Denon AVR 1705 - Repair for going into protect (Ep. 83)

[@Dutchamp]

He Trevor, you did find the power supply error nice quickly. Yes those standing boards are notorious of cracked solder joints. Personally I would never go for multiple channel amps. Although DENON isn't a bad amp. You did well on repair. Why pre repair guy left out screws he must have found those ones left on his beach. I find that move messy. Nice work Trevor.

[@TrevorsBench]

I know all about leftover screws and other bits on my bench...lol Cheers digger, thanks

[@Dutchamp]

@@TrevorsBench me too but I'm more into tube amps so lose sitting tubes or transformers easily checked. That DENON looks like a pc motherboard layout with lots of connection... Problems. I enjoy soldering floating with wire taps. But into transistors almost impossible. You did found the regulator damage real quick. What could be the course of damaging... Caps or resistor going bad?

[@TrevorsBench]

@@Dutchamp I've noticed on other gear I've fixed a lot of negative voltage regulator failures. That's why I had some new regs on hand. Not sure why but the 79xx regulators are prone to fail before the 78xx regs. I don't expect it to be caused by any other components, probably just heat stress

[@Dutchamp]

@@TrevorsBench must be heat and some owners are not so careful with placing it. Fibrations breaks up solder joints too. In tube amps even worse course they are heavy.

[@Domino33-SSTB]

I am an electronics hobbyist. I am not sure what I can use for an insulator on the back of the regulator. Are they specific to small electronics repair and available somewhere?

[@TrevorsBench]

Thanks for asking. These insulators can be bought at Digikey and other places. They can be made of mica or silicone rubber. Some think the silicone ones are better because they don't need the thermal paste. For general purpose uses like this you can use anything that fits and provides insulation properties

[@AF7U]

Just a thought about the mute issue; often on CPU-controlled receivers the audio is muted while the system changes the audio signal path, i.e. changing from FM to CD or Phono to VCR for example. Similar in fashion to the way FM audio is muted during periods of signal loss. It gives the audio stream a graceful way to switch between modes.

[@TrevorsBench]

Correct. I've seen these muting circuits on older gear too. They use reed relays to silence the audio during the transition between inputs

[@christophe5380]

Hello, very interesting your video, I myself recovered a DENON AVR-1804 which presents the same problem, as soon as the power is turned on, we hear the relays switch and a second later the amp goes into safety with an indicator light red, weird thing the first time I tested it, it had worked I wonder if when moving the amp, there would not be a bad contact or a weld that would have a weird problem. There is no longer any case to check the state of the welds and the interlocking of the cards on the connectors, because this one on the card side, it has what it takes!

[@rotaxtwin]

The A/V units really pack a lot in there. I have a mid 90s Sony that gives me some grief, almost like mictophonics. I bet it's a12 pin connector gone funky, will have to chk that out.

[@isiso.speenie5994]

I'm an electronic tech that has lost he's focal points because of macular degeneration. Can you fix my beautiful Denon AVR 5803 that has a problem with the left front channel going distortion and clicking on the protection relay when the bass hits ?

[@TrevorsBench]

Sorry, I can't take on any extra outside work at this time, I'm swamped

[@perherbert]

Is the +15volt regulator changed also? it looks like an metal backed part.

[@TrevorsBench]

I only replaced the dead part, the +15v was working fine, changing it won't improve anything

[@slipagent6]

I have an older avr-97 and I had an external amp ran from the front l/r preouts. Well that amp somehow caused a surge that messed up the denon. So now it has more red lights on the display than just the normal standby light, and if I turn it on it just clicks the main relay and the screen comes on and off repeatedly. I think I hear a thud too each time maybe power supply? It was a good unit and it has phono too so Id like to be able to use it for cd/turntable music at least. Any tips for troubleshooting? This was around $1,000 new but I picked it up a few years back for $100. Im afraid a repair shop would be more expensive than its worth but Id hate to toss a good stereo out. I took it apart and visually the only thing I saw was a bad spot on the board near the preouts and I repaired that but same problem. Any tips would be appreciated

[@TrevorsBench]

Usually, the first thing to fail in these AVR receivers is power supplies. They are complicated inside and require several different power supplies. If you have the skills to open it up and check for all the correct voltages, find yourself the service manual and give that a try.

[@adrian.conisca]

Hi , got the same simptome at denon avr2015 7.1 chanel. After start, in 5 seconds goes to standby ...

[@Luke-12V]

Hello Trevor, when the transistor is changed to the same one, it is necessary to set the block current, or in what case to adjust it, thanks for the possible explanation

[@WattanaRatanaaparoj]

Could you please share us some knowledge? . Which Board / IC chip does provide protect signal in AVR 1705 or AVR 1604 ?

[@TrevorsBench]

The protect signal for the audio amplifiers comes from transistors (one for each channel) that monitors the output signal for abnormal DC. This is then fed to the main CPU which handles all protection functions

[@matthewfafalios2690]

What can it mean if a AVR channel/channels is making a squeaking sound occasionally once the unit gets warmed up? Its a Denon AVR S500BT

[@TrevorsBench]

It's impossible to say without hearing it but a few things come to mind. The most probable would be cracked solders in the unit. It could be picking up interference from something radiating RF like a cell phone or tablet. Or it could be dirty power on the outlet your using.

[@zy9872]

Hi, I have a Denon AVR-2105. The Standby Green LED stays ON, no blinking and no Red LED. Nothing happens when pressing other buttons. What could be the problem? Thanks in advance.

[@TrevorsBench]

I can't really say without seeing it but if I had to make a guess I'd say there might be a power supply voltage missing

[@rafaelbenitez200]

Hello, where can I get transistors for Denon Receiver

[@shananarocks]

Mine can play but after awhile it shut down and then can play again later. I presume it is the heat sink. What do u think? Thanks.

