Denon AVR-1912 E2/EA

[Michael Studio1]

BTW, Here's a link to downloading the same Service Manual I am using for this Denon AVR-1912 E2/EA

Denon AVR-1912 | Electrical Connector | Insulator (Electricity) - Scribd

Michael UK

 

[Tha fios agaibh]

...problem when there was terrific arcing in SMPS. I... (wonder if)... arc'ing had any effect on other components on the SMPS_B'D

There was a point right at the beginning of this Power problem when there was terrific arcing in SMPS.

It's certainly possible ic106 is bad but I don't like that there is only 10.78v going into it. It should be 12v or more.
First I would check the input and output voltage of ic107 (-8v) as a comparison. I would expect a similar voltage. Also, you could try removing ic105 to see if it's the 5v rail is overloading your +8v rail.
If you don't mind blowing a quid or two just replace them.
Also take a look for shorted electrolytic capacitors in the supply path such as c808, c843 or c134. Ideally checking with an esr meter.

Above all, I hope you have a lot of patience, and a hand steadier than mine.
Sometimes the best plan (for me) is to just take a few days off from a puzzler like that, and come back later with fresh eyes.

 

[Michael Studio1]

Now 2 1/2 hours later and the AVR is temporarily re-assembled, turned ON (working OK) and the +8V. Tails have been tested. A propos the ewxtra 'Tails' I thought 73's de Edd was proposing - I now do NOT think this was so, but had some other context which is escaping me, but to do (I think) with 'Isolating'. (I hope Edd will correct me on this!)
Now. With the AVR turned on, the voltages at three salient points:
CN13A pin 7 (+4.59) CP5 pin 11 (+4.59) and CN101 pin 1 (+10.756V. with slight fluctuations)
So there we have it. I am inclined to agree that IC106 in +8V. rail is suspect. This could be a result of the surge when the connector CX102 in the SMPS_B'D soldering broke away causing quite disturbing arcing? These six IC's on the REGULATOR_B'D have easily accessible contacts. According to the specifications I downloaded from JRC, pin 1 is IN, pin 2 is GND, pin 3 is OUT. If I take Voltage readings from all six IC's it may give some indication as to their state?
IC 108 is a 4pin 2388 Low Dropout Voltage Regulator. IN = +12.43V OUT = +8.957V
IC 103 is a 3pin 7805A Positive Voltage Regulator. IN = + 10.29V OUT = +5.1V.
IC 104 " " 7905A Negative " " IN = - 0.00V OUT = -4.998V
IC 105 " " 7805A Positive " " IN = + 4.6V. OUT = +1.56V
IC 107 " " 7908A Negative " " IN = - 3.55V OUT = -11.39V.
IC 106 " " 7808A Positive " " IN = +10.8V OUT = +4.6V

So that Table is the result of the above readings from the three salient points.

And here is the Link to download the Denon Service Manual I am usin:
Denon AVR-1912 | Electrical Connector | Insulator (Electricity) - Scribd

Michael UK 20:56GMT

 

[Michael Studio1]

Odd isn't it, Tha fios agaibh, that the answers to your questions were being worked on before seeing you Post! Yet you are right and the week-end should help recovery from both the 'Lurgi' (which my wife currently has - sickness &c. and over-close scrutiny of excesssive small-print in this Denon Service Manual..
So it's 'Good Night from Me for the week-end. Michael who, I believe, has just turned 83 - but who's counting??

 

[73's de Edd]

Sir Michael . . . . .

There was a point right at the beginning of this Power problem when there was terrific arcing in SMPS. I found the cause - the chassis-mounting power connector CX102 has its two legs through the SMPS pcb. The soldering had 'given' and done some damage to the foils side. I re-soldered it in place and added a jumper to one of its legs between 'it' and the end of a jumper where it is supposed to be. Whether this quite spectacular arc'ing had any effect on other components on the SMPS_B'D I don't know - but it's worthy of consideration, I think. Michael 3:31 GMT

Looking at any involved CX102 wiring routes, it looks like it is only being related to the female AC line socket, and then with one wiring routing being directed to one of the MAIN /heavy linear power transformers primary winding, and the other CX102 wiring route is connection through the power relay contacts , thru to the other transformer primary connection.
If there was a poor /skimpy flow soldering operation to board connections involved in that flow path, a ring solder joint could have developed on a pin and cratered, with a high current arc occurring within that reduced conductive path . With time, it starts arcing across and further vaporizing solder until a board warming occurs at that site, and the final condition is where the arced area develops an open circuit ring.



