Washing Machine / Dryer Controller Board Repair (LNK305 Failure)
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- čas přidán 8. 07. 2024
- A tale of synchronicity and obviously planned obsolescence …
↓↓↓ Complete description, time index and links below ↓↓↓
So one week the washing machine of a friend of mine gave up on him. He was able to isolate the fault to a fried switch mode voltage regulator on the controller board. A resistor and an inductor were gone too.
The week after that I was talking to the owner of a dead dryer. Guess what: the voltage regulator on the controller board, a resistor and an inductor had it. Fortunately there are repair kits for that controller board on eBay …
00:00 Intro - a dead washing machine and a non-matching inductor value
02:48 Schematic - from the datasheet of the LNK305
06:41 Desoldering - the dead parts, plus a tale of synchronicity
16:09 Post mortem - blown resistor, exploded chip and inductor with tiny gash
17:48 Soldering - the new parts
20:10 Success - it’s alive
20:32 Remark - about the packaging of the spare parts from eBay
Repairs: • Repairs
Mailbag: Instrument Case, Lead Bending Tool, Assortment Box and Hot Plate: • Mailbag: Instrument Ca...
#robertssmorgasbord #repair #fix #LNK305 - Věda a technologie
Thanks ,very informative sir ,please keep posting more video👍
You're welcome! And I'll will keep on making videos ;-)
Very helpful, thanks !!
You're welcome!
Wow! Talking about synchronicity...I should have subscribed to your channel three years ago! A month ago my Zanussi dishwasher failed. Similar issues as in your video. The culprit in my case: a LNK362GN that failed, causing a resistor to explode (couldn't see the colorbands anymore). No repair kit, schematic or CZcams videos to be found, but after some guessing and replacing I got it to work again!
Yeah, the parts in the LNKxxx circuitry of most washing machines, dryers and dishwashers are a wee bit undersized. So they're bound to fail at some point (after the guarantee period of course). So I guess it's this is not a case of synchronicity but more a case of simple statistics 🙂 Anyway, I'm happy you were able to repair yours too.
Great video
Thanks!
Great Vedio... Thanks
I have a broken dishwasher. The SMD on it looks burnt and I couldn't be able to read the number on it..... Can you help please!
Thanks and you're welcome. If you can't read the number on the burnt SMD (note: like in my case it might not be the only component that has been damaged) you have to search (Google) for the manufacturers name and the numbers(s) that are printed on the board, maybe in conjunction with "repair". Hope that helps and you get lucky.
i have the same auto washing machine that wont turn on. the lnk430pn seems ok but the output voltages are 1vdc each in a 2x 6 pin ribbon cable. what do you should be the correct output?
Well, if the output voltage (of the buck converter I assume) is 1V, then I'd say there is something wrong with it. BTW what is a LNK430PN? Is that a typo? I can't find any information on that chip.
i appreciate the video but i would love your idea of how to really generally trace the fault of this kind of washing machine pcb's..that will be a great help thank you..
Well, it's really like finding a fault in any kind of electronic device: 1. check the power supply, 2. depends on the type of device and the type of fault. To be honest, the failure of LNK305 and that inductance was clearly visible. Without those obviously destroyed parts, the information about that specific fault on the internet and a schematic of the circuit I would have had a really hard time.
I have a motor control board that isnt working. I have taken it out and I see what is wrong with it I just dont know how to go about fixing it. Would you be able to help?
Well, maybe ... What kind of motor control board is it? Is it from a dryer, a washing machine or some other appliance? What's the manufacture/type of the appliance? Disclaimer: I don't repair appliances' controller boards on a regular basis.
Thanks for the video. I found it quite useful.
I had the same problem on a dishwasher. Replaced the lnk305 and the resistor but not the inductors. The machine is back to work but the water is not heating up.
If anyone has any tips they'll be very welcome. 🙄
You're welcome. If the water is no longer heating up the failure of the power supply (LNK305) probably has damaged some more components on the board. 😞 Finding that failure will be an uphill battle.
@@robertssmorgasbord hii, can you test the LNK305 through multimeter?
@@julietechotangohotelalphai1148 Well, not really. I guess you could check if its power transistor has a short (disconnected from mains AC). Or you could measure the output voltage of the transformer (Warning: Mains AC can cause injury and death). But beyond that a multimeter is not the right tool for the job.
