Panasonic Music System from eBay - NO POWER - Can it be Fixed?

[@marcotinnirello6010]

So much to love in this video. 1) Vince’s utter disappointment when the relay doesn’t fix it. 2) The brilliantly funny “I feel nervous about turning this on without the cover on. I’ll just do it quickly”, 3) his ever joyful reaction once he makes it work. Vince, you are a legend.

[@steelcityreseller8170]

Another big piece of electronics brought to its knees by a tiny tiny tiny part. Well done!

[@Google_Is_Evil]

You had me screaming at the screen the moment I saw the relay. This is a classic case of a power supply that consists of a main supply, that is switched on by a standby power supply that is on at all times. The relay gets triggered by the press on the power button and having the power supply disconnected from the rest of the machine will not get the relay activated. You did find the diode, well done. You will want to exchange it for a fast switching diode (schottky) that can be super simple, low voltage, 1A should be just fine, you can scavange it from some switching power supply donor I should think. The 1N400? you have in here will get too hot and will eventually pop, but that may be 20 years from now, or 20 seconds. Learning some layouts of "generic circuits" will help you recognize them and figure out the functions of the components in them. Once you are there, you will be able to much quicker figure out what makes the thing tick and where and what to measure to find what is actually wrong. You have gotten much better at finding things, but the next step for you would be to "see through the matrix" and recognise the patterns of circuits so you can much quicker do a proper diagnosis.

[@TechGorilla1987]

I'm glad I scrolled down before I commented.

[@al_7778]

👍 I had to stop watching the video at this point. I wouldn't do videos on things that I do not understand.

[@MrAsBBB]

Hi Vince, This shouldn’t give you a false sense of security but you could where electrically insulated gloves when working on something you think may still hold a charge. Also you could get a capacitor discharger. I am now 56 but when I was in my teens I would take stuff apart and I spent a many a day being shocked and blown across the room. I must have been so lucky. I did burn a hole in my thumb once . Well done by the way. Really love the work you do. You have what most people lack which is patience. All the best from Alex

[@RossTheGenMan]

was almost screaming at the screen... LOL. The reason for the two rectifiers and the relay is that the power supply has a standby circuit that runs all the time and when you hit power it engages the relay and activates the bigger circuit with the bigger rectifier to run the unit. I was hoping as you did that you would eventually figure out to connect the power supply to the board. Great video

[@hamdzuii]

warning: the original diode is a fast switching/recovery diode. 1n4007 is a standard diode, it does not meet the switching time of the transformer and may explode at any time. You can replace by any 1A switching diode

[@patrickcraenen5163]

Yes indeed. I was scratching my head when I saw Vince pull out his Velleman diode assortment...

[@Tim_3100]

​@@patrickcraenen5163yeah but vince does say he didnt know the correct one but i imagine he will put right on in

[@manolisgledsodakis873]

Yep, I was going to write fast soft recovery diode but you beat me to it. The 1N4007 will fail sooner or later.

[@TheLastPhoen1x]

Reminded me of the Hydraulic Press channel - "It is very dangerous and can explode at any moment."

[@digihorse6730]

I was joining you with the screaming at the screen. Well done Vince.

[@opticaltrace4382]

"I'm going to plug it in and face the other way" That's the spirit Vince 😂😂😂

[@pceefixer]

NAILED IT VINCE! I'm consistently impressed with your ability to track down issues like that. I have never been able to do it myself but I think it's like a great machinist - they can determine the PROCESS to make a part. If I tried it I would screw up the process and have no chance. Like I said - always impressed!

[@BuyitFixit]

Great Job Vince 👍shottky diode on the output of the PSU standby section. If in doubt of the voltage you could have looked at the voltage of the smoothing capacitor, and I don't think the amps would be much as it just powers the standby section of the unit. Well done on getting it working 👍I'm not sure if the diode you used is fast enough. Voltage drop is usually about .2 on shottky diodes.

[@dodgydruid]

I bought one very similar last year as a spares repair to fix up, turned out it was the plug fuse and has worked perfectly since. My one has the "space station" door but also has a section that pops out from underneath it for the iPod plus it has bluetooth from a fone and a USB socket. I mounted mine on the wall, very happy with the stereo.

