I want to try something new. Something more live. So I’m running a 3-part live workshop that takes us on… A Time Travel Through Vintage Electronics. We’ll rewind the clock, dive into the tech of the times… (and study the very history of how things were broken and repaired has evolved) From the 1950s all the way to 2020s. It's still just an idea. The dates and times are to be confirmed. But if you're reading this, then the workshop hasn't yet taken place. So if you're interested and don't want to miss out, you can sign up here: menditmarkk.ck.page/6e8fbd9521

That ending with the red led dimming, definitely like the death of the Terminator in the first film!

@Merciless2011

Жыл бұрын

That's exactly what I thought

@summerforever6736

Жыл бұрын

It was cool!!!

Best tech repair channel on the tube.

Cutting your losses with a smile, thats a great attitude. Thanks for uploading the dead ends too.

@luminousfractal420

Жыл бұрын

This guy..and theres a guy who cooks pies on here.both i think are from the same place and both are amazingly happy all the time..must be idilic

@NOWThatsRichy

Жыл бұрын

@@luminousfractal420 I know the channel you mean, Is it 'Bald Foodie Guy'?

While I enjoy a successful repair as much as anyone else, what I most enjoy is the process of trying to find the fault in the first place. In that regard, this video did not disappoint.

@lucasRem-ku6eb

Жыл бұрын

You need repaired 2000 gear, you can have it all ! Radio's, HD HDD recorders, DVD, come and take some trash if you need it, i did repair it all, not needed by anyone, so come and take them please !

@carpandrei7493

Жыл бұрын

Totally agree! I don't know why, but finding the root cause, regardless if it's repairable or not, is very rewarding.

@smythie08

Жыл бұрын

Fully agree. It's great to see some old school diagnostics AND explaining what is going on for a semi noob like myself. Thank you.

@misterbonzoid5623

8 ай бұрын

It's really the only interesting part for me. And I did a few thousand of them between 1986 and 2000.

That receiver may be repairable. The RESET MCU line is two-way. It can be a watch-dog timer output if the MCU is stuck in a loop. According to the MCU TMP87CM71 datasheet section 1.11 "Reset circuit", in watch-dog activation mode the RESET line can be a pulsed output with a period of 2^20 / Fc [s] = 131ms at Fc = 8Mhz. In this unit the crystal gives Fc = 4MHz. Thus the watch-dog output period here is 262ms which gives 3.8146 Hz, which is virtually exactly what you are seeing at 9:32. Therefore the MCU may be stuck, glitched. This can be a classic case of supercap holding up the stuck MCU. I recommend you gently fully discharge the memory supercap which seems to be C401. Don't bother with reset procedures, the supercap is THE reset procedure. Simply pressing power a few times is NOT the official reset procedure. And check for shorted outputs. That (protection mode) and other reasons may also be why the MCU does not come up. Please keep trying. It is highly probable that the unit can be fixed. It is highly unlikely that the MCU is bad. Good luck. Let me know if I can be of further assistance. [ Edit ] One more thing: Please be aware that for complete grounding often the complete back panel must be attached or jumper wires connected to fully connect all grounds. Failure to do so can often lead one down the wrong path. Perhaps not in this unit, but still good practice.

@MrMegaTubs

Жыл бұрын

Hope Mark tries this

@marcseclecticstuff9497

Жыл бұрын

Nice detective work Tim. It never would have occurred to me that the reset line was bi!

@razortim371

Жыл бұрын

@@marcseclecticstuff9497 Me neither. But something was odd. There was nothing else connected to that reset line. I don't know why I took the time, but I was just very suspicious. I have never seen that or at least bothered to look it up before. I should look closely when examining datasheets. Likely more of them do that. Hope it helps. Happy listening ... yet ... ?

@pavelsalac5571

Жыл бұрын

I was just about to post this. Something making the MCU go to reset loop. Does not mean MCU itself is dead.

