If I gave this to my seven year old, told her it has a bar of chocolate inside and that it will open if she gets the numbers right...I'd have her busy for a day.
The biggest issue is the bare copper traces for the switching. If they were plated this would be a great tool. Might be usable with DIY tin plating, but gold would be more reliable.
I've modded mine with 2 Watt resistors to go from 1 Ohm to 1 meg and put decent banana connectors on it. It's quite accurate. Instead of using a single resistor in the "5" position I've used 5 resistors in series. So I've used 9 resistors per switch since there's plenty of room inside.
@@EngineersFearYeah and it's much cheaper to buy a lot of same value resistors. I've just ordered 20 2W 1% resistors of each value and hand picked the ones closest to the stated value for best accuracy.
@@Hyxtryx I removed the SMD's and kept the leads of the new resistors pretty long and bent the end of the leads 90 degrees to make tiny "feet" on the leads. I soldered these flat to the board so the resistors are standing up. The resistors themselves are then about half on inch above the board. There's so much room in the case, you could even do this with larger ceramic resistors.
You can also remove the switch and resistors and then self-nickel plating the copper using the conventional DIY technique then replace the resistors with whatever wattage you want.
@@TheHuesSciTech Nickel plating is surprisingly simply to do. The only problem with this is you'd need to remove (or jumper) all the resistors to get the proper current flow, but if you were going to replace them anyway maybe not so bad. Or check with PCBWay etc to see what it would cost for a new board with hard gold plating, add thru hole while you're at it.
I already have a couple of lab-grade decade boxes, but for $12 I think I'll get it just for the box and the easy access, rugged contact, rotary switches for projects and experiments.
I'm a big fan of having test gear which is suitable for "close enough" measurements. A lot of sanity checks and basic testing is good with a 10 percent error, I just need to know that the thing turns on. So I use the crappy but good enough gear. I don't need it traceable to NIST, I just need it good enough. This seems perfect for that, and at 12 bucks, you can't beat it.
I've got a few of these at work and they've proved surprisingly useful in some of the more fiddly physics experiments. The best part is one it has a sticker on the side saying "Tested for electrical safety 03/1971". Fun winding up the students with that one who treat it like it's about to explode.
If you replace the 0.5 ohm resistors with 1 Meg ones, you can sacrifice precision in return for range. If you replace the resistors with higher power ones, be careful with the plastic case. It looks like it may have a low melting temperature. Maybe drill some vent holes?
I bought a simliar box on ebay from China 20 years ago. The box seems to be made of bakelite, it is heavy, which is explained by the heavy duty gold-plated rotary switches inside and resistors made from enameled wire wound on ceramic posts. It will stand a good deal of current, but the label has fallen off and I don't remember how much. It was dirt cheap, but apparently not cheap enough for China of today.
This is a nice design. I would use two resistors from the next decade in parallel to get the 5 though. You get away with half the resistor values in your BOM and only need 6 more resistors for twice the current handling capability. That's a pretty good compromise.
I have the 5 decade version, same experience, including the switch-bending part😂 I replaced the resistors for 1 watt resistors and the binding posts. It is indeed ridiculously cheap.
Mine just arrived today. Ordered it from an Ali seller called seablue as the one Dave linked to was out of stock. Mine doesn't suffer from the backwards top row issue. Internally it looks the same but I added some contact cleaner/lubricant to the bare copper to help prolong the life of it
My grandpa was a Test Engineer, and i have the underside of one of the knobs from his hand made resistor box! I'm not sure why he disassembled the box, but he took it all apart and all he could guess was that he was being a cheap skate and wanted to use the resistors to repair a clock or a radio haha. After he left his Engineering job, he was allowed to take essentially his whole lab's stock with him and he left me a massive supply of jelly bean parts from the 50's (mostly resistors, caps, diodes and a million fuses). My grandpa also had a little bundle of resistors soldered together that would provide different values based on where you clipped into it. From what i can gather, he would use it to load test circuits. It was basically a grid of resistors that looked like a waffle lol.
I’m fortunate, in the U.K. you can pick up old decade resistance boxes very cheap. They’re usually either ex military, or ex polytechnic/university lab stock.
It's not that uncommon, the Chinese that put stuff together often have no idea what they are doing, they are told to do something and they do that, if something does not fit, just finetune with a hammer, I have seen it with other Chinese things also.
Don't forget that they're probably assembling hundreds of those things per shift. So, it can be just a fatigue. The problem is that they have zero to nothing output QC.
An easy way to improve the contacts would be to pen-plate the PCB with gold just in the areas where the wipers make contact, you won't even need to dismantle it. If you already have some gold solution it will cost only a few cents as very little gold is needed. I have fixed some cheap multimeters in that way changing them from a not very good paperweight into actual multimeters that can measure voltage and stuff.
I bought a 5 Switch version about a year ago for about $A24.00 from Amazon because I couldn't believe it would work but was surprised. And first thing I did was replace the binding posts with decent ones. Works well, but I would expect the switches to eventually fail if you used it a constantly.
dang, that some low prices you got over there downunder.. Here in northen Europe (EU) also on choice, but 13.55US for the 5dial and 22.71 for 6dial, inc.. VAT.. I dont think its the actual prices your showing, it looks like its welcome deal prices that aint that relevant, as they are often cut with 4 to 7 bucks for new AliE-accounts.
Yep. it's discounted prices for new accounts and why it says "welcome deal" in red lettering 0:33 and where AliEx themself eat some of the cost.. its an attempt to show platform-growth on accounts to sh. holders, it ain't the seller that is selling to that price (pls have that in mind) also why you can't purchase fx 2 or one of each to those mentioned values, it's not the actual price the seller is selling them for.
