Good fix. Great work. Note at 3:40, unit powered on, gloves on, moves meter and brass screw driver rolls toward exposed live module. Was expecting sparks and a loud bang. Oh well, next time perhaps.
This was such a stressful watch experience. Clive moving the meter and bumping the brass screwdriver, (and the small screws rolling about) were just about a short circuit BOOM 🎆 away!
Available for a few years in Tesco, I found them to be pretty reliable even if you're just using it to check the time, I wondered what they were like inside, thanks for showing!
Awesome....a rare fix video from Big Clive and a successful one at that! Add to that the totally thorough, electronic engineers explanation of causes and remedies in the video description and we have one heck of a video...Thanks Clive...
Ah, another night owl. Over the Christmas holidays, I've gradually rolled forwards to my natural 5am bedtime. Getting up for work this morning was brutal.
I love how every piece of equipment has modifications that would drive some organizations insane but make your life easier because you have at least a basic understanding of how stuff works.
Nice to know about the Battery fix and problem. Here in the USA the most common time switch always has the same failure in that the Zenor diodes short out. It takes a bout 9 months for the under rated Zenor's to die. I have repaired 4 of them so far by replacing the Zenor's with higher wattage units of the same voltage rating. They work fine after that. But now I know about the battery's lifetime problems. So, thank you Clive for sharing this video with us.
I had some with failing mains voltage capacitors. Running at 230V, 50hz) I never replaced a Zener I always replaced the battery with a standard aa rechargeable battery. I don't use those any more. Those tiny batteries are expensive for no reason., aa is cheap and indestructible for infinite trickle charge
@@CyberlightFG Must be some differences with the units they sell in the USA for 120 VAC only, never had a failure other than Zenor diodes. But I do expect to see the batteries fail now that I have seen this video.
I repaired two of these a couple of months ago. I had to replace the electrolytic capacitor and the x2 dropper capacitor. The failure mode was the following: When plugged in the relay would turn on and off. But when the controller was on an you plugged the time-switch in the relay wouldn’t turn on. You first had to toggle off and on again. I only noticed this after a power outage. Great video :)
Hi Clive. Love the channel and have followed you for several years. I have 5 timers that use the same logic module and after the first year 2 of the batteries leaked (1 did a very spectacular explosion inside the case as it shorted the 13 amp contacts with conductive fluid and left copper plating all over the board). I have now replaced all of the batteries with AAA cells and have had no further problems even after 8 years. Love the LED hacks keep up the good work.
Had a similar looking immersion timer that the backup battery failed, a Poundland garden solar light became the donor and it was still going strong 7 years later when we sold the house. I feel quite chuffed but it was all down to your solar light reviews,cheers Clive.
You had me tightly clenching the arm of my chair as you were trying to measure the Zener diode with that nice brass screwdriver rolling around on the bench just needing a very slight nudge to send it under the energized PCB and give us a fireworks display.
Getting the solar light just for the battery is fascinating. Just checked prices: The battery by itself is actually more expensive than the whole light 🤯
That's actually a good reminder to check on my time switch. It's been sitting in a box for quite some time, and I suspect the cell has probably failed.
nice detective work. I'm slowly getting back into some electronic detective work using channels like yours for inspiration and learnings. much appreciated. love your work.
Omg I can't believe you did a video on this exact unit. They're sold by grow shops for indoor grow operations in my part of the world, and they are known for welding shut from taking inrush load current of magnetic HPS/MH ballasts. The random button is the first thing to go. Who thought that was a good idea, and so easy to bump!
👍 another great video Clive, I’ve got about four by the looks, identical around the house, one permanently powered for an outdoor pond fish feeder, the others as random night lights for when I’m away, never had any issues with any of them 😊
I've got a couple of these. I was quite surprised that, not having used them for years, the backup cell hadn't gone crusty and still worked. I was using one to switch a solar inverter temporarily and it welded the contacts of the dreadful Songle relay. So my cannibalised repair was with a slightly less dubious relay from another timer and it's been fine since.
I've got a couple of timeswitches exactly like that, but they have weird anti tamper screws that I can't find any screwdriver for. However at present they both still work. I have a mechanical one somewhere that quietly self-destructed after only a few months.
I've got one or two 10 year old time switches with the same problem. Thank you for giving me a heads - up, and I'll probably have a go at repairing them (with the "at risk" components all being replaced).
I have one of those, and it’s still working after more than 10 years of use - well technically it’s only used for less than a month every year to switch our outside Christmas lights on and off. The display goes off after about a month once it’s unplugged (stored on a garage shelf), but returns with a push of the reset button once it’s plugged back in. I guess in reality that running the battery flat and only having “used” it (plugged in) for less than 12 months in total is the solution for a long life? Great video as always.
I just watched a video from Adam Savage on conductive fabrics like sticky tapes, Velcro, etc. Apparently it doesn't require resistors for LEDs because the very fabric has built in resistance. I thought of you immediately, incase this sort of thing hasn't reached your radar yet. Cheers and Happy New Year Clive!
I had a similar issue with one of the mains power monitor devices. Though in Australia, it was more for the battery than to buy a whole new replacement unit. Australia still hasn't got on to the whole reduction of land fill.
Ta for pointing out the obvious source of cheap NiMH cells to replace those in timers that have failed. I've seen solar garden lights for as little a 50p in a Sainsbury's end-of-season clearance but never thought of them as a source of backup cells.
BC: Warns about danger of working on unshielded live equipment. BC: Performs live test in immediate vicinity of tubular metallic objects that could roll under live PCB. Conclusion: BC has no fear (certainly of H&S staff). Happy New Year, BC. Lang may yer lum reek and your screwdriver turn.
