Denon AVR-1912 E2/EA

[Michael Studio1]

Lets hope not.
If sparks are flying you've go bigger problems than an open Gnd.

Ah! - Yes!, John, I agree. However I have just made, following your 'Jumpering' between CN/CP14 pin19 (Page114/E1) and Chassis GND suggestion, that CN/CP14pin20 has only 3.3Ω value ref. ChassisGND. I checked also the Ω value between CN/CP14pin18-19 and ChassisGND and got that strange rising Ω value - rising 1Ω per second. This we had before - remember? - and I suggested it's like a capacitor charging from the DVM. Anyway, if a strap or Jumper can be placed between pins CP/CN14pin18 and 20 will it blow up? Michael Studio1 UK 10:22BST 07-06-2018

 

[Tha fios agaibh]

Ah! - Yes!, John, I agree. However I have just made, following your 'Jumpering' between CN/CP14 pin19 (Page114/E1) and Chassis GND suggestion, that CN/CP14pin20 has only 3.3Ω value ref. ChassisGND. I checked also the Ω value between CN/CP14pin18-19 and ChassisGND and got that strange rising Ω value - rising 1Ω per second. This we had before - remember?

All Agnds should be connected together, and have continuity to Chassis Gnd. We know Agnd merge together to chassis. You said you had continuity at all point except CN13A. So now I presume we are adding CN/CP14 along with CN13A in the open Agnd category.

Yes, when you get a wandering reading its obviously open and does not have continuity as it should.

Forget pin 20 (RetGnd) as our focus should be only on Agnd at this point.

If you add a jumper wire to tie CN/CP14 (open Agnd) to a point where you know Agnd is good or even Chassis Gnd, it will likely correct CN13A reading open Agnd also.

 

[Michael Studio1]

All Agnds should be connected together, and have continuity to Chassis Gnd. We know Agnd merge together to chassis. You said you had continuity at all point except CN13A. So now I presume we are adding CN/CP14 along with CN13A in the open Agnd category.

Yes, when you get a wandering reading its obviously open and does not have continuity as it should.

Forget pin 20 (RetGnd) as our focus should be only on Agnd at this point.

If you add a jumper wire to tie CN/CP14 (open Agnd) to a point where you know Agnd is good or even Chassis Gnd, it will likely correct CN13A reading open Agnd also.

OK, John, I'll look into this over the week-end. Thanks indeed for the suggestion. Michael Studio1

 

[Michael Studio1]

I have just conducted continuity tests on Page114/E1 (CP14 pin18-19) & G1 (CN115 pin 1-2) There should, according to the Cct.Diag. be continuity - but there isn't! So I have checked continuity between the two groups of three resisitors on Page114/K5 and find there is continuity as shown on the Cct.Diag P114. There is also continuity between the common contacts of the two groups of resisitors and CP14 pin18-19. But there is NO continuity between CP14 pin18-19 and CP115 pin1-2 and according to the Cct.Diag. on Page114 THERE SHOULD BE.
Question: Looking at the 'FOIL' side of any Denon PCB, what is the purpose of all those small circles with a hole through the PCB in the middle? Anyone? Are these 'Testing Points'?? Michael Studio1 UK 12:17:BST 13-06-2018

 

[Michael Studio1]

All Agnds should be connected together, and have continuity to Chassis Gnd. We know Agnd merge together to chassis. You said you had continuity at all point except CN13A. So now I presume we are adding CN/CP14 along with CN13A in the open Agnd category.

Yes, when you get a wandering reading its obviously open and does not have continuity as it should.

Forget pin 20 (RetGnd) as our focus should be only on Agnd at this point.

If you add a jumper wire to tie CN/CP14 (open Agnd) to a point where you know Agnd is good or even Chassis Gnd, it will likely correct CN13A reading open Agnd also.

Hello John - before I start adding Jumpers, I have made further continuity tests and found there is no continuity between CP14 pin18-19 and CP115 pin1-2 - and , according to Page114, there should be. I am also wondering whether I have missed out on a 'known' fact of PCB's - that of the many small green circles with tiny holes in the middle - on all PCB 'FOIL' sides. Are these 'Test' points? Michael Studio1 UK 13:22BST 13-06-2018

 

[Michael Studio1]

That vacillating measurement seems to have 'gone' and gives an 'Open Verdict' Michael Studio1 UK

 

[Tha fios agaibh]

Hello John - before I start adding Jumpers, I have made further continuity tests and found there is no continuity between CP14 pin18-19 and CP115 pin1-2 - and , according to Page114, there should be. I am also wondering whether I have missed out on a 'known' fact of PCB's - that of the many small green circles with tiny holes in the middle - on all PCB 'FOIL' sides. Are these 'Test' points? Michael Studio1 UK 13:22BST 13-06-2018

Well you'll have to sort out where your losing it. One technique that helps determine where, is putting a jumper at each missing point and connect them one at a time to ground and see how it impacts continuity on the other points.

I'm not sure about the green circles, they could be test points or laid out for components on another model.

