[LAU] Multiple M-Audio Delta 1010s

[Nigel Henry]

On Wednesday 13 February 2008 19:18, Joe Hartley wrote:
> On Wed, 13 Feb 2008 10:03:25 -0800
>
> Kevin Cosgrove <kevinc at cosgroves.us> wrote:
> > > When I took
> > > apart the breakout box, I saw a quadrupling circuit on the left hand
> > > side of the bottom board (toward the front of the case, underneath the
> > > small board that's on top) that had a couple of oozing caps.
> >
> > That happens more often in electronic equipment than the public generally
> > knows. Remember the laptop battery recall from months ago?  I've seen
> > quite a few recalls for capacitor problems over the last 3 decades of
> > working in the electronics industry, first as a part-time soldering
> > and assembly person, and now as an analog IC designer.
>
> There was a brand of motherboards that famously had capacitor issues
> a couple of years ago as well.  I'm glad that having worked throughout
> my high school years as an electronic assembler, I know which end of the
> soldering iron to hold.  I've been able to revive a lot of "dead" gear
> over the years!
>
> > > The 35v caps are recommended, it was the underspec'ing of the caps that
> > > was causing the problems in the first place.
> >
> > Did you measure the voltage somehow, or did you get documentation
> > from M-Audio somehow to figure out the new recommended voltage rating?
>
> I remembered a discussion on the Planet CCRMA list about the caps when I
> had my problem, and there was a great post from someone who knew more
> theory than I did about why 25v was too small for the circuit, and that 35v
> was the way to go.
>
> > Excellent write-up.  Thanks a bunch!
>
> No problem; we all learn something when we post our successes here.

IIRC the caps problem on some mobo's was due to someone having stolen the 
formula for the electrolyte from someone or other, but the formula was not 
complete, and the caps that were manufactured were obviously faulty. They 
ended up being used in various mobo's, and consequently failed.

This takes me back to the 60's. We had an Alba TV, a console set. like a piece 
of furniture, and our first TV. I seem to remember, and being very young at 
the time, the first program I saw was horse racing. Not too interesting for a 
youngster, to say the least. Anyway this TV worked ok at first, and there was 
only one TV channel available in Jersey CI at the time, which was BBC1. Then 
came Channel Television, a local commercial tv station, ads , and all. Now 
you had to change channels, and the Alba had a turret tuner, a rotary switch 
that had the coils tuned to the various tv frequencies slotted in around it. 
Switching tv channels using physical contacts didn't seem to be a good idea, 
and there were always problems trying to get some sort of reception, and 
having to waggle the turret tuner back and forth to get to see TV became 
unbearable.

Back to the caps thing, we decided (that is my dad) to buy a new TV, so down 
we went to a local store (Fortuna), and Brian the owner explained to us the 
virtues of the new polyester caps that Sobell used in their TV's, and if the 
TV went down the tubes we could take it back and wrap it around his neck.

Well we bought the Sobell TV, and it worked ok. Only black and white, but 
that's all that there was at the time, and we didn't have to take it back and 
wrap it around his neck because of failed caps.

Sorry for this being totally OT, but just some stuff from my past.

Nigel.