I like the glove with one finger cut off for touch screens, the same finger that is also used instinctively to touch other things and pointing at live electronics :)
Very nice job there. I think that to finish the job I would have replaced the zener with one with longer leads with small loops in each to raise the zener away from the board.
Elementary my dear Clive Holmes, when all possible errors have been eliminated, whatever is left is the fault. Well done mate, most of us would have slung it in the to do drawer, and popped off to Poundland and bought another iffy plug in timer. Good job 👍
I remember when I used these and the analog ones for Christmas lights. They didn't like the cold...analog ones would just not turn properly and battery on the digital ones would usually fail and explode. So glad to have smart plugs for this now.
Handy info , thanks Clive ❤ I've just bought the same model from Morrisons for my lava lamps , so I'll know what to do in a year or so when the same fault inevitably appears.
I've used the timer module from a Tesco version as a compact timer for a Land Rover, to power up the fuel burning heater to preheat the cabin in winter. It worked very well for the task, and used basically nothing from the 12 Volt vehicle battery.
Thanks for the video! ❤I have the same timing relay with the same problem. So far it hasn't bothered me, but now that I know the problem, I'm going to fix it. Surprisingly, it doesn't lose the settings even after 2 hours of power failure.
I have one like this. It was unplugged for a long time and the screen went blank. I left it plugged in for a few months and it still did not come back. I opened it up and gave the cell a charge at the bench. It was working fine since. I now park items like this which I know have cells in them in an outlet strip which is only on a few hours a week (at the washing machine) to keep the batteries up until I need them again somewhere else. I don't see the need to leave the washer plugged in anyway so it all works out.
With many of those units, if the display has gone completely blank & it doesn't come back on after being plugged in for a while again, you normally have to press the reset button once or twice to make it display again.
@@NOWThatsRichy Good point! I have encountered that on calculators. The one I have has no reset button but perhaps that was a bean counter delete and my poking around did the same thing.
Thank you Clive that should save someones job when they can fix a problem just by changing the batteries out on some old system that now doesn't have to be replaced. Jim from Scotland
I got one of those from Aldi a year or two ago in The Netherlands, obviously a 220/240V one. Been working fine so far, got a rechargeable internal battery inside.
This reminds me of a not so fun childhood anecdote/memory: Back when I was maybe 6 or 7 my parents had a slightly similar timer plug that I liked to play with when it was not in use. But one day my father suddenly disliked it and slammed the timer against the floor. (He very angrily said something like Wanna play with the timer ?! Play with the timer ! Now that it's broken...) It popped two of the screws holding it together and the case was partially open at the top. I don't remember how but I closed it back somewhat, maybe using tape to keep shut then I plugged it but unsurprisingly it wasn't working anymore. The red LED was faintly glowing but the timer wasn't usable although I don't remember if the display came on or not or if the outlet was live or dead. And now I wonder what component broke and how fixable it would have been if it had happened nowadays.
Instead of cutting the tip off, just stick a bit of foil on top of the glove. The capacitance from your finger to the foil (and thus to the screen) is enough to operate a touchscreen without risking electrocution when you touch other things with an exposed fingertip. This works on my phone.
About those disclaimers: The manual for old cars had information on how to time the contact points, what order the spark plugs ignite, what torque the head-bolts needed... Modern car manuals just say "don't drink this liquid" and "don't touch those moving parts" or "don't slam your d**k between the doors" .....
@@lint2023 It was sarcastic exaggeration ;) Yes, car manuals still have a lot of info, but not nearly as much as they used to. And a lot of warnings that should be common sense.
@@angeldelvax7219 I wasn't pushing back on you and I apologize for letting it sound like it was. I should have included that it is 550 pages and has no real maintenance information like you described. I liked the comment you posted about manuals from earlier times.
@@lint2023 Probably a combination of my autism, and the "state of the internet" as far as general negativity goes that gave my that idea ;) These days I find myself automatically in deference mode when replying :(
Good fix. I usually modify the circuit with a second, 9V zener (lower might work as well, have not tried it) with a transistor in series in parallel to the existing one and switch that inverted to the relay coil. Increase the 2K7 resistor and add a zener parallel to it (make a crude voltage regulator, to not overcharge the battery). It drastically decreases the standby power and they last longer.
I saw few of this timers and power meters where battery wasnt charged through voltage divider 22K/2k7, but only by resistor - something like 22k from 24Vsupply and when NiMh battery fails to open circuit, full 24V appears on low voltage microcontroller and (intentionaly) burn unit. I always added Red LED parallel to battery.
I have exactly the same timer switch. I think I bought it from Wilkos. The battery died in mine and I think it was a lower mA than your example but I replaced it with the same as yours has. Mine just wouldn’t hold its time, although I hadn’t used it for ages and the battery must have drained too low. I guess that’s the issue with this type of battery. Ironically I have an electric razor that was stuffed in the back of a cupboard and I kinda needed it. I thought that this bugger is going to require a new battery, but no! Lo and behold it charges and doesn’t run down rapidly either. I recon that’s progress for you! Great videos BTW 👌
Interesting to know that a lithium cell going bad isn't always indicated by a lower output voltage . I knew batteries go higher impedance through working on laptops over the years but I don't think I've ever thought that the output voltage could be higher than normal. I usually think about it's behaviour as reaching "full capacity" ( a false state ) too quickly and then discharging immediately. Very useful bit of information which really, I should have previously thought about more.
Clive, not a week too late. I have the exact same timer (although with a proper EU plug, not that huge bulky UK rubbish ;) ) that went south a few days ago in a similar way. Since I don't like throwing things out to landfill I'll check if my NiMH isn't shot as yours was. Especially that it was unable to keep the screen lit for more than a few minutes when unplugged. Cheers Sir!