@e42_channel

Жыл бұрын

Thanks Tim. I dig a little bit deeper and as far as I understood according to the TMP87CM71F datasheet (1.10) the watchdog behavior must be initialized after reset. So my guess is a "Adress Trap Reset" caused by degraded rom (for example cant find qualified reset vector) and matches the timing diagram. There is also a OTP replacement part (TMP87PP71F) but without firmware and special programmer (example: Xeltek ~1k$) I think is hopeless.

Be like telling someone a Family member has died. You can't win them all Mark. Keep 'Em Coming.

Great detective work Mark! At least there was a datasheet and schematic for you to use to try to fix this. (Unlike so many computers I try to fix)

@Tech-NO-City

Жыл бұрын

Your that 2-bit guy

I've never seen anyone proceed with electronics disassembley with such evil delight. Charming!

I have this excat denon amp from over 20 years ago it's my baby I actually cleaned it out recently and it's still alive after all this time I'm sad to see this one has died this was my first ever Amp it has a special place in my heart ♥ After watching this video I pray it's got many more yrs to live

Excellent video, I love the ‘Hal 9000’ quote at the end. I’ve been repairing vintage and modern electronics for a long time now and I find your videos extremely informative.

"That 80-pin rectangular bastard has all the answers" LOL

@stephenhookings1985

Жыл бұрын

It was an illegitimate repair ... almost :-)

@pw5192

2 ай бұрын

😂😂 that tickled me too .

I like that you don't faff about unnecessarily testing unrelated stuff to find the fault, you get right to the issue. Excellent work, as always.

What a knowledgeable and friendly man! I just found your channel and been bingeing on your content lately!

Iam so glad your Channel came up on my KZread. It was great to see you go through diagnosing the fault .I Have Subscribed and will be checking some other videos of yours, Great work Mark.

One of my favourites from you Mark this one! Love the detective work more than anything. Fix or not, it's always an education.

Your opening sequence is such a joy. The subsequent repair etc is the icing on the cake.

You are one of the best electronic repair channel on KZread. I definitely learned more about electronics with you than in school. Thank you for sharing your passion with us.

Thank you for this educational video, very nice to learn more about electronics.

Recently found your channel Mark and love it. A true engineer at work. Keep up the amazing work. Cheers. Matt

Worlds, happiest component level, electronics repair person.

Amazing, I got a Denon AVR receiver just last week with the exact same issue -- only the standby light on, no other display and no reaction from the power switch or any other switches no matter what -- AND all of the output voltages were there so it acted like it was on. I came to the same conclusion -- dead CPU. I learned a lot in the troubleshooting though, and also learned never to bother with a Denon showing only a standby light again. Thanks for the video, now at least I have some confirmation I wasn't way off base!

@andygozzo72

Жыл бұрын

maybe a common issue with these? premature failure of the cpu? or killed by that dry jointed regulator

@sorcererstan

Жыл бұрын

@@andygozzo72 In my case, there were no dry joints or any power issues so I don't know what killed it.

Back in the 80s, when these computer controlled audio receivers became popular, we had a lot of success "discharging" the MOSFET inputs by power off, connecting a jumper to ground and swiping it across all the legs of the MCU. Not exactly sure, really didn't care since it worked, this worked, and I hadn't thought of it in 30 years. It might be worth a try, if you haven't trashed the Denon yet. I enjoy watching you work. I've been away from component level repair for more than 20 years, having gotten into IT when I saw the repair business disappearing, with "swap while in warrantee, and trash when out" manufacturer philosophy. Thanks for sharing.