Btw, make sure you dont have a varnish or monolithic coating that interferes with your test leads continuity when probing around.
Sometimes slight scraping is warranted to get a good contact.

 

[Michael Studio1]

Well you'll have to sort out where your losing it. One technique that helps determine where, is putting a jumper at each missing point and connect them one at a time to ground and see how it impacts continuity on the other points.

I'm not sure about the green circles, they could be test points or laid out for components on another model.

Btw, make sure you dont have a varnish or monolithic coating that interferes with your test leads continuity when probing around.
Sometimes slight scraping is warranted to get a good contact.

Thanks, John - That's an interesting concept - putting a Jumper at each missing point &c. I shall follow this when I'm fresh tomorrow. I am continuing my test on the bench - out of the Chassis - so I can't blow anything up. I do get the feeling I'm close to a break-through. Test leads. Mine are thick Bass Piano string - about 0.045" - ground to a virtual point in order to cut/scrape through any varnish or monolithic coating - these are insulated and clamped to a standard test lead using a standard screw-tightened double connector. One interesting thing I have found in Ctrl+F and searching for R571, say, is the number of 'hits' one gets in any search by using the 'NEXT' or 'PREVIOUS' button. One such 'hit' is an explanatory Page86 - though I haven't yet worked out why when 'Finding' Resistor R571 it arrives at Page86. Yet. Michael Studio1 UK 22:11BST 13-06-2018

 

[Tha fios agaibh]

Why when 'Finding' Resistor R571 it arrives at Page86?

Because R571 is on page 86 next to connector CN2 of the HDMI board (bottom right)

 

[Michael Studio1]

Because R571 is on page 86 next to connector CN2 of the HDMI board (bottom right)View attachment 41474

Yes, John, So it is! However I 'Ctrl+F'd' it on another page showing a photo (whatever) of the PCB and was able to pin-point it for probing purposes. Michael

 

[Michael Studio1]

There is an 'open' in between CN/CP14 pin18-19 ( and CN/CP115 pin1-2. This should not be, according to the Cct.Diag. Page114. Find: CN/CP pin1-2 have continuity to pins 5,8,11,14,16. & CHASSIS_GND. This should not be - according to the Cct.Diag. Page114. LATER : : : : I have now reassembled the AVR and powered it up. As anticipated there are still no Signal Tones at Speaker Terminal FL or FR, but the Tones are arriving at IC801pin84[VAUX_L] and pin83[VAUX_R] and leaving IC801 from pin54[A/D_L] and pin55[A/D_R] and are arriving at IC30 pin1(R) and pin2(L).
Power: Arriving at IC30 [DA+5V] = +5.1V ref. AGND. So we're back to where we were a few months back. I must power up my pocket Oscilloscope to see if there's any indication of a digital signal OUT from IC30 pin9 [DATAAD]> At least pin9 is easily accessible for probing. I can check whether there's any change in the IC30 Output by simply turning the SigGen OFF/ON. Yes? Michael Studio1 UK 16:26BST 14-06-2018

 

[Tha fios agaibh]

There is an 'open' This should not be - according to the Cct.Diag. Page114. LATER : : : : I have now reassembled the AVR and powered it up.

Why did you reassemble if you haven't resolved the 'open' problem?

I wouldn't try probing around for signals until your certain you've got Vcc, Vdd on all ICs, and all the missing Gnds ring true.

 

[Michael Studio1]

Why did you reassemble if you haven't resolved the 'open' problem?

I wouldn't try probing around for signals until your certain you've got Vcc, Vdd on all ICs, and all the missing Gnds ring true.

Just keeping my hand in, John - ensuring everything still goes back together - and just to check we're back where we were - and we are (just as I feared!) Tomorrow I shall take it apart again and see if I can find out why, on Page114, that CN115pin1-2 are connected to all the AGNDS on that connector block. Something's just not right there. And that AGND fromCP14 pin18-19 (it comes straight from Page110 CN13A pin4-5) seems to be going nowhere other than that cluster of 6 resistors on Page114. Any ideas? I shall also, before taking it apart again, check that all the IC's and 'Q's are getting their Power. We know that Relay2 is working at least. Michael Studio1 UK 22:21BST 14-06-2108

 

[Tha fios agaibh]

CN115pin1-2 are connected to all the AGNDS on that connector block. Something's just not right there. And that AGND fromCP14 pin18-19 (it comes straight from Page110 CN13A pin4-5) seems to be going nowhere other than that cluster of 6 resistors

Ok, page 114:
CP14 pin 18-19 (Agnd/RETgnd)should have continuity to CN115 pins 1 and 2. Yes/No?

If you don't have continuity from there to the other Agnds, they merge elsewhere, likely on CP11 found on page 112.
I believe how these Gnds interconnect on 112 is where you want to look.
Check continuity from where The CP's plugs interface with their CN mate. (from one side to the other)
Go back to basics. Which one doesn't have continuity?

 

[Michael Studio1]

Ok, page 114:
CP14 pin 18-19 (Agnd/RETgnd)should have continuity to CN115 pins 1 and 2. Yes/No?