@@robertssmorgasbord got it sir! Thank you! ♥
@@julietechotangohotelalphai1148 You're welcome 🙂
I've done it - on an AEG Lavatherm Protex PLUS sensidry tumbledrier - used to be dead before. Now it powers up nicely but now I get an E91 error code. Only when I remove the communication cable (the one with thin black wires) between mainboard and sub-board (the one next to pump), the error code disappears and I can start up the main interface and even go into diagnostics mode. Of course, without sub-board connected, when I try to start the machine with START button, it displays 'Err' this time not E91. As soon as I connect the sub-board communication to the mainboard again, machine powers off and back on, with E91 code. Sometimes also does 3 consecutive beeps repeatedly. PLEASE HELP !!!
First a disclaimer: I don't repair washing machines on a regular base. What I've shown in the video was a one off following some internet instructions for a friend. That said, the meaning of error E91 is:
Communication incongruence between main PCB- display board (versions not compatible). My best guess is, that when the LNK305 went some digital components on the boards where damaged due to a voltage spike. I guess the best course of action would be to get new boards. But that would probably set you back 100 to 200 bucks :-(
@@robertssmorgasbord Many, many thanks for your reply and kind advice.
@@chrisdenaro You're welcome!
My sharp front load washing machine while starting control it showing error END messages
can you help me for this problem how resolved
Nope, I sorry, but I really can't. That was a one-off repair for a friend who did all the research but did not have the equipment/experience to actually do it. Beside that board I never touched the electronics of any appliance.
So can we use LNK306GN instead of 304 and 305 ?
I cannot be absolutely positive, but a LNK306 should work . As I understand it the only difference between LNK304/305/306 is the maximum current they can handle (LNK304 the lowest, LNK306 the highest). There are no other differences mentioned in the datasheet.
Hi Robert,
I wonder if you could help me...
I've got a Bosch Drier WTB86200AU/02 which has a problem with the controller board 9000774044.
I've been to Bosch but they don't want to give me the controller diagrams.
I have taken the relay out which needs replacing but I have put a 12V=DV relay in instead of the original 9V=DC as I didn't think it matters. The 9V=DC is hard to get in New Zealand.
But it still does not work?
If I wanted to get a diagram where would I go?
Thanks,
Trevor
Hi Trevor,
unfortunately manufacturers nowadays no longer publish the schematics of their products. You can try googling for "WTB86200AU/02", "9000774044", "schematic", "circuit", "circuit diagram" (I tried it and came up empty). Unless someone had a lot of time at her/his hands, reversed engineered a product (e.g. your Bosch Controller board) and uploaded the schematics to the internet you're probably out of luck.
At least here in Europe you can usually get spare parts for Bosch. Sometimes even for a reasonable prices (though the German version of your controller board goes for 170 € here). Maybe that's an option for you.
Sorry I couldn't be of more help.
Regards
Robert
What about the relay could I use a 12v instead of a 9V?
@@videos_for_y The 12V relay probably doesn't get actuated with just 9V. Also, when replacing the relay make sure that the coil's resistance of the replacement is not lower than the original, otherwise you might damage the chip/transistor driving the relay coil.
Pls. Anybody have data sheet of tlp3062a ic used for lg fc1007s5w inverter washing machine pcb
Here's the link to the data sheet: toshiba.semicon-storage.com/info/docget.jsp?did=30346&prodName=TLP3062A
Hi...can i replace tny276 with tny278?
In principle yes. The two major difference are that the TNY278 supports a higher drain currents than the TNY276 (typical 445mA vs 310mA) and that the THY278 has higher values for the circuit protection current limit than the TNY278 (standard typical 550mA vs 350mA). The latter can pose a problem if too much current is drawn from the DC output. In that case your switch mode power supply components, being designed around the TNY276 for lower currents, might get fried. But if the current drawn from the DC output stays within the initial design limits for the TNY276 everything should be fine.
The size of L2 being 1000mH was probably to pass conducted emissions testing. Certainly not going to emit noise that would cause problems, but there to pass the emission requirement.
You're probably right. I guess it was either making L2 extremely large or coming up with a more complex (and expensive) filter.
@@robertssmorgasbord The solution is most likely the skills or lack there of of the poor slob that got stuck taking it through emissions testing. I enjoyed doing this, as I always learned stuff, but most co-workers hated the environmental labs. Mainly it showed how poor quality their design was. Stopping microprocessor radiated and conducted emissions after the design is done, sometimes just gets a quick bandaid to get it out the door.
