As I upgraded my tools for SMD work, I will need an assortment of shunt resistors, Schottky and Zeners, some capacitors and whatever else to mod some drivers. Perhaps some members will guide me here as digging in Ali has taken much time without much results…
My background is mechanical so electronically I’m a muggle. I can rationalize and infer what’s going on, but the inner workings are above my abilities to design drivers or attempt to re-code MCUs.
Firstly - looking for some Shunts, All I found was this. The values are what I would probably use, but the size (2512) is not. Any source for 1206 or smaller packages?
My first attempts are not without failures. I dropped and lost a component from this Convoy 6A SST-40 driver. Thinking it was a polarity protection diode (Schottky?), I bridged the pads and didn’t have any output thereafter.
Picture from Convoy Store
Another of my failures with an S9 driver. The shunt was not the 33 mOhm but a 5 mOhm. Bridging another .005 thinking to uptick the 2.4 Amp output caused a constant dimly lit LED. Perhaps an overdriven eSwitch capacitor that trickles some current? And where is this cap?
Again, picture from Convoy Store.
So any links to an assortment of parts, or to some insights on the failures would be much appreciated.
By the way, I ordered new drivers from Simon. Digging in my boxes of miscellaneous boards, not much in SMD components that can be salvaged.
If you need something very specific, its usually better to order from Digikey, Arrow, Mouser, Newark, Cutter so you get exactly what you need.
Order several different values or add in some leds to make the shipping more justified.
You can find 1206 shunt resistors on Ali but they dont make the search easy. https://www.aliexpress.com/item/4000444304539.html?
Sometimes hunting for the specific value gets you a few hits. https://www.aliexpress.com/item/4000051999011.html?
Thanks, moderator007.
Your first link has reference to the C & G Semiconductor store that offers assorted kits.
Can’t be too specific; not inclined to purchase a few components on the standard electronic stores - the shipping is a deal-breaker. And buying 100 pieces per item on AE plus the transit time, that’s a ‘no-go’ also.
As I had OP, just “muggling” and would like to have some parts at hand to change a few board components.
My expectation of these kits they were more common. But as not many have responded, I take it I’ll have to do some digging in Ali. Their search isn’t good at all; very time-consuming.
Just as in mechanical design with materials, and bolt strength and hardness factors, in the electrical world you have to consider design margins such as derating of power and voltage. This is likely why they went with the larger 2512 format (3W rating vs .25W).
For example there are differences in thin & thick film, ceramic body, power, wire-wound, etc.
So you really have to determine the design parameters you require. Pot luck with generic grab bag parts likely won’t cut it.
digikey or mouser .
both have cheap shipping options.
many of the parts are so cheap that you save by buying at the 100 up or greater level.
some its cheaper to get 100 than 50.
As I had said in my opening post, I’m looking for component kits of various values for SMD mods as shunt resistors, Schottckys, zeners and others.
This to have at hand some basic parts. Wouldn’t want to take apart a light, consider the shunt resistor to change and then wait for a specific part (and perhaps add some ball-park values to the order). The wattage of the shunt is not a concern - doubling (bridging) takes care of that, and I’m reducing the value. Just that a 2512 footprint may not fit on the driver.
As for other things, I lost an SS24. Wouldn’t it be grand if I just had a spare? As is, the driver is inoperational.
Piece purchases are not an option. 10+ days transit, shipping of $8 (Digi-Key) & more in other stores. Perhaps in the states it’s faster and cheaper. But I don’t need 100 pieces of a fixed value. I wouldn’t know or could foresee future needs.
That is why I asked if some of the members could draw a list of re-occurring parts for the basic mods.
But, eventually, I did find these various kits on Parity and C & G. They’re not random values but specific series of values (E12, E24)* and in 10 or 25 pieces* of each. Cost is rather low: from ~3 to ~13 $ w/shipping.
Just the digging in AE is very time-consuming.
These are ball-park numbers. The zeners are 27 values, the Schottky are 19 and the caps at 50.
Edit (21/01/23 14:30);
After much work, purchased some 320 different values of resistors, caps, and diodes ~52 CAD + $10 for a blank book w/20 pages.
good.
now for the inevitable its not in the dammed kit moment
i get them often.and you should see my parts stock.
built by ordering what i need at the time but at the qty break point.
its worth it to me as i often get emergency repairs to industrial stuff.
