The 7805 in one of my regulated supplies has failed. I was just going to order one of the cheapest ones off of eBay. Most likely, this would be a Chinese clone. Might this be a problem down the road, or should I order a better brand and what are your suggestions? Thanks.
a) A princely $0.65 from Digi-Key. b) Might this be a problem down the road? Three possible answers in the most likely-to-occur order: - Yes, but not right away. So you will be making the same repair multiple times. - Yes, but in such a way as to cause additional cascade failures - so you are putting the device at-risk. - No.
In fewer words: Don't be stupid.
Peter Wieck Melrose Park, PA
And, if you download the Digi-Key paper order form, fill it out by hand, and mail it to Digi-Key with a check for the full cost of the component, they'll pay the shipping charge. Yes, they're still offering this service (as of about three months ago) although they don't go out of their way to publicize it.
"Cheap is often very expensive."
Wow, I never knew this! Do I go ahead and pay shipping for which they'll refund later, or just pay for the device?
Are there no electronic supply stores in your city/state? I'd try them first. I do use DK and Mouser and Element 13 of course, but for single and small orders I go to my local electronics supplier. In my case (Vancouver/Burnaby, BC, Canada) it is
John :-#)#
RP Electronics? I wonder if they're the successor to the old Rendell-Paret shop on 4th and Arbutus in Vancouver. That was a real old-timey ham shop--stuff stacked to the rafters, and old Hedley Rendell chain-smoking behind the counter.
I used to buy stuff there when I was a kid. Freaking ex-pen-sive compared to now.
Cheers
Phil Hobbs
John Robertson wrote: ================== >>
** Element 13 ?? Aluminium ?
Just pay for the device, and include your local sales tax if any. Don't pay for shipping.
To quote from their current Terms and Conditions document:
"6. Shipping Charges.
"Products Shipping from Digi-Key's Warehouse. Except as otherwise provided on the Site, (1) shipping or freight charges and insurance will be paid by the customer*, (2) all sales are made FOB Digi-Key's warehouse in Thief River Falls, MN, USA, and (3) shipping or freight charges from Digi-Key's warehouse in Thief River Falls, MN, USA are prepaid and added to the invoice, billed collect or billed to a third party.
"* When a check or money order accompanies your order, Digi-Key pays all shipping and insurance (our choice for method of shipping) to all addresses in the U.S. and Canada."
"Our choice of method for shipping" has always worked out to be the same as their basic-price ground shipment, in my experience. The two or three times I've used this method, I've not had a package delayed unduely through having been sent on a slow horse via Mongolia, or anything like that.
As far as I know there's no way to take advantage of this if you're using their online ordering system, as you can't have a check or money order "accompany your order". It might be possible to start the process of order entry and then print out your "cart" and mail in the printout, but I'm not sure this would give them all of information needed to process the order. I just download the PDF of their paper order form, print it, fill it out by hand, and mail it with a check. If I write my Digi-Key customer number in the right place, I even get an email from them when they process the order.
This manual process is a nice thing if you want to order just one or ten small items (where the parts cost is less than their normal shipping charge) and you don't mind the order taking an extra week or so.
I take it you grew up in Vancouver, BC. I started out in Toronto. Great surplus stores in Toronto back in the 60s!
You knew Rendell Paret back in those days? I used to love hanging out in that old shop too, along with the other electronics surplus store (run by Peter - AIR) at Main and 17th or there about. Peter had very nice monstrous TEK surplus oscilloscopes that I couldn't afford back in the late 70s and early 80s...And of course Main Electronics around Main and
29th - but they are all gone now.RP sold out to Andrew back in the 90s I believe and he kept the name ever since. No longer surplus, which is a shame, but that market kinda dried up. And the High schools in Vancouver no longer have electronics as a course - although they do have robotics and other tech classes.
John :-#)#
You could dig out an old Digi-Key catalogue and use the order page from that - I assume - to get your free shipping. Photocopies would probably be fine.
John :-#)#
Sure. Or, web-search the phase "digi-key order form" and you'll quickly find the PDF version.
Yup. Born at VGH, UBC undergrad, then went to grad school in California and moved to NY to work at IBM Research.
Never went to either of those ones. I lived just up the hill from Hedley's place.
Interesting, thanks!
Cheers
Phil Hobbs
That was too easy:
Thanks.
That seems like bad business: processing a paper order is going to be much more expensive than an automated online order. And it encourages itsy-bitsy orders which are certainly money losers. I suppose that it's basically a customer-relations thing & not for-profit.
I like DigiKey and try not to abuse their no-minimum with trivial orders. And when I do, I'm happy to pay for shipping.
Is there a dumpster / bin that you know of with electronics waste in it that you can take items out of (legally or otherwise)? It is quite likely that you can find a 7805 in a device in the bin quicker than ordering one, and the parts are much more likely to be good than random e-bay purchases.
Look for something that runs off a heavy wall-wart, like a really old modem from the mid-90s, that likely has a 7805 in it, but a lot of other stuff would too - e.g. CRT monitors or fax machines.
Really? Dumpster Diving for a $0.65 (+ tax) part? And a used one at that?
Peter Wieck Melrose Park, PA
Element 14, the distributor formerly known as Newark.
I ordered from Digikey via the snail mail system to avoid shipping. Ordered some other goodies too. Where I live, I think I'd be locked up if I tried dumpster diving. They won't pull you over for driving like a jacka** through town, but if they see you taking stuff out of the dumpster, look out!
Fair point, but you might find a Faberge egg while you're snorkeling through the offscourings.
I'll happily take a genuine Motorola, National or TI part out of a dumpster and available today, over whatever you might receive in a month's time from a random ebay seller in China (which was the OP's original suggestion). Heck on ebay you might end up with a used part anyway, albeit with carefully straightened pins and a freshly lasered part number on it, perhaps related to its internal circuitry, perhaps not.
If you're building things for yourself, or even prototypes at work where time is of the essence and you don't have the new part you need, there is nothing wrong with testing and reusing the occasional part from scrapped high-quality equipment, (unless you're building pacemakers or satellites, or for production use where you need traceability etc.). Some newly made TO-220s have more bendy thinner tabs to save copper, so I prefer the old ones with the thick tab anyway - less chance of cracking the die when you do up the screw.
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