Fixing a digital oven timer module.
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- Опубліковано 10 бер 2016
- This timer module is a very common component used in a wide range of European ovens and possibly in other parts of the world too. It seems to be prone to progressive failure, with the display getting dimmer and dimmer until it just stops working completely.
A replacement unit costs anywhere between £40 and £100 depending on where you buy it, and if you get an appliance service engineer in to change it the cost will be even higher.
These things are easy to change. Once accessed they simply unclip and the connections are a few spade terminals that just pull off. As usual, you should take a picture of the way the wires are connected before disconnecting them. But in this module there were just four wires. Live and neutral to power the unit and two connections to the relay contacts that obviously switched power to the oven.
In this case the metallised film X2 capacitor used as a capacitive dropper power supply had dropped in value from its original 330nF to just 56nF which meant there simply wasn't enough power to run the clock/timer circuitry any more. Note that for different styles of timer (some have two relays) and different supply voltages, the dropper capacitors value may be different.
If you enjoy my videos you can help support the channel with a dollar for coffee, cookies and replacement capacitors at / bigclive - Наука та технологія
Must be cool to know your video is still helping people 8 years down the track. Fixed my problem and saved me a truck load of cash. Thanks for sharing.
Having been born in '88 I may be young to say this, but it's always refreshing to see someone else willing to attempt to do a repair (or at least failure analysis) on goods more often considered "disposable" these days.
Honestly, 75-80% of the time I just want to know why it broke. The potential reward of being able to return the thing to working order is merely bonus points.
Sir, you are a genius! First time I've ever seen this cooker clock working and so cheap.
I cannot believe you got away with those opening lines. Pull the knob off etc. You are a bad (and funny) man Clive :)
So bizarre, long time follower of big Clive, & when “I needed to find a fox for an old cooker he comes with the fix in a video from 8 years ago , thanks mate your a diamond, cap is ordered..
Thanks for this just replaced the said capacitor and all working fine, will send the £50 replacement back when it arrives
Big THankyou for this repair advice. Just saved me over £100 . replaced a similar capacitor to yours, had to order 5 though. Wonderful. Keep up the good work.
Hey Big Clive... love your channel. I have nearly 45 years of hobby/professional electronics experience, and VFDs have always been one of my fave components. I have a few bare VFD tubes in my parts box that have been there well over 30 years... I just don't have the heart to dump them. I wanted to comment on you finding AC on the cathode heater element. Any properly designed VFD circuit will use some form of AC or switched supply. The problem with a DC filament supply is that, as you pointed out, there is typically about a 1.5 - 2V drop across the heater. This means that the cathode voltage will be 1.5V higher at one end than the other RELATIVE TO THE FLUORESCENT ANODE. This makes the display brightness vary noticeably across the face of the display. Using an AC heater supply will give an AVERAGE voltage at ANY point on the cathode of half the total voltage, which solves the problem.
You don't need a sinusoidal AC supply, in most of my old VFD designs I just switched the two ends of the filament 180 degrees out of phase. You can use an H-Bridge for this, but depending on the size of the display you can often get away with using a resistor to Vcc on either end and a bipolar transistors to alternately pull each end down to ground while letting the other end get pulled up to VCC. As long as you alternate the drive circuit fast enough the switching filament voltage will be smoothed out by thermal inertia and you won't see any flicker.
Cheers.
Thanks for sharing this video really helpful.
My failing AEG oven timer unit had the same fault, resetting itself with a constant buzz noise.
Replacing the capacitor saved the money and brought the unit back to life.
Just cheked a certain 'E' site for those and I'm shocked Clive - they cost so much!
I love fixes more than buying and this is so simple. Cheers!
"If you want to pull your nob off in front of the oven..." I had to stop the video as I was laughing too hard. Now go back and re-watch the first minute of the video and listen to one of the best monologues in UA-cam history!
😂😂😂
Thanks mate.... saved me a new oven.... just repaired my Chef Finesse wall oven, a little different but fixed by changing the capacitors!
Don't know why I've never watched this video before, thought I'd watched all of your earlier ones. Seems I missed a bit of a classic, too! I prefer to tug my knob off in front of the microwave, it's quicker!
