Denon DRA-F109DAB flashing red light repair

[@matthewgriffin4761]

Thank you for sharing this most interesting video. It's one of those frustrating things not knowing how the fault occured. We've all been there!

[@michaeldranfield7140]

and its been over a week now and its not come back .

[@vegardxf]

Thank you! Had the same issue as you had and measured as you did. Reset it and now my parents take it home and hope it does not cut out again

[@michaeldranfield7140]

Glad to have helped you , mine has not come back yet and its over a week ago .

[@vegardxf]

@@michaeldranfield7140 my parents have been using this one for hours every day like normal now with no more issues 👍

[@vegardxf]

This one died now, cutting out all the inputs in periods. Dont turn off or go in protect but not usable as is

[@adamdavies163]

Another useful video Michael, I think anyone would've gone down that rabbit hole.

[@leetucker9938]

very strange , you still repaired it so well done .

[@ashleycox432]

This is really common for these power supplies. Likely this unit was just connected with the speaker cables shorted, or it was run too hard for too long and sent the amp into protection mode.

[@michaeldranfield7140]

Dont think so as this would have caused a Amplifier protection message , I know this because I burnt out a pair of speakers testing the unit ! if you look back at the video I started off with a small pair of speakers , forgot they were only 10 watts ,turned it up full and the speakers went up in smoke , so I swapped to a bigger pair for the rest of the video !

[@y2kwarrior2001]

Man... you are genius. Worked exactly as you said. Thanks alot !!!!! 😍😍😍😍

[@walker55able]

Well done once again Michael

[@andic6676]

Reminds me of a Technics system I repaired years ago...it kept shutting down - once in a while - because its uP sensed that its cooling fan's bearings were very very very slightly too tight!!!! You can see why I left electronics.

[@michaeldranfield7140]

yes , a lot of fans have 3 wires and a tacho coil to see how fast its rotating ,I had the same with a capstan motor in a video once , replaced a chip that was overheating and then found same as you tight bearing causing the chip to overheat .

[@tenmillionvolts]

I replaced many of those fans. They are used in CDPlayers as well. They give trouble there too. You can rev the motor for a while to loosen them up but they bind after a while.

[@4bitsystem]

I love your repair videos! On the 32 V line there is this voltage devider "PVDD_Protect". Sounds like this voltage is monitored and there might be something wrong? And a little load dependent regulation is normal, I would have thought.

[@michaeldranfield7140]

yes , I noticed that but the 32v rail was spot on , I would imagine a short in the amplifier would cause this to drop and trigger an Amplifier protection message , its gone back over a week ago and not returned so I guess we will never know .

[@sw6188]

A variation on the output load (audio power) should not affect the rest of the system rails (+12 V, -12 V, 5 V etc) especially where those voltages RISE as the output power rises. I can understand it causing some shift on the 31 V rail that supplies the output stage but the way this amp works is just out to lunch.

[@repairitdontreplaceit]

@@michaeldranfield7140 could it be some class d amp weirdness ?

[@michaeldranfield7140]

Might have been something as simple as a glitch on the mains, dont think I will ever know for sure .@@repairitdontreplaceit

[@reacey]

Hi Micheal. Love your videos. How about some more old tv repairs? Ty.

[@michaeldranfield7140]

its already on the cards , I keep buying old TV sets to make videos but just short of time at the moment .

[@reacey]

@@michaeldranfield7140 looking forward to them..appriciate you're a busy man. Im 34 so alot of this stuff is before my time but I find it fascinating . I used to sit watching my dad mend tellies and vcrs in the 90s. Id love to be a fly on the wall on your workshop haha. Thankyou for all the work you do with the videos' editing ect. I for one massively appriciate them and you dispensing some of your vast wisdom.

[@michaeldranfield7140]

@@reacey I don't do editing , I'm not computer orientated , in the early days when my daughter use to do the youtube videos she did the editing but now shes has two childeren I have to do the videos myself.