I expected a low value cap, like my remote controlled switch. I think I would have fitted an AAA NiCad and reduced the current with a 33K resistor (had I managed to work out the battery was at fault). Nicely done Clive*. *(Note a "sir" no longer has a positive value, but you deserve honouring for your service to education & entertainment).
That's why I grabbed a few of those old-timey timers with the spinny thing, motor, and 48 tabs that you push in or pull out for half-hour intervals. They Just Work.
I sometimes use an old shaver socket as a cheap isolation transformer. That way I feel more relaxed about poking my fingers in a Live pcb. I believe the shaver socket is current limited aswell reducing the flash bang surprises😅
I have some similar time switches from Homebase; ordinarily, they operate quite happily, but if the load is anything especially inductive (even a small electronic ballast for a domestic compact fluorescent), they tend to self-reset after the relay has switched the load off (probably back EMF or similar). They are fine with LED equipment, however. An equivalent product from B&Q (made to a completely different design) is made of tougher stuff, and is much more capable with induction switching - not that I've tried it on a 400 W SON circuit (yet...), mind you! Yes, a lot to be said for all of those safety warnings, though "forgetting that the mains is on" has been my biggest downfall - wiring up a 135 W SOX ballast to a table lamp (as I didn't have any spare bayonet lampholders at the time) was my first zapping (nice belt off the capacitor too), and because I don't learn, I made contact with a completely non-IP2X terminal on a mechanical time switch case not too long after that...still just about here to tell the tale, mind you!!
The warnings can still be useful just as that regular reminder. I do think people can go overboard as usually all you really need is a quick “This is mains voltage. Don’t be stupid.” You don’t really need to go into crazy detail every single time it pops up. Liability is a lot more nuanced than many people think. Otherwise a lot of things that we’re used to wouldn’t be available.
I prefer people using actual protection like isolation transformers and/or inrush lightbulbs and dedicated workbench FI and mentioning them. (Having said that it’s good that Clive at least mentions sometimes to use battery operated (ground isolated) scopes.
I remember having to change batteries live to avoid losing the program. I kept a second soldering iron with the earth disconnected specially for that product.
Nice fix and Thanks Big Clive. Watching you trouble shoot stuff is a master class for sure. Curious about the Zener Diode running hot. Is there a fix for that. The discoloration seemed legit. Would a different diode of the same voltage handle the current better?
A higher wattage diode could be fitted, or two 12V zeners in series to spread the load. Some units use a switched resistor that turns on when the relay coil is off.
Some older PLCs use rechargeable cells or capacitors to hold the operational program of an industrial process. Tends to be the one thing nobody checks, or has read the manual to know to check.
The Zener diode and its associated components are looking like a future point of failure with that scorching going on. I have a pair of gloves just like that, Clive. Mine are the left handed version, of the index digit touch screen feature.
Well, hot on the heels of meeting you in a dream, Big Clive, you're tearing down my timeswitch! ... I have one of these timers, which I bought in Wilko many years ago. It's currently in use, switching a USB Plasma Ball on and off at the side of my bed! It has a built in rechargeable battery. EDIT: The LCD display is REALLY hard to read!
I wouldn't mind watching re-flowing the pcb soldering. Any one else feeling that recent videos are getting shorter, and jumping too quickly to a summarized ending? I miss "the boring parts" (-actually the best parts) - of watching and hearing every relevant, as well as irrelevant thoughts during the whole process ! And, why haven't I heard you say "masticating" in like 4 ever !? 😛😁😁
I have found that these timer circuits use very low voltage logic for the clock circuit, typically 1.5 to 2 volts ( spec value of 1.8 volts). These misbehave with any small over voltage on the supply rail. It seems bad practice to use the standby battery as the supply regulator. When the battery inevitably fails it has a tendency to destroy the timer circuit with prelonged exposure to the over voltage on the supply. A problem I discovered on a radio locked version of one of these switches. Such is the poor tolerance of this type of logic to excess supply voltage, it is difficult to add any protection, such as a second zener diode or an LED( acting as a zener) to protect the timer from damage when the battery goes high impedance. Its only protection is the current limiting provided by the resistor divider in the battery charging circuit.
I used to work as a KP, I found some durable gloves from Wilco I know they went bust but they did have some good gloves both for touch screens and dealing with hazardous chemicals usage. Perhaps they return online only
I see this failure mode at work sometimes. We have an older generation embedded controller that uses a NiCd/NiMH battery for NVRAM. Predictably, this battery is usually trickle-charged by an onboard charger somewhere in the system when it's powered up. After ten plus years, the battery will go screwy and allow the voltage to rise higher than it should be on this rail. This'll actually crash the controller in wild and screwy ways that aren't exactly intuitive. Replacing the battery fixes it.
Before making safety claims for PPE it's a good idea to test it. Especially if it's black because quite often, especially if not electrically rated (or worse it's ESD-rated), the pigment used is often something conductive like carbon black.
It will be interesting to see how many of the radio locked versions of these time switches continue to work after the Droitwich RTS signal on 198kHz is switched off after June 30th this year.
I have 3 of these, the oldest one is a genuine Smiths model, the newer ones like yours are generic brands using the same case design & button layout but with a smaller display panel, the smiths one must be over 20 years old, but no longer works, (the relay only stays on for a few seconds, then turns off on it's own, no matter what the timer is set for).
That does sound like the classic dropper capacitor fault. The capacitor can't pass the required current to keep the relay latched on after the electrolytic has given it the initial bump.
