Very similar looking chassis, dropped in by a friend. It’s a European model KRF-V4070D, different IPM’s of course and who knows what options. Has a flashing standby light and power relay clicking on then off again. Display comes on ok. Protection issue of some description not responding to reset procedure. I suspected and ordered new IPM’s but will be rechecking more closely for dry joints throughout when I return to the bench! Interesting that the unit dates 11 Aug 2002 just a few months before yours. Love this channel!
I didn’t expect the unit to be in good condition inside after seeing how dirty it was from the outside!! Good job fixing it!! It seems that more than 70% of these complex AVRs got problems with bad solder joints.
This guy is the best , it make me nervous when he start touching live circuits with bare hands. Safty ,safty first rule, stay alive, God bless you, I enjoy watching your videos. Thank you .
All the early electronics in the RoHS era are like this, amps, car electronics, the lot. They hadn't figured out yet the proper way to solder and everything has cold / broken connections. I saw this was from 2002.
Nice work! Got one like it . Standby light on. Fm radio works. Everything else dead. Was about to toss it but after watching this I’m going to open it up and take a look! Great video!
I find it easier to flex the board a bit as I am scanning. The crack width will fluctuate making them easier to spot. Then again, I don't have one of those magnifying ring lights.
Thanks for voltages and pointing out bad solder joints on board, mine has bad spots also! . Bye the way.. I want to say something with infinite meaning, for you that would be about electronics. I worked at Texas Instruments, they have manuals on their transistors, and charts of Family of Curves, using different voltages on transistor. I found a way to make transistors and Field Effect Transistors the most sensitive to an input. Connect a load resistor to collector and resistor to adjustable voltage power supply (you can buy one as I did), ground emitter. Turn on power supply. All voltage will be dropped across transistor. Turn up voltage till transistor shorts out. Then turn voltage back just a little so transistor isn’t shorted out. Then put signal on base, WOW, sensitive!
All of these black plastic receivers don’t even come close to receivers of the 60/70s where quality was intact , I’ve got a similar kenwood with the same problems, maybe I’ll dig it up and give it shot. Mine is a kv r 7040, and yes what’s the deal with having to take the entire cabinet apart just to access common failure power transistors?
Hi 12Voltvids, I really have to thank you for the great 'Kenwood VR606 AV Receiver Dead' video which has rekindled the hopes for my kVR-5580D whose display has been off for a few years! I would like to ask you what magnifying glass you use (10x - 20x ..) to check the 'cold' welds and also what power the soldering iron has (mine is a 100w but I think it's too high). Thanks for any answers .. you are great! Patrizio
No I am not that concerned about solder fumes. When I worked in the business working at the shop, the shop owner did nothing to mitigate fumes from chemicals and solder smoke. He even put a door on the shop, and kept it closed so nobody could see in, and more importantly, the techs couldn't waste time by watching what went on in the store. So any damage that has been done has already been done. Back when I was in school we used to play with liquid mercury too. Pour it on the table. Throw it around, stick wires with power on them and watch it boil. You know, stupid stuff all under supervised instruction. Of course now break a CFL bulb and they call in the hazmat team and spend a few thousand dollars cleaning up a pin head sizes spill.My shop is an open garage, there is plenty of fresh air blowing through it.
I really liked your method of troubleshooting and solving the problem. I do have a question, though. What causes the solder to crack and why did the solder crack in some connections and not others? Thanks a lot, Tom
There are many things that can cause solder to crack. The most common is not enough heat during initial construction. not enough solder applied, and thermal shock.This is a much bigger problem with lead free solder. On high power connections or components that get hot, heat travels down the lead, and as it does the copper wire expands at a different rate than the tin/copper or tin/silver alloy which is what most lead free solder is. Older lead solder was softer, and could handle this expansion contraction of the copper component leads better. With the more brittle lead free solder, when you get constant thermal expansion / contraction eventually it will weaken the bond then, it goes open.
Lead free solder is an example of irony, wouldn't you agree? It's supposed to be good for the environment, except it has led to an early death for many electronic devices whereupon people wastefully toss them and buy replacements.
Awesome. Thanks bud! I have the same problem in kenwood avr 615, he turn on, relay arm, but have to wait about 10 minutes to play any sound. I found 8 cracked solder in the same board. He is better now, thanks for share.
Smashing job :-D, another perfectly good device saved :-D. . The old "Solder drum" problem, often the component pcb holes are too big or not enough solder, nice thin drum of solder ready to crack. Ive seen that problem on monitor/tv crt drive pcb's, also c.b radios. One type of c.b radio was so bad that every one i repaired had a bad synthesiser, blanket solder that small area and it would work spot on, no returns ever :-D. Im no lover of the stk or sanken modules, i like the discrete transistor power amps, im just odd that way LOL :-D.
IPM were the Achilles heel of electronics. Horrible. Sony used to use 3 channel IPM for the convergence drive IC for their projection TV of the day. Lots of failures.
Oh dear, convergence all fecked up lol. Never liked the sealed in sort, a nice ovan to cook the parts. Im waiting untill we get a better way of mounting mobo chips, solder used as (glue+connection) is just batty. Also sockets mounted on pcbs with just the solder holding them in, no no its a bad method. if say sat nav's had there usb socket mounted on a bracket and flexable wires for the connection they would never cause problems. And whats this thing about stupid micro sockets, daft buggers.