So, I was just over at Ashens and they're talking about you in the comments, Clive. Apparently your voice is calming and your videos are great, even though they don't know anything about electronics.
my display went 6 month ago, i took it apart then i never got around to fixing it! Good video
Superb video as usual Clive - keep 'em coming
they use AC on the VFD filaments because it prevents one end of the display being darker than the other. If you put DC on the filament, one end will be brighter than the other- the end closer to ground. This is because there is a voltage gradient across it then. Noritake had a cute trick where their later VFDs run DC on the filaments and they compensate by tilting the filament so it's closer to the grid on one end and farther apart on the other.
+kevtris Years ago I messed around driving the filament with a hefty pulse in between driving each digit. Not sure if that's an officially sanctioned way to do it, but it did work. It meant that while the digits were driven, the filament had zero gradient across it.
I had some trouble though, the microcontroller I was using did not have a particularly high clock frequency, and if I ran the timer at a high enough frequency for the pulses to be above audible frequencies, I did not have enough resolution to accurately control the filament power.
Of course there are ways around this, but I was just mucking around in my spare time. There would be concerns with fatiguing the filaments etc.
yeah this is possible; the filament doesn't care how it gets heated, so long as it is hot enough to emit those electrons. I like the idea of pulse heating it to prevent the gradient though, that's a great idea!
Ah, this has got me thinking about VFDs again...
For a while I have toyed with the idea of designing up some hobbyist type modules using the various inexpensive Soviet VFDs that are available. Everything on-board, only requiring a 5V power supply and data via SPI or UART. Full Arduino support etc. Target RRP of somewhere around US$20/pc.
I would peddle this through the usual channels for such items.
But I am really unsure if this would be desirable... Comparable items were quite scarce last time I looked for them.
May I ask for opinions on this matter?
Edit: Had another look. There have been some reasonably priced, fairly capable looking modules released but it appears they did not do overly well. Perhaps this ship has flown.
+kevtris Thanks for reminding me what the DC drive trick was.
Would not doubling the cathode back on itself achieve the same thing ?
I seem to remember that running the heater wires on dc will work but it makes one end of the display dimmer.
A.c makes sure that does not happen.
Well done clive, a simple fix ;-D, and that capacitor looked ok as well, deceptive.
+zx8401ztv Had the same problem with my refrigerator. Whenever you opened the door, the light would turn on, then the whole fridge would go dark (incl. the temp. display) and light up again only to go dark again and so on. It was also the X2 dropper capacitor. A 2€ piece. If I had called some company, they would've switched the whole control unit for a few hundred €€€.
+Markus Birth (mbirth)
Oh yes they would, ripoff merchants :-(
Often things fail for silly reasons, some are obviously planned like electrolitic capacitors with a short life (switchmode psus).
.
I think for your x2 capacitor i would get two capacitors of half the capacitance value and parallel them to share the work.
I dont trust manufacturers much.
+zx8401ztv There's a video specifically about their failure mode. ua-cam.com/video/qGc9-ToEiIQ/v-deo.html
+zx8401ztv Yes, that is the problem of supplying DC to VFD. If I recall good, different "cooking" of the electrodes as well.
The film capacitor usually fails like that, lowering value, unlike electrolytic which get dry, increase ESR and end up popping. Advantage: you don't need an ESR meter :D
Also it is a must check when repairing ballasts and half-bridge power supplies where a film capacitor 'suffers' all the current trough it.
+Electronica y Reparaciones
Ooow im thinking about the capacitor that connects to the half bridge primary winding end, i think that is the one you are hinting at :-)
Typically 1uf in value for small supplys?
Excellent work Clive
My failing AEG (Electrolux) oven clock had exactly the same fault. It's another common unit with LED display and three buttons. It would constantly re-set itself and the relay would buzz away like a mad thing. The dropper cap was kaput and replacing it brought the unit back to life. Saving £70 ish !!!
What model is your cooker?
Interesting introduction...! Yeah, Creda cookers from the 90's have these. I could never understand why there was never a battery-backup for the timer. A power-cut lasting only half a second will reset the time to 0:00, and also wipe your oven Auto on/off settings. Even a large electrolytic cap would give a little buffer, but everything costs money I suppose.
*glorious*
I have a very similar oven clock at home and got annoyed by the constant buzzing sound it makes. (and that it consumes power for nothing.)