It can be a real Ark-ee Spark-eee situation during the final days of an ever reduced conductive metal area, and its resistance , trying to conduct the same current that a much a larger metal area had done before . . . . along with the onsetting of much more board heating being created.

Considering the "impenetrable " cluster of interconnected boards, I think that would be a good idea of getting the unit back together and back to the state where you can power up and monitor the +8 DC supply from the unit to see if it is still being down to a ~+5VDC output level .

Then it would be an easier task to work with the power supply section and then monitor the +8VDC output and then prepare to insert ***** a series ammeter / milliammeter to then see how much of a current pull is being demanded by the 3 downstream cluster of boards that are being fed by that +8VDC level power supply.
(*****Just prior to putting the current metering inline, confirm if you are actually starting out with a full +8 VDC. )

73's de Edd

 

[73's de Edd]

Sir Michael @Studio1. . . . . .

Back at my last posting I did not have this info available

IC 108 is a 4pin 2388 Low Dropout Voltage Regulator. IN = +12.43V OUT = +8.957V
IC 103 is a 3pin 7805A Positive Voltage Regulator. IN = + 10.29V OUT = +5.1V.
IC 104 " " 7905A Negative " " IN = - 0.00V OUT = -4.998V
IC 105 " " 7805A Positive " " IN = + 4.6V. OUT = +1.56V
IC 107 " " 7908A Negative " " IN = - 3.55V OUT = -11.39V.
IC 106 " " 7808A Positive " " IN = +10.8V OUT = +4.6V

All is good for the top 3 regulated voltages . . . the bottom 3 are being completely off the wall.

Reference to your manuals phantom shadow layout of the REGULATOR Component side. Page 97.
Its schematic counterpart is being on Page 110.

On the top 3 good voltages you should have been . . . . and surely must have been using . . . . . .CP100's pin 7 or 8's Vgnd for your meters negative leads referencing.

On the 3 erroneous readings, that supply source is being derived from a completely different and separate winding on the power transformer secondary.
Look down to CP101 and see that you should have been using either Pins 3-4-5-6-or 7 AGND, for your meterings negative connection referencing.

Test out the unit in that manner now, to see if there is still a supply output error on the 3 RED REFERENCED output voltages. Or, if we actually have a fully functional set of all supply voltages.

If so, then we start at the beginning and asking if the unit turns on and stays on and what malfunction(s) are then seeming to be presented by the unit ?

73's de EDD

 

[Michael Studio1]

Sir Michael . . . . .





73's de Edd

Hello 73's de Edd.
You will have already seen the result of my having temporarily re-assembled the AVR in order to establish that it was still 'turn-onable' - and it is. My idea in doing this was to check not only the three 'Tagged Test Tails' - to see if there was any miraculous improvement (there wasn't) but also to check the Voltages at the (+) and (-) contacts of the six IC's. I established the order in which they are mounted on the REG_B'D from Right hand side looking from the front) which is:
IC108. IC103. IC104. IC105. IC107. IC106