Ho letto i messaggi di alcuni utenti su queste discussioni per il raggiungimento della riparazione finale, per far tornare in vita l'apparecchio. E sono sempre più convinto che 40anni fà ho fatto la scelta giusta, per aver deciso di studiare l'elettronica. Il mio indirizzo di studio era radio e tv. Grazie a Mark e a TUTTI QUANTI VOI, per aver conosciuto anche soltanto leggendo, le vostre assolute grandi capacità di arrivare fino in fondo alla riparazione. Mark è assolutamente eccezionale nel riparare di tutto, ma leggo con mia grande gioia che ci sono altrettanti Mark a cui poter tranquillamente affidare in riparazione i propri gioelli elettronici. GRAZIE A TUTTI VOI ❤

I love your British expressions. Dry solder joint. Across the pond we call it a Cold solder joint. It's still dry but it's cold. And it didn't get wet with molten solder lately. I've gone through some of these cold solder joint parts before. Sometimes you can't just re-solder them. You have to remove them. You have to clean the leads. Scrape them down. Then reinstall. Then re-solder. Otherwise you might get some crappy connections that don't seem to be dry or cold. But they are insulated! They have insulated themselves. That's how they got that way. It's a metallurgy phenomena of, nonidentical metals being connected with each other. And their molecules begin to fight each other. And they start to out gas a fine white film. To insulate itself. And that's why you need to physically clean and scrape down those leads. For a truly good solid electrical connection that will last for decades, to come. You see…… You are only being tasked. With fixing a cheap old stereo receiver. It's a bit different. When you are trying to restore, recover, refurbish, rebirth a, 1978, $85,000, custom-built for NBC-TV News, in Washington, DC. A British Rupert Neve 36 input, custom console. That has to work like new again. And continue on for an additional 20 years. Working like new again. I've done it to that one and others. And it is no easy short-term chore. Way beyond fixing a cheap consumer stereo. And amazed at your own lack of knowledge. For a Brit? My goodness man! Have you lost all your self-respect?! Or is this all blasphemy? And by the way how is your Queen? Is she still dead? Good. She should stay that way. Now her,, inbred son is ready to destroy the monarchy. And then to dump, Queen Camilla Bowles. For a younger hottie! Yeah baby! It's good to be the King. And off with her head! And where's Princess Diana? Is she also still dead? Good! Now neither will know who's pussy I shall grab! As if you are King. They let you do it. And I'm sure he can, hardly wait. I mean just because he's already 74 doesn't mean anything! Just ask brother Andrew. He likes them really young. And enslaved. Don't ask me why? He was a friend of Jeffrey Epstein. Who was murdered in jail by the Trump/Rudy/Bannon Mafia. Where they all wanted to be the Fixer. And they fixed Jeffrey just fine. And now his 16-year-old girlfriend has nobody to help her. And she was the good-looking one. As it wasn't, Jeffrey. He looked like a Jewish nerd. Because he was. And liked young underage girls. Go figure with these schmuck's? Who wants a young girl? They don't know anything. They don't know what they want or how they want it? I like women who know such things and how to do them. Not the stupid young ones you have to teach everything to. What the hell is wrong with those boys in their 40s and 50s and 60s? There little happy but he doesn't get hard over people their own age anymore? I guess not? I think older women with gray hair are very sexy. WOW! And they know what they want. And they can articulate that. So always a good ride for both. And experienced boy man only wants inexperienced little girls? What kind of maturity is that? It's at least between the 6th and 7th grade girls? And not younger than 12. In Texas. Before you can rape them. They have to be at least 12. According to Texan law! Which will be enforced! Because if you rape a little girl earlier than 12? You are in big trouble buddy! Of course it will also be your child. And you do not have to allow for her to have an abortion. Otherwise you can have her parents and the doctor arrested and thrown in jail for 20 years. Which is the perfectly moral thing to do. To an immoral act of abortion due to rape. Why? It's a miracle! If she doesn't want that baby? We will take it! And raise it with Jesus. And so she will have the next, immaculate conception. That Donnie won the election. The election conception. And all of the liberal Democrats aborted him! Which they should die for! Or at least go to jail for the rest of their lives! But we don't want to pay for them! So they will have to grow their own food in jail. Or they can have the outdated dog food. As it is still delicious and nutritious and dogs love it. They never complain. YOU SHOULDN'T EITHER! This then would all work out well. In the Soviet Union. Pre-apocalypse. RemyRAD

