I was wondering if there was any way of testing a 555 timer or a 4017 decade counter (to make sure something internal is not broken) without putting it into some kind of circuit. Like maybe something with a multimeter, or something, just as long as I don't need a circuit.
You want to test something W/O a circuit? Well there is a sub-standard way and it's called a parametric test where you test certain nodes for some parameter, but you will still need a test jig and by the way, it is sub-standard in the sense it catches big obvious things like shorts & opens, capacitance, resistance.
Most big companies use parametric test but they still test. For a 555 you may have some 10 parameters that you would need to test so that would need a jig, test sockets a DMM of some sort and someone who looks at the data and decides go, nogo.
Your look at nodes and these nodes are generally diodes so you measure them usually reverse. Some measurement are input to output in meg ohms. You can start with a 555 data sheet but it's your decision not to functional test, so you own the parameter test.
FYI the parameter test is as stated gross in the sense it won't catch latent defects (some yes, others no). Also as stated all big companies use parametric test to go from incoming test to stock shelves even, believe it or not, something that goes into space.
The difference is that the manufacturer assembles the device and then performs rigorous robust testing on the finished product.
All of this I am telling you from direct experience, not 2nd hand, even the space stuff.
Again you own the parameters so you have to decide.
Aaah the advantages of simple microchip !! How the world has changed Simply write one tiny little bit of software , One tiny little timer interrupt and gosh would you believe it One 555 timer One 4017 decade counter all In one chip
Lovely say bye bye 555 Say bye bye 4017 Hello Microchip how easy!!
Yes that easy and to test even simpler write on standard test routine which tests all Blow the chip as many time as you like within reason and bingo Job done time to test = time to bow chip place this in a simple test circuit with a few led’s and a couple of switches Job Done !!
Yes forget 555 my friend wasting your time Know how it works = Yes Know how the 4017 works Excellent because that is all you need to know now You won’t be using them soon
Yes I’m afraid gone are the days of the 555 pwm you can do this with microchip Timer set your frequency as you want even better than the 555 and 4017 well what is exactly this chip ? A divide by n clock interrupts
You want a one shot bitable you write software to do this now
What ever you can do with that 555 Now what you do is write software for it That’s how its done now
Yes I’m sorry to say yes this is what you should be studying and learning to do
If you want ultra precise timing you use an RTC clock NXP semiconductors right on this page right in front of you
You want motor control you use a pic micro or similar
You want microwave oven control, you write software for a processor to do this
You want internet control as well is micro
You want web server its micro chip technology or some other manufacturer RPI for example
You want Infra red control its microchip or some other manufacturer
You want Rf control its microchip or some other manufacturer All of which require that you must now be able to write software for that component
Even audio and video now Its software hardware orientated now
Even for working inside an office its imperative that you know how to write WebPages how to automate How to query databases , report writing , integration with office documents , spreadsheets , how to export results how to communicate across TCP IP and extranet technologies even mobile phones exactly the same
You don’t by a mobile phone now unless you know what you want to do with it same for email You need to know how to extract data , automate this filter this set up automatic replies iterate through lists
Messaging need to delay an appointment or contact several hundred customers its automated You wont be sitting there trying to desperately send one message after another via sms or email or phone call You write some software to do this for you one touch One button One multithreaded application Job done
Grabs data in database selects phone number , calls modem sends messages and emails Same for hardware
Its a tool and you must know how to write software for it
Why you need time to train people time to do jobs and time to sit back and take it easy Less stress less headaches and more of the must have to do work by hand or instruction
Thats why
Said this would come to you soon to most of you Ive tried to tell you this for years
Oh I get it now. No means no, and yes means Yes. The person is simply asking how to test without a functional circuit. I suppose if the person were testing many they would automate. On the othet hand tht's not how it's done the real process is to use process control to get the defects to within 200 ppm or so and except that as a number to live with.
Then for the rest don't even test them at all because the handling in of itself will introduce another 50 - 100 failures in ppm.
The function could be replaced as you have indicated but he is already gone, that ship has sailed.
Earl relax , make life easier not harder make a component re- usable , not throw away , develop with the modern world not against it , move with the times not against them , produce something that is within time of the world not past tense , move towards the future don’t get left behind
In other words earl train some one who is younger than you with a whole life to come and must work to be ever up to date with technology not left behind wasted , not knowing what to do , not being able to get a job
Not much fun having no money in your pocket , no pension , no where to bloody live a load of companies that ripp you off and take advantage of you because your not in a position to say anything because you don’t know how and haven’t kept up to date
Come on earl even i know this think about someone worse off than you my friend not exactly all their fault I know but at least lets attempt to try and undo what this lot have done
Im not having a go at you earl but times have changed time to move on You cant beat this anymore my friend You either work with this or be beaten
Thats why i dont sit and waste my time now Earl every spare minute Im lewrning something Im 50 years old now I dont have a choice either
Thanks for the advise, and yes all that you say is spot on. We need a different forum for this discussion. The one at hand that I am trying to contribute to for the moment is.