[@wisher21uk]

Wow Vince that one hell of a repair, I think that diode is to stop back EMF from the coil so it probably is important as it protects the main circuit from damage. Keep em coming thanks 😊

[@gadgetmind]

Quick way to check everything up to the high voltage DC side: Connect a bench supply set to 5V (and I use a USB battery bank and croc clips for speed but PP3 or whatever) to the L and N inpit pins or the plug, and you should get 5V minus two diode drops on the DC pins of the bridge(s) and HV cap(s). Then wait for voltage to drop or short the pins, reverse the supply, and check again. That's all fuses, chokes, bridge(s) checked very quickly without using mains. Give it a quick go on any SMPS you have lying around. Also try connecting a meter to the cold side of the 817 opto(s) and you will get 1V if the switcher is running and the output rail that's used for feedback is OK. You can also measure the VCC on the switch/PWM to see if it's starting up and if its power supply on the auxiliary winding is running. I fix these at Repair Cafes where time is limited to keep trying to work out faster (and safer!) ways to zoom in on where the issue is. Nice fix, but as others say, you need a fast recovery schottky.

[@gadgetmind]

Ah, I now see from the schematic that the SYS5V side of things doesn't have opto feedback and instead uses the auxiliary that supplies VCC to also drive FBTR. That's one to watch for when trying my quick and dirty "It it switching?" check. I also see that Panasonic use their own useless part numbers even for things like diodes and resistors, so "B0JAMF000011" is the part but no good way to work out replacement other by staring at circuit and thinking a bit.

[@marcellipovsky8222]

Hi Vince, it looks like you need to do a bit of studying around stand-by power. A standby power rail provides power to essential system components even when the main system is powered off. Typically, the standby rail operates at a lower voltage (e.g., 3.3V) than the primary power supply. It’s supplied by a separate, low-power circuit, usually from the same power source but regulated independently. This is why you find the 3.3V on a Laptop's power button or in this case on the Radio power button. Connecting the 3.3V rail to ground signals the chip that starts the device to begin the startup sequence. Regarding the diode, yeah, you need to replace it with a faster one. The one you put there may not last. I assume that the S607 is a Schottky diode (low forward voltage drop and fast switching speed)

[@GadgetUK164]

Lovely work Vince =D Very difficult working on something with so many sub PCBs! One quick point, when trying to discharge caps with screwdriver, be very careful just dragging the screwdriver around like that - if one cap is charged, with say 337V DC, bridging that to a point nearby that isn't the other side of the cap would kill something else on the board - if you see what I mean? It's best to identify the points on each cap, and ensure to only bridge those.

[@Mymatevince]

Great advice Chris, so very true. Thank you 👍

[@GadgetUK164]

@@Mymatevince Keep up the great work!!!

[@maxz8807]

I destroyed a 5V USB wall charger this way :) made a good bang I guess I learn by making mistakes - don't we all?

[@patrickcraenen5163]

Could indeed be a very nasty surprise!

[@stevedebeukelaer1424]

Should be 1a shotkey diode sb170 will be a replacement

[@bathesheba111]

Vince love the videos but please use a resistor to short out caps. A screwdriver could damage other components. Also MOST important please use an Isolating Transformer when working on live power supplies. It might save your life!!

[@dash8brj]

An enjoyable fix Vince. As everyone else has said, schottkey or fast recovery diode in that smps rectifier output. That 1n4007 will blow out eventually.

[@jonnyduncan7056]

Top fault finding and you have patience of a saint.

[@devttyUSB0]

There's something quite soothing to cleaning a device you fixed. It works, now it's yours proper. :) Very nice fault finding and fix!

[@Mymatevince]

Thanks devtty 👍

[@danielross868]

Vince. When testing relays, the correct way is to check "resistance" across the contacts, not just continuity. So as you did, connect meter probes in resistance across contacts, then power coil on/off multiple times. You should see very low (0.13 etc) across contacts. TIP: You can zero out your probes on your meter by touching together and pressing the REL button ( Relative refence point) . Will only work that one time, after that need to repeat for further resistance test if required. If higher , the contacts need cleaning. Be careful, a lot of contacts are silver or gold coated. DO NOT sand or scrape them. Best to wet some paper with contact cleaner or deoxit and drag through whilst applying "mild" pressure closing contacts. Some allow actually taking off a spring and removing contacts, like yours. Then can be cleaned with car polish etc and flushing that off with contact cleaner before reassembly.

[@BillyNoMates1974]

The diode is a fast switching power diode (sometimes can be a schott key) used to create a DC voltage with a capacitor. I bet that power supply has a 12volt and a 5 volt power supply and its the 5 volt power supply that was shorted to ground via the diode. so the transformer (before the diode) was working harder as part of the secondary was shorted a normal diode (1N4007) is a slower switching diode. i am surpised it worked as the switching power supply is probably switching around 100Khz

[@beogeek]

Nice work Vince, even though you have very limited knowledge of how SMPS and how they work you managed to find the fault and fix it, very comendable! NOW before you do any more work on high voltage appliances I urge you to buy yourself an isolation transformer, and at the very least make yourself a dim bulb tester ASAP!!!!!