I have a similar era Denon receiver, an AVR 2500 that I bought new in 1996 or so. I've used it heavily and it's my favorite receiver ever. It has the ability to make any set of speakers you hook up to it sound fantastic. It ran a pair of Klipsch Chorus IIs for about a decade, it lived through 8 years on a modified sine wave power inverter in my cabin, now it runs a sub/satellite Bose speaker system in my office. It was my 2nd "big" audio purchase ever and I hope it lives another 27 years. Only quirk it has is sometimes the buttons on the unit will act like you pressed a totally different button.

I have a Denon 35 watt am fm receiver I bought in the eighties. It's class A and can be cranked up to maximum volume with little distortion. Great video on this one Mark............

Bummer... Nice job chasing it though. Your logic is sound, it was interesting following along and you're tenatious.

really enjoy learning from you, Thanks

10/10 for sheer perseverance on this one Mark, I'd have given up not long into that one. The sheer amount of dis-assembly on that beast was challenging. I have a love of electronics and worked in the industry from my first job aged 16, assembling circuits and parts for a small electronics company that supplied covert communications gear to the police and security services. Later on towards the end of my working career I worked for Omron the Japanese electronics giant on their EPOS systems and gained a life-long interest in computing and programming (pre-internet floppy disc era!) which took me away from electronics. I haven't done much with electronics for a long time except the occasional repair job but just recently I've re-kindled my interest and decided to try a little project in my retirement. My electronics knowledge is fairly limited, so I'm hoping someone can help me with a quick techie question... I have a small folding electric bicycle gathering dust I converted many years ago using a kit purchased from China that has a standard 36V DC motor and controller, which I'd like to bring back to life and get some use out of. Originally it had a custom-made Chinese Lithium-Ion brick battery rated at 37V DC 15Ah. However that battery has long since died. Rather than replace it with another Lithium-Ion brick-style battery that ends up in landfill, I want to have ago at designing a more eco-friendly battery and take a serviceable modular approach using 18650 type (similar to AA size) 3.7V 3600mAh Lithium-Ion cells connected together in 4 or 8 cell battery holders. And a simple voltage regulator and charging circuit to provide 36V DC and around 10-15Ah (or more) output. My question is, would using 16 to 20 18650 cells (or similar small cells) rated 3.7V 2300mAh-3600mAh be sufficient to power my electric bicycle's motor or wouldn't they be up to the job and drain too quickly? Assuming they would be up to the job and provide a decent charge-cycle usage time, how long can I expect these cells to work from new? Are they likely to need replacing more regularly compared to a custom built Lithium-Ion bike battery which typically use fewer and much larger sized flat cells joined together? The original battery I used performed remarkably well. I could get 20-30 miles easily between charges without pedalling with an average speed of around 18-20mph, and those batteries typically lasted about 4 or more years before they started showing signs of performance degrading. I'd welcome any suggestions or technical expertise to save me engaging in a potentially wasteful and fruitless exercise! If anyone has any specific suggestions on small battery cells I should use I'd be grateful. My plan is to design the battery housing using a 3D printer to enable easy opening and replacing of individual cells when they eventually degrade. With some LED's to indicate cell failure and maybe a Bluetooth link to an Android app to show battery cell health. I might also look at incorporating a decent 12-24V solar panel onto the battery enclosure lid for trickle charging the cells when the bicycle is outside or not being used. Feel free to reply on here if you have some suggestions or advice... or you can find me on Facebook by searching my name. If you leave a reply, give me a like to get my attention as I've disabled comment-reply notifications as I get too many. Cheers.

Great to see, hopefully further advice from comments will see this working. I used to work at Marshall Amplification in test & service (88-93), then Alpine Car Audio (93-97), before the days of in-circuit firmware upgrades so regularly replaced similar controllers.