"Testing a 555,"
What shall we call it? Open it up and let's have at it!
I at the side of Colin, it is for 17 cents to cheap to spend time. And yes i do not like to bin it when defect or suspected, it is just i prefer to repair say job solved and drink a beer.
You could analyse this another way couldnt you You could say lets move this into FPGA design then it would make sense to do this would it not Hence why we create simulators for micro chips and so forth Then it makes sense
For repair purposes Colin is right Peter is right replace the chip
For Future purposes change this into a 12F6XX, 16FXX or similar and only use one component plus a five volt supply
In other words write some software for this and make 12F675 with far fewer components than Collin and low and behold every time you want a 555 timer you simply blow a pic and if you want something else you blow the same chip with another bit of software
So for Collins expense account for four projects Collin here has spent( 99cents * 4 ) plus anotjher 5 * 10 cents another ic holder plus another pcb and another another variation which has cost five times as much and is still not reusable
I’ve only spent $1.20 unless you replace the Ic of course which is still only a fraction more expensive than a 555 and what’s more I can do at least 99 to 100 easy projects from one simple pic micro giving far wider range of functionality and far better meaning full purpose than Collin 555 timer projects why because I don’t need as many components
I only need one Ic a five volt regulator the rest is done internally and via software Free fro download from the net Internal RC osc which can be calibrated Internal port five outputs or inputs no crystals no caps and bang one bit of code and Job done for however many I want or how many times I want to use one single 555 timer making it cheaper more cost effective
If this goes wrong I attache an in ciurcuit debug tool and low and behold I have the fault and can tell this IC that IC or whatevere far easier You obviously didnt see Motorola's Software fault analyser which allows you to clamp over the Ic PLCC or what ever examine a picture of various wave forms and compare with working waveform on each pin of the IC in one shot
With a Multi processor board sometimes emplying some 6 , 7 maybe 8 processors how are you ever going to find the fault unless you can send messages or isolate the IC Surface mount are you going to be able to do this ?? I dont think so somehow
Imagine doing this via scope or test meter Crikey you be there for ever
Which solution will you choose as say a electronic Kit manufacturer
I know the answer to this, I know exactly how the manufactures will think and I know exactly what the environment people will think Build a re usable component
If you want to learn about 555 timers etc and shift registers and decade counters
This is what you do now Try this its free for download http://www.logiccircuit.org Save yourself allot of money will you and spend it on something that will benefit you for now and years to come Go and buy and raspberry pi that would be far better or Amicus 18 board
You can create as many 555 timers as you like then with decade shift bit registers or gate and gates or multiplexers or what ever you need to do plus internet workings
Plus rs232 , , I2C , single wire , lcd or 7 14 segment displays bcd decoders
That’s your answer
Try it and see for yourselves Learn something different, new, exciting, and challenging and rewarding without the massive cost
When constructing a project its always an idea to use IC holders plus its far neater and far easier to replace, what’s more its more professional
See designing for after sales service so to speak Now its making sense
That’s the difference between rushing to get a job done and taking your time ensuring you get professional results and are able to provide long lasting results ,after sales service unlike so many companies who don’t put a single thought into any of this at all anymore
Not good for anyone is it this !! hmmm still one day
✨ Testing a 555 timer or a 4017 decade counter without a functional circuit is challenging and generally not practical. The common approach in industry is parametric testing, which involves measuring electrical parameters such as diode junction voltages, resistances, and capacitances at specific IC nodes using a test jig and multimeter. This method can detect major faults like shorts or opens but cannot guarantee full functional integrity or catch latent defects. Without a dedicated test fixture, parametric testing is difficult to perform effectively. Many recommend simply replacing the IC if suspected faulty, especially given the low cost of these components. Modern alternatives include using microcontrollers (e.g., Microchip PIC series) to emulate 555 timer and 4017 functions with programmable flexibility and easier testing. For learning and experimentation, simulation software and breadboard testing remain practical solutions. Additionally, using IC holders is advised for easier replacement and testing in circuits.
