EEVblog 1586 - Stranger Things Decade Resistor Box + Repair

[@treelineresearch3387]

It's not just a passable resistance box, it's also a fun puzzle to solve!

[@andreasu.3546]

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.

[@bigclivedotcom]

That's a pretty clever construction, and as you say, a wipe of grease and upgraded resistors could improve it.

[@tomkatt2321]

BAH - that's just putting lipstick on the pig.

[@Ni5ei]

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.

[@EngineersFear]

Nice, I also noticed 5 resistors don't exist but rather 4.99 so you improved accuracy as well within the tolerances at least

[@Ni5ei]

​@@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]

@@Ni5ei Did you drill holes through the contacts, or just solder them on top with a blob of solder?

[@Ni5ei]

@@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.

[@Hyxtryx]

@@Ni5eiThanks. That sounds like the way to go.

[@alistairmackintosh9412]

Actually a rather well engineered design. Most of the problems seem to be in the actual construction.

[@PhoenixRevealed]

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.

[@kentswan3230]

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.

[@RK-kn1ud]

Depending on your usage, you could probably even just slather it with Dielectric Grease.

[@TheHuesSciTech]

Seems like less effort to just order a identical, properly plated board than DIY plating, but maybe that's just me!

[@j.f.christ8421]

@@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.

[@kentswan3230]

@@TheHuesSciTech You have a good point. Hummm...

[@johnwest7993]

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.

[@phillyphakename1255]

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.

[@drunkenhobo8020]

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.

[@AndreasDelleske]

Oh I'd enjoy to amp that up!

[@markwebcraft]

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.

[@Zardox-The-Heretic-Slayer]

I used the box and made my own PCB (just same layout with through-hole options) and used gold plating on the boards

[@andymouse]

Great Idea!!

[@mrb5217]

Would you mind sharing the gerber files?

[@ionstorm66]

That's what I was thinking. Box is great, and the ball detent/PCB wipe prevents the switch wiggle issues

[@Zardox-The-Heretic-Slayer]

@@mrb5217 ordinarily I would love to but thanks to EAGLE being a cunt, they got corrupted

[@bzcup]

Just scan the existing PCB and then you can easily draw your project and customize it as you want.

[@Frank_K4FMH]

I have this exact same unit. My values tracked ok. But the binding posts instead of banana plugs really “trigger” me! Thanks for the teardown!

[@digitalradiohacker]

This looks to be a simple region problem. Half of the knobs were correctly supplied to Australia and the other half were for the UK market.

[@dagobertkrikelin1587]

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.

[@trickyrat483]

I'm sure Marco Reps would love to improve its precision and temperature stability. Send it to him. :)

[@tiagoferreira086]

I'm pretty sure if he saw something like that, he would had nightmares for a week lol

[@lmamakos]

I'm sure all the PPMs would fall out along the way.

[@helgew9008]

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?

[@WhEE443]

Wow, what a clever design! I would have never thought of the 5 resistor design like that. Good engineering.

[@Foetusmachine]

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.

[@Murgoh]

Thanks for taking the time to sort it out. I have the 4 decade version of this and when it arrived I found it was useless and just put it in the closet in case I'd find some use for the box at some time but now that I know what's wrong with it I'll maybe be able to fix it and make it actually usable. Mine even has grease on the contacts.

[@TheRetroChannel]

Bloody bargain! Even if they got half the switches wrong, you're getting in there anyway to add some protection to that bare copper

[@Gunbudder]

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.

[@AndyWilliams8]

I've been using my Heathkit IN-11 six gang box for at least 40 years. 1 ohm to 999,999 ohms. They're very accurate, and they're dirt cheap on Ebay.

[@internetvideoenjoyer]

A few years ago I bought one of these but I suspect it was an earlier version. Mine did have grease inside but the switch operation was so unreliable that I returned it. Good to see the design has apparently improved.

[@ThePetaaaaa]

I got rid of mine, too. Just wasn’t worth the hassle with contact issues. If I remember correctly mine however was a 5 decade one.

[@TomLeg]

I guess the thing is to calculate how much current the PCB traces can handle, and upgrade the resistors to that level

[@TheRetroChannel]

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

[@nonsuch]

I made one similar to that one but, I also added "fine pots" in addition to the decade so I can really dial in whatever I'm doing.