[@colinboneham7387]

Nice job Vince, as always great fix.

[@UltimatelyEverything]

Personally i like the long videos i find them relaxing and chilled.

[@rondickson1491]

Is it a bird or a plane. No, it’s my hero Fixit Vince! Best wishes to you, and the family, from Virginia.

[@Nine_Violets.]

Thanks for playing our music buddy

[@Mymatevince]

My pleasure 👍

[@jonnafry]

Sounding good!

[@retrocomputinggrotto]

Cool to see a solenoid in action like that!

[@Synthentic]

I have one of these. Well, a similar. The SC-HC3DB. Got it about 2012 or so. Still use it but just plugged into my PC as it still sounds pretty decent.

[@ivanburrows6832]

To avoid youtube content matching issues with radio stations on the equipment you repair you could use a wireless transmitter, it just plug into the headphone socket of a mobile phone, laptop or pc and you tune the radio equipment into the frequency of the transmitter and play youtube library music on the radio. they are about £5 on ebay.... Just a thought. :) sold on ebay as - Wireless FM Transmitter 3.5mm Tool car MP3 Music Radio Player Transmitter -

[@machman23]

Hello Vince, I took one of these apart the other week as there were several issues, door not sliding across and volume was very low. I am no tech when it comes to electronics so I am watching lots of video's. I want to learn repair of electronics and am just at the start point. I just saved the components to look at and learn from. I have a radio that just suddenly stopped turning on, first tried new batteries (nope) Opened it up and that's as far as I have got. Want to learn repair. Your video's are great.

[@the_joker190]

Love you videos man! You the only person I watch everyday. Keep up the good work!

[@TheSkaldenmettrunk]

I really like the iPod Dock. It displays it very nice.

[@MikeB_UK]

Another great fix. May I make a suggestion: since you always seem a bit scared around power supplies (and rightly so). If you buy a used "BT mains conditioning unit" (these come up now and again on ebay for less than £80) - say a 5 amp version, this is a cheap mains isolation transformer - and well made as BT don't use rubbish. With something you are testing plugged into an isolation transformer then the 240v live is no longer referenced to earth (you), so unless you touch both sides of the power at once then you won't get any kind of shock. Saves an issues if you accidentally brush the powered on live. Alternatively having a pair of rubber palm and finger gloves on whilst you poke around with the power on also prevents a lot of chances for getting zapped although you lose some dexterity. I have used a BT transformer for over 20 years and it gives a bit of peace of mind whilst probing something live. Maybe of help?

[@KB1UIF]

This is a good idea, but it does not protect you from charged capacitors, which Vince was worried about. The 300V plus DC is still going to bite if you get across it.

[@barbaravintson1217]

Good afternoon hope your have a wonderful day On this Sunday your and your family Thank your for Share your Video with us God bless you and your family

[@matteo_z]

I once had to replace a diode on a power supply (I'd suggest to immediatly check the diodes on power supplyes, then caps, because they are usually the one breaking the most) that was marked as SB5100, and it was a schottky, my best guess is that that one also is a schottky, they are preatty common on psus Also: Psus with the enable "functionality" (for a lack of a better term) should have a pin labeled "EN", if that's the case, you can just jump the EN pin to GND, most of the time that's the trick, but, if it's still not working, you'd have to find the lowest possible voltage rail and jump it to EN. Oh, you don't have to work fast when the psu is connected to nothing. Also 2: The big cap may have drained fast because it has a drain resistor somewhere near it. It's rare, but I love when it's there.

[@GeorgeKaye-f4w]

0:15 Hi Vince Great video. I had the same issue on this model. It broke down in Southern Spain. I found a repair shop, he fixed it within a couple of days. Cost €25. Guess what?, he didn’t speak a word of English!, I don’t speak Spanish in. I got the translation, sort of, it was a diode. The issue I have with this model is the control panel access and the iPod swivel plastic bit, it broke. Sounds ok, nothing brilliant. Fortunately, I was gifted the item. It looks a nightmare to open up, let alone put back together, especially the swivel door. My greatest fear, which I believe holds anyone from doing anything, is whether I’m able to reassemble and ultimately binning it. I currently dismantled a Philips steam generator, it’s in bits, non the wiser, need a steam pipe as it’s splitting every time I try to reengage it to the sole plate. I’m loathe to purchase two metres for 6 inches. So it’s on the table, working progress. Your video was amazing, captivating, absorbing, engaging. How do you keep the family at bay, perhaps your editing comes into play here. My latest disaster was trying to pry open a Fit Bit watch. Prying open the top, severed two ribbons that connected the screen. Watched a you tube video that was not the same model. The battery needed replacing. Ah well. Thank you for the amazing work you do 0:15

[@electronash]

17:03 That's what is generally known as a Common-Mode Choke. It helps reduce noise on the mains, both coming into the device, but going out of it as well. The inductance resists rapid changes in the current, so it filters off some of the higher-frequency noise stuff. You see the same kind of setup on almost any switched-mode PSU. Mains input -> Fuse -> X2 filter cap -> Common-Mode Choke -> (maybe more filter caps) -> Bridge Rectifier -> Chonky DC smoothing cap -> Switcher IC / MOSFET -> Transformer. If you see a smaller bridge rec on a PSU like that, it's probably a small separate Standby power supply on the same board.