1. I also found that I had NOT connected CX104 before I made that test. Today I wanted to establish what the (presumably) IC is which has 3 pins, is mounted on the SMPS_B'D via a mini pcb to which four short black wire connections are made to the SMPS PCB. It has printed on it: D25SC6M and a double rectifier logo. I am looking for IC102. Oddly, I found there are two IC102's in the list of IC's - one on page 182 (PCB FRONT ASS'Y) and one on page 177 (PCB SPK ASS'Y) - which, I assume includes the SMPS_B'D. I still haven't found it - but I'm supposed to be taking the week-end off (Ha-Ha!) I'm making vegetable soup in the Kitchen as my wife is recovering from some dread sickness bug she picked up at her Nursery School.
2. Here then are the Test results. First the +8V. CP5 pin 12 = +4.536V. CN101 pin 1 = 10.84V. Now the Voltages from the IC's
3. IC 108 IN = +12.5V OUT = + 8.9V
4. IC 103 IN = +10.33V OUT = + 5.09V
5. IC 104 IN = - 0.35V OUT = - 5.01V
6. IC 105 IN = + 4.66V OUT = +1.48V
7. IC 107 IN = - 3.61V OUT = - 11.44V
8. IC 106 IN = + 10.89V OUT = + 4.55V That's it for now. I hope these readings are indicative of something useful! Michael UK

 

[Michael Studio1]

Sir Michael @Studio1. . . . . .

Back at my last posting I did not have this info available

IC 108 is a 4pin 2388 Low Dropout Voltage Regulator. IN = +12.43V OUT = +8.957V
IC 103 is a 3pin 7805A Positive Voltage Regulator. IN = + 10.29V OUT = +5.1V.
IC 104 " " 7905A Negative " " IN = - 0.00V OUT = -4.998V
IC 105 " " 7805A Positive " " IN = + 4.6V. OUT = +1.56V
IC 107 " " 7908A Negative " " IN = - 3.55V OUT = -11.39V.
IC 106 " " 7808A Positive " " IN = +10.8V OUT = +4.6V

All is good for the top 3 regulated voltages . . . the bottom 3 are being completely off the wall.

Reference to your manuals phantom shadow layout of the REGULATOR Component side. Page 97.
Its schematic counterpart is being on Page 110.

On the top 3 good voltages you should have been . . . . and surely must have been using . . . . . .CP100's pin 7 or 8's Vgnd for your meters negative leads referencing.

On the 3 erroneous readings, that supply source is being derived from a completely different and separate winding on the power transformer secondary.
Look down to CP101 and see that you should have been using either Pins 3-4-5-6-or 7 AGND, for your meterings negative connection referencing.

Test out the unit in that manner now, to see if there is still a supply output error on the 3 RED REFERENCED output voltages. Or, if we actually have a fully functional set of all supply voltages.

If so, then we start at the beginning and asking if the unit turns on and stays on and what malfunction(s) are then seeming to be presented by the unit ?

73's de EDD

Hello 73's de Edd. You may start pulling out your hair when I admit to using Chassis GND for all my measurements . . . . Oh dear! OK. I'll start again and see if there's any changes when I use CP100 pin 7 or 8 for the Neg. referencing for the readings on IC 108, IC 103, and IC 104. Then I must change to CP 101, pins 3 - 7 AGND for IC 105, IC 107 and IC 106. OR have I got that wrong? and should only be reading the NEGATIVE IC's 104 and IC 107 this way? I am dismantling the AVR as I write (not really, but shall be) in order to attach 'TaggedTestTails' to those GND connections. Michael

 

[Michael Studio1]

Hello again 73's de Edd. Monday Noon.
I did NOT appreciate the sheer sophistication of the electronics in this AVR-1912 E2/EA. Your latest Post made me aware of this - to the extent that I hadn't noticed the two different voltage sources with their accompanying (separate) GND referencing!! Mea Culpa (big time) Thanks for this 73's ed Edd!! Now we have a totally different can of worms - but more tasty than the previous can. The two triptych of IC's, each trio with its own power source and GND points give the following readings.
IN OUT
IC108 +12.45V +8.963V ]
IC103 +10.31V +5.114V ] CN100 pin 7 = VGND
IC104 +0.001V -4.992V ]

IC105 +8.164V +5.12V ]
IC107 +0.002V -7.835V ] CN101 pin 5 = AGND
IC106 +14.28V +8.164V ]