I have a 23-year-old time switch that hasn’t got a built-in battery, but relies on a changeable AAA battery. As it isn’t charged by the device, you can both use primary or secondary cells. Quite neat. I dislike the use of capacitive droppers in devices with relays - including motion sensors. They waste a lot of energy when the relay isn’t powered (usually 0,7 W up to over 1 W). I wonder why the manufacturers don’t use switching power supplies that, as a side effect, need much less space on the circuit board and have a more stable output voltage. Smart plugs usually use switching PSUs with a quite low standby power (~ 0,2-0,4 W), so why can’t other other devices?
The NiMH cell was my first guess because I had to replaced the battery in a similar device already twice. It was obviously already leaking. Worked perfect until the new cell was toast.
I have a really ancient one that switches on\off my internet router each night. It uses a PCB mounted Nicad in it - not easy to get hold of a new one of those these days. Over the years the LCD display did the opposite of this and was getting fainter to read. After replacing the Nicad all is good again. It would be nice to add an ethernet interface to it so I could power off my internet router remotely from my PC.
Just a thought, would it be beneficial to put another diode in series with the isolation diode going to the battery? This would drop the charging voltage from 2 Volts to 1.4 Volts, a better trickle charge Voltage for a Ni-Cad battery.
Hi Clive, For your own personal safety I'm just wondering if you use a mains isolation transformer when working with open appliances. When I was a teaboy (in the 1960s) at a local electrical shop I recall there was one installed under the workbench but don't recall you ever mentioning them.
I came across a bit of commercial equipment that was 'cost optimised' beyond reason. Rather than using an (e)eprom for the program they used half of the battery backed config SRAM (6116 I think) to hold the program. A bit of logic inhibited writes to the half that held the program. It all worked fine until the rechargeable battery aged and power was removed from the device for any reason. Then the cell voltage would drop below the voltage required for the low power mode of the SRAM, draws microwatts in that state, and the program became corrupted and device no longer worked.
We have 2 of those - one of which kept our Bearded Dragon on his 'sunlight cycle' for years The way they toggle On/Auto/Off is BEYOND annoying tho - "press hard-to-see button and guess what mode it's chosen"
Interesting video as I have a few of these and had biffed a couple with this fault. On another issue have a delonghi Vacuum with the motor not running at full speed. Brushes and armature are good but It has two identical capacitors on the circuit board. If one or both of these were faulty would it cause the motor to run about 15% slower? They are Polypropylene Film 0.33uF 275VAC X2
1:21 My sister has a vivarium heater relay that seems to have that failure - load buzzing and clicking from the relays. Can’t see anything obvious wrong, but would the dropper capacitor be likely culprit? If so, you’ll have saved my sister about fifty quid, and I will have the satisfaction of not having to throw something electrical out.
@ Thanks. I can probably get them for under a quid from one of the electronics shops, so I’ll try checking the capacitance, and then swapping it out. She said it stopped working after a power cut, but I can’t see any signs of a power surge having damaged it.
If it uses a capacitive dropper then that capacitor is a suspect. If it uses a switching power supply with a transformer or inductor, then the electrolytic capacitor on the secondary side is the main suspect.
@@cortanajpn It was probably on the edge, having deteriorated over time, and the surge caused by the mains appearing part way through the AC cycle across the discharged capacitor may have finished it off. These capacitors look OK unless they have had a catastrophic failure. They are "self-healing" - designed not to explode if the dielectric gets pierced by a surge.
I was expecting you to say the fingertip of the glove was lopped off so you could test whether capacitors were discharged.
That too.
Best done with tongue 😊
@@RS-Amsterdam - 🤣
If, you touch the capacitor with your other hand... it feels like, someone else, is doing it... 😄Cheers-
Good fix. Great work. Note at 3:40, unit powered on, gloves on, moves meter and brass screw driver rolls toward exposed live module. Was expecting sparks and a loud bang. Oh well, next time perhaps.
Yeah, I really should add an anti-roll thing to that driver.
Next time gadget, next time.
I thought the exact same thing... Previous experience? Maybe.
ElectroBOOM ⚡😂
My anxiety was high during the video, not because of you handling mains voltage (you know what you are doing) but ... that screwdriver 😮
Your "problem solving" videos are my favorite, Detective Clive
Deteclive
3:40 just for a bit of jeopardy and excitement we will just scoot a metal screwdriver a tad closer to the spicy boomy bit.
This was such a stressful watch experience. Clive moving the meter and bumping the brass screwdriver, (and the small screws rolling about) were just about a short circuit BOOM 🎆 away!
I don't think he would have wanted to compete with ElectroBOOM 🔌.
Another "trademark" etching of the table averted !!! 😆🤠😎
I was watching that screwdriver rolling closer to the powered PCB. LOL.
Yes, my heart stopped for a second seeing that.
I felt the same way!
Available for a few years in Tesco, I found them to be pretty reliable even if you're just using it to check the time, I wondered what they were like inside, thanks for showing!
I have a new Tesco one here. I should open it and have a look inside.
@bigclivedotcom ahh, please do 😅
Nice one Clive
Awesome....a rare fix video from Big Clive and a successful one at that! Add to that the totally thorough, electronic engineers explanation of causes and remedies in the video description and we have one heck of a video...Thanks Clive...
Ah, another night owl. Over the Christmas holidays, I've gradually rolled forwards to my natural 5am bedtime. Getting up for work this morning was brutal.
I love how every piece of equipment has modifications that would drive some organizations insane but make your life easier because you have at least a basic understanding of how stuff works.
Nice to know about the Battery fix and problem. Here in the USA the most common time switch always has the same failure in that the Zenor diodes short out. It takes a bout 9 months for the under rated Zenor's to die. I have repaired 4 of them so far by replacing the Zenor's with higher wattage units of the same voltage rating. They work fine after that. But now I know about the battery's lifetime problems. So, thank you Clive for sharing this video with us.