I am no electronic tech but I do marine and automotive electrical. I know you probably wont read or reply but the process I would of used it trace back from the relay back through the circuit to find out where the voltage starts and where is stops . You used the shot gun approach and soldered everything. I was surprised. You are a very good tech most would of traced it out. And you put flux on the IC but only soldered one side ? Very puzzling 🤫🤫🤫🤫🤫
These are very different than marine and automtotve. All microprocessor. Tracing back does nothing on these becauae a fault that may have been momentarily can shut the processor down. Lead free solder connections cause more faults than you can imagine. So flaky looking connections are checked first.
@@12voltvids Interesting seen other techs check voltage in and voltage out to check circuits that are non op . But this was on the older vintage equipment. Is this mainly on the newer systems ?
@@12voltvids Oh ok . Even as long as you have done this I bet you are constantly learning. Where is the processor on this ? Thanks for the reply I know you are busy .
Clean it up with some Novus, might help to get you another five bucks! :) What's that item on your desk marked 936D? Camera / radio accessory? I see a future YT repair video in your future to get your Weller up and running!
My weller needs a new iron because the thermocouple is shot. The 936D is my cheap chinese soldering iron. I already repaired the factory faults in that one when I bought it.
Wow this is exactly the problem I have. A standby light is on...but when I presson theres no click...nothing? Im heartbroken but its 14 yrs old so is it game over? Theres no display...nothing..but there is a standby light??
That would be because they weren't done properly at the factory. Not enough flux applied, not enough heat on wave soldering. Many factors cause broken solder. It was a common problem back in the day. Still is, with BGA connections on modern stuff.
I've had this problem on 3 Sherwood Newcastle r925 . The radiator is identical. I take it the heat also doesn't help with solder joints? The r925 I've had use 800w power consumption and they get pretty warm. The amount of caps that need replacing in them is crazy. In all 3 the main filters were puffed out and a stack load of the samwha SD caps had there jackets stretched down there sides. Crappy caps in a hot amp I feel is total nonsense. Oh and hours and hours worth of resoldering badly cracked joints. Great fun tho and worth fixing. They have a superb sound and lots of power. Thanks for the video, I've learned a lot from your vids 🙂
hi ...i have kenwood vr507 no pwr on no standby light.no clicks...100% dead..main fuse ok...i test the large transformer and i get 0vdc...any help would be appreciated...ill have to look at the standby voltage area like u did.
Google everything! I have the VR606 and suddenly no light, no power! A quick google said a simple fix. And it doesnt get more simple then this! Ready? Hold Power button on. While holding it put the power plug into the A/C, then release the power button. Finally....press power ON. Bazinga! Working with power and light again! Happy this day AUGUST 9, 2023!
Mate i have some serious issue going on with my sony hifi which was made during the 90s i believe. I have heated up all the cold joints and serviced the deck and cd drive. Now the main problem, i have no sound coming out of the unit. But there's noise interference, buzzing sound. Like for example, if i plug AV cable on the phono port and touch the socket on the other end, it gives me the signal noise that means the signal is going in. But no sound, music comes out of the speaker except for this buzzing and signal sound. Do u think the STR IC might be damaged? The model is HCD-V8900AV. It has 2 STR's. One for the surround which is a smaller one and the bigger one is for the main sound. I have checked all the fusible resistors and transistors on the amp board, all seems fine. The amp board also have some fuses, all seems fine.
I think you might have a broken connection or a broken trace, happened to me once I was going mad cause everything checked fine. Before you do anything too radical use a magnifier and inspect those traces cause sometimes the heat is putting stress on them and when it gets cool down you cant see a broken one with the naked eye...
My Kenwood VR 407 turns on but once it starts to get warm it automatically kicks into flashing red light standby. Any suggestions? It went out while running music high volume and probably over heated before protection enabled. Thanks for your great video!
Hallo, ive got a big problem. Ive got a Pioneer VSX-415 and it does nothing. Its completely dead. I dont know where i can check the Standby voltages. Can you eventually help me?
I have a question for you I have an originally owned vr-715 looks exactly the same... my left speaker input clicks on and off when i push on the terminals with a good amount of pressure. not able to find the problem i bought what i thought was a direct replacment. But i didnt read the description of the model and i got this unit vr-606 i have the same issue with the back of the reciever with the center channel do you have any solutions to this problem? or help trouble shoot what the issue may be?
Anyway I got a question not related to this video, but still interesting, is there in the market any add-on boards for TV to get HDMI Out for recording screen? As I have LG TV 2 years old with "Time Machine" option to save TV shows but it is a protected recordings with no way to get them to transferred to PC. HDMI Out would be solution in my opinion...
HDMI recordings are encrypted and protected for that very reason, to prevent you from recording them.There are some HDMI to component and HDMI to composite adapters on the market that will take an HDMI signal and give you an analog output for recording. I have reviewed both of these devices, and repaired them. The HDMI to component adapter I have gives a 720P component output from a 1080 input, which can be recorded using an HD capture device with component input. There are commercial HDMI capture boards, however they observe the copyright bit and if set they will not record. For my TV provider I have an old box that has component output so I can record anything in HD I wish, but if that box ever packs it in, and it gets replaced with a new one that has no component outputs I will be screwed.
What is the problem? A broken connection?? Where?? On the Board?? Hmm...maybe you should say it again! Don't forget to yank the front cover a few more hundred times too, just to be sure... XD
I have a question... Well 2 questions... 1. Could I send you a amp to fix? 2. I recently picked up a 90's Kenwood amp from Goodwill (model Krv87a). So I get it home, plug it in.. Amp comes on... But....none of the buttons on the front work (minus volume). I'll post a video underneath
Like hell it is. Only Americans pronounce it as SODDER. Just like they pronounce Roof as RUF and spell COLOUR without the U. Oh and by the way it is pronounced ZED, not ZEE.. lol :)
