Denon AVR-1912 E2/EA

[bushtech]

Now we're out of my depth. Where's the green tree monster?

 

[Michael Studio1]

Now we're out of my depth. Where's the green tree monster?

You mean John? (Tha fios agaibh?)I don't know - but he comes on quite frequently. Without both of you and the occasional 73's de Edd, I would not have got anywhere.


Well here's something of a conundrum: I am examining two channels (FL and FR) in the AVR-1912E2/EA and attempting to compare them like-for-like on the Cct.Diag (Page106). One area of interest is that of equating the Cct.Diag. with the Parts List of 7CHANNEL_AMP B'D (Page 173-6). I had questioned, in the failure of FL, the Electrolytic Capacitor C515 - it will be found in the 7CH.AMP. Parts List and, physically, within the curtilage of the FL Channel Amp. on the PCB - but NOT in the Cct.Diag. This C515 gave some strange readings whilst still in the PCB, but proved OK when removed for test. I notice that in the Cct.Diags many components are marked as 'OPEN' and take it these components 'do not apply' to this particular model of AVR - but that the Cct.Diags are for all models of the 1912 range. So: Where is C515 to be found? On which Cct.Diag? Anyone? Michael Studio1 UK 10:02GMT

 

[Tha fios agaibh]

Hi folks, the green treemonster and wife has escaped the cold habitat to Mexico for a week.

Michael, i see your progressing fine with some help from bushtech.

I can't offer much help at the moment but keep tinkering and you will have more of those "ah ha" moments.

I will pop in when i can to see your progress.

Audios amigos.

 

[bushtech]

Ok

C515 on pg 120 of 196, bottom left hand corner. Look at ref line A to O at the bottom of page. Between C and D, right above the division between them.

 

[Michael Studio1]

Ok

C515 on pg 120 of 196, bottom left hand corner. Look at ref line A to O at the bottom of page. Between C and D, right above the division between them.

Thanks, Bushtech. Well done for finding them - what gave you the inspiration? I shall obviously have to spend more time mastering the layout of the Service Manual. How C513, ( on FR Channel) C514, ( on SL Channel) C515 ( on FL Channel) which are on the 7CH.AMP B'D come to be on the Cct.Diag of the HDMI B'D. is beyond me - Poetic licence? Then there is this business of the information about these three Caps.[AVR 1712 ONLY OPEN] - how is this to be interpreted? I can only think that - with the three caps actually on the 7CH AMP B'D, this information only applies to the 1712 model - and that 'OPEN' indicates 'not there'. Michael Studio1 UK 17:20GMT

 

[Michael Studio1]

Hi folks, the green treemonster and wife has escaped the cold habitat to Mexico for a week.

Michael, i see your progressing fine with some help from bushtech.

I can't offer much help at the moment but keep tinkering and you will have more of those "ah ha" moments.

I will pop in when i can to see your progress.

Audios amigos.

If we could take advantage of a road to a warmer country we'd do the same! Happy Holiday, John! Michael

 

[bushtech]

I noticed that the caps are numbered more or less consecutively on a page eg. C6XX will be on the same page.

I think you're right with the 1712 inference, but to find out why they are there we need to figure out where something like "To Digital Connect" leads us

I have managed to find C515 on the wiring diagrams pg104 just to the left of IC15. Hope that helps.

 

[Michael Studio1]

I noticed that the caps are numbered more or less consecutively on a page eg. C6XX will be on the same page.

I think you're right with the 1712 inference, but to find out why they are there we need to figure out where something like "To Digital Connect" leads us

I have managed to find C515 on the wiring diagrams pg104 just to the left of IC15. Hope that helps.

Hello Bushtech - Thanks for your interesting reply. Though I cannot find C515 on Page104 - that's the component side of the HDMI_B'D. Maybe you'd like to use the reference bars to help me locate it please - like Page104/G6 - or whatever. I think DIGITAL CONNECT is Page129/O1 and shown there as DIGITAL CNT ?? I haven't followed this up yet. Re: Component numbering - yes, the chances are that C4xx will be on the same page - or - on a continuation page (as in the 7Channel Amp.) but - of course C515 defeats that reasoning! Michael Studio1 UK 07:22GMT

 

[bushtech]

Page 104/6F

 

[Michael Studio1]

See Page120/J8 the bottom row of that Grid labelled 'AC'. The last four squares on that row are: AC20/AIN1, AC21/AIN2, AC22/AIN3. AC23/DGNDI - this must be a multiple switching Unit.? I fear I am totally out of my depth here. Rather like Mother Bell's 'Cross-Bar' system in telephony. I must check Page120/A10 the: 'TO DIGITAL CONNECT' to follow up the rail: VDI_SC[VDISC> to which the GND side of all three Caps are connected via R241 - R245 (Page120/B10) - I hope you get along with my 'referencing'? Michael Studio1 UK 09:11GMT

 

[Michael Studio1]

Page 104/6F

Thanks, Bushtech. I think you have uncovered a whole new can 'o worms here! The one on Page104/6F isn't the C515 we're interested in - which is physically adjacent to the top two pins of CN404 Page93/D2. Maybe we should sub-divide these references by 1/10 to give a closer hit? = Page93/D0.3x2.2 - it's actually etched on the PCB of Channel FL C515 just below the + leg. This is the 2nd double-entry in the AVR-1912E2/EA I have come across. The other is in the Parts List Page177 and Page182 - there are two IC-102. Anything is possible here! You'll also find that Page 168 refers to an IC801 - the pins of which bear little resemblance to the IC801 on Page114. even though the numbers ascribed to both are identical. More food for thought. I'm just off to Brighton-on-Sea (about 10 miles away) so I'll check for comments on my return. Michael Studio1 UK10:12GMT