This is why I steer clear of all Denon receivers. I've seen way too many broken ones and I'm not a skilled enough technician to keep them alive. Thanks for sharing this video Mark!

@brnmcc01

Жыл бұрын

I have a Denon receiver that I bought about 10 years ago as a 'demo' unit. Was the last one on the shelf at the store, it had been a powered display unit for awhile. It's been a great unit, sound quality is fantastic, the 5 channels inside are separate. Only thing I've had to do once in awhile is take the remote apart and clean the button pads, especially for the volume up/down etc. But since it's going to be over 10 years old soon, if it ever dies, I'll chuck it. Was on sale at a pretty good discount since it was 'open box'.

@bryanmiller2023

Жыл бұрын

I quit buying Denon products many years ago when they were known as a somewhat "high end" brand and all I seemed to have was bad luck with them. Too many better options out there to take the risk in my opinion.

electrical appliance repair It's a stressful job. But you're playing for fun. ..extremely appreciated

Mark is like the Bob Ross of electronics.

@meowcula

8 ай бұрын

I like his jovial nature

Hi Mark I stumbled on your videos, I must admit I really enjoy the videos, how you're repairing equipment. Very impressed with your test gear. Keep up the good work. One day I may need you to fix some of equipment. Brian

Have repaired thousand of thousands of Denon Hi-Fi between late 80's to early 2000. Do even have a DRA-275 for my pc.. :P It's was a very very reliable receiver. Most common thing was blown inputs (due to user connecting/disconnecting stuff with all stuff turned on) or a cooked mains transformer because of stacking things on top and drive it hard. The transformer has a temp fuse you can locate and wiggle out and replace with some handywork. Your thing is rare and seems more of just get the remote and turn it on or manual reset by first discharge all caps completely then use a solderwick and ground all legs on the mc by drag the grounded wick over the legs of the mc. Feel free to holler if you need Denon tips.

well tried I forgotten a lot I learned since my stroke so admire you and being a radio ham i need to repair things but often i just leave them , thanks for the video

Very interesting video. Thank you very much.

only came across this channel, absolutely brilliant!!!!

Great analysis of the problem. I would never have found it.

Absolutely fascinating. I detest the way we have to throw away stuff now. I recently repaired my 1994 akai integrated amp. Cost 17p for a couple of capacitors and resistors . Sadly went again 6 months later so beyond my skill to fix. I then wnet for a marantz costing over a grand. Sadly I know some day maybe ten years from now something will go and it will be another bin job. It is crazy. Thanks for the video, I am subscribing.

Showing things that can't be rejuvenated is assume. Most tubers don't do this.great job sir

I enjoy so much your very interested channel. Thank you so much, please never stop to make fantastic videos. Thanks so lot !!!

Thanks for showing us the ones that got away!

Ohh I love a quick troubleshot without 5 min watching how you unscrew a box, I love it. You have a new subscriber!

Hi! I recently found your channel. I really enjoy your videos and your knowledge. You troubleshoot and fix the problem without going on a tangent. Great job!

Really enjoy the logical approach and tips.

If I still may suggest, provided it is not yet scrapped, I would suggest you to check main Vcc pins on MCU on an (fast DSO) scope during power on. If some capacitor on power rail is dead, which I can imagine there may well be some, the inrush current to MCU will cause a voltage drop, simply causing MCU to reset. All I am saying this could be as simple as power supply issue.

@Knaeckebrotsaege

Жыл бұрын

I'm surprised he didn't notice or mention the multiple, easily visible puddles in the dust at the beginning of the video, where things have obviously gotten wet at some point. I'm betting a lot of the caps have leaked onto the board and are now effectively nothing more than resistors to the circuit

@Fireship1

Жыл бұрын

I’ve fixed more older inoperative electronics with recapping then anything. They loose their value with age and they short other components when they leak.

@jb678901

Жыл бұрын

@@Knaeckebrotsaege Yes, there were some tell-tail signs of leakage on that board in the beginning of the video.