Brand: Diehl
131 47-001
Typ: 311-20 T120
Props to you for showing how to further diagnose and possibly fix such a device. I just disconnected it. (but was curious enough that I did find your video.)
I fixed a Siemens wireless heating controller a few weeks back and it had the same dropper capacitor and the same failure mode exactly. I ordered a replacement cap from Farnells and had the exact same problem with the footprint as well!!
Interesting thing to point out about these is that they use line frequency to drive the clock rather than a crystal (most do anyway)
The trouble is it only costs a few pounds for the part but tons for the labor . unless you are a man with your talents well done
Well.... I guess we all solder the same way: hold the board with three fingers and the solder with the other two. Great dexterity, Clive. :)
Cheeky git. :) I love your videos, Clive, they're very interesting and tickle the imagination.
Filthy beginning lol
+cremationpete The subtle art of smutty double entendre.
+bigclivedotcom Subtle eh ? lol.
+Dan Harris That was nearly triple entendre.
I thought the same, so I thought "is it me or what".....? so I look in the comments to see if others commented on it hahaha lol
+Ben McKenna Clive is the best one on UA-cam doing tear downs, reviews and repairs. Julian Illet is good too! John ward does my head in, irritating little man, I just watch him to fill my hump of hate lol. Usually get a laugh with Clive though.
3 Indesit & Hotpoint Employees disliked this video
Where I work we would say, "Cap it!" meaning replace all of the stupid things.
Cheap insurance when the work is warranted for 2 years! ;)
Thanks for the VFD explanation!
I understand that people have used the large complex ones to build audio amplifiers and such. They really do seem pretty cool.
Thanks big man- just what i needed.We bought house with oven timer kaput.Will investigate
VFD heating filaments are mostly AC driven to avoid uneven illumination.
When for example the heating voltage is 6 volts and the driving voltage is let's say 30 volts then the voltage drop across the heating filament is significant compared to the driving voltage. 30 volts on one side of the display and only 24 volts on the other side. Thus they are AC driven to lessen this effect.
I've seen that bloody Digikey advert 3 times today, on your channel, John Ward and Dave Savery. I'm already a customer, enough!
If you have the same issue with an oven which is similar to this you can check get your main oven to work by disconnecting the two tags on the relay which looks like the one on the left hand side when the clock is rotated around showing the back and connecting them together. This will bypass the relay which will activate when the clock is set to allow you to use your oven.
This is a safety feature to prevent the appliance from automatically powering up if you had children who like to fiddle or you had a power cut for example.
I've got a Beko oven and the module started doing a rapid reset. I had a quick look but didn't determine a fault, so bypassed it to use the oven. I will revisit this as it will most likely be the cap. Thanks! While I'm at it, I'll pull my knobs off. Oo-er.
Pull it gently until it comes.... Right out. Oh Clive. Love your videos!
I didn't know about the reactivation trick by passing a high current through it, but the same trick is used to clean the filament that emits electrons in scanning electron microscopes ("flashing"). The vacuum gets contaminated and the filament gets coated with crap; passing a high current through it just burns it all.
Thanks Clive! Another good 'un!.
Everytime I see how you are holdingg the things while soldering im impressed because my hand would crack if I would hold the things in this way.
+Max Power Years ago I saw that used in a TV repair shop and tried it myself, not so successfully. A little daily practice and about a week later it was if I had always been doing it like that. Nowadays it is not so easy what with lack of practice and older hands although it still beats trying to use those third hands and assorted fixtures for small items.
Mike (o\!/o)
Experiencing Technical Difficulties
Maybe I should practise a little bit because it looks kind of cool and is practical.
Max Power Just practice manipulating small items like screws and nuts, tying knots, etc. Soldering can wait until you are able enough to not have to endure burns and the like. Kind of like juggling, don't start with chainsaws.
Mike (o\!/o)
the drill sound is fine the scraping was spine tingling
As I followed the instructions about pulling the knob off.......it quite took my mind off the broken timer and it's repair, many *anks.....sorry, I meant thanks.
That intro was pretty epic
Learning all the UK slang from you.. got muff and knob so far, so my anatomy lesson is almost complete
There's a dictionary full of them on google, type in something like "UK English slang dictionary"
"Footery" is Scots dialect, not UK slang.