This is a totally new Ball Game. As to the unit staying ON - yes, it does. The only times it has turned itself OFF are my own most grievous fault - that of moving the PCB's - thereby interrupting something and causing a 'fault' and the AVR turning itself OFF.
So, having also made a final repair on the HDMI PCB (I had clumsily knocked off a S.M.Capacitor (C831 on page 126) when separating the PCB's early on,) This original Capacitor tore up the FOIL connecting trace on one side. I found the next in-line component and made a new attachment to it and a new 10mF 50V (not S.M. though) and it seems to be working OK. Michael. UK

 

[Michael Studio1]

Tuesday 12:45 GMT. Here's the latest on my progress with the Denon AVR-1912 E2/EA
With the AVR back together and powered up, I have been confirming Voltages (all as last report) and injecting two Frequencies from the FeelTech 3200S sig. gen. into the AUXR (700cps) and AUXL (400 cps). These tones only get as far as IC801 (page 114 on your Hymn sheet - I was a Cathedral Chorister) at pins 83 and 84. I checked for them at IC801 pins 55 & 54 but there was no sign. I checked the AVCC at IC801 pin 30 and had a reading: +7.393V with reference to AGND on IC801 pin 56. I also checked the continuity between IC801 pin 56 and AGND - there was 0 Ohms - so 100% continuity.
Where do I go from here, please?? Is IC801 suspect? What tests should I make to confirm IC801 is OK?? Michael UK

 

[Tha fios agaibh]

I'm no choir boy, but I would check for output at pin 21 and 23 with respect to pin 17 (ampc) Have you verified -7v on pin 52?
Are you saying all functions seem to work except you have no audio?

 

[Michael Studio1]

I'm no choir boy, but I would check for output at pin 21 and 23 with respect to pin 17 (ampc) Have you verified -7v on pin 52?
Are you saying all functions seem to work except you have no audio?

I'm no longer, either. That was in the late 40's. . . . I am experiencing strange events with this AVR. There's no Audio at either pins 21 or 23. of the IC801 (is this what you're calling ampc? I shall now check -7V. on pin 52.. I am reading: +0.3712V. at pin 52 (AVEE) according to the Service Manual. So that's just another fail. Sometimes the Audio tones I have fed into the AUXL and AUXR get through to the HDMI B'D. There's no saying why they don't always get through. Re: pin 17. COUT. Is this needed to pair up with pins 21 or 23? With tremendous luck I can probe any one pin, but to probe two at the same time is not possible - physically. As to the various 'functions' the left knob selects things like AUX, DVD, etc. and there are push buttons on the front panel which select give the option 'Quick Select (whatever) All this reads out on the front panel. So something is working at least! Michael

 

[Tha fios agaibh]

I'm no longer, either. That was in the late 40's. . . . I am experiencing strange events with this AVR. There's no Audio at either pins 21 or 23. of the IC801 (is this what you're calling ampc? I shall

How are you checking the audio path? I initially thought ampc on pin 17 was the audio common, I'm not sure now. It might be ground. Not a bad idea to read the spec sheet for ic801 R2A15218FP. Look for a nearby connection to probe instead of trying to cramming your leads into the chip.

You definitely need the pin down why you don't have the -7v Avee on pin 52.

It's tough trying to decipher that schematic from my mobile phone.

 

[Michael Studio1]

R2A15218FP.