@scottwillis5434

Жыл бұрын

Maybe not the inrush current, however you can get shorts, oscillating power regulators, etc. Electrolytic caps tend to die with age, as Fireship1 posted earlier.

@scottwillis5434

Жыл бұрын

@@Knaeckebrotsaege or, someone clueless used spray cleaner (shudder).

Hey Mark, I have one of the same model that is also dead. I hope you can solve this. I look forward to seeing your second episode. I get motivation from your smile. Go ahead.

Great video - I worked in a Hifi shop at weekends 30 years ago when I became interested in electronics and building amps and active crossovers. I was horrified at the amount of nasty cheap components in the signal path - stuff I would never put in my own builds - carbon film resistors in the signal path - even in the NFB in amps costing a months wages! Marketing, Gimmickry, proprietary protectionism and planned obsolescence, not much has changed.

What a shame !! I love your channel-and your good and cheery humour,I’ve watched you successfully fix quite a number of products-but sadly ‘you can’t win ‘em all’ !!

I had a Denon receiver around that time. It didn't have an issue removing from standby mode into playing mode. Mine also had an enhanced bass button near bottom right next to the variable loudness. It worked very well, I added a graphic equalizer to it using the first cassette player input which gave more control and doubled the volume.

My compliments for your endurance anf skills. A pitty to waste a Denon. I still have an AVR 1000 pro logic recoevet with excellent audio quality. Build around 1992 and still going strong. Greetz from 🇳🇱

Every identifiable date code in that is from 1996. That’s way before the transition to lead-free. But cracked joints (not “dry joints” - dry joints are a specific type of soldering error, which does not include thermal cycling induced fracture) happen to thermally cycled joints with leaded solder.

Yes when AV Receivers and the like are controlled by a Microprocessor it's a ticking bomb. Onkyo AV receivers are also notorious with similar problem in their Syscon boards. With this Denon you may succeed in fidling for the On/Off control to power up but other function like source selection, etc. may not work either so yeah it's parts out unit then. I love watching videos on this channel which give good information. Mark is really patient at work and always smile.

Great video, enjoyed watching that, have subscribed and will be watching more of you! Excellent work!! Thank you!

As usual excellent video. Thanks 👍

Age-wise, according to HiFi Wiki, the manufacturing years for that Denon receiver was from 1996 - '98. I have a 'DRA 425-R' receiver that's older, but still runs fine. Maybe one aspect that has kept it in shape was using a power-strip as a power-on/power-off switch; as I am suspect of push-button on/off switch's lifespan.

Just love the time lapse repair thanks to editing. That was some good troubleshooting, your eyes are doing better than mine. Would have a difficult time counting the leads on that controller, yikes.

@lucasRem-ku6eb

Жыл бұрын

you all say weird things here, why you people need Radio in 2023 ? you did not read what you already types here, you all say the same thing .......

I can not stop watching your videos! I have no words! Just brilliant! Perfect! I am not sure about your background. Priest? School teacher? Bilioner hobbiest? All together?

“Rectangular bastard”. That’s the funniest description of a quad flat package IC I’ve ever heard :D

Excellent work. The comment, "That's weird?" .........is something I have muttered a hundred times when trying to debug a circuit. I know the unit is old, but to be unable to fix a receiver because of software in a discontinued chip is very disappointing. That software/chip is just an unnecessary (control) wart in the circuitry: I am old school....all you need is: input jacks, selector switches, preamp, amp, speaker jacks. Leave the software to iPads.

I repaired a similar vintage receiver the other week. What was odd is that the reset was not clean / fast enough with the "dim lamp" in series with the mains and the micro failed to start. As soon as I went back to straight mains the unit it worked fine. It had me flummoxed for a minute!

It might just be the watchdog timer resetting the processor, so it might still be caused by some other external circuit.