I had some with failing mains voltage capacitors. Running at 230V, 50hz)
I never replaced a Zener
I always replaced the battery with a standard aa rechargeable battery.
I don't use those any more.
Those tiny batteries are expensive for no reason., aa is cheap and indestructible for infinite trickle charge
@@CyberlightFG Must be some differences with the units they sell in the USA for 120 VAC only, never had a failure other than Zenor diodes. But I do expect to see the batteries fail now that I have seen this video.
I repaired two of these a couple of months ago. I had to replace the electrolytic capacitor and the x2 dropper capacitor.
The failure mode was the following:
When plugged in the relay would turn on and off.
But when the controller was on an you plugged the time-switch in the relay wouldn’t turn on. You first had to toggle off and on again.
I only noticed this after a power outage.
Great video :)
Hi Clive. Love the channel and have followed you for several years. I have 5 timers that use the same logic module and after the first year 2 of the batteries leaked (1 did a very spectacular explosion inside the case as it shorted the 13 amp contacts with conductive fluid and left copper plating all over the board). I have now replaced all of the batteries with AAA cells and have had no further problems even after 8 years. Love the LED hacks keep up the good work.
Had a similar looking immersion timer that the backup battery failed, a Poundland garden solar light became the donor and it was still going strong 7 years later when we sold the house. I feel quite chuffed but it was all down to your solar light reviews,cheers Clive.
Thanks x2 - first for the video - always a fun puzzle to guess ahead - and Second, for the detailed analysis and commentary in the notes.
You had me tightly clenching the arm of my chair as you were trying to measure the Zener diode with that nice brass screwdriver rolling around on the bench just needing a very slight nudge to send it under the energized PCB and give us a fireworks display.
Getting the solar light just for the battery is fascinating. Just checked prices: The battery by itself is actually more expensive than the whole light 🤯
That's actually a good reminder to check on my time switch.
It's been sitting in a box for quite some time, and I suspect the cell has probably failed.
nice detective work. I'm slowly getting back into some electronic detective work using channels like yours for inspiration and learnings. much appreciated. love your work.
Omg I can't believe you did a video on this exact unit. They're sold by grow shops for indoor grow operations in my part of the world, and they are known for welding shut from taking inrush load current of magnetic HPS/MH ballasts.
The random button is the first thing to go. Who thought that was a good idea, and so easy to bump!
So satisfying to fix something and not bin it ! Well done Clive and Happy New Year matey :)
👍 another great video Clive,
I’ve got about four by the looks, identical around the house, one permanently powered for an outdoor pond fish feeder, the others as random night lights for when I’m away, never had any issues with any of them 😊
I've got a couple of these. I was quite surprised that, not having used them for years, the backup cell hadn't gone crusty and still worked. I was using one to switch a solar inverter temporarily and it welded the contacts of the dreadful Songle relay. So my cannibalised repair was with a slightly less dubious relay from another timer and it's been fine since.
I've got a couple of timeswitches exactly like that, but they have weird anti tamper screws that I can't find any screwdriver for. However at present they both still work. I have a mechanical one somewhere that quietly self-destructed after only a few months.
I've got one or two 10 year old time switches with the same problem. Thank you for giving me a heads - up, and I'll probably have a go at repairing them (with the "at risk" components all being replaced).
Warns about safety. Doesn't discharge the cap, leaves a metal screwdriver right next to a live board. Classic Big Clive! :^)
I have one of those, and it’s still working after more than 10 years of use - well technically it’s only used for less than a month every year to switch our outside Christmas lights on and off. The display goes off after about a month once it’s unplugged (stored on a garage shelf), but returns with a push of the reset button once it’s plugged back in. I guess in reality that running the battery flat and only having “used” it (plugged in) for less than 12 months in total is the solution for a long life?
Great video as always.
Maybe put two conventional and one Schottky diode in series across the cell, limiting it to about 1.5V?
Thanks Clive. You taught me a good process for going after this kind of issue. Great work as always!
I've had one of these since 2021. The fact that it's lasted over 3 hours has quite surprised me!
I am yet to watch this in its entirety but this is fantastic - I have one of these time switches that does this too so here's hoping...
"Do not drink gasolene" - well thats my evening ruined.😢
Wow, such an unexpected failure point given the symptoms. I love you getting the battery from a cheap solar light, cheaper than ordering online.
Very interesting, but also, educational - love these "how to" videos...always something to learn
I just watched a video from Adam Savage on conductive fabrics like sticky tapes, Velcro, etc. Apparently it doesn't require resistors for LEDs because the very fabric has built in resistance. I thought of you immediately, incase this sort of thing hasn't reached your radar yet. Cheers and Happy New Year Clive!
Unbelievable! I've just repaired 2 similar units with the same fault just before Christmas.
Yep. They mostly fail like that. Even the mechanic ones.
I had a similar issue with one of the mains power monitor devices. Though in Australia, it was more for the battery than to buy a whole new replacement unit. Australia still hasn't got on to the whole reduction of land fill.
Ta for pointing out the obvious source of cheap NiMH cells to replace those in timers that have failed. I've seen solar garden lights for as little a 50p in a Sainsbury's end-of-season clearance but never thought of them as a source of backup cells.
BC: Warns about danger of working on unshielded live equipment. BC: Performs live test in immediate vicinity of tubular metallic objects that could roll under live PCB. Conclusion: BC has no fear (certainly of H&S staff).
Happy New Year, BC. Lang may yer lum reek and your screwdriver turn.
I like the glove with one finger cut off for touch screens, the same finger that is also used instinctively to touch other things and pointing at live electronics :)
Very nice job there. I think that to finish the job I would have replaced the zener with one with longer leads with small loops in each to raise the zener away from the board.