[@TrevorsBench]

Hi Mike, does it get hot before it shuts down? Just guessing here but it sounds like a problem in the biasing of one of the amplifiers. Could be a bad transistor or out of spec resistor. The protect circuit is sensing a imbalance and causing shutdown. It will need to be serviced

[@shananarocks]

@@TrevorsBench Thanks you for your great advice as usual. I guess you are correct since when I plug into the CD input instead of the Aux input there was no problem with the output sound. So probably a chip problem. Thanks a million.

[@mohanapritha]

How to identify which IC control the volume on denon avr? Please reply

[@sivadasanmadathilmsdmdm5849]

Hello.I have 1507. Standby is not getting on.! Power supply ok. How to find the fault. Pls help

[@gasinmars1]

could you please show up the measurements of these two transistors ?

[@2tehran1]

You are fantastic

[@TrevorsBench]

No, I'm not

[@kasturiGM]

hi, does anyone know how to find the schematic or datasheet for my denon avr x3300w. one of the diode between the relay popped. i believe it is a flyback diode. but it doesn’t have any marking on it. how can i find a replacement part for it.

[@tominexile]

Great video Trevor. I've got a very old Denon AVR-85, and have been having problems with the digital inputs. When I first start to try to listen to music, I would often get a loud pop from my speakers. The sound would be somewhat muted as well. If I wiggled the cable or took it out and put it back in again things would be ok. At first I thought it was just a bad input for the optical cable, but even the input for coax digital cables would do the same thing. It's gotten to the point I'm worried about my speakers being damaged by the popping sound. Any ideas what might be going on? Thanks and keep up the great work.

[@kofikwakyeagyekum6487]

HiTrevor, what could be the possible fault of my AVC 3020 that distorts @ about half the volume, when I lower the sound the distortion disappears.

[@TrevorsBench]

It's really hard to say without a proper diagnosis with a DMM and other test gear. If I had to guess, it could be a bad transistor or open resistor in the amplifier circuit. Does it happen in both channels? If so look in the areas that are common to both such as the line level switching.

[@kofikwakyeagyekum6487]

@@TrevorsBench yes it happens in both channels,there is a jumper that connects the pre amp and the power amp, I removed the jumper and played the preamp,it did not make any distortion but when I played the power amp alone it distorted

[@kofikwakyeagyekum6487]

@@TrevorsBench thanks very much for your response, I will continue to trouble shoot, I will feedback my findings

[@TrevorsBench]

@@kofikwakyeagyekum6487 The power amplifiers should be independent from each other but they do share the power supply. Maybe the power supply is failing. With a voltmeter measure the amplifier supply voltage and see how it behaves when the distortion starts. It shouldn't change much, maybe 5% or 10% when loaded

[@kofikwakyeagyekum6487]

One other stuff is that the center and surround sounds great with clear sound but the power Amp is the problem more when AVSE button is activated which activates more bass like loundness button

[@bigbaduncleboris3329]

Hi, my denon avr590 won’t play audio and will only play the test tones in the setup menu. Any guesses as to what that might be?

[@TrevorsBench]

Sorry, I'm not much help with the A/V receivers as they can get complicated with menus and such. Find a copy of the manual and go through the setup and troubleshooting. If you haven't already, try different inputs and try turning off the surround, different speaker combinations

[@leeanow1011]

Hi trevor, I have denon avc 1530 and its distortion when i plug on phono help me 😭

[@Martin_Vail_Esq.]

Can you please help me find someone to repair my Denon AVR-3313CI that recently stopped working after a bad thunderstorm? It was connected to a Panamax 5300pm voltage regulator/protector and after the house power flickered for a second or two, stopped working. Doesn’t even have standby power. The Panamax is fine, as are all other connected devices. I don’t have the funds to replace the unit, and was hoping for some advice on finding a repair shop. Thanks in advance.

[@frankmartin2322]

hello I have a denon avr 1803 it always worked fine but now when I switch it to prologic mode it goes into protection mode it can only be heard in sterio mode

[@LifePhilosophyy]

Hi Trevor, my Denon 2311CI makes a noise an left channel, what a can be?

[@gl.72637]

Maybe speaker issue? Try swapping speakers and see if it happens on the other channel where the speaker went.

[@Atelierul29]

Looks decent!

[@marscellkudus]

do you sell mcu denon avr 1311, toshiba T5CN5

[@TrevorsBench]

I don't sell parts, sorry

[@warl01]

Hello. My 1705 have wrong d2390, i take it out then i can turn on the amp but this chanel not working. After i bought replacement 2sd2390, solder it back but still not working this chanel.

[@TrevorsBench]

Hi Mario. If a transistor fails it usually takes out other components too. I suspect there are more blown parts that need replacement

[@bryanbrowder8549]

Can you get an amplifier board for a den avr x3600h

[@frankmartin2322]

Any specific advice would be appreciated, thanks.

[@katarzynaraczka7954]

Witam posiadam denon 1705 i po włączeniu zasilania odrazu go rozłacza przyczyn mignie raz zielona dioda i nic nie działa

[@DADEMANA]

nice trev

[@MrTopsoil911]

I have worked on numerous Denon & Yamaha both same configuration what a pain in the butt.all common issues. Thats why i would never buy these plastic receivers i will stick with my vintage silver faced pioneers and kenwoods.good job tho Sir!

[@dbriddie9525]

This blowing of the 15v regulators on Denon amps is well known. The access is terrible on all with no lower plate removal and massive breakdown required. My Avr-1906 was the same. Great amps when they work but I would never recommend one.

[@izzydizzy1115]

2005

[@raross6119]

Chinese demonstration are pure garbage if you want a good denon have to buy before 2011 Japan made where some of the best relievers made