Soooo much screws, you definitely need a DeWalt DCF680. I enjoy your videos very much. I am a hobbyist from Vienna Austria. I try my best an learn from you. Rock on and best regards.

Found this channel at random. Very interesting and more views to you, very educational.

Excellent channel on the topic of repairing electronics, on par with NorthridgeFix, which is based exclusively on microsoldering. Mark seems to be much more versatile and modest than NorthridgeFix guy. At the same time Mark shows his work very entertaininly...

I had this exact amplifier, I'm fairly sure from memory that you need it's remote control to bring it out of standby and that was the only way you could do it. I assume the processor is generating it's own reset cycle. Thanks for the excellent continue, reminds me of my TV and audio repair days.

You poor little Denon, I will always carry you in my heart 😞

@lucasRem-ku6eb

Жыл бұрын

You still do Radio in 2023, muhuhahahahahaha

My 40 year old Sansui Amp is still working with the only issue is scratchy pot’s. Some of the good stuff are still Made in Japan!

What a lovely and educational video! You´ve got yourself another keen subscriber :)

Thanks Mark, lovin' the content of your videos.

Nice to see the use of an Aldi screwdriver, I must have missed when that was for sale! I have a Lidl one, branded 'Parkside' - bloody brilliant, has survived use and abuse over several years. Lithium Battery is getting a bit weak now, but only to be expected after all this use. As a hobby user, I wouldn't spend the money on 'De Wilt - sic' etc...

thank you again keep on with awsome good channel.

your excellent video, along with the incredible insight from the commenters, has earned you a subscription! looking forward to binging more of your videos.

Excellent work, the fading of the LED at the end really made me sad tho hahaha

I had a fair share of such repair attempts. Most of the time I ask the customer if they want the amplituner back with just the "amp" functionality, bare minimum, and most of them say "yep", so I just disconnect everything that is not related to the amp/preamp or power supply, and add an "AUX in" functionality. But it's sad to do such a thing, only because the IC that died is no longer being made, and it has to have proprietary software on it...

i picked up the same reciever about 9 years ago for 30$cad at a yard sale. It's been my bedroom radio for quite some time. I always thought there was more on the inside. So far i been lucky no issues yet

@andygozzo72

Жыл бұрын

open it up and check for dry joints!

That pulse looks quite digital (timing etc.). So I expect the CPU still runs fine. It's probably the program running on the MCU trying to initialize some peripheral, then gets stuck waiting for it to respond. The watchdog unit then attempts to reset the MCU hoping that the next boot will be successful. Maybe there is some i2c bus you can monitor. But it's a lot of work :)

Happens more and more, ending up with a factory programmed chip making repair completely impossible, absolutely frustrating !!!

@nickking1510

Жыл бұрын

That’s why I went to industrial electronics and mechanical and heavy equipment not a good business model repairing consumer electronics and business cost rise as consumers equipment drops in price tv so cheap many send to ewaste stations

The microcontroller is reprogrammable, and still available. The Denon allows for DFU ( direct firmware update ) using a DOS/Windows program to perform the first update. It is an older Denon ( being 20 years old indeed ) which doesn't support many modern features that are needed for HDTV's ... but it is a pity that it's for the bin.