TL;DR: To “test without a circuit,” you’re limited to parametric checks; factories target ~200 ppm defects and, as one expert notes, “use process control to get the defects to within 200 ppm.” [Elektroda, Earl Albin, post #21666629]
Why it matters: This FAQ helps hobbyists quickly decide when a multimeter-only check is enough and when to build a small test jig.
Can I test a 555 or 4017 without any circuit at all?
You can only do limited parametric testing with a DMM. That finds obvious faults like shorts/opens but not full functionality. A proper evaluation needs at least a simple jig or breadboarded circuit. Treat multimeter-only checks as screening, not proof of good operation. [Elektroda, Earl Albin, post #21666623]
What is a parametric test on an IC?
A parametric test measures electrical characteristics at specific pins, such as diode junction behavior and high-resistance paths. It detects gross defects but misses many timing and edge-case issues. Use it to weed out dead parts when you cannot power a full circuit. “It catches big obvious things like shorts & opens.” [Elektroda, Earl Albin, post #21666623]
How do I do a quick parametric test on a 555 with a DMM?
Use a socketed jig so you don’t stress pins. 1) Measure diode-like junctions between pins per datasheet orientation. 2) Check input-to-output resistance; look for megaohm-level isolation where expected. 3) Compare readings across known-good parts to flag outliers. This is a gross screen, not a full functional test. [Elektroda, Earl Albin, post #21666626]
Do I really need a test jig or socket?
Yes. A jig stabilizes connections, protects the IC, and lets you repeat measurements. As one expert puts it, “Without a test jig you won’t be successful.” A quality ZIF or machined-pin socket also reduces handling damage and speeds go/no-go checks. [Elektroda, Paulo Borensztein, post #21666625]
Will parametric testing find every fault in a 555 or 4017?
No. It often misses timing, threshold drift, and intermittent failures. It’s designed to catch obvious problems, not subtle ones. Expect latent defects to pass; use a functional breadboard test to confirm oscillation and counting behavior before reinstalling. [Elektroda, Earl Albin, post #21666626]
Is it worth testing or should I just replace the chip?
If the IC costs ~$0.17, replacement is often faster than building a jig and analyzing data. This is common in repair workflows when time matters more than part cost. Keep spares and standardize on sockets to simplify future swaps. [Elektroda, Peter Evenhuis, post #21666632]
I didn’t use IC holders—what’s the best next step?
Desolder carefully, then add a quality socket so future replacements are trivial. Designing for serviceability is part of professional practice and saves hours over a project’s life. It also keeps boards neater and reduces heat stress on parts. [Elektroda, Mark Harrington, post #21666636]
What’s the simplest functional test for a 555 on a breadboard?
Drop it into a solderless breadboard with a known astable or monostable circuit and verify the output waveform or LED blink. This confirms core timing behavior quickly and exposes failures missed by static DMM checks. Keep leads short to reduce noise. [Elektroda, Frank Bushnell, post #21666637]
Can a microcontroller replace a 555 or 4017 for timing and counting?
Yes. A small MCU can emulate 555 timing and 4017 counting in software, often adding flexibility. This reduces component count and enables precise control via timers and interrupts. “Say bye bye 555… Hello Microchip.” Consider PIC or similar devices. [Elektroda, Mark Harrington, post #21666627]
Is there free software to simulate 555/4017 logic before I build?
Yes. The thread suggests LogicCircuit, which lets you assemble virtual timers, counters, and glue logic for quick validation. Simulation won’t catch soldering faults, but it reduces iteration and parts stress during bring-up. Try it before hardware. [Elektroda, Mark Harrington, post #21666634]
Why don’t manufacturers test every single parameter on every chip?
They rely on process control to keep defects near ~200 ppm, then avoid extra handling that can add 50–100 ppm failures. Full testing on every unit can backfire by introducing new defects. Screening is balanced against yield and reliability. [Elektroda, Earl Albin, post #21666629]
Any handling gotchas while testing 555/4017 parts?
Yes. Excess handling and repeated insertions can create new failures, estimated at 50–100 ppm. Use sockets, minimize touches, and standardize your jig to reduce wear. Store parts in antistatic foam and avoid bending leads during swaps. [Elektroda, Earl Albin, post #21666629]
What exactly is the 4017 ‘decade counter’ in this context?
It’s a divide-by-N counter advancing on clock edges to drive sequential outputs. In projects, it replaces chains of flip-flops and simplifies LED chasers and step sequencing. A microcontroller can replicate this with timer interrupts if desired. [Elektroda, Mark Harrington, post #21666627]
