Power Supply E 030-3 (30V 3A both adjustable) without the remote connected. The amp doesn't draw any current so that's a good thing. But when I connect the Remote to B+ it shorts out (Amp draws the full 3A).
Here's a picture of the amp's board in current state:
Green arrow: Parts newly installed
Red arrow: Parts removed
What could be the problem? Is it because there are parts missing?
Parts from Farnell arrived
Alright, thanks for explaining
.
Well, the parts from Farnell finally arrived.
The first thing I did was soldering new MMBTA56's and 06's. I also replaced all other SMD resistors and some other parts (see picture below).
After that I tried powering it up. When connected to B+ and GND the amp doesn't draw anything, so far so good.
But when I connect the remote to B+ it draws the full 3 Amps (just like before). On the bright side, the power LED shows sign of life
Here's a picture of the amplifier in current state:
Green arrow: Parts newly installed
Red arrow: Parts not installed
I measure 3.89V on the right and 1.50V on the left speaker output. When the power supply draws the full 3 Amps, the supplied voltage goes from 13V to 9V.
What could be the problem? Does it need more components installed to see if the power supply of the amp is functional? I want to make sure that it is and its safe to install the other parts.
Perry Babin said:
Alright, thanks for explaining
.Well, the parts from Farnell finally arrived.
The first thing I did was soldering new MMBTA56's and 06's. I also replaced all other SMD resistors and some other parts (see picture below).
After that I tried powering it up. When connected to B+ and GND the amp doesn't draw anything, so far so good.
But when I connect the remote to B+ it draws the full 3 Amps (just like before). On the bright side, the power LED shows sign of life
Here's a picture of the amplifier in current state:
Green arrow: Parts newly installed
Red arrow: Parts not installed
I measure 3.89V on the right and 1.50V on the left speaker output. When the power supply draws the full 3 Amps, the supplied voltage goes from 13V to 9V.
What could be the problem? Does it need more components installed to see if the power supply of the amp is functional? I want to make sure that it is and its safe to install the other parts.
An externally hosted image should be here but it was not working when we last tested it.
The one on top
The rectifiers are OK. There's something beyond the rectifiers that is causing it to draw current.
Measure the voltage across the large filter capacitors (no voltage applied to the amp). If it's near 0v, measure the resistance across the capacitors. You should read a low resistance initially and it will increase slowly. If you read 0 ohms and it doesn't increase, one capacitor may be shorted (rare but it happens).
Are you sure that there are no solder bridges anywhere on the board? Sometimes solder drops off of the soldering iron or is bridged between two adjacent solder pads.
Measure the voltage across the large filter capacitors (no voltage applied to the amp). If it's near 0v, measure the resistance across the capacitors. You should read a low resistance initially and it will increase slowly. If you read 0 ohms and it doesn't increase, one capacitor may be shorted (rare but it happens).
Are you sure that there are no solder bridges anywhere on the board? Sometimes solder drops off of the soldering iron or is bridged between two adjacent solder pads.
Allright, I measured the large capacitors and they hold about ~0.3V on each of them. When I set the multimeter to resistance, the resistance increases.
I don't find any solder bridges where I've been soldering.
// EDIT
Wait a sec. I found a, what seems to be a burnt lead below the High-level input connector. I haven't seen it before (maybe overlooked it).
Here's a picture of it:
It appears to be only underneath the High-level input connector. I measured it, and it isn't broken.
Maybe its got something to do with the current drawing issue?
I don't find any solder bridges where I've been soldering.
// EDIT
Wait a sec. I found a, what seems to be a burnt lead below the High-level input connector. I haven't seen it before (maybe overlooked it).
Here's a picture of it:
It appears to be only underneath the High-level input connector. I measured it, and it isn't broken.
Maybe its got something to do with the current drawing issue?
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