+zh84 Scotland is in the UK 😂
I used to work for Currys and often noticed how different appliance manufacturers used almost but not quite the same layout for controls and I do agree that the optional extra (but unused) contacts are likely there for use on different models, even different makes, even where Swedish Megaconglomerate Inc. hadn't even bought out (yet) Howthehelldotheycompeteonpricewithsuchsmallvolumesales of Wednesdbury West Midlands UK ... (before they went bust of course). Highly entertaining video as usual!
+Robert Horwat In my base-model Indesit washing machine the control panel has a PCB with all the locations for the extra knobs and buttons used on the "luxury" models with the only major difference being a different front panel and different software. (Which can be programmed from the back of the machine.)
I didn't get any of the innuendos at the beginning, didn't notice anything wrong with what you said until I read the comments. I guess I'm not as dirty and/or bright as I thought.
On a completely unrelated note - Clive, could you please show us some overview of your workbench? I would love to see all those bits and pieces you pull into the shot every so often.
Fixed an LED-based one for a friend a year or so back. Same problem - the 1u0 X2 dropper cap measured 620nF which was more than enough to stop the relay pulling in. Seems some brands of X2 caps are prone to this kind of failure.
Edit: And of course when used as a filter a dramatic drop in capacitance would probably go completely unnoticed.
so if you use a 3.3uF capacitor but instead of 250V or 400V, you use a 630V cap, it will have ticker insulation so would it last longer under regular 240V conditions than the 400V?
if I use a 630V cap on my 120V supply will it last much longer?
+chems I wouldn't increase the capacitance value, but a higher voltage rating would definitely last longer.
Thank you for this video.
a "vacuum florendus err florescent display" We love you Clive!!!!!111
+ bigclivedotcom to release fiddly PCBs like that easier and with less risk - first warm the enclosure with a hairdryer for a few seconds to make it less prone to cracking.
Then gently lever with a screwdriver like you did, but push cut-down bamboo BBQ skewers in next your screwdriver before you withdraw it to prevent re-latching.
Trim some of the the sharp tip off the skewer with a side cutter if you need them thicker/if the thin tip is too long. Don't snap them - the splinters are very sharp.
The hairdryer technique works great for many types of thermoplatics to make them less brittle when you release clips and is especially important in cold rooms or if the kit has been stored at cold temperatures just before you need to open it.
Overvolting the filament heats the thermionic emitter surface (a barium compound iirc) and reactivates it. CRT rejuvenators used to do this
+TheChipmunk2008 Yeah and they use to warn that there was no guarantee it would work and that it may destroy your tube still cheaper back then to give it a go. :)
+TheChipmunk2008 They act more like a vacuum tube. The grid is like the grid, the digits like a plate, and the heater like a filament. Just like a tube, the filament/heater is thoriated. The thorium lets you have electron emissions at lower heater temperature. With the filament at a lower temperature, you get a longer life and don't obscure the green digits with the heater glowing like a lightbulb. When you overdrive the heater/filament you "boil" more thorium to the surface.
The construction of a VFD is akin to a triode valve - filament, grid & anode. And folk have been able to make it amplify an audio signal, albeit weakly, or to oscillate.
I worked at Invensys, I have no doubts about it being a QC problem. Rumor was they lost a contract once for sending a shipment of test failed boards to a manufacturer.
VFD's can be used as valves (tubes) they are closer related to a valve than a crt
I'm not 100% sure how many drinks I'm supposed to take while watching this.
+zed wolf Just enough to lose control.
Clive - I was on Patreon.com a few minutes ago checking on my pledge-ees. Then I suddenly remembered, Clive has a Patreon account!! So I immediately became patron #470!! Do you have a new pledge goal in mind? I see the last one was reached.
Thanks again for all the great stuff, Clive!!!
I love VFD dispalys
LOL Clive! your filthy mind!, LOVE it !! :D
I used to use dentist drills to drill PC Boards. They give very clean holes of a perfect size, and you can get them for free from your dentists, if s/he is willing to put them aside for you.
"If You Want To Pull Your Knob Off In Front Of The Oven, What You Have To Do Is Gently Caress It Between Your Fingers And Then Just Pull It Gently Until It Comes" - Oh yes, Clive, I liked your technique though I'm not sure if the oven was suitably turned on by the experience.