There was the temptation to replace it with two 12V zeners in series to spread the dissipation.
I have that timer but it’s working at the moment, but handy to know when it fails 😊 thanks Clive
Elementary my dear Clive Holmes, when all possible errors have been eliminated, whatever is left is the fault. Well done mate, most of us would have slung it in the to do drawer, and popped off to Poundland and bought another iffy plug in timer. Good job 👍
I remember when I used these and the analog ones for Christmas lights.
They didn't like the cold...analog ones would just not turn properly and battery on the digital ones would usually fail and explode.
So glad to have smart plugs for this now.
Handy info , thanks Clive ❤ I've just bought the same model from Morrisons for my lava lamps , so I'll know what to do in a year or so when the same fault inevitably appears.
I've used the timer module from a Tesco version as a compact timer for a Land Rover, to power up the fuel burning heater to preheat the cabin in winter.
It worked very well for the task, and used basically nothing from the 12 Volt vehicle battery.
Thanks for the video! ❤I have the same timing relay with the same problem. So far it hasn't bothered me, but now that I know the problem, I'm going to fix it. Surprisingly, it doesn't lose the settings even after 2 hours of power failure.
I have one like this. It was unplugged for a long time and the screen went blank. I left it plugged in for a few months and it still did not come back. I opened it up and gave the cell a charge at the bench. It was working fine since. I now park items like this which I know have cells in them in an outlet strip which is only on a few hours a week (at the washing machine) to keep the batteries up until I need them again somewhere else. I don't see the need to leave the washer plugged in anyway so it all works out.
With many of those units, if the display has gone completely blank & it doesn't come back on after being plugged in for a while again, you normally have to press the reset button once or twice to make it display again.
@@NOWThatsRichy Good point! I have encountered that on calculators. The one I have has no reset button but perhaps that was a bean counter delete and my poking around did the same thing.
Thank you Clive that should save someones job when they can fix a problem just by changing the batteries out on some old system that now doesn't have to be replaced. Jim from Scotland
Interesting to know.
I have one of those timers, possibly 30 yrs old, which is working fine but I now know what to watch out for if it fails.
Me too
Thanks for this video Clive. I had the exact same make and model as this, and mine failed in exactly the same way too.
I’ve long had two of these units providing occupancy lighting when I’m not at home. Hopefully they are still working as I’m not currently at home.
I got one of those from Aldi a year or two ago in The Netherlands, obviously a 220/240V one. Been working fine so far, got a rechargeable internal battery inside.
This reminds me of a not so fun childhood anecdote/memory:
Back when I was maybe 6 or 7 my parents had a slightly similar timer plug that I liked to play with when it was not in use.
But one day my father suddenly disliked it and slammed the timer against the floor.
(He very angrily said something like Wanna play with the timer ?! Play with the timer ! Now that it's broken...)
It popped two of the screws holding it together and the case was partially open at the top.
I don't remember how but I closed it back somewhat, maybe using tape to keep shut then I plugged it but unsurprisingly it wasn't working anymore.
The red LED was faintly glowing but the timer wasn't usable although I don't remember if the display came on or not or if the outlet was live or dead.
And now I wonder what component broke and how fixable it would have been if it had happened nowadays.
Instead of cutting the tip off, just stick a bit of foil on top of the glove.
The capacitance from your finger to the foil (and thus to the screen) is enough to operate a touchscreen without risking electrocution when you touch other things with an exposed fingertip.
This works on my phone.
About those disclaimers: The manual for old cars had information on how to time the contact points, what order the spark plugs ignite, what torque the head-bolts needed... Modern car manuals just say "don't drink this liquid" and "don't touch those moving parts" or "don't slam your d**k between the doors" .....
The manual for my car is 550 pages!
@@lint2023My newest car is like this and the manual is still mostly useless!
@@lint2023 It was sarcastic exaggeration ;) Yes, car manuals still have a lot of info, but not nearly as much as they used to. And a lot of warnings that should be common sense.
@@angeldelvax7219 I wasn't pushing back on you and I apologize for letting it sound like it was. I should have included that it is 550 pages and has no real maintenance information like you described. I liked the comment you posted about manuals from earlier times.
@@lint2023 Probably a combination of my autism, and the "state of the internet" as far as general negativity goes that gave my that idea ;) These days I find myself automatically in deference mode when replying :(
Good fix.
I usually modify the circuit with a second, 9V zener (lower might work as well, have not tried it) with a transistor in series in parallel to the existing one and switch that inverted to the relay coil. Increase the 2K7 resistor and add a zener parallel to it (make a crude voltage regulator, to not overcharge the battery). It drastically decreases the standby power and they last longer.
I saw few of this timers and power meters where battery wasnt charged through voltage divider 22K/2k7, but only by resistor - something like 22k from 24Vsupply and when NiMh battery fails to open circuit, full 24V appears on low voltage microcontroller and (intentionaly) burn unit. I always added Red LED parallel to battery.
Thanks. Repair vids are my favourite.
I have exactly the same timer switch. I think I bought it from Wilkos.
The battery died in mine and I think it was a lower mA than your example but I replaced it with the same as yours has.
Mine just wouldn’t hold its time, although I hadn’t used it for ages and the battery must have drained too low. I guess that’s the issue with this type of battery.
Ironically I have an electric razor that was stuffed in the back of a cupboard and I kinda needed it. I thought that this bugger is going to require a new battery, but no! Lo and behold it charges and doesn’t run down rapidly either.
I recon that’s progress for you!
Great videos BTW 👌
I have owned many of these over the years. They work great for hydroponic systems.