[@electronash]

oic, you did find the service manual. ;) Very common to see a standby voltage present all the while the mains is on, especially on stuff with a remote control. Not all of them use a relay for the main part of the PSU. Some will drive an Enable pin on the main switcher IC (via an optocoupler), some will have a way of shutting down the main supply by messing with the feedback voltage on the main opto. Good find on the shorted diode. On page 78 of the service manual, btw, it shows a block diagram, including the separate small standby PSU (on the same PSU board). tbh, I think any standard diode meant for lower-current switching / rectification would work OK there. The SM says the relay only draws about 60mA, and the main MCU only draws less than about 50mA. I guess the replacement diode should be fairly fast-switching though, as an SMPS generally works at quite a high freq, like 50-100 KHz. But I reckon, for this low-current draw, the 1N4007 should be OK.

[@electronash]

btw, if you just search the service manual PDF (Ctrl-F) for "D5896", it shows you the actual part number. Which is B0JAMF000011 (Panasonic). Unfortunately, that's not the "real" part number, but Panasonic's internal code, so I couldn't see a proper datasheet. Anyway, the 4007 is probably fine. lol

[@electronash]

Oh, another commentor (Google_Is_Evil. lol) said it's probably a good idea to replace the 4007 diode with a fast switching Schottky. Else, the 4007 might get quite hot, and eventually fail, due to the fast switching freq of the PSU transformer output. Makes sense. I reckon the current draw on that 5V Standby rail is very low, but still.

[@RickMahoney2013]

Vince your videos are great to watch but too complex for me I was wondering if one day you would do a video on how to use a multi meter just the basics I am sure it would be a short video. Thanks.

[@andrasszabo7386]

Nice music system, Vince :) I always loved iPod docks because they are premium quality. I have a few iPod docks in my collection. One is JBL, the other one in the weekend house is Harman/Kardon. They both sound really nice, with rich sound, with a nice powerful sound. I hate switching PSUs because they are almost always unfixable for me and my engineer friends. Last night I tried to fix a laptop power supply from 1987, it was an inbuilt one, and I cannot buy the two cracked bipolar transistors anymore. Watch out for those big capacitors, Vince, Sometimes there is a bleed resistor besides them, and that is why you cannot measure leftover voltages when unplugged.

[@technixbul]

42:42 You are looking at the block diagram, you won't find parts names there, you should be looking at principal schematic, 45:00 The diode should be any 1A fast recovery diode or schottky diode, it has to be fast because the PSU works on high frequency, 1N4007 is slow diode, it doesn't work properly on high frequency, it can kill the MCU.

[@Jammerk40]

Very nice fix! i haven't seen a video of your for awhile

[@TerryLawrence001]

The equivalent part would be a Shottky Diode 60V 5A. if you have a donor board from small switching power supply like a cheap wall wart cellphone charger, you will find one feeding the filter cap on the output of the switching transformer.

[@santi308]

5A on that super tiny diode is a lot, a 5A diode are big in comparisson and on that part of the circuit it doesn´t make any logic, why 5A on a stand by source? look at the 1n4148 those are 0.7A and that diode looks even smaller in size. 60v yes maybe.

[@TerryLawrence001]

@@santi308 5A Peak current is only occurring for a very short time in high frequency switching supplies. IN4148 is rated at 60Hz while a schottky will see 10Khz or more. Switching supplies use hi frequency magic to make them smaller in size.

[@ErrorMessageNotFound]

The "S" in S6 indicates a Schottky diode. They are faster than regular diodes. They also have a lower voltage drop.

[@richardhemingway6084]

Looking at the circuit diagram you pulled up, that diode is a rectifier to supply a half wave DC, from the transformer. As it is a switched mode supply it will probably be at a high frequency. The diode is in a DO-41 package and starts with an S. So, as others have suggested, it is a schottky diode, for fast recovery in high frequency applications. The 1N4007 is a very good all purpose diode and will probably work OK. (It may run warm). The only equivalent I could find for the job is a 1N5817, Schottky, 1A and 20v max. Should you need one.