[@LuLeBe]

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?

[@nonsuch]

​@@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.

[@SherlockOhms119]

Fun to watch video. These type videos make me happy and increases my Ohms Resistance to certain drains.

[@karllangeveld6449]

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.

[@herbybey7698]

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.

[@listerdave1240]

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.

[@carlubambi5541]

Great device for the money .I remember in electronics lab in high school we had a very expensive unit that used independent switches and a circuit board for the resistors and proper binding posts .Great diagnosing device

[@nathantron]

"everyone should have one." 1 Minutes later. "This is shit." lol. I love you Dave.

[@edgar9651]

I just received my order. I ordered two of them with the 6 dials. They work and the labels are correct.

[@HPD1171]

you could certainly make a new PCB with ENIG and big through holes for larger resistors. that would be a nice simple project.

[@KeritechElectronics]

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!

[@MoseyingFan]

Managed to rescue a bunch of decade resistors and capacitors (plus misc school lab equipment) from the e-waste bin at the city dump.

[@thomasmroz]

Nice video as always. I'm just finishing up a small side project for a USB controlled programmable decade box using an Arduino, a lot of 1% 5W resistors and relays.

[@dynorat12]

i bought one a few years ago works like a treat

[@gjebertsystem2388]

Well, you get what you pay for. I built my 6-decade box with 100-watt power resistors, and instead of using switches I opted for banana jacks. It probably cost me 100 USD to make the beast, but it's built like a tank.

[@rustandmagic]

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.

[@MSP_TechLab]

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.

[@gleggett3817]

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

[@Zetex2000]

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.

[@garypoplin4599]

14:56 - It’ll last longer if you keep your screwdriver out from under the knobs! Nice review.

[@gamesmithoz]

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.

[@ekenpad8482]

Anyone design a 3D print yet to reduce the massive wasteful base if you don't intend to mod it? Or a whole new shell that you can move the PCB and knobs over to fully? Also note that those prices Dave showed are the "New user after 1 time use coupon" prices since he was not logged in. The real price of the 5 knob version is right around $10-$12 USD usually for existing users.

[@EEVblog]

Ah, didn't notice that, thanks.

[@kevincozens6837]

A clever design except for the wattage limitation. I looked up the information for an IET decade resistance box. You have to request a quote for one. They won't tell you how much up front. As Dave has said, "If you have to ask the price, ...".

[@ravenbarsrepairs5594]

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.

[@Jonathan_Doe_]

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.

[@docvolt5214]

I got one, I use it for offset finding, replaced all resistors with 0.1% ones and leaded solder

[@shazam6274]

Great 4 minute teardown, diagnosis and repair! What? It's over 15 minutes? Well, I guess Dave gets paid in Ozzy Bucks and by the minute.

[@EEVblog]

You must be new here, welcome.

[@shazam6274]

@@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.

[@brianclimbs1509]

I really like the cleverness of this design. It does however make me wonder what it would be like to live in a world where all that effort went into making products of higher quality and durability instead of saving the cost of 5 SMD resistors...

[@xxportalxx.]

Eh, I work in an industry where cost is no object, however the result is often just as chintzy, but 100 to 1000x the price you'd expect. Quality doesn't really track linearly with price unfortunately, it basically just let's them cut more corners while arriving at the same result, instead of cleverly designing the switches in like that they'd use equivalent 300$ Japanese modules. At least that's been my experience in my field.

[@brianclimbs1509]

Newer products are cutting corners more and more, but when it comes to test equipment quality matters. Are you saying you can't tell the difference between a Tektronix and an Owon oscilloscope, or the ripple and protection circuits on a quality linear power supply vs a cheap switching supply? @@xxportalxx.

[@JKtheSlacker]

They accidentally sent it partially configured for the northern hemisphere and partially configured for Australia, all the knobs were supposed to be upside down.