[@OaklynHall]

Thank you for sharing this interesting and educational video with us. Perhaps the service manual was written by someone who was not involved in the technical design of the product? At least there was a service manual available even if it omitted a key fact about the variable voltage...

[@michaeldranfield7140]

Its a far cry from when we had technical descriptions in the service manual but these days with most stuff been a board replacement job only I guess you dont need a technical description .

[@sw6188]

@@michaeldranfield7140 Precisely. They don't give you a technical description or any fault-finding info because they really don't want you to repair the unit.

[@michaeldranfield7140]

i know , its a good job i didn't order a new psu board .@@sw6188

[@peterensinger1770]

hi Michael I would check if there are any opto couplers in the feedback from the secondary to the primary as it looks like there is no regulation on that psu. I have had similar problems with SMPSs having low rails caused by no voltage regulation feedback caused by a failed opto coupler or a failed tl431 voltage reference ic. these psus generally have both voltage and current regulation the symptoms shown on that unit looks like the current regulation is working but the voltage regulation isn't working thus when rhe power amp draws more current the voltages will rise. I noticed whwn the volume was turned up the 12v rail went over 12v again telling me that the voltage feedback is not there.

[@davidknightaudio934]

I know right anyone who is actualy as good as this guy makes out would know that lol this guys probably wrong i doubt its repaired itl be back ot on a bin soon i dont know if you noticed but he got a low reading before a 7812 hahaha does he think thats ok and the rail just rises up till the regulator works or somthing thats hillarious whats he think happens before the regulator is working does he thinl the currant just goes strait thru hahahhahaha

[@mattsan70]

Another reason to avoid buying this tat in the first place - thank MD

[@michaeldranfield7140]

unfortunately most modern HI/FI gear is like this now

[@sw6188]

@@michaeldranfield7140 Which is why there's a strong demand for vintage audio.

[@michaeldranfield7140]

@@sw6188 I know and most of this stuff was built to last and be repaired , biggest problem I find with vintage hi hi is the STK audio chips are virtually un obtainable unless you buy a Chinese fake .

[@MrDudefication]

Thanks a lot, worked for me. Haven't used it in years 😂

[@truthreigns7]

Very interesting. Thank you

[@michaeldranfield7140]

Many thanks for watching .

[@ralphj4012]

Well discovered. Something very odd with that manual. Unless I'm mistaken (has been known) a KA7812 (12:55) has a dropout of 2V so with 13.3V on the input, expecting12V on the output, would make a great unregulated supply, ho, ho.

[@michaeldranfield7140]

Without any technical description its hard to know whats going on with modern stuff now , I remember a similar fault on a LG sound bar trying to trace why a rail was low only to find it was the wi fi module and the rail went up when the thing was switched on

[@guntermoser368]

Not only Denon has criminal minds ;-)

[@Johny666EU]

Have a check bad solder joins, its typical in modern equipment's as leaded solder. Also maybe someone made a shots on a speakers outputs, most of the time people dont say that and they blame device gets faulty.

[@michaeldranfield7140]

its not come back yet !

[@genenomidic1393]

Kudos for sharing 👏👏

[@darrenmurphy6251]

Brave to go against all the, how to fix things without a schematic, KZbin channels ive had a hard time with customers because of those channels, do you have to sign up to a special, non fake KZbin ha keep up the non fake good work

[@michaeldranfield7140]

this would never have been fixed without a service manual , unless of course you could have guessed how to enable the service mode, I had a similar fault with a Neff microwave and I think they made it deliberately un guessable , the procedure was to plug the oven in , set the clock to 12.00 then press a button sequence and all this had to be done within the first 10 minutes of connecting the mains , then after repair you had to erase the codes out of Eeprom A , press the wrong button and erase Eeprom B and the operating system would be deleted and you need a new board .