Bless you, KZread algorithm 🎉. Subscribed

I had to repair my 1987 DENON DCD-900 CD player, due to it skipping. Here I had to invest about 6 drops of electric shaver oil, to fix the problem. The mechanical movement was somewhat inhibited, due to the partially hardening of the old old lubricant. I just fixed my 15 year old coffee maker about 1/2 an hour ago. It had a blown thermal fuse. Other than that, after a few repairs over the years, my 2004 stainless steel microwave oven is still up and going. I purchased it for about $45, due to it being a display model, or so they said. In truth, only half the keyboard worked, so I fixed that by simply cleaning the keyboard electrical contacts. At one point about 5 years ago, with just a couple of drops of glue, I repaired the turntable motor, in which there was slipping occurring between the spinning center donut-magnet, and the gear that sits inside it. Also at another time there were the required replacements of the door micro-switches and the main fuse. These replacement parts were obtained from someone else's oven that they had tossed out to the curb for disposal. And I also fixed my 2009 SAMSUNG TV, which I am watching this video on today. I had to replace one bulging electrolytic capacitor in the power supply section. Then at one point my computer monitor brick power supply became intermittent. It was a bad soldering joint on the transformer, where one wire was poorly soldered to one of the multiple transformer posts. So it was not even a PCB soldering problem. Other than that, my old backup computers PSU was causing a boot looping problem. I replaced the bad PSU electrolytic caps, and that fixed the boot up problem, and it cost about $9.50 for the parts. So all of these items are still up and going, and the repair costs were less than $20 overall. I love saving money.

quite an unusual failure -makes me wonder if that 6v regulator went dry jointed on its ground pin first so input voltage got sent straight to the output pin as unregulated and blew the micro -but then the micro wants a 5v supply not 6v unless its going through a diode for a memory backup cap then 6v is about right-now i want to find a schematic to check my guess !

@andygozzo72

Жыл бұрын

thats what i suspect, commented elsewhere on here about it ,, its what kills commodore 64s,

This lets me know I should stick with older stuff for repairs .. too small more my liking. Love the vid though, very interesting!

Dear Mark. Many thanks for your efforts. However, in my experience, the only good Denon is a doorstop!!!!! The A.V. amps are utterly unserviceable. Also no ready backup. I commend you for trying on this "basic" one. Better luck next time. Regards Allan. Commiserations.

@wheelhorseman2306

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Yes. My experience with 2 Denon AVR is the typical processor overheat and needs reballing due to no connections. Dislike Denons due to known issues for which repair parts are no longer available.

I own a DRA 45 that was dead after power switch cycle! The only repair shop wanted more in a bench check charge than what the receiver was worth ! I decided to at least try resetting board connections , and clean internal power switch ! The receiver powered on with no other apparent issues !😁

I'm new, I like, I subscribed. Cheers from Canada!

I knew it would be a micom failure. It's the only thing that will stop my shop from fixing one of these too. Micom failures are rare and so disappointing when they're encountered.

I admire your patience! You are well equipped. If there was some form of backup there was a possibility to restart the processor. Now how much time is it worth?

First time I see this channel. IT IS GREAT. Love the old HiFi stuff.

I always put these machines on the floor outside and give them a good blasting with the hosepipe, then leave them to dry, they look like new afterwards. They are always fixable afterwards :)

I repair electronic equipment for a hobby (self taught) and I usually get everything working, but when I start to open some device to repair, I always dread that an unobtainable IC has failed in it. For example, in this video, where you will have to bin the Denon. That's why I enjoy working on pre-IC equipment like old Dansette record players, where the parts are still easily available.

Ive actually seen a number of amplifiers where the only thing that was wrong was the microcontroller and maybe the 5 volt supply for it. Depends on design mostly.

Hi! Great video! Enjoyed it! You disappointed me by not making the metal plate that was missing, between the PCB and the Heatsink! It compensated with the transistor protection shield! Eagerly waiting for the next! Love from India! bussypaul A. T., G. Mail

I'm sure I had that amp pre 2000 or it looked just like it. The volume control was motorised when you used the remote and it sounded pretty good.

Can't win them all. But this video is a great example of investigating and finding the source of the problem. I have a Denon DRA-325R from 1989. Was given to me. Lightly used in an office (they guy listened to AM radio through some fairly expensive speakers).. I got it some years ago and just started using it again when my NAD C368 failed. Died in 3 years yet the old Denon still works. Go figure!

4:01 Mark sounds like DCI Meadows from The Bill. 🙂

10 out of 10 for determination Mark, Thanks for that , interesting job.😉😉

looks exactly like my Kenwood here in the States from around the same year, mine has optical, and Dolby 5.1 also, Works almost like new to this day.