Interesting to know that a lithium cell going bad isn't always indicated by a lower output voltage . I knew batteries go higher impedance through working on laptops over the years but I don't think I've ever thought that the output voltage could be higher than normal. I usually think about it's behaviour as reaching "full capacity" ( a false state ) too quickly and then discharging immediately. Very useful bit of information which really, I should have previously thought about more.
Clive, not a week too late. I have the exact same timer (although with a proper EU plug, not that huge bulky UK rubbish ;) ) that went south a few days ago in a similar way. Since I don't like throwing things out to landfill I'll check if my NiMH isn't shot as yours was. Especially that it was unable to keep the screen lit for more than a few minutes when unplugged. Cheers Sir!
Good diagnostic and repair! From your comments, I'm convinced this was not the first time switch you disassembled 🙂
I expected a low value cap, like my remote controlled switch.
I think I would have fitted an AAA NiCad and reduced the current with a 33K resistor
(had I managed to work out the battery was at fault).
Nicely done Clive*.
*(Note a "sir" no longer has a positive value, but you deserve honouring for your service to education & entertainment).
Tricky one in that the battery was still good enough to power the circuitry when the device was unplugged.
That's why I grabbed a few of those old-timey timers with the spinny thing, motor, and 48 tabs that you push in or pull out for half-hour intervals. They Just Work.
I sometimes use an old shaver socket as a cheap isolation transformer. That way I feel more relaxed about poking my fingers in a Live pcb. I believe the shaver socket is current limited aswell reducing the flash bang surprises😅
I have some similar time switches from Homebase; ordinarily, they operate quite happily, but if the load is anything especially inductive (even a small electronic ballast for a domestic compact fluorescent), they tend to self-reset after the relay has switched the load off (probably back EMF or similar). They are fine with LED equipment, however. An equivalent product from B&Q (made to a completely different design) is made of tougher stuff, and is much more capable with induction switching - not that I've tried it on a 400 W SON circuit (yet...), mind you!
Yes, a lot to be said for all of those safety warnings, though "forgetting that the mains is on" has been my biggest downfall - wiring up a 135 W SOX ballast to a table lamp (as I didn't have any spare bayonet lampholders at the time) was my first zapping (nice belt off the capacitor too), and because I don't learn, I made contact with a completely non-IP2X terminal on a mechanical time switch case not too long after that...still just about here to tell the tale, mind you!!
The warnings can still be useful just as that regular reminder. I do think people can go overboard as usually all you really need is a quick “This is mains voltage. Don’t be stupid.” You don’t really need to go into crazy detail every single time it pops up. Liability is a lot more nuanced than many people think. Otherwise a lot of things that we’re used to wouldn’t be available.
I prefer people using actual protection like isolation transformers and/or inrush lightbulbs and dedicated workbench FI and mentioning them. (Having said that it’s good that Clive at least mentions sometimes to use battery operated (ground isolated) scopes.
I remember having to change batteries live to avoid losing the program. I kept a second soldering iron with the earth disconnected specially for that product.
Well done and happy new year big boy 😊
I have the same one, no issues but good to know how to fix this issue, thanks big man
Nice fix and Thanks Big Clive. Watching you trouble shoot stuff is a master class for sure.
Curious about the Zener Diode running hot. Is there a fix for that. The discoloration seemed legit. Would a different diode of the same voltage handle the current better?
A higher wattage diode could be fitted, or two 12V zeners in series to spread the load.
Some units use a switched resistor that turns on when the relay coil is off.
Some older PLCs use rechargeable cells or capacitors to hold the operational program of an industrial process.
Tends to be the one thing nobody checks, or has read the manual to know to check.
I don't really understand any of this, but it's comforting background noise and reminds me of my late partner
The Zener diode and its associated components are looking like a future point of failure with that scorching going on. I have a pair of gloves just like that, Clive. Mine are the left handed version, of the index digit touch screen feature.
Well, hot on the heels of meeting you in a dream, Big Clive, you're tearing down my timeswitch! ... I have one of these timers, which I bought in Wilko many years ago. It's currently in use, switching a USB Plasma Ball on and off at the side of my bed! It has a built in rechargeable battery.
EDIT: The LCD display is REALLY hard to read!
I wouldn't mind watching re-flowing the pcb soldering.
Any one else feeling that recent videos are getting shorter, and jumping too quickly to a summarized ending?
I miss "the boring parts" (-actually the best parts) - of watching and hearing every relevant, as well as irrelevant thoughts during the whole process !
And, why haven't I heard you say "masticating" in like 4 ever !? 😛😁😁
Also a Screwfix special. Maybe time to go back to using those old school rotary timers.
還是一個使用「1:56黃色安規電容」7:11廉價電子產品常見的阻容降壓電路 故障常見因素可能是阻容電容器正常損耗所以電流越來越低導致無法對電池充電與對電磁繼電器線圈供電 推動電磁繼電器 以及無法給微控制器正常供電
分壓電阻保護了定時器的微電腦 以及充電電池
10:51可以對分壓電阻輸出處並聯一個紅色的 LED 或是提高22KΩ阻值 以及改成高功率齊鈉二極體
I have found that these timer circuits use very low voltage logic for the clock circuit, typically 1.5 to 2 volts ( spec value of 1.8 volts). These misbehave with any small over voltage on the supply rail. It seems bad practice to use the standby battery as the supply regulator. When the battery inevitably fails it has a tendency to destroy the timer circuit with prelonged exposure to the over voltage on the supply. A problem I discovered on a radio locked version of one of these switches. Such is the poor tolerance of this type of logic to excess supply voltage, it is difficult to add any protection, such as a second zener diode or an LED( acting as a zener) to protect the timer from damage when the battery goes high impedance. Its only protection is the current limiting provided by the resistor divider in the battery charging circuit.
