Re: Repairing Alesis M1 Active mk2 Monitor Speakers

Thanking you again, sir.

It was actually much easier than that (I knew that this was a good, working board). I had actually unsoldered one side of R15 and forgot!

I will have a look at those links you posted, I knew about Ohm's law but had clearly not used my brain, so will read up on that again.

Many thsnks, sir!

Re: Repairing Alesis M1 Active mk2 Monitor Speakers

Ok, I have 2 boards, side by side.

The other, working one read 15k across R10.

Does that meant there is something wrong in that circuit?

Re: Repairing Alesis M1 Active mk2 Monitor Speakers

Errm, maybe not the last question. So R10 reads just under 1k in circuit with R15 in place (on the bad board).

Once I take R15 out, everything reads fine. I have tried a couple of different resistors in that location, all causing the same result???

Logic tells me it must be R15 but somehow it must be something else in that part of the circuit?
Unless it is because all the resistors I tried are wirewound. That's what I ordered from Farnell (and I had lying around) and until I get something else...

Re: Repairing Alesis M1 Active mk2 Monitor Speakers

Hi, one last question as otherwise we are good to go, Khron.

I seem to have read a post by you somewehere here not t use wirewound resitors for R15, due to induction?

Induction remains a dark art to me, can you confirm and/or explain why it is nescessary to use a non-wirewound resistor in that place?

Many thanks

Re: Repairing Alesis M1 Active mk2 Monitor Speakers

And I kind of answered my own question re the inductors myself, but it is always good to get some moral support...

Re: Repairing Alesis M1 Active mk2 Monitor Speakers

Ok that great to know. I mean the voltage divider/current divider knowledge.

Measurements are with U1 removed from the circuit. So I'll just wait until the bits arrive from Farnell and see what it all reads after refilling the board with fresh bits.

Thank you muchly, Khron, and if you have the time and patience maybe you could try and have a guess why those bits mentioned went kaput?

It would help me understand circuits better (which is the thing I struggle with).

Many...

Re: Repairing Alesis M1 Active mk2 Monitor Speakers

Morning all. Especially Khron…

I too have acquired a pair of these speakers, one as faulty.
A little bit of background: I am a keen hobbyist, have been repairing- and recapping HiFi for years, am good at soldering, have a good Fluke meter with capacitance- and diode tests and know how to use it.
So far on the broken speaker I have found the following:
The obligatory C8 is….actually ok (!!!)
U1 s/c
Q1, Q2 s/c
R11 is toast, o/c
R15 o/c
Q3,4,7 s/c
D14,...