OT: Electronic components retailer in L.A.

Coursedesign wrote on 7/13/2009, 8:37 PM
My Alesis M1 MkII monitors died when a substation transformer blew up nearby (20,000 customers were without power for a while).

Their untimely death was not prevented by a competent surge protector, because these monitors appear to have had an uncorrected design flaw for at least the last seven years.

After some online searching, I found that factory repair costs about as much as a new pair.

"Fortunately" so many other people have experienced this problem, that usually happens a few weeks after the warranty expires, that detailed DIY repair instructions are available online.

The problem is in one or two electrolytic capacitors and a single smoking 2W power resistor that is mounted right next to one of the wet caps and apparently is set to dry it out shortly after expiration of the warranty,

The key cap is a 330uF/50V@105C, which is a bit rare. They're easy to buy in 500-paks, but I only need one.

Does anyone know of any place in Greater Los Angeles that might sell components like this?

Yellow pages and Superpages were no help, you'd be amazed at what's listed under "electronic components."

I have three Fry's stores within driving distance, but they're each about a one hour drive in each direction on a good day, so I wouldn't mind finding something closer.

Any L.A.-based tinkerers here who could recommend a good source?

Comments

DavidMcKnight wrote on 7/13/2009, 8:42 PM
Is Van Nuys near you? (I'm in Texas, what do I know...)

All Electronics Corporation
14928 Oxnard Street
Van Nuys, CA 91411


Also try Mouser, here:
http://www.mouser.com/contact-california/


Coursedesign wrote on 7/13/2009, 9:20 PM
David,

Van Nuys is less than 15 miles away, albeit through a very crowded mountain pass with an immense traffic load.

In the meantime, Mouser has a great great web site with an excellent component search facility and even photos. And they sell onesie-twosies!

Many thanks for these two!!!

wm_b wrote on 7/13/2009, 10:34 PM
Electronic City in Burbank also has a reasonable selection of components. You might look them up. They are off Hollywood Way not too far from Fry's in Burbank.

It's likely that the cap is in the power supply portion of the unit and finding a cap of similar value will likely work just fine without changing the sound.

I might also suggest you fabricate a stand-off for the resistors if they they are over-heating the caps.

Mouser or Digi-Key is also a good source but sort of a pain to actually pick a component and place an order.

You will feel like a king once you get them repaired.

Good luck.
Coursedesign wrote on 7/14/2009, 7:14 AM
Thanks, appreciated!

The value of C8 just needs to be over 220 uF to work, otherwise there isn't enough power for the low end (and with a blown C8, the power supply oscillates...).

I'll definitely separate it from the power resistor next to it, exactly how will depend on the caps I find.

Mouser's component selector looks identical to Digi-Key's at first, but it works much better and faster for this kind of common search.

King again? :O) At least I feel like a subordinated junior princeling now with my old Roland monitors, they're at least headscratchingly good for their size.

Not exactly competition for the M1s though. I can't master with them by ear.

I still don't understand how Alesis has gotten away with this summer intern-designed self-destruct feature for seven years (online owner complaints about this exact problem have been posted from 2002 through 2009).

Ah well, one lives and learns.
johnmeyer wrote on 7/14/2009, 7:23 AM
If these are in the power supply section, you need to make sure that you not only match or exceed the uF and voltage spec, and also meet or exceed the temperature spec, but these also probably need to be low ESR caps.
rich__r wrote on 7/14/2009, 8:23 AM
It's not local. But I've had good luck with Parts Express (www.parts-express.com).

They certainly have your capacitor:
http://www.parts-express.com/pe/showdetl.cfm?Partnumber=020-1668

rich
johnmeyer wrote on 7/14/2009, 9:11 AM
This is the part I would order:

Radial Aluminum Electrolytic Capacitors 330uF 50Volt 105C

Manufacturer: Cornell Dubilier
Product Category: Aluminum Electrolytic Capacitors
RoHS: Details
Capacitance: 330 uF
Voltage Rating: 50 Volts
Termination Style: Radial
Product: Low ESR Electrolytic Capacitors
Packaging: Bulk

R0cky wrote on 7/14/2009, 9:47 AM
Any low ESR cap at least 330 uf and at least 50V rating will work. If it will physically fit. It does not have to match exactly, but only be up to the minimum specs.
Coursedesign wrote on 7/14/2009, 10:34 AM
John,

The Cornell cap looks good, but the min. order is qty. 1580, special order only.

Its Xicon brother looks fine though, no?

What's the difference between a regular capacitor and a "High Temp" capacitor with the same temp rating?


Parts Express looks like another great resource. It's been a long time since I bought electronic components at retail, I think a lot of the stores disappeared when radio amateurs and CB junkies got more busy online :O).
apit34356 wrote on 7/14/2009, 10:55 AM
Coursedesign, These types of capacitors can be rated up to 260°C for a variety of applications that include, but are not limited to, down-hole oil and gas exploration and drilling, jet engine ignition systems, etc. Basically, temperature change does not effect its "charging" or "holding" of the charge at high temperatures. But its really comes down to materials that make them up. The materials do not degrade as quick when expose to high temperates, like, plastic cover cracking, expansion of liquids and breaking of seals........etc....
Coursedesign wrote on 7/14/2009, 11:11 AM
Yes, I'm just baffled that the "High Temp" capacitors would have the same temperature rating.

Is this because the capacitor temp rating standard is like the federal tire treadwear standard in that it is only moderately realistic?
apit34356 wrote on 7/14/2009, 11:27 AM
"Is this because the capacitor temp rating standard is like the federal tire treadwear standard in that it is only moderately realistic?" Yes, but the difference is more that it, non-rated, can survive up to before failure for "short time" with "degraded" performance.... while the high temperature rated assures similar performance over its temperature range without degradation.

I assume that you are familiar with function of capacitors in low/high pass filters, timing circuits, feq grounding, motor capacitors...etc.... so, for those who are not, any change in the capacitors "response" function can have a "BAD" effect on the circuit. ;-)
johnmeyer wrote on 7/14/2009, 11:35 AM
The Cornell cap looks good, but the min. order is qty. 1580, special order only.Oops!

Try this one, from Digikey:

CAPACITOR 330UF 100V ELECT TSHA

Check the dimensions to make sure it will fit, but it looks like it is in stock and available in quantity 1. Using higher voltage is generally a good idea when replacing power supply caps that have failed. In fact, the two "rules" I always use when replacing switching power supply caps are: 1. Low ESR; 2. Slightly higher voltage rating.

blink3times wrote on 7/14/2009, 12:20 PM
I've used digkey for years.... GOOD outfit!

We only have one electronics store left in Winnipeg (Active components) who only stocks pretty 'main street' stuff so i've been doing mail-order from Digikey. In the 15 years I've been ordering from them... not once have they screwed up.

Ask for their catalog in your shipment... it's pretty extensive.
Coursedesign wrote on 7/17/2009, 11:40 AM
Thanks for the recos everyone, appreciated!

220uF was the absolute minimum, but more should be OK.

This capacitor looks like it should have at least a little bit of spare capacity, what do you think?

:O)