[@ekens6344]

Wow great fix! I thought it was going to be a horrible complex problem with an IC somewhere not sending the signal to turn that relay on. I fix stuff like this as a hobby also and have only seen dual power supply designs like this in high end audio equipment before, I believe there's normally a low-power "standby" power supply that runs all the time and powers things like the remote control receiver circuit, and a separate high quality power supply that drives everything else and the audio output that's only turned on when you actually need it. I believe the reason is it's hard to build a high quality high-output power supply that also has a very low standby current when it's not being used. So instead they have 2 separate ones and the standby one switches on the main one when you go to play music. As this isn't the most high end device I would guess it's more about not wasting power, having low standby consumption, than it is about sound quality. I can't help with the diode. I think it's on the output of one of the switching transformers so it's probably some sort of fast diode as you first guessed (Schottky type)

[@Mymatevince]

Brilliant comment, thank you!

[@jobit_joseph]

The small transformer is for the standbay supply and the diode must be a fast recovery one. You can try something like Fr107 or fr207

[@ultimabear]

Relays have diodes across the coil because when the power is cut to the coil it causes a voltage feedback which will destroy components like transistors, so the diode leaks that away to ground.

[@RobTaylor-HiTech]

So Vince, enjoyed the video. A couple of things. I personally think the diode you used is just fine. Yes it's not fast switching like the original, and yes if this was the switch mode side of the PSU then I would say to replace it with one that is capable of handling the switch mode frequency. But from the brief image of the schematic you showed this looks like an always on low current side of the power supply used only to provide power to the power latch circuit. Would a fast switching diode be better, sure. Does it matter in that circuit which looks separate from the high frequency high current side? Highly unlikely. If you have doubts, take your thermal camera and look for a hot spot.

[@questionmark8500]

Inspector gadget of the electronics world lol nice work.

[@baileyboy3021]

1000th like 👍Enjoyed the whole vid. The song at the end was nice too.

[@radio-ged4626]

Re: Power supply 17mins 39 seconds in - "why would you have two bridge rectifiers?" - typically the smaller bridge rectifier would be for the standby circuit. I haven't seen the schematic, it's just a guess. I would also guess that when the power switch (fed by the standby circuit) is activated, the relay you found switches on and connects the main bridge rectifier to the main power circuit. The fault at this point (having not watched the rest of the video yet) looks to be in the standby circuit. Edit: 44mins 44 seconds in - it doesn't matter what diode you use it's only a low current low voltage supply for the standby circuit the 1N4007 should be fine.2nd Edit: 51 mins 39 seconds in - It's good that the main capacitor drains so quickly, if it didn't it would be a sign that the main switching power supply was faulty. Final edit: Watched it all now. Great fix! I am sure you know more about electronics than you let on and ask the naive questions to encourage comments. Either that or you are just really good at working things out without any background knowledge. 😀

[@dglcomputers1498]

Hopefully that's better than the Panasonic one I've got, it creates so much RFI that not only is the radio reception crap on both DAB and FM (and the joke that it came with two aerials, one for strong and one for weak signal areas) if you connect another radio via the aux input it affects it's signal too! It spends it's life as a speaker for my laptop so luckily radio reception is not an issue.

[@audibell]

I really enjoy all of you videos

[@claudiolebandit9408]

Great work as always

[@laurigardner6227]

The capacitor raises in voltage due to a process called dielectric absorption. As for the USB-C port it’s for a security padlock and cable.

[@philsinclair]

A fraction of a second was all I needed to hear to know that was Bob Dylan's Like A Rolling Stone

[@pepealexandre]

⚠ Like others have said: get yourself an isolation transformer and a dim bulb tester. Stay safe, sir!

[@electronash]

15:35 - Welp, if there was any charge on the big cap, that's a sure way to kill something else on the board. lol I did that before on my old Denon amp (AVC-A11SR). I was too lazy to (safely) discharge the caps, before taking it apart to fix a dry solder joint for the Center speaker audio. I unbolted one of the main power cables, but the ring terminal touched some other pins, and I saw a spark. The charge in the big caps (about 30-40 Volts or so) zapped one of the pins on the main MCU, so then it wasn't able to control the analog input board. sigh I had to pay about £35 just to buy another MCU, with the Denon firmware pre-programmed into it. lol If you do see some voltage across some of the larger caps on something, you should only ever short across the cap itself. (with an insulated screwdriver, like you used.) But really, any large-ish cap should be discharged through a power resistor, say 2K Ohms, 5 Watts.