I enjoy your channel, as I'm learning stuff. Your RS422 analysis is very interesting. The company I worked for used this on a serial bus in the early 1980s. CSDB (commercial serial data bus, but previously was Collins serial data bus). Using a standard UART was the basis of this back in the early microprocessor days. Their mistake was using a bastard baud rate, which made custom test equipment at those odd bauds for production and service center testing. But that was before my time there why they made that choice. The world is moving to ethernet for everything from what I see, either wired or wireless.
@@f.hababorbitz Well, I have to admit that this EMC stuff is not really my forte. When I have for example to integrate switch mode power supply I usually go with the reference design for EMC compliance.
RS-422 is a quite old serial interface standard, but it's still in use. I guess RS-485 (bidirectional serial bus, also Profibus) is more common in industrial applications nowadays (you can still use a standard UART plus an additional I/O pin). And yes, using uncommon / not standardized baud rates can definitely get you into trouble 🙂 Especially when you come to the point where you have to use dedicated UART chips or something like a serial-to-USB chip.
And while a lot of things are moving towards Ethernet, the implementation of a Ethernet interface is still a cost factor (especially software development, but hardware too). Even things like CANbus are more expensive to implement than good old RS-422/RS-485/Profibus interfaces.
@@robertssmorgasbord I didn't start out as a EMC sort, I fell into it, as I got stuck as a new kid qualifying a huge box of modular avionics (~1989). And I was ignorant to all RF methods of design. I could do analog and digital down at low speeds. 6MHz was a killer microprocessor speed in the mid 1980s. So I had to learn how to fix the existing design. This box had 12 microprocessors. The testing is for avionics use. So you don't want harmonics in the communication or navigation radio bands. And worse the program schedule did not have time to respin the circuit cards, so I had to figure out fixes that mostly were adding capacitors or changing the power supply line filters (28VDC power input). Any noise on the low voltage outputs (+5/+12/-12), and the transformer looks like a capacitors with the output windings overlapping the input windings (a torroid). Stuff I didn't learn in school. But I learned to enjoy doing this qual stuff. And the product would get respun for the next aircraft program, adding features and such, and I got good at designing for compliance to the test standards. The big ones I had to learn was HIRF (high intensity RF both radiated and conducted) and lightning. Lightning is interesting on an aircraft, there are several modes of how that gets injected into the signal pins. The one you don't think of is the airframe fuselage where lightning attaches at the nose, and exits the tail. You have 200Kamps or more, that causes an IR drop through that resistive structure. And this produces a pin injection voltage to the avionics equipment. The other modes are like a single turn transformer coupling, of this current running parallel to the wiring.
It was an interesting career.
The company I worked for, did avionics for the Fokker 100 (Netherlands). I think that company is defunct. We also did systems for SAAB, on their turbo prop, SF340 and 2000 models. Another company that dropped out of commercial product build. Also they did Shorts Brothers (Ireland). Just before I retired, they got their "foot in the door" with Airbus. But Boeing was their big commercial customer, that we competed with Honeywell for system content.
As for serial bus, the mainstay of aircraft is the ARINC429 bus. A 32 bit bus, with twisted pair, two phases, bit rate of 12.5KHz and 100KHz. Very smart, initially built with discrete ICs of shift registers, counters and gates, but custom silicon became the mainstay of this. It's return to zero, so self clocking, with 10volt differential swings (+5/-5 each line). The edge rate (slew rate) was required by the specification, as they didn't want bus reflections EVER. Very smartly thought through by the original designers. It's the only specification that you can see the thought process of the writers, from my view as a end design engineer. So that's the bus that replaced all the CSDB.
I happen to be playing with RS485 currently, and trying to mimic a MODBUS master. I got this power meter from China KWS-301L, that uses this bus, but I can't get it to reply to my bus sequences. It's supposed to be slave address 03, but no luck in it putting any communication out. I'm using Arduino Due, mainly for the dedicated serial ports.
Sorry this got a little long.