[@donaldbundy3499]

😂

[@1ytcommenter]

Would have expected a Bakelit housing. 🤣

[@johncoops6897]

Note that the 5-knob is x0.1, x1, x10, x100, x1000 so max 9,999k which is kinda useless. My idea is to get the 5-knob and leave the x1 range, but change and rearrange the resistors to flip the remaining knobs to make the layout... Top: x10,000, x1000, x100 Bot: [¤] x10, x1 [¤]

[@EEVblog]

Yeah, 0.1ohm is dumb. On a 5 decade even 1ohm is dumb.

[@johncoops6897]

@@EEVblog - Yeah, plus I already have dedicated solutions for

[@quandiy5164]

Was thinking of getting the 5 knob and changing the values to kilo ohms so I can get 0 to 9.9999M in 100R steps.

[@zyeborm]

Spray of contact lube would probably make the contacts last longer against corrosion.

[@jaycee1980]

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

[@tommiller1315]

@ 6 minutes - AliExpress is all out of stock 🤣

[@qzorn4440]

Amazon $38 🐬 GLTL 6 Decade Resistance Box Adjustable Lab Rotary Resistor Substitution Box Precision DC Variable Knob Switch 0-99999.9 Ohms 0.5W 🥳 Very creative.

[@JAKOB1977]

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.

[@JAKOB1977]

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.

[@mattrenaud7573]

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.

[@t1d100]

Would it help to prevent wear of the traces to put the (bare) board in tinning solution? Or, coating them with solder?

[@davebarcus7118]

That was my first thought...

[@OtherDalfite]

Dielectric grease would help a lot

[@tubastuff]

There are nickel-plating kits available that allow one to brush on a thin layer. Look, for example, at Caswell Plating kits.

[@j.f.christ8421]

DIY nickel plating is pretty simple.

[@procrastinatingnerd]

I feel like you might get a better bang for you buck if you look for a antique/vintage decade box instead. If you are patient you can find them for not much more and they usually have a higher rating and a better long term tolerance. At least with what I have seen. I have one I got at a thrift store for $30 I think it was, it has precision resistors and still measures right on.

[@SidneyCritic]

I was looking at DIY home plating just last week, I wonder if they have something hard because that copper ain't going to last.

[@jamesmauer7398]

"Will Bob be my uncle?" 😂 Good call on fixing the issue

[@tonyh6309]

Doesn't look to be make before break - which could be a problem for some use cases.

[@paulkocyla1343]

I´d worry about the wetting current on those boards. You can never trust the resistance when the contacts don´t conduct. But fair enough, you can measure it before using - for that price no one would f%/ care. Besides that: the vintage looking knobs are already worth the buy :)

[@lezbriddon]

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

[@arcrad]

Would slathering the whole bottom of the board in dielectric grease (silicone) prevent the oxidization of the bare copper?

[@jaro6985]

yes

[@donepearce]

To make this work properly clean the copper tracks with metal polish, then coat everything with Vaseline. If you don't do this contact resistance will raise to several ohms. (I have one)

[@Hyxtryx]

Won't the contacts scrape the vaseline away where it's needed the most?

[@donepearce]

@Hyxtryx six months now, and it doesn't seem to.

[@FirstLast-jl6fr]

An even better mod.... Change it to a Capacitance Decade Box using SMD caps instead.... much cheaper than buying a cap decade box!

[@L4b3n]

bought one years ago ... as I remember, it was working correctly out of the box. The biggest mess are indeed, the bad connectors 😑

[@daveys]

I have one of these, but I can’t remember what I originally bought it for. I may have a look and see if the switches are backward on mine too.

[@hansurmann]

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

[@jonathanreedpike]

If nothing else it makes a great prop, or a "fidget clicker" if you will.

[@PhillipRhodes]

Is it wrong that I now find myself wanting to order one of these things, swap out the binding posts, add 5W resistors, and maybe even add a fan and a temperature sensor, etc. etc? #OverEngineering FTW!

[@EEVblog]

Do it.

[@robegatt]

You can put 5 x 1 ohm in series instead of a 5 ohm... just to solve the power problem...

[@hackleberrym]

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.

[@ChrisJackson-js8rd]

clever how they reduce the bom cost with that resistor arrangement

[@sikkepossu]

11:54 Actually aren't those remainder of the resistor always parallel with the series ones?