I used to work as a KP, I found some durable gloves from Wilco I know they went bust but they did have some good gloves both for touch screens and dealing with hazardous chemicals usage. Perhaps they return online only
I see this failure mode at work sometimes. We have an older generation embedded controller that uses a NiCd/NiMH battery for NVRAM.
Predictably, this battery is usually trickle-charged by an onboard charger somewhere in the system when it's powered up.
After ten plus years, the battery will go screwy and allow the voltage to rise higher than it should be on this rail.
This'll actually crash the controller in wild and screwy ways that aren't exactly intuitive. Replacing the battery fixes it.
Maplin Precision Gold meter, I still have a couple I use as well.
Where would we be without the Pound Store - long live Poundland 🙌🙌
Before making safety claims for PPE it's a good idea to test it. Especially if it's black because quite often, especially if not electrically rated (or worse it's ESD-rated), the pigment used is often something conductive like carbon black.
It will be interesting to see how many of the radio locked versions of these time switches continue to work after the Droitwich RTS signal on 198kHz is switched off after June 30th this year.
Nice to see you fix something for a change 😅
Almost everything I take apart gets rebuilt.
I have 3 of these, the oldest one is a genuine Smiths model, the newer ones like yours are generic brands using the same case design & button layout but with a smaller display panel, the smiths one must be over 20 years old, but no longer works, (the relay only stays on for a few seconds, then turns off on it's own, no matter what the timer is set for).
That does sound like the classic dropper capacitor fault. The capacitor can't pass the required current to keep the relay latched on after the electrolytic has given it the initial bump.
I have a 23-year-old time switch that hasn’t got a built-in battery, but relies on a changeable AAA battery. As it isn’t charged by the device, you can both use primary or secondary cells. Quite neat.
I dislike the use of capacitive droppers in devices with relays - including motion sensors. They waste a lot of energy when the relay isn’t powered (usually 0,7 W up to over 1 W). I wonder why the manufacturers don’t use switching power supplies that, as a side effect, need much less space on the circuit board and have a more stable output voltage. Smart plugs usually use switching PSUs with a quite low standby power (~ 0,2-0,4 W), so why can’t other other devices?
Component cost probably. A simple capacitor dropper is cheaper to implement than a switch mode PSU.
Clive regularly takes the opportunity to test his house hold RCD. Applying a test probes to a faulty PCB 😊 out go the lights.
The NiMH cell was my first guess because I had to replaced the battery in a similar device already twice. It was obviously already leaking. Worked perfect until the new cell was toast.
I have a really ancient one that switches on\off my internet router each night. It uses a PCB mounted Nicad in it - not easy to get hold of a new one of those these days. Over the years the LCD display did the opposite of this and was getting fainter to read. After replacing the Nicad all is good again. It would be nice to add an ethernet interface to it so I could power off my internet router remotely from my PC.
Just a thought, would it be beneficial to put another diode in series with the isolation diode going to the battery? This would drop the charging voltage from 2 Volts to 1.4 Volts, a better trickle charge Voltage for a Ni-Cad battery.
That could be a bit random in the result. The forward voltage varies with current.
Hi Clive, For your own personal safety I'm just wondering if you use a mains isolation transformer when working with open appliances. When I was a teaboy (in the 1960s) at a local electrical shop I recall there was one installed under the workbench but don't recall you ever mentioning them.
I use a type A RCD.
I came across a bit of commercial equipment that was 'cost optimised' beyond reason. Rather than using an (e)eprom for the program they used half of the battery backed config SRAM (6116 I think) to hold the program. A bit of logic inhibited writes to the half that held the program. It all worked fine until the rechargeable battery aged and power was removed from the device for any reason. Then the cell voltage would drop below the voltage required for the low power mode of the SRAM, draws microwatts in that state, and the program became corrupted and device no longer worked.
We have 2 of those - one of which kept our Bearded Dragon on his 'sunlight cycle' for years
The way they toggle On/Auto/Off is BEYOND annoying tho - "press hard-to-see button and guess what mode it's chosen"
Interesting video as I have a few of these and had biffed a couple with this fault. On another issue have a delonghi Vacuum with the motor not running at full speed. Brushes and armature are good but It has two identical capacitors on the circuit board. If one or both of these were faulty would it cause the motor to run about 15% slower? They are Polypropylene Film 0.33uF 275VAC X2
It could be many things. If it has electronic speed control the power supply may be struggling to drive a triac on one half of the sinewave.
"3:52 am...I should probably be in bed! Anyway, so here's the device..." :D Yup, that's Clive!
1:21 My sister has a vivarium heater relay that seems to have that failure - load buzzing and clicking from the relays. Can’t see anything obvious wrong, but would the dropper capacitor be likely culprit? If so, you’ll have saved my sister about fifty quid, and I will have the satisfaction of not having to throw something electrical out.
Yes, these capacitors deteriorate. There are all sorts of things you can salvage them from.
@ Thanks. I can probably get them for under a quid from one of the electronics shops, so I’ll try checking the capacitance, and then swapping it out. She said it stopped working after a power cut, but I can’t see any signs of a power surge having damaged it.
If it uses a capacitive dropper then that capacitor is a suspect. If it uses a switching power supply with a transformer or inductor, then the electrolytic capacitor on the secondary side is the main suspect.
@@cortanajpn It was probably on the edge, having deteriorated over time, and the surge caused by the mains appearing part way through the AC cycle across the discharged capacitor may have finished it off. These capacitors look OK unless they have had a catastrophic failure. They are "self-healing" - designed not to explode if the dielectric gets pierced by a surge.
Just in time too, also.!
Good job Clive.😆