Hello, Tha fios agaibh - I'm searching for the data sheet for IC801 (R2A15218FP.) but all I get are capacitors. You are right - I need to examine a data sheet for this in order to establish just what is required for it and on what pin. I am following the Audio path on the Service Manual Schematics and using the FeelTech signal generator to inject a Left and a Right tone into AUXL and AUXR. Ensuring that the screen says STEREO V.AUX by using the 'Source Select' knob. I then probe the various contacts starting at the 40xWay ribbon CX4 between the Front PCB and the HDMI PCB, at pins 6 & 8. On the HDMI pcb I probe C801 and C833 (page 126) which are the ADINR and ADINL on their way to IC30 pins 1 & 2. I'm using a very sharp probe (made from thick Piano wire) going to an old PC speaker and reference to Chassis GND. (maybe I should be referencing to AGND - but I don't thing it matters so far as test tones are concerned. I have probed for L & R on the IC801 (pins 53 & 54) using my sharp probe and an endoscope - for that IC801 is totally hidden on the AUDIO VIDEO B'D under the HDMI B'D. But again, you are right, I must find that -7V rail, coming from CP14 pins 16 & 17 as A-8V. on the SIDE_CNTR B'D. I will reference it to AGND and solder a 'TaggedTestTail' to it. Having now done this, it reads -7.809V. Whether that's close enough to -8v. I do not know - but at least -7V has got to that point. The Cct Diag, (page 114) shows an in-line Diode D801 so I must test the voltage on either side of that (if I can!) How you can see these Cct Diags. on your 'phone I do not know, I have to use magnifying lenses to read an A4 size print-out. Michael UK Tra-la-la

 

[73's de Edd]

Sir Michael @ Studio1 . . . . .


You say you are short of negative 8 VDC supply on pin 52 of IC801.

That IC801, located on the AV1/3D1 board, gets it negative 8VDC supply from either of the dual pins of 16 or 17 of the CP14 connector and your ground reference is being the AGND of its pin 4.

And indeed the HEFTY D801 is being in series in that power line, thus the voltage drop and a renumeration down to it being a -7 vdc supply due to the incurred voltage drop.

If you get semblances of -7thru -8VDC on both sides of that diode, just seems like you need to go back and check the EXACT dedicated single foil path trace leading into that IC801's pin # 52.

BTW . . . I don't know how CRAMPED you are in probing that region, but a nearby Agnd connection is at its pin #51 right beside target # 52 or a nearby Agnd is also over at pin # 48.

73's de Edd
.....

 

[Tha fios agaibh]

I would make sure you select an audio mode that will pass an analog signal such as bypass mode as opposed to one that might be looking for a digital signal.

You also might want to use a .01uf capacitor inline with your probe to block dc going to your speakers.

 

[Michael Studio1]

IC801 I now read -7.01V. Michael 12:26 Wed.31st Jan

 

[Michael Studio1]

Sorry, IC801 (pin 52) I now read -7.01V. Michael. (am I getting somewhere?)

 

[Michael Studio1]

I'm also getting the two tones at IC801 (pins 83 & 84) Now I find that the 40xWay Ribbon Cable is 'suspect' and the two tones are intermittent at the HDMI end of the Ribbon.

 

[Michael Studio1]

Sir Michael @ Studio1 . . . . .


You say you are short of negative 8 VDC supply on pin 52 of IC801.

That IC801, located on the AV1/3D1 board, gets it negative 8VDC supply from either of the dual pins of 16 or 17 of the CP14 connector and your ground reference is being the AGND of its pin 4.

And indeed the HEFTY D801 is being in series in that power line, thus the voltage drop and a renumeration down to it being a -7 vdc supply due to the incurred voltage drop.

If you get semblances of -7thru -8VDC on both sides of that diode, just seems like you need to go back and check the EXACT dedicated single foil path trace leading into that IC801's pin # 52.

BTW . . . I don't know how CRAMPED you are in probing that region, but a nearby Agnd connection is at its pin #51 right beside target # 52 or a nearby Agnd is also over at pin # 48.

73's de Edd
.....

Thanks for joining the discussion, 73's de Edd. Things have moved on a bit. But although I now have A-78V. at the A-8V. Test Point and -7.05V. at IC801 (pin 52) there is now a Very Nasty Suspicion of a dodgy 40xWay ribbon cable between the Front B'D and the HDMI B'D (page 130) extreme Left of Cct Diag. A Tone into VAUXL & VAUXR on the Front Panel is intermittent at the HDMI B'D end. This is CX4 (page 129) bottom right. I don't know whether all the RCA sockets for BD, DVD, CD etc. on the back panel use this ribbon cable - but if not I can inject tones into, say, the CD rca sockets and continue . . . .