I'm up for the challenge on this Denon AVR-5800 once touted as "The Beast" it's heavy and got a toroidal transformer that mostly only high end AVRs sport.
It's totally dead as in dead, only semblance of life is an LED standby light, and it doesn't respond with the processor reset procedure. The -----
I believe it is not the amplifier section as I have junction tested all the transistors and they all appear to be healthy; junctions give the 0.6V on my multimeter.
I'm thinking it could be a processor issue or a power supply refusing to power on the unit for a short in the power supply section.
Any wild ideas are open, I really would love this beast to come alive once again and would want to hear it. Doing this on a part time basis, and it's not going away anytime soon.
If you guys have any idea where I could start to check please do so. Any help would be much appreciated.
Things I've done so far.
1. Checked all fuses - they are all good in the power supply section.
2. Power switch / standby switch is good, I tested with the multimeter and it conducts when pressed.
3. Power transistors all good
4. There is power going to the mini transformer what I believe would send a signal to the main unit to come alive, the mini transformer - the one that gives 12V, 6V, and 33V is good as it is supplying power (AC to the components)
5. Diodes and Zener diodes appear to be okay on power supply as they give junction volts.
6. Currently stuck there, as I am waiting for my ESR meter to be shipped to check on the capacitors.
More help is needed to point me in the right direction if anybody has had this problem before. ANY I mean any ideas would help, except going down the road of throwing this away.
Thank you.
It's totally dead as in dead, only semblance of life is an LED standby light, and it doesn't respond with the processor reset procedure. The -----
- Press and hold the DIRECT buttons and STEREO buttons, and at the same time, plug in the AC cord." -- nope doesn't work.
I believe it is not the amplifier section as I have junction tested all the transistors and they all appear to be healthy; junctions give the 0.6V on my multimeter.
I'm thinking it could be a processor issue or a power supply refusing to power on the unit for a short in the power supply section.
Any wild ideas are open, I really would love this beast to come alive once again and would want to hear it. Doing this on a part time basis, and it's not going away anytime soon.
If you guys have any idea where I could start to check please do so. Any help would be much appreciated.
Things I've done so far.
1. Checked all fuses - they are all good in the power supply section.
2. Power switch / standby switch is good, I tested with the multimeter and it conducts when pressed.
3. Power transistors all good
4. There is power going to the mini transformer what I believe would send a signal to the main unit to come alive, the mini transformer - the one that gives 12V, 6V, and 33V is good as it is supplying power (AC to the components)
5. Diodes and Zener diodes appear to be okay on power supply as they give junction volts.
6. Currently stuck there, as I am waiting for my ESR meter to be shipped to check on the capacitors.
More help is needed to point me in the right direction if anybody has had this problem before. ANY I mean any ideas would help, except going down the road of throwing this away.
Thank you.
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Hi thanks for the feedback. After some searching one person in youtube with almost the same line as this denon, his has a microprocessor problem. Hopefully mines okay. I have voltage checked most of the components in the mini power supply, most appears to be okay. Except for a transistor that gives a voltage twice the voltage as indicated in the service manual.
Transistor appears to be okay though.
I'm getting the feeling this is going down the microprocessor road.
Get the schematic, some small caps in the standby power supply are used to check the voltage needed (time based).
If they give results later than expected by the processor, it will not allow the process further.
Check the supply (ies) to the chip (uP) as well.
If they give results later than expected by the processor, it will not allow the process further.
Check the supply (ies) to the chip (uP) as well.
This is a breath of fresh air. I am getting there. Doing this step by step. This receiver has a lot of boards inside, rightfully fitting for a former flagship.
Wow this is good info🙏. I have this cheaper multimeter that can check the capacity of the capacitors (uf) and capacitors seems to be within the capacity printed on the caps. Doing this as a hobby so after many years of no esr meter finally decided to buy one. Still waiting for it to arrive.
Just wondering if the voltages stated on schematic are on the dot when tested in the real world. I'm getting mostly higher voltages ,i.e. 14.4V instead of 12v. They are mostly like this. One voltage does bother me though. It is -88v instead of a -33v stated the schematic.
All transistors looks to be doing ok on the mini power supply. Instead of the internally resistor biased transistor (BRT), which I have no idea how to test either in circuit or out.
Get a new lithium watch cell, they are 2.96V for most of their life.
Put a fresh (preferably alkaline) cell in your meter.
Use the watch cell to check if your meter is accurate, a lot of occasionally used meters are not, as their comparator voltage is off the battery, and a wrong reading will make you think in terms of something wrong in the circuit.
Brand new cells, cheap meter, up to 3.2 is okay, if not, check your meter.
Denon used such complex circuits that even experienced technicians would sweat, or outright refuse to work on those.
Not for the newbie, I think.
Put a fresh (preferably alkaline) cell in your meter.
Use the watch cell to check if your meter is accurate, a lot of occasionally used meters are not, as their comparator voltage is off the battery, and a wrong reading will make you think in terms of something wrong in the circuit.
Brand new cells, cheap meter, up to 3.2 is okay, if not, check your meter.
Denon used such complex circuits that even experienced technicians would sweat, or outright refuse to work on those.
Not for the newbie, I think.
I believe the meter is a little accurate as I use it for several voltage checks, car battery, dry cell batteries, phone batteries, thus couldn't discount it for its intended purpose for a weekend warrior.
Good, then find why the discrepancy in voltage.
That will tell you how to find the fault.
It died on you, or you got a dead unit?
That will tell you how to find the fault.
It died on you, or you got a dead unit?
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The unit I got dead for a price I couldn't resist. Here are a few of my readouts. I might have missed the reading with 0V on ZD701, I'll be checking it again once I get my ESR. Just too much weight for me and too little room to keep working on it again without the ESR meter.
Attachments
You need to start from the secondary side of the transformer, a failed Zener is possible.
Other component damage is possible due to it.
And look for signs of attempted repair...then it is a bigger job if experiments were done, those are difficult units.
Other component damage is possible due to it.
And look for signs of attempted repair...then it is a bigger job if experiments were done, those are difficult units.
would really want to know how to test those without an oscilloscope, no plans of buying one just doing a diy.
You can get toy scopes for less than $100.
See sale listings around your area, sometimes bargains do turn up.
The scope may come in handy later.
Particularly for this, even Onkyo are difficult.
Changing the resonator may be cheaper as a one off, just to check.
See sale listings around your area, sometimes bargains do turn up.
The scope may come in handy later.
Particularly for this, even Onkyo are difficult.
Changing the resonator may be cheaper as a one off, just to check.
https://www.amazon.com/Quimat-Oscil...ords=cheap+oscilloscope&qid=1654445167&sr=8-5
Less than 50 USD, others within 100.
Walmart is cheaper:
https://www.walmart.com/browse/industrial-scientific/oscilloscopes/6197502_3495604_8200071_9450276
Less than 50 USD, others within 100.
Walmart is cheaper:
https://www.walmart.com/browse/industrial-scientific/oscilloscopes/6197502_3495604_8200071_9450276
I got a comment from a friend that the circuit around it acts as a voltage doubler or tripler thus the suspicious readout.
Also said that the -30ish on the manual might be a misprint as the circuit somehow looks to be a doubler and was designed to have no caps on it. Said misprints are common on service manuals and are corrected subsequently on later service memo (not sure if its the correct term).