AS you say it's worth it for the box and knobs alone. You could easily design a PCB to be made by JLCPCB or whoever with ENIG coating that would just drop in place
30 euro now, I saw these 6 months ago and I really liked the style and was expecting them to be good old wafer switches and big 1970's old stock sausage resistors.... no lol, I would have paid for old, but I aint paying that for SMD
@@EEVblog Been with you since you started in '09 😁 With the 'Mercan Dollar sinkin', your Ozzi bucks may be worth more soon! Love ya Dave! Maybe Sagan could edit your videos a bit , you know to conserve the bandwidth of the internet. Doesn't YT get to put in 3 adverts if its just over 10 min? Maybe a goal for short stuff like this.
A small gear-motor to retract 4 bolts when you have dialled in TWO sets of correct values within a certain time, Reduce the risk of someone trying to crack it.
This decade box is what engineering is all about. The chiense or whoever designed it actually had some thought into this and didn't wack resistors in series like most of them do. A very nice and clever solution involving your own switches, saving cost and manufacturing hassle. A good engineer might design something like IET decade box. A thinking engineer will design something like this.
What's the actual use of a decade resistor? I remember using them in a lab at the university but can't really come up with a use for it in my workshop.
If you want to enjoy electronics, then immediately buy a normal “Resistance Standard Box Resistor P33” made in the USSR (produced approximately 1960-1980). You can also buy a cooler P4831. You will immediately understand the difference in the quality of products produced by different socialist countries: USSR vs China
That switch contact is going to be knackered in no time at all... that's so stupid. Copper is soft AF and PCB copper is thin AF... so it's gone before you know it.
@@helmut3356 It's lab equipment intended for industrial application. Of course it was expensive--but it was accurate, dependable and lasted for decades. For comparison, look at some of the old (>50 years) resistance standards.
Such a silly device. If you instead go to your local university's surplus store you may find decade boxes made by reputable companies, for like $7 each on a good day. Those have wirewound resistors good for a Watt or two. And rotary switches with silver contacts. From reputable companies like Leeds and Northrup, Yokogawa, ESI, General Radio, even Heathkit.
@@Graeme_Lastname - heat pipes and/or water cooling for better over-clocking! 😃 That reminds me of my latest unfinished project that uses 4 x 0.2 ohm 100w resistors in Series/Parallel to pull 20A from a single lithium cell. The idea is to test 18650s in old tool packs. However I am needing a far larger heatsink and fans than I anticipated, even for quite short duration test runs 😃
Don't forget Zhang, this is going to Austria and you know what that means! Why they then corrected just the upper row of knobs is kung pao for thought.
Instead of taking complete switches, they just copied switch innards ... but clearly not to Bourns or equivalent standards. But really ... 1/10 ohm at 1/16 watt resistors?
My review of the 5 stage version of this:- ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-JpfmKM9i4B8.html Looks to have better plating on the PCB, but the box is crappy.
Nice thing. But... The placement of the switches is weird! More logical: Top Row: x10k x1k x100 Bottom row: x10 x1 x0,1 More like WE read. Is this a cultural thing?
Wow, I have never seen a design like this. Its extremely clever actually. This seems like a good arrangement for using precision resistors with to keep the cost down.
Not too shabby, but not even by a far shot close to my super heavy vintage decade box made by Ulrich (Germany, 40s/50s). Being that old and bought secondhand, it unfortunately had open contact on several 1k and 10k wirewound resistors, and I recently replaced them with 2W 1% MFRs... good luck finding wirewound resistors capable of handling a bunch of watts with tolerance and thermal coefficient tighter than Ethel Granger's laces. I really need to put that video together and publish it. Upside Down, eh? Did you get that thing from HNL? I like the wide traces - but they used SMD resistors, really? 0804 at most, the way they look... C'mon, for crying out loud! The reduced number of resistors with 5-1-1-1-1-1 arrangement is very clever and nice, I really like it. Always appreciating Spinal Tap references!
If you were serious about it... buy two cheaper 4x knob resistance boxes, series them together with your new replaced 5w resistors. You could have 0.1, 1, 10, 100, 1k, 10k, 100k & 1M ranges. Could also completely rebox with a 3d printed case to suit the 8x dials. The print would be super easy - seems to be very little stress on the box itself.
Wait fine pots? Why? You already have all those other pots for the lower values, don't you? Or did I misunderstand what you mean, and you're talking about more of a calibration thing or so?
@@LuLeBe Yes and yes. Fine pots to get the exact or close resistances. Also, I didn't start my decade box with 0.1, mine goes into the megaohms instead.
rather than dismantle to swap out the blinding posts, one could conjure up a "bracket" (3d print) that fitted over the factory posts and carried mutliple ( banana, screw, wago ) connection points
They accidentally sent it partially configured for the northern hemisphere and partially configured for Australia, all the knobs were supposed to be upside down.
Just received one from AliExpress. Opened it up to check the quality of the resistors, figuring it was using through hole resistors, so I could upgrade them as possible with precision resistors. Was disappointed to find tiny surface mount resistors, as well as finding out the binding posts weren't banana jacks. I've got plenty of banana jacks I could install. One other disappointment, once I discovered the internal circuitry is confusion over why they used the depth of case they chose, as they could make the case 1" deep, and still have plenty of free space inside.
Actually might like to take the 5 position box and upgrade it to a kΩ resistance box. I do a lot of work with vacuum tube amplifiers and that would make this particularly useful.
