Hello people

[Goldie]

Better picture posted (old removed)

[baguette]

This is best, unfortunately component side is not so good. I'll try another one

that would be good, because bottom side without component side does not give a lot

[Goldie]

Better picture posted (old deleted)

[Goldie]

alesisd4-1.jpg

Ok i managed to make better one. Anyway nice feature beeing able to upload pictures directly to server.

[Goldie]

alesisd4-2.jpg

And here is new bottom one.

[baguette]

Ok, so let's start with the power supply - the new pictures are really better but unfortunately missing the important part
I hope the images work...

The power regulation part is in the lower left corner of the component side (old pics).
You could check if the capacitors leak or look somewhat stoned - however i doubt that because in this case the sound would most propably be with a buzz like a ground loop, and not 10 min delayed.
The caps are these:



The next thing to check are the voltage regulators:


they should have a number like 7805 , 05 being the output voltage.
The pinout is usually input - ground - output, from left to right (seen from the front, the pins downwards).

1. Start with the upper one: check immediatly after plugging the voltage between in vs ground and out vs ground.
BE CAREFUL not to shortcut the pins, otherwise you are almost sure to burn a fuse inside the power supply unit! (or damage it otherwise)
Consider not to touch their pins directly but just follow the copper leads on the board to more distant areas.

2.repeat the mesurements once the board has auto-circuit-bent (ACB)


Now there are 3 cases:

1-input voltage is about the 11 volt you measured at the supply unit, output voltage is as expected (^= conforming the part number) BOTH before and after ACB
-> no problem at power supply

2-input voltage is always the 11 volt, output voltage drops after ACB
-> change the voltage regulator

3-input voltage is the 11 volt before ACB but drops after ACB, output voltage drops too
-> check the diodes that are before the regulators!



the diodes are these:



you can check the voltage between the both ends of the diodes (after ACB). It should be less than 1V. However i doubt that they would take more than an hour to "recreate", and it would be a strange diode defect however.
If the diodes are ok and you were in case 3 above, it means that the supply unit has a problem - its voltage goes down after ACB.
Inside the unit there will be 4 diodes (or one component that comprises them). We will check it if this is the case.

[Goldie]

Thanks man.

I see what is missing, and i am gonna scan it now. Yes you heard me , scan . Real DIY spirit. I see you are concentrated around power . I dont know very much about electronics, just thought it would be easy to pinpoint because of nature of failure. As i said before same thing happened to Alesis HR16, maybe Alesis decease.

[Goldie]

alesisd4-3.jpg

Missing part.

[Goldie]

7805 (Positive Output Voltage Regulator) = Input, ground, output
7905 (Negative Output Voltage Regulator) = Ground, input, output

I dont get any reading using pin shematic on 7905, so i use same as 7805

Power on :
7805 - 24,5v - 10,3v
7905 - 28,8v - 17,6v

I waited 4 hours for crash, and it didnt . I'll try again tommorow.

[baguette]

I dont get any reading using pin shematic on 7905, so i use same as 7805

what do you mean?

Power on :
7805 - 24,5v - 10,3v
7905 - 28,8v - 17,6v

where did you measure these?
can you measure the power supply unit voltage in AC mode of your mulitmeter?

I waited 4 hours for crash, and it didnt . I'll try again tommorow.

propably it does not overheat anymore because the heat dissipates better without the case.