[@electronash]

That is so the (possibly huge) peak discharge current doesn't do damage to the cap, or any other components around it. It also prevents pitting and burns in the solder joints and traces. lol You can build a cap discharge tool with just the power resistor, just be sure to insulate the legs of the resistor very well. Only leaving about 5mm of the legs exposed. Ideally, it would also have some (well-insulated) leads to hook up to a multimeter, so you can watch the voltage drop. This might sound a bit over-the-top vs simply shorting across the cap(s), but it's easy enough to build, and generally safer.

[@electronash]

Bearing in mind, btw, that with our 240V mains in the UK (yes, 240V more often, not really "230V"), that's measured as the RMS voltage. This means that when that goes through a FULL BRIDGE RECTIFIER and across a smoothing capacitor, the (DC) voltage across the cap will be closer to 330-340 Volts. :o The larger caps can have a pretty huge peak discharge current, even if it's very brief. That's what makes them a bit dangerous, as it could in theory zap your heart. (it's a fairly rare thing, tbh. It depends how much the board self-discharges the cap, the size of the cap, and the exact circumstances, but it can/does happen.) You also have to put quite a lot of trust in your multimeter... Even with the discharge resistor tool, you should *always* measure the voltage left on the cap, and maybe short across it with an insulated screwdriver once the voltage reads below about 20 Volts.

[@therealtrip9723]

Hiya Vince, was wondering what UK retailer you got that multimeter from, i can only find it on American sites!

[@Tim_3100]

Nice fix

[@andersmmvfc.8376]

🎉❤thank you, one of the best foult finding travel this year! Even an idiot like me was following al the way! Was worried that diod had something to do with draining the big capasators but you checked that ad well!! I wish you start on a broken iPod soon, because I'm stuck and really want it to work. Thank you so mutsh for the entertainmemt!!❤❤ Ps. That lego supermario that have been in the dishwasher three times is not going, my two year old have not released his hand from it, he have got a new one but it is not mario he even start to sleep with him. Sry about that. Best regards

[@Mymatevince]

Thank you Anders 👍 No worries on the Mario, fully understand 😎

[@justjack3075]

nice fix

[@tomharris1457]

1n400X are pretty universal rectifiers. Last number is voltage rating.Not fast switching but rugged and probably fine IMO

[@gadgetmind]

If the switching/PWM chip is running, then it will slowly discharge the big HV cap just to run its own VCC, and some switchers detect mains being cut (and I've seen extra diodes for this in the bridge area) and drain the X2 diodes as well - see datasheet for NCP12400 if you're as sad as me. It's when the PWM isn't running that the voltage can linger and cause big problems. BTW you can check cap voltage on the DC legs of the bridge rectifier, which isn't always easily but you can usually get a scope probe to them.

[@mrjsv4935]

Nice device and fix.

[@SymbolTech21]

Vince you need to build a dim bulb and when you are not sure that a device is ok and to don't go BANG the dim bulb will lite up and this is a sign that what you plugged in is shorted.

[@sean9595]

Sound fix Vince 👍🏼👍🏼

[@JasonPurkiss]

Hi Vince, Do you ever use chat-gpt to answer the questions you cant find on google? It seems like you're referring to the S607 diode, which might be part of the S600 series of SCRs (Silicon Controlled Rectifiers) rather than a regular diode. Specifically, the S607 is a type of thyristor used for rectifying current in power control applications. The S607 is likely an SCR rated for around 600V and 4A in current, typically used in applications like motor controls, light dimmers, and other AC switching. SCRs (thyristors) are a form of semiconductor device that can handle high voltages and currents, making them popular in industrial and consumer electronic circuits.

[@carllockpick6179]

Nice job mate.

[@euc-chasingpavements7332]

You got another channel otherwise someone is stealing your videos. Search what happens when.

[@gavshomebrew]

hear we go. Again pcb way yet again

[@electronash]

48:26 - Vince - you've learned so much in such a relatively short amount of time. Don't beat yourself up so much, stick with it! Think a bit more logically about what the relay is there for. ;) The standby part of the power supply runs the main Microcontroller, so it can respond to the IR remote etc. The MCU controls the relay, to turn on the BIG part of the PSU, to power the rest of the hifi. You already found the service manual - On page 96, it shows the schematic of the PSU... The "SYS5V" red line is the Standby 5V from the smaller transformer (from the diode you replaced). If you then find the transistor (Q5899) which drives the Relay, you'll see the "PCONT" signal drives the Base of that transistor, to turn it on. Connector CN2015 is the ribbon that connects to the rest of the HiFi. Pin 1 is PCONT, Pin 2 is SYS5V. If you were to short those two pins on the ribbon, the SYS5V would drive the transistor, turning the relay on. ;) But yes, sometimes it is a PITA to have to hook up most of the system to troubleshoot stuff further. Even more so, when it's something like a modern AV Receiver, with a big stack of boards that all need to be plugged in. At the factory (or repair shops, if those are even a thing any more), they usually have extension boards/cables, so the main boards can be accessed more easily with a multimeter or o'scope. That is often the biggest challenge when repairing some stuff, as you've already seen - just getting into the damned thing. lol

[@electronash]

Oh, btw. I wouldn't recommend shorting Pin 1 and Pin 2 on the ribbon with the rest of the HiFi connected... The main MCU runs on 3V3, so has a 3V3 output signal voltage on it's IO pins. But with the PSU disconnected, it should be fine to drive the relay transistor with 5V, since it even has a 4K7 series resistor on its Base.