@@f.hababorbitz Wow, what a career! Avionics no less! Well, I started out in electronics during high school, doing tests for a small company that made remote controls for forestry vehicles (fewer people needed if you can remote control the tractor with the winch when pulling out lumber). I think my first project was a D/A converter (TTL and R2R network) on a euro card. My senior high school years I spent at a "technical high school", that taught beside the usual stuff electronics, mechanical engineering and computer science (we even had to spend a few hours a week in a metal shop). During that time I somehow "descended" into the software realm. So I ended up studying computer science. Good thing my university didn't really "believe" in computer science back then (there was no computer science faculty, just an institute). So during the "Vordiplom" (~ bachelor) it was mostly mathematics, physics and electronics (one of the exam questions was to design an asynchronous (!) multiplier or adder - I don't remember). Only during the "Hauptdiplom" (~ master) we really got into computer science. My professional career after that always revolved around software. Though in between I did some private electronics projects (e.g. adapter to connect an IDE hard disk to an Atari ST). But these were mostly digital. Only in recent years I found my way back to electronics and microcontrollers as a hobby. It's actually fun to rediscover all the stuff I learned during senior high and at the university.
You were writing about RS-485 and MODBUS. Funnily enough I'm just finishing a video series about RS-422. While reading up on RS-422 I was of course exposed to its big brother RS-485 too :-) But I won't go down the PROFIBUS/MODBUS road. My final destination for now is NMEA 0183 (a marine communication standard).
And don't worry about your posts getting too long ;-)
5:55 That what for the Inrush resistor RF1 is. It is spcecial make *Fusible* *Fireproof* resistor. As the function says it also acts as a *FUSE*. And it is 38R 3W 5% fusible. Bar code orange,grey,black,gold. If you put ordinary 3W resistor it will fry the board next time LNK305GN fails and have a risk of your machine going on *fire*, really. If you put LNK306GN you will have to put 1mH 370mA inductor also. Check functions of the elements you replacing, you can do more damage if you replace with incorrect ones.
Sorry for the late reply, somehow your comment slipped by me. Anyway, your probably right. To my (weak) defense: I got a repair/parts kit from my friend that he ordered on the internet and just did the soldering job for him. But of course I should have checked if the parts in the kit are up to specs. Interestingly the blown inrush limiting resistor ( czcams.com/video/IJEkP6iIN2E/video.html ) looks like an ordinary power resistor (without any bar code) and is labeled as just R76 on the board, not RF. But that doesn't mean it wasn't a special fusible/fireproof one. However, since the board didn't implement the reference circuit one to one, maybe they didn't need the inrush limiting resistor to be fusible/fireproof and instead relied on something else.
@@robertssmorgasbord Od it blew it could get gray making the bar codes not readable. By the spec it should be a fusible fireproof resistor.
@@Lycras I don't think that it got that grey. Actually that gray color is typical for power resistors from some vendors. But again, that there were no markings on the resistor doesn't mean it wasn't a fusible type.
Please how can i get the circuit diagram 2:54
Just google for "lnk305 datasheet". Or have a look directly on the manufacturer's page: www.power.com/products/linkswitch/linkswitch-tn/lnk305dg 🙂
Nice work , But I will not go through this hard work removing a resistor Just solder the new one at the back of the board Leaving the old one in place or beak them
Thanks! Your way would have been certainly less work, but it wouldn't have look as nice, would it? Though, if it has been my washing machine I might have done it your way ;-)
@@robertssmorgasbord Yes I agree as far as the cosmetic look of it , Thank you for your good video
@@magdylast9408 Yeah, it was just for the looks because it was for somebody else :-) And thanks again for the praise!
My technique to take them out is: instead of taking solder out, I add a little more solde and keep it liquid with iron while I pull it out . Basically is how you do it @Robert, but adding solder instead of removing it. Believe or not it actually helps.
Once the components is out, I then use the pump to clear the hole.
So dout for you
Well, to be honest, I really don't know what to reply, because I don't know the word "dout" :-)
This shit always blow up,...
Yes, it does :-) That's why, at least here in Germany, there are repair kits from third parties available for that board. I think I mentioned it in the video, but for just a few cents more they could have used the LNK306 (225mA instead of 170mA).
@@robertssmorgasbord I use 306 always, lasts longer :D
@@darthfate2139 Exactly 😁
TooOoooooooooooooooooo muccccccccch longggggggggg{spoiling of time)
Pleaaaaaaaaaaaaaaase, accept my apology for wasting your time :-)
Why you bloody nasty !