Well, the Quick Test has shipped, it was purchased from RS Components in Sydney. Its first job will be for fixing and testing a motorised roller shutter motor. Weird thing was two vastly different prices for the same unit, but under two different SKU codes.
Driving the filament with AC is better than DC, because with DC you get a voltage gradient from one end to the other, and that results in one end of the display running a little dimmer than the other.
Very interesting, timer module de Dietrich oven displays oven temperature set point and actual temp, crystal display, single button, knob to press to scroll between timer modes. When we press the button it no longer scrolls... Would be interesting to have your skills.
Unbelievable with same oven , oven light stays on,when the off zero position is selected on cooking mode selector. De Dietrichs are dear and parts scandalous. Delighted to subscribe to your channel, i might learn something!
I have one in my cooker, but it has 4 buttons plus an encoder.
And to set the time you press cook time and end time together.
Clever little thing, I've always wondered whats inside.
i wasnt paying attention and i heard "How to pull your knob off in an oven, just pull gently till it comes"
I could not stop LOL'ing in the beginning XD!.
My Whirlpool hob has a display unit exactly like this :)
Dont pull your knob off in front of your oven in front of a window,the police will arrest you for indecent exposure,among other things.lol.....
Excellent video. I have a similar timer module on my oven, where some of the segments on the display have stopped working. Consequently the display time is illegible. What would I need to do to repair the segments that don't light up please>
I'm pretty sure DC filament drive is only really an option for short VFDs as it causes a potential gradient between the filament and the grid. AFAIK the filament should be driven with AC.
+Mezgrman Yes, came here to say this... DC on the filament causes the display to vary in brightness across its length. Have seen it before in some VCRs
I always wonder what extra buttons and jumpers do, once they are installed.
If you didn't know, you can use a VFD as a preamplification tube(valve), though a crappy one. Still a fun project to do.
You may like to know that I used to be in charge of spare parts for a company that serviced white / brown goods.
Those timers are pretty standard and cost £4.95 each for the company to buy, they would charge the customer £120 to fit a new one and that was way back in 1996
I had the same fault on my cooker, in fact that module is identical to the Cooke & Lewis one I repaired, I guess they are all made in the same factory,think the capacitor cost £1.32 from eBay compared to £94plus Vat B-Q quoted.
Its common for vfd's to have ac across the heater, in fact its better for them.
DC introduces a voltage drop across the heater wire making a brighter display at one end, this isnt as bad with ac.
Proper vfd drive chips that run off dc produce a square wave for the heater using a H bridge.
Clive, do you know anything about ultrasonic wire splicing? If so how would I go about making one on the cheap :)
By any chance do you know the DC voltage out of the rectifier bridge? I am getting 0.5 volts and there is no way to know the real value of the two zener diodes test them and one is 12.3v and the other 2.3v
Clive, it would useful to shed some more light on refreshing these tubes to get better display brightness. I am sure many DIY types who refuse to buy new, simply because of age or style superseding older, perfectly good machines.
A testament to the quality of Samsung brand this mid range unit must be near 20yrs old, and though it was a trick to source the control/display module, most listings have it as discontinued or out of stock. Not cheap either. This microwave owes me nothing, but recently have been boiling stuff I only meant to reheat cause I can't see miskeyed input on the display
+Chris Leech emission may be restored by raising the filament voltage. a 33% voltage boost can rectify moderate fade, and 66% boost severe fade. The displays were designed for rugged use.
+Jeffery Rowan Thanks for that. I am going to have the unit apart to fix the door release and will do a bit of probing with a DMM to see what I have got . Mine has a few more functions and will be a little more engaging I should think. Does one need to limit the current I wonder. All I have is variable buck and boost converters running off LiPo's to get these voltages.
Whenever I repair anything with those rubber buttons with conductive studs, I clean them, and the PCB pads with meths. Most TV remotes use them and they often become inoperative after a while.
I think most devices with VFD displays run AC current through the cathodes. If it was DC, then one side of the display would be brighter than the other.
+themaritimeman - Yes, I was almost shouting at the screen 'It's AC, Clive!'. I don't recall ever seeing a VFD with a DC cathode/heater.