[@darrenmurphy6251]

@@michaeldranfield7140 yes these things are spitefull ! its more sad that these things are thought up and done by engineers (supposibly the good guys) not the accountants

[@darrenmurphy6251]

@@michaeldranfield7140 ive never seen the internal paint /plasicoat coating in a microwave last long enough to have a electronic fault happen ,they seem to delibratelly not ventillate the steam/condensation out now. now killed by rust/paint flakes in your food

[@diegomoschini4493]

I have f-109 not Dab, the issue is when push to turn it on, the green light flashes once and nothing happens...if you continue to push power button, green light keeps flashing regularly. Any advice about this? Thanks

[@whitesapphire5865]

So, let me get this straight..... If the cat is playing on the shelf next to the speakers, and accidentally yanks out the speaker lead, that would cause an underload on the outputs and cause the PSU to shut down and lockout? Then you need to buy a manual to tell you how to clear the fault record from memory before you can use the amp again? - Or take the amp to a repairer to do the same thing? What a performance! I think I'll stick with my Technics!

[@michaeldranfield7140]

Correct, you need the service manual on a lot of modern HI/FI equipment, just like you need a hand held scanner to find a problem a modern car , only a couple of months ago I had a fault on a microwave oven which wouldn't do anything and the service manual said if it has failed to start more than 3 times it would lock out ,the worlds gone software crazy , I guess we will never know why the hi fi locked out as it has not come back yet and its a week ago when I did this repair .

[@sw6188]

Yes, keep your Technics (which I presume is a vintage unit). None of this microprocessor controlled junk!

[@Iraanian]

Hi there thanks for your great videos on youtube, it would be great if i can get your shop address to see if its local or same city i would bring my tv for repair

[@Trucam2020]

Thanks for sharing this great video 😊

[@michaeldranfield7140]

No problem, many thanks for watching .

[@markpirateuk]

I remember when Denon made decent gear, this thing certainly is not! What a pain to sort out, if it was a short on the speaker terminals that caused it to shut down, why it could it not see the short was cleared & simply reset itself? Another reason not to repair this modern tat! You need to get back to some vintage gear that is a pleasure to work on 👍

[@michaeldranfield7140]

Not a short on the speaker leads , this throws up a Amplifier protection , I know that because you may have noticed in the video I started off with a couple of small speakers , then in another clip I had swapped them for a pair of large speakers , I forgot the small speakers were only rated for 10 watts and they both went up in smoke after running the amp on high volume triggering the amp protection !

[@sw6188]

This is a shining example of why I refuse to work on this modern junk. The service manuals (if you can get them) don't give proper diagnostic information and invariably leave out the most important things that we as service people need to know. Hi-fi gear now mostly relies on switch mode power supplies that can be dynamite to repair, and are often coupled with class D output stages which to my ears sound bloody awful. Give me a nice 70s or 80s amp to repair any day. Easy to work on, most I can do without a schematic and there are no microprocessors or other digital garbage to deal with. If the service manual says there should be 12 volts on a rail, then that's what it will be as long as everything is right - and I won't be wasting time chasing red herrings.

[@michaeldranfield7140]

modern TV s are worse than HI/FI , no schematics at all , just 3 or 4 boards and a part number for each , the truth of the matter is the manufacture does not want these items repairing , they just want to sell a new unit which I think is wrong, in the 70 s there were service manuals for a pair of headphones and you could order every single part as a spare.

[@sw6188]

@@michaeldranfield7140 Dead right - they don't want you to repair them. Chuck it out and buy a new one. I refused to buy into this madness. I'll hang on to my 20th century tech and appliances as long as I can (for as long as I can keep them working!) I take my hat off to you for the work you do in getting these modern sets up and running again.

[@moodyga40]

Hi Michael

[@michaeldranfield7140]

Hi .

[@angelosanagnostou5550]

absolutely weird. Would have stuffed me around too.