 

[bushtech]

Hmm. Sloppy design work by Denon or purposely obfuscatory? Whichever, I'm out of my depth here, need somebody who can make sense of this

 

[Michael Studio1]

Another possibility is that the Cct.Diags. which came as a part of the AVR-1912E2/EA Ver.6 SERVICE MANUAL (which also covers models: JP, E3, EK, E1, E1K, E1C as well as AVR-2112C1 model E3) do not cover this model E2/EA specifically. If so then we shall not find a Cct.Diag. with: electrolytic caps: C512(SBR), C513(FR), C514(SL), C515(SL) included, as mounted on the 7Channel Amp. PCB. (note - the caps: C512, C513, C514, C515 on Part List Page193 are not electrolytic.) So there is something strange going on here. Anyone think of an answer? The other important thing is to discover the reason Q464, Q470 and Q469 along with their associated R640, R641, R646, R647 (all 2WJ-0.47Ω.) and R655 (22Ω-J.1W.)power resistors burned out. I shall continue my researches. Michael Studio1 UK 16:55GMT

 

[Michael Studio1]

Hmm. Sloppy design work by Denon or purposely obfuscatory? Whichever, I'm out of my depth here, need somebody who can make sense of this

I agree. Maybe 73's de Edd may be able to cast some light? Michael Studio1 UK 17:32GMT

 

[Tha fios agaibh]

caps: C512, C513, C514, C515 on Part List Page193 are not electrolytic.) So there is something strange going on here. Anyone think of an answer? The other important thing is to discover the reason Q464, Q470 and Q469 along with their associated R640, R641, R646, R647 (all 2WJ-0.47Ω.)

They are duplicate cap numbers.
For instance C513 is a electrolytic on page 106, But there's also a C513 ceramic cap on page 120. I wouldn't read too much into it, just use what the circuit diagram shows and use the parts list as a reference.

Hard to say what caused your transistors to fail, but obviously if one shorted, any components in the path would not enjoy being spiked with the full current the power rail could deliver.

 

[Michael Studio1]

They are duplicate cap numbers.
For instance C513 is a electrolytic on page 106, But there's also a C513 ceramic cap on page 120. I wouldn't read too much into it, just use what the circuit diagram shows and use the parts list as a reference.

Hard to say what caused your transistors to fail, but obviously if one shorted, any components in the path would not enjoy being spiked with the full current the power rail could deliver.

Thanks, John - Hope you're enjoying the warmth of Mexico. So, in the failure of the SBL Channel Power Transistors and Resistors, a Transistor can just 'short-out' and, in failure, cause a whole lot of collateral damage? If so the chances of my finding any real 'cause' for this failure is nil. But I wonder whether in conducting the Idling Current Test (Page56) I inadvertently shorted two contacts in TP406? Would this have caused the failure? It could have happened before I made up that small three-socket test plug. When the replacement components arrive I shall just install and test. In the quest of the FL failure I have been comparing FL with FR but must first see how much of each Amp. is actually depicted on the Cct.Diags. There seems to be more on the PCB than on the Cct.Diags.! Bit of a mine field actually. Now that I see C513 &c on Page106/N6 - thanks for this, John - I shall continue tracing and comparing. There's still a chance of diagnosis and repair! Michael Studio1 UK 08:13GMT

 

[Tha fios agaibh]

Thanks Michael, we're having a great time in the warm weather. I guess down here "warm" means 95F (35c) Back home, we call that Hot.

Yes, component can just short out out for no apparent reason, but from my limited experience, The components that usually lead to their demise are things like capacitors and diodes that play an important role of keeping the circuit working as it was intended.
For instance if a capacitor is starting to go bad, it's lowed capacitance causes the impedance and frequency response of the circuit to change. A diode leaking or improperly working can also be a big problem.

When you shorted out the testpoints (to each other) it wouldn't hurt the circuit because it's almost a short circuit as it is.
It would only change the resistance a fraction of an ohm.

Whatever happened that caused the voltage rail to go astray may have been where things went wrong? Idk.

Stay vigilant, and be as thorough in checking for bad components as you can.

 

[Michael Studio1]

Thanks Michael, we're having a great time in the warm weather. I guess down here "warm" means 95F (35c) Back home, we call that Hot.

Yes, component can just short out out for no apparent reason, but from my limited experience, The components that usually lead to their demise are things like capacitors and diodes that play an important role of keeping the circuit working as it was intended.
For instance if a capacitor is starting to go bad, it's lowed capacitance causes the impedance and frequency response of the circuit to change. A diode leaking or improperly working can also be a big problem.

When you shorted out the testpoints (to each other) it wouldn't hurt the circuit because it's almost a short circuit as it is.
It would only change the resistance a fraction of an ohm.

Whatever happened that caused the voltage rail to go astray may have been where things went wrong? Idk.

Stay vigilant, and be as thorough in checking for bad components as you can.

Thank you from a cold, snowy Sussex Coast to a hot Mexico. I'm waiting for the replacement Transistors now - plus one 22Ω power resistor which is in the immediate circuitry of those pairs of new 0.47Ω 2W. Until them I shall study the AVR Cctry. Michael Studio1 UK 20:30GMT

 

[Michael Studio1]

Thanks bushtech, I thought for a moment Michael was talking about Tea and scones.
Lol

How do you pronounce 'Scones'? - to rhyme with . . . ?

 

[davenn]

How do you pronounce 'Scones'? - to rhyme with . . . ?

going going gone silent e

not as cone or bone