I think the only type where it would be satisfactory would be a single-digit tube.
I have a few of these displays, but it's doubtful that I will ever do anything with them. In particular, I've never run across any that were fairly generic, in the way that 7-segment LED displays can be. From what I understand they're all pretty much custom-made for the item of equipment that they're going into. And I haven't (yet?) run across any good technical info on these devices in general, or specifications on any specific devices.
My mother has an Amana convection range with that same sort of button layout. They would just fall out on their own after a while
First impression was partly shorted electrolytic capacitor, shunting voltage. Yet, if cap dropper fixed it, it was current issue? In either case, main input voltage or current was obvious. This because even the piezo and relay was buzzing. I've seen too many such defects as low negative supply rail as being one of the electrolytic caps being partly shorted. Anyway, as long as circuit is up and working again and relay latches as it should, its fixed.
Both informative and entertaining but the main thing I like is that it is in proper English (OK, Scottish but that's fine) not USA-ish, which grates on me unbearably, especially when solder is called "Sodder"
The innuendo i also appreciated.
The dropper capacitor going low in value over time is a really common fault in all sorts of appliances. It's the first thing to check when the product becomes intermittent or drops dead entirely.
Hi, there is a SMD component close to the rectifier bridge. It has marking QX 09 V. Any idea what that one is? A shottky? If so.. what is kathode and anode? Mine measures high impedance on both sides
Do you have one of those cheap ebay LCR meters? I got one for about $10 in kit form that measures ESR. It seems to work, but I don't have a decent ESR meter to test it against.
+KingNast You may be able to test it with low value resistors instead of capacitors.
Bigclive can you please explain how to fix a solar light that stays on all the time. I have cleaned it all out stays on in daylight and flattens the battery
Thanks
is it a phase alternating display if its so low voltage ?
How can I get someone to fix my cannon double Oven cooker. The module button not setting the time hence I can’t turn the oven on and no gas. Any recommendation or time for new cooker? Thanks
Hi I've got one of these and replaced the component as you have done. I see that the relay looks a little brown and get no continuity across it, so suspect that has failed. I'll order the component and try my luck.
If the relay is discoloured then the contacts may be burned out.
Where you bought electric test case for hot wires? how it is called?
that innuendo tho! lol
I think I liked this video..."I'm not 100% sure" :-)
firstly... "if you want to pull your knob off".. coupled with "you have to gently press it between your fingers".. then adding "pull it gently before it comes"... was that planned? if so rofl!It'd be great if you could tell us how to replace a thermostat on a microwave though... I've killed 3 thermostats in as many combination ovens and it's getting too expensive coz I don't know how to replace 'em.. please help! You're the man!
+motormusic1 If you search for your oven model and "thermostat" on youtube you may find there are already videos covering the specific models.
I like when clive is fixin' sh*t :)
I *really* like VFDs, it's a damn shame they're few and far between as far as manufacturers go. Noritake did a promo a while back where they gave away like 100 of their new VFD modules, but barring another one of those, they tend to be *very* expensive for nice ones, since the market's been taken over by x-segment LCDs.
Lovin' your videos Uncle Clive :) But for whatever reason I became curious, whilst watching this video, about just how you record/produce them. I do remember you mentioning an iPad, but how are mounting it, and are you actually viewing via the tablet's display as you work. A quick mention in next video would nice.
Thanks Clive. Always look forward to see what Uncle Clive's up to as part of my daily wind down. 😊
+MickeyDJ1 I ahve a shelf at the correct height above my bench to give the correct recording area, and the iPad sits across two pull-out slides. I have it high enough to work directly on what I'm doing, but can also check what is actually being seen too.
+bigclivedotcom Thanks for that Clive, that's satisfied my curiosity now :-D
Can't believe you're tugging on that knob at the start... Talk about Indesit exposure.
+Chrausis I though that was the hotpoint of the video.
+bigclivedotcom (Although I think I may have lost my creda bility.)
+bigclivedotcom I think you made a miele of it
+Tom Transa The timers are pretty Neff quality though
What the smeg are you lot on about?
Hi.....how have you powered this up on the bench?
Thanks
The more Big Clive videos I watch the more suspicious I become that he shares my affinity for, shall we say, plugs rather than sockets.