EMU 0404 usb 2.0 with a power on problem
I bought this for parts from ebay.
Like seller told me, it damaged by opposite power polarity or by power polarity bridge, probably.
After power on, nothing is happening!
Because we have not any circuit diagram, I am looking with the continuity of multimeter the paths after power switch.
It is a searching in blind, sure! Maybe the best solution is to find the appropriate flex connector for working with the both parts open, not closed like now.
After that, I found some electronics to have a relation with the power paths. At the attachment photo I have mark some of these.
I have changed 2 of these (by yellow circles) and now lights on the green led (power on led) above headphone level, but no any other led.
1) Any suggestions?
2) Can someone find to me the appropriate code (farnell, mouser) for extra flex connector? I want to work, with both sides open.
With marvelous instructions of diyAudio wiki and some appropriate conductors (finally splits my emu), my emu has repaired 90% almost.
I must changed three power converters.
But, I have problem with phantom power, still. 0V!
As I saw to the wiki, the part U10 (PHOI) has the responsibility for the 47V (probably).
I measured the round area of U10 to mine emu and an other well function emu.
At the photo attachment, with yellow notes are the identical voltages btw two emu's. The red ones are differences and in brackets are mine values.
I thought the problem was to U10. I found a PHKI (same but with a less current) but it is nothing changed, unfortunately!
Any suggest, please!
For some reason the attachment photo, seems to appearing to my computer but not to others...
Here it again!
It looks like you don't have a High (3.3V) on the Enable (pin 4) of U10. Is the top board connected and does the 48V LED come on when you press the switch?
The 48V should appear between pins 2 or 3 to gnd (pin 1) of a XLR connector, not on a TRS (6.3mm).
Yes, the top was connected with a long 20cm conductors (I had split the emu).
OK, I found the problem. The pin4 of U10 had a cold solder, some Chip-Quik flux and now is perfect.
PHIKI now gives almost 41V (has 1.1V the pin3, FB vs 1.23 of PHOI).
sidiy, thanks for the interesting.
Andrea, I have note to the two photos the parts has changed with yellow circles. The last one is U10, for the other parts, must to find in my files a big photo to see what type of marks are.
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