[@NICK-uy3nl]

Interesting design and amazing price people should stop calling Chinese designs 'cheap junk'.

[@brianlink391]

8:06 thanks for your fingerprint information

[@organiccold]

Dave couldn't resist to this 😂

[@JaenEngineering]

It's worth it just for the enclosure and knobs, even if you then completely discard the guts and spin your own internals.

[@TrickyNekro]

It´s a multimeter in reverse!

[@ventusprime]

I always wanted to crete digital version of this , but I did not hade time for it.

[@DadofScience]

SOLD!!!

[@eimparas]

Bots aside. What is the real world use of a decade box? I had the same question back when Dave showed of his diy box, and the only one that I was able to come up with was prototyping a lm317 based psu and the box would act as a r1 in between the pot & lm317 for finding the ideal resistance to get the best vout A very very specific use case 😅...

[@johncoops6897]

I use them for tweaking 555 timer and oscillator frequency etc. Much better than an imprecise potentiometer, and can reliably handle moderate current. Another use is in troubleshooting where you suspect that an old resistor is causing problems. You measure and find the resistor has increased in resistance, usually from overheating.... Rather than desoldering, just clip the decade box across the leads and adjust the parallel resistance until it's back in spec. If your circuit comes good, then you know what to repair.

[@Basement-Science]

If you have one with power resistors inside, it can also act as a dummy load for example. And it can pretty much replace ANY potentiometer or resistor in a circuit in general. Of course that means it's most useful for analog electronics in general. It can also for example be a better constant current source than your bench power supply if you need current in a range where your supply is not able to be set very accurately. Like, you could test the brightness of an LED from its max rating all the way down to microamps without reconnecting anything with such a box.

[@j.f.christ8421]

I use mine when brightness matching LEDs. Also good for op-amps offsets.

[@Zetex2000]

I use my decade box a lot, and I always wish I'd built another one. If you plan to buy or make a decade box, make 2! Some uses I've had (altough, I've had much more!): 1. Find and tune a frequency compensation network for error amplifiers, some kind of trial and error. 2. Find a good resistence value for an LED, in order to get the brightness I want - you can calculate a pretty close value, but sometimes you want your leds to be a little more dim.

[@edgar9651]

Thanks! Ordered.

[@simonhopkins3867]

I'm thinking a trim pot. And something like a cheap LCR tester put in circuit with a switch taking the input out of circuit. 🤔 Edit LCR tester

[@JohnSmith-lb3ge]

You should do a vid on modding the box

[@jasen963]

Can you please make a video on upgrading it?

[@Peter-Groenink]

This would be fun to mod in to a puzzle geocache

[@KallePihlajasaari]

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.

[@georgegonzalez2476]

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.

[@Eduardo_Espinoza]

reminds me of smart old electro mechanical technology :)

[@sfdntk]

Amazing how much thought went into getting the cost down, just to save the expense of a handful of SMD resistors that cost a fraction of a cent each at scale.

[@dosgos]

Awesome cheapo design!

[@Mtaalas]

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.

[@EEVblog]

Decade boxes typcially don't get used much though.

[@tubastuff]

In the old days, the slide would be silver or gold plated with a silver ball on the rotating part.

[@tubastuff]

@@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.

[@motogee3796]

Looks promising in a diy radionics setup

[@nasko8605]

Sorry for the stupid question, but what is this thing used for?

[@cosmolittle1395]

In over 50 years of electronic designing, I have never had any use for a resistor substitution box. Consider the average modern design made with surface mount components. You have an 0603 resistor that you want to vary, to optimize some performance parameter. To use the resistor substitution box, you will have to solder 2 wires to the resistor pads, which will probably pull the pads off the board. You will be adding an enormous parasitic capacitance which at any frequency above 1MHz will completely change the circuit operation. I have found that a surface mount resistor placed on the pads without soldering, and pressed firmly down, will usually make contact. Alternatively a subminiature trimmer can be soldered to the pads.

[@fir3w4lk3r]

Just design a new board with gold plating. How mush is it on JLCPCB etc? :D :D :D

[@microknigh7]

Ye I got one about a year ago for £5 and it's total garbage LOL. The rotary switch contacts are very hit and miss.