[@wisher21uk]

I hate red herrings you waste so much time, nice result though thanks Michael 😊

[@MagnusPaul1976]

I reckon it went into Protection Mode for one reason and one reason only... It was played too loud for a long period of time, way past of what it is capable of. Too much bass and treble for extended periods of time, causes the unit to enter protection mode and shutdown immediately. Consumers wouldn't expect something to just blow on a brand name like Denon.

[@michaeldranfield7140]

dont know but its not come back yet .

[@MagnusPaul1976]

@@michaeldranfield7140 That is great to hear, Sir. I am no expert on fixing hi-fi components, however I try to repair as far as my knowledge will take me aided by service manuals. I do generally just give them a service, check fuses, lubricate scratchy dials, knobs and switches. However, I now have an issue of my own that occurred yesterday. I have a Pioneer A-307R, which I bought brand new in 2012, that I serviced yesterday morning. The unit played extremely well for most of the day. Later on in the early evening, I switched it on again and it was completely dead. No power nothing. Upon inspection, I noticed that the Voltage Selector dial at the back of the unit advanced to a different voltage. Previously, this dial was locked onto 220V, but somehow the dial advanced to the US voltage of 110V and I never thought of looking at this before applying the power. Now the dial moves freely and does not lock onto any voltage and it seems to be a bit loose, which I am absolutely sure wasn't the case before. I am not sure what has blown. There was also no smoke or burning smell emitted from the amplifier. The fuses (3 of them) are okay and I would have thought these would blow first to protect the power supply and or transformer, which they did not. Could it be the Power IC ? So, off the bat, I cannot say what has blown, because I do not have the testing equipment to diagnose the no power issue. This is a tremendous loss for me, at this stage, because this amplifier looks brand new in every sense or way. I do have the downloaded Service Manual at hand, however I am none the wiser. Could you perhaps give me any advice ? I would really appreciate it if you can assist me with what I need to be on the lookout for... Many thanks, Magnus South Africa 🇿🇦

[@tenmillionvolts]

Denon gear is cheaply made and problematic these days. There are modifications to try to improve the power supplies in some models. Power supplies and output stages dying all the time. Many brands are the same now. Especially AV amps. If you get quality, it's a bonus. Plenty of warranty failures

[@jasejj]

​​@@tenmillionvoltsDenon isn't really Denon anymore. The Japanese company sold up quite a while ago and it's all made in the same sweatshops as everything else. In Denon's case most of it is designed and made by the Korean company Inkel, who were pretty good in the 1990s (they owned Sherwood, and made a lot of stuff for Harmon Kardon and others) but their modern gear is just the usual rubbish, made in Vietnam but with mostly sub-standard Chinese components.

[@richardh100]

maybe the owner is deaf and turned up full volume and jammed the speaker seems to be a bit sensitive the over voltage protection😮

[@michaeldranfield7140]

Dont think so as this would have triggered an Amplifier protection message

[@richardh100]

thank you Michael another great video what a strange fault maybe a mains power surge put into protection mode , i can remember buying that CD from Willow Vale best cd for the eye pattern 😊👍think it had a silent track two minutes

[@michaeldranfield7140]

guess we will never know why it tripped out , its gone back now and not returned so far.

[@davesdigitaldomain]

power supply is faulty, looks like a fault in the feedback circuit.

[@techslfink9722]

Don’t you just love modern self thinking equipment 🙄 Nice job though!

[@michaeldranfield7140]

trouble is all this modern stuff is getting far to overcomplicated and far less repairable .

[@darrenmurphy6251]

What a weird no fault found, that must be some eco complexity that sends more gear to landfill for u you know, eco!

[@michaeldranfield7140]

too right, if I did not have access to the service manual this is where this would have ended up .

[@moodyga40]

its real rubbish this unit give me a big 300 B amp any day

[@michaeldranfield7140]

Valves are far more forgiving and dont just blow up at switch on when you have a fault, I love valves .