[@electronash]

51:37 - Definitely won't be the multimeter across the big cap that caused the PSU to shut off. Very likely just the MCU on a timeout, because the CD player etc. aren't connected, so it shut the Relay off again. A typical multimeter has quite a high-impedance input, and the big cap / mains would be capable of a LOT of current if shorted. So the multimeter isn't going to cause any fuss to that cap. Just don't do what I did when I was younger (as I'm sure many people did), and try to measure current in AMPS "across" a battery or something. lol The 10-20 Amp range on most multimeters is literally just a "short" across a big chunky wire inside the meter. The wire acts as a shunt resistor (with a very low, but known resistance), so the meter can just measure the voltage across that chunky wire, and work out the current passing through it (Ohm's Law). So if you have the meter probes in the COM and Amps ports, it is actually a dead SHORT across the probes! The lower current setting (up to say 2 Amps) will often have an internal fuse instead, but not always. Remember, "Current THROUGH... Voltage ACROSS". ;)

[@jeremylewis4450]

Even if your videos are fake or real I've learned a lot from you. Thank you. Please make a shop video where you buy a bad item from shop and fix it. Would be super cool

[@roberttco1]

Is that extra "port" for a lock - e.g. a Kensington lock ?

[@RaceDayReplay]

Imagine getting a copyright strike from Daniel O'Donnell 😆

[@aphynia]

Vince! I have a speaker that's also not powering on. I've opened it up myself and beyond replacing fuses I don't really know what to do with it, plus it's clearly not designed for repair as lots of things are glued together. Would you be interested in having it? Is your PO box still open? It would either make for an interesting or frustrating repair.

[@adamgrimsley2900]

Yeah, this is such a classic switching diode..strewth

[@KorAllRBare]

Rest Easy The circuit is a very Dirty "Half Wave" rectified DC supply No doubt smoothed by a capacitor that will end up charged to a designed voltage long enough for the next rise and fall to the AC wave" that normally would be handled by a full wave recifier, long story short as the diode allows voltage to rise AKA "Current to Flow" it charges the capacitor up, and as the voltage falls "Current will slow to a trickle, ergo the Capacitor discharges it's charge, now because only half of the rise and fall of Alternating current is passed through, the peak voltage Will rise and fall and then have a small gap where voltage is lower compared to a full wave rectifier where diodes will keep the voltage higher "due to a full wave". Anyway, the circuit is a low voltage circuit and therefore any diode "the faster the better" due to gaining as much current flow the better" will work as long as it's rated to operate at the working voltages, So if operation is erratic then just google for a Fast diode that has a working voltage that is a little over what the circuit is operating at..

[@jestempies]

You can easily clean contacts with a small nail file, they sell those disposable ones, they're very cheap.

[@MothKeeper]

Raaaoooorrrrr... Good afternoon to all you sir's, mushroom omelette for dinner and a mushroom omelette for tea and I think I've booked a mushroom omelette for supper... Tomorrow, yep you guessed it breakfast, dinner, tea, supper and several snack breaks I'll be having a mushroom omelette... I really think mushroom omelettes are the future and will be eating at least 7-8 per day till my right foot falls off... 🎵🎵🎵 VIVA THE MUSHROOM OMELETTE 🎵🎵🎵

[@hollgo626]

You need a fast switching Diode in this switching Power supply. The one you have used dannot stand the fast switching cycles vor a oont time, IT May Work for a while but sooner or later it will Go gank. Watch for any 1A fast switching diode...