If you don't have continuity from there to the other Agnds, they merge elsewhere, likely on CP11 found on page 112.
I believe how these Gnds interconnect on 112 is where you want to look.
Check continuity from where The CP's plugs interface with their CN mate. (from one side to the other)
Go back to basics. Which one doesn't have continuity?

Yes, and thanks for the reply, John. This is, according to the Scriptures, where there should be continuity - but there isn't. Surely that continuity is made within the circuitry of the AV_B'D? though, finding that CN115 pin1-2 are connected to ALL the AGND pins on CN115 - AND all the Resistors: R800-807 - made me sceptical of that. From this I concluded that the AGND from Page110 CN13A pin4-5 only served the group of 6 Resistors on Page 114/K5 instead of doubling back to CN115 pin1-2 as [DACRTGND] (DAC meaning the Digital Analog Converter, RT meaning Return and GND) or so my intuition tells me. It's interesting how the GND Ccts. take on new names , coloured by their use. As for positive interconnection in the 'Plocketry' - thanks for this suggestion, John. Once I have disassembled the 'stack' and rebuilt it on the bench making a continuity check of all CN/CP's will be a 'doddle' which I shall do today after checking the VCC's &c. Michael Studio1 UK 07:02BST 15-06-2018

 

[Michael Studio1]

Today I have been disappointed to find my Endoscope is not functioning on the Lab PC. Therefore I have created an Audio 'path' to identify the IC's and 'U's this path goes through in order that I can check the power being supplied to them. This I shall not be able to do until the Endoscope is working again - due to the positioning of the various IC'c and 'U's on the PCB's it is necessary to be able to see the pins to place the probes. Here is the 'Audio Path': Page126 IC30 -> Page124 IC21 -> IC22 -> Page125 - U8 -> Page124/H10 then immediately out again at Page 124/K10 -> Page126/F1 (MAIN DAC) -> IC29 (this is the DAC - see description P161) -> IC28 -> through various plocketry to Page114 IC801 where they go > CN401 pin1(FL) pin9(FR) into the 7CHANNEL_AMP. Michael Studio1 UK 14:36BST 15-06-2018

 

[Michael Studio1]

AVR-1912E2/EA The remote control has been found - so the future's more rosy now! Michael

 

[bushtech]

Now that's a bit of progress!

 

[Tha fios agaibh]

Sorry about your endoscope. I hope you get it figured out soon, or at least have a plan "B" such as a powerful mirror.

When you do get to sifting through all the plocketry, (a Michaelism?) you may have to just trust your own intuition.
Prints and forum correspondings be damned.

If you know you have it at X and not Y, you'll just have to get in there and methodically follow the circuit. Use a Sharpy tip marker to keep track of where you are on the traces.
The Gnd path can be confusing, but its merely a daisy chain you have to follow.

 

[Michael Studio1]

Sorry about your endoscope. I hope you get it figured out soon, or at least have a plan "B" such as a powerful mirror.

When you do get to sifting through all the plocketry, (a Michaelism?) you may have to just trust your own intuition.
Prints and forum correspondings be damned.

If you know you have it at X and not Y, you'll just have to get in there and methodically follow the circuit. Use a Sharpy tip marker to keep track of where you are on the traces.
The Gnd path can be confusing, but its merely a daisy chain you have to follow.

Thanks for the encouragement, John. These endoscopes are inexpensive - say about $12. so I have a replacement on order. There's no room in there for any mirror - the HDMI and AV_B'D's being so close to each other - so I have come up with, as you say, a Plan 'B'. It is simple. I have followed the Audio Path and documented the IC's through which that path goes. It looks like this: (1)IC30 (16pin) Page126 HDMI Component Side : [DA+5V] pin6-7&14-15 [DAGND] then I extracted similar DATA for (2)IC21,(3)IC22,(4)U8,(5)IC29,(6)IC28 A&B,(7)IC801. On each IC I have stuck a very small square of label paper and written the IC's I.D. My instructions to myself are: "Now DVM continuity tests can commence. In strict order." These Tests are Continuity between each IC Power and GND pin and the source of that Power or GND on that PCB. Following this will be the Plocketry Test - where, with the 'Stack' built on the Bench in the Lab I can confirm continuity between all Plockets. (a plocket, in this case being, of course, the interconnecting CN/CP - or whatever). But before that we are off to a Concert in an ex-Church (Saxon in origin with Regency additions) in which, about 30years ago I gathered a team together and, in true Community Spirit, dismantled, documented, repaired, re-engineered and rebuilt, in a new position, a 100 year old Two Manual William Hill Pipe Organ. In the Opening Recital, under the aegis of the Carnegie Trust, it was played by Dr.Francis Jackson, Organist of York Minster. The Concert this morning is Strings and Oboe only - but the group are coming to the end of their Annual Festival, and one of their Members is an Organist - so I want to introduce them to the Organ for future inclusion in, say, next Year's "Lewes Chamber Music Festival". (Look it up on Internet) "Plocketry" Yes - it answers the requirement for a generic name I think. Michael Studio1 UK 09:07BST 16-06-2018