[@Tynipツ]

Love your videos 😁

[@santi308]

It´s posible that S607 are panasonic own diode and that´s why there´s no info, only they have the specs, but you have enough information to put a situable even better reeplace. What we know: it´s tiny, knowing that it´s possible deduce maybe 0.5A or 0.7 (like 1n4148, see the size and compare) i don´t think that diode is 1A is so small... And for the possition in circuit its a fast recovery or schottky one, doesn´t matter what you choose. But a 1n4007 is a common rectifier and SMPS have more efficient fast time foward current recovery diodes (for the high frecuency) and sure high reverse voltage (like 200v and above) at the output. They can be schottky or fast/ultra fast recovery. A FR107, UF4007 (Ultra fast version of 1n), MUR120, even if the consumption current is very low, you can use 1n4148, those are better options. A normal rectifier surely it will blown sooner or later, cuz it´s slow and not for high frecuencys. If there´s not info for an unknown diode, you can put other more available replacement diode who has datasheet, no matterif you choose Schottky or Fast recovery / ultra fast only having a few hints like the phisical size or where is located. Well technically yes, if the frecuency is below 100KHz a fast rectifier would do the job, if its above that, its better a schottky or ultra fast super fast rectifier the hint its the switching frecuency on that pwm ic. Any of those would make the job on that part of the circuit having only 2 or 3 hits of info, the code on the diode may help. If there is a Relay on a SMPS surely it has 2 power supplys in one thing. One it´s called a stand-by, secondary or sub power supply, always on, no matter what only interrupted by maybe a power switch, if your device doesn´t iluminate a led at the moment of connecting it to the power outlet you need to look at that part of the psu. Normaly at the output of many PSUs are 5V on that secondary supply and in newer units it can be 3v3, older psus may have 9v even 12v. When you turn on the device, the microcontroller send back to the psu a power on state and activates the relay for the Principal or main PSU, and if there is any problem on that, you may experience a not fully working device when you turn it on, or if there is any type of short at the moment of turning it on it will blown up the fuse. Activating a PSU externally outside of the load, you need to make a contact always over the ground if you don´t know, like on any computer psu, if that doen´t work, then connect the power on pin to the vcc of that secondary stand-by voltage. What happents if the psu don´t show on the connector what pin is ps-on or on/off whell, trace that power on pin back, how? tracing back where the relay connects, in that case sure it has a driver transistor, you need to trace back where the base on that transistor connects may be a resistor or a diode to the ps on pin. The other way is looking at the schematic but not always you will find it, sometimes it simply doesn't exist like in chinese things.

[@voltare2amstereo]

pick yourself up a ryobi 36v inverter good for about 400watt pure sine wave, will give you an isolated supply that would make working on mains powered stuff safer

[@kriswillems5661]

The small supply is the standby supply, it closes the relay to switch on the main supply.

[@telecomsuk]

Could you use the ipod interface as an input from a Bluetooth module ?

[@Teslamaniac]

It`s part of the startup circuit. That`s why it has 2 bridge rectifiers

[@karlpantling-james]

When testing DAB, to avoid the copyright is it not possible to tune into a talking station like LBC?

[@1998eclipse1998]

You can run uf4007 because you need a fast switching diode because of transformer output

[@manolisgledsodakis873]

Can or can't? I say can't.

[@1998eclipse1998]

You can run a uf4007 ( 1 amp real fast switching diode) because the one he took off is a (.5 amp fast switching diode)

[@KB1UIF]

You should not drag a screwdriver over the board. You could accidentally connect a voltage to something and blow it up. Just discharge any high voltage caps with a suitable resistor.

[@roysigurdkarlsbakk3842]

I really doubt that diode will make a problem. My first thought was it was an 1N4007. It certainly doesn't look like a shottkey, that one has another symbol than the one on the schematics.

[@markvandesande8855]

Retroid pocket 3 smaller screen but good enough for console emulation and some streaming.

[@TheBronk9]

enjoy the video Vince.

[@Timothycan]

Regarding the diode issue, maybe it's worth looking at Wikipedia 'Flyback diode'. Whereas a schottky diode is preferred, as it has a faster response and lower forward bias voltage drop, in most applications it is not essential, and a 1N400x series diode is adequate. I've not personally had a problem using 1N4007 in this application in the past, and the Wiki article seems to back that up. I would not expect that diode to fail, but a schottky one would be better, for peace of mind.

[@kriswillems5661]

If the diode is gone the electrolytic capacitor behind it (if there is one) got AC and it is damaged too.

[@vlatkosurlan545]

Immediately thought "Why are you taking the relay out, that's the thing that turns it on. Just pop 5V on the cold side terminals and it should power up!"

[@leewright6101]

HER607 Diode, perfect for the job it stops voltage return from, 5v standby voltage, i used to repair loads of these cat returns warejpuse i worked at as engineer common issue, also panasonics also suffer with bridge rect,

[@hmello3250]

I worked on a home theater receiver recently and the caps would drain so fast I thought there was a problem. I ended up replacing all caps for no reason.

[@richchester187]

on that diagram you showed it looked like the symbol for a Zener diode

[@RobisonRacing68]

This was epic

[@dodgydruid]

Ooo some Specials :D :D :D