Denon AVR-1912 E2/EA

[Michael Studio1]

I haven't looked at the schematic/board layout in a few days but I was thinking there might have been a plan "B" or should I say plan "C" for cheapskate?

Look if there is a convenient place to tap into missing conductors 5 and 8 with separate conductors while leaving the ribbon cable as it is (was).
Alas, the carpet shears put an end to that idea.

It's surprising just what Carpet Shears can do! However, this morning I have removed the 20lb. weight of bull-head rail and the grab is firmly stuck to the back (printed side) of the ribbon end. Now I simply (?) need to think up a way to gently remove the ribbon covering and reveal, undamaged, the conductor tabs . . . . Any ideas? There's a YouTube about ribbon repairs and the guy is using a high speed Dremel with a grinding bit . . . I have the tools but . . . . Michael 08:47GMT

 

[Michael Studio1]

Hello, 73's de Edd. Thanks for you research into a replacement 40 way ffc. The 'Google Translator' wouldn't translate. However, looking at the photo of the 40P (presumably 40 way) I notice the overall width dimension here is 35mm. which is too narrow. The CX4 Ribbon measures 41mm (nominally 40mm) so the contacts wouldn't line up. The 'grab-tab' has successfully stuck on the back of the ribbon's end (if CA glue isn't correct for this application I just don't know what is - time will tell!) Now I need to devise some cunning methodology to remove the covering of the contact tabs. The end I cut off with the Carpet Shears was in Very Poor Condition - there were many contact tabs coming away from the back - so it would not have successfully plugged in again. I noticed a YouTube on 'Ribbon Repair' where the guy was using a Dremel tool with a rotary file 'bit' to do just that. I have the tools so I'll try that method. Michael 09:11 GMT

 

[Michael Studio1]

I just looked closely at the end I sheared off and confirmed that many of the contact tabs were raised from the back - coming away - and would not have plugged back successfully. In the event of 'Plan A' or 'Plan B' not working, this 'Plan C' seems to be the only way!! Michael 09:16GMT

 

[Tha fios agaibh]

I need to devise some cunning methodology to remove the covering of the contact tabs.

If you have a hot air gun, it'd be ideal to heat up the insulation at the end and then you could scrape the plastic off with a flat blade (not too sharp)knife.

Maybe a hair dryer could work but much harder to pinpoint the heat and get the right temperature. It could make the insulation come off like a messy mozzarella cheese. Perhaps a metal heat shield over all but the end you want to get off?
You sound resourceful. I'm sure you'll do brilliant. As they say on your side of the pond.

 

[Michael Studio1]

With a fine metal file I had just started to gingerly file away that printed side of CX4 Ribbon cable and found it is extremely thin - possibly even sprayed on - possibly even paint? I am therefore going to try a curved sharp scraper where the edge is not nicked in any way. Who knows - the kitchen knife may do the job! Keep you posted.
Michael 11:31 GMT

 

[Michael Studio1]

We have success! A bit qualified, perhaps in-as-much-as the contact tabs cleaned off down to the copper. I didn't manage to leave the nickel plating on - but . . . I have 'buzzed' it through from the CX4 connector on the Front board to the CX4 connector on the HDMI_B'D - both test points were on the solder terminals of each of the 40 ways. Next job is to add Power, see if it turns on and stays on, then inject tones into VAUXL & VAUXR - and see how far they both get. Keep you posted
Michael 14:36 GMT

 

[Michael Studio1]

We have success! A bit qualified, perhaps in-as-much-as the contact tabs cleaned off down to the copper. I didn't manage to leave the nicke

If you have a hot air gun, it'd be ideal to heat up the insulation at the end and then you could scrape the plastic off with a flat blade (not too sharp)knife.

Maybe a hair dryer could work but much harder to pinpoint the heat and get the right temperature. It could make the insulation come off like a messy mozzarella cheese. Perhaps a metal heat shield over all but the end you want to get off?
You sound resourceful. I'm sure you'll do brilliant. As they say on your side of the pond.

Hello Tha fios agabh - I do have a hot air gun - I used to use it to re-flow the MoBo around the CPU of my Acer 9300. But think the 858D (as dismantled by Dave Jones in one of his famous YouTube Videos) would have been better. But you're right about the mozzarella cheese syndrome and since the ribbon size is of paramount importance I bethought me to tread more carefully and scrape it off. Well, that did work and now I can start getting the AVR back up and working. But first . . . where's that VAUXR gone??
l plating on - but . . . I have 'buzzed' it through from the CX4 connector on the Front board to the CX4 connector on the HDMI_B'D - both test points were on the solder terminals of each of the 40 ways. Next job is to add Power, see if it turns on and stays on, then inject tones into VAUXL & VAUXR - and see how far they both get. Keep you posted
Michael 14:36 GMT

Having added the Power, the AVR remaining ON checked A+8V = +8.153V at CP13A. Checked A-8V = -7.814V at CP13A pin 6. Signals now. Only the VAUXL Channel is getting to the HDMI_B'D. via CX4 pin 8. VAUXR is lost somewhere in the Front board. I must get a new CX4 Ribbon cable before the copper tarnishes!!
But I have had enough of this for now and am signing off. I'll check to see if there's any response first.

 

[Tha fios agaibh]

Great progress Michael!
Take a break from it and come back later with fresh eyes and a fresh perspective.

If I don't take lots of breaks, I'm inclined to get mad and throw things at the wall.

 

[Michael Studio1]

Thanks, Tha fios agaibh - I am taking the week-end off the project (to stop me throwing things at the wall!) going out for a coffee and window shopping in Lewes (4 miles away) I think I really must source a new CX4 ribbon cable and so will contact Denon in London on Monday - and get the real McCoy, pristine, new, unused . . . for having measured the two tones from the VAUXL and VAUXR only the VAUXL is reliably getting through the CX4 - in fact I'm tearing my hair out because VAUXR isn't getting any further than pin3 of CP103 on the VAUX_B'D.
Michael Sat. 09:51GMT UK

 

[Michael Studio1]

HOWEVER . . . I had a message from one Arghno at avsystemparts.com (thank you for this contact, 73's de Edd,) who has found a CX4 Ribbon Cable and it is already in the post on its way to Jolly Olde England. Cost: $10. + $4. postage - so it should be here in about a weeks' time. Then hostilities can recommence.
There was still an intermittent problem on that ribbon which caused the A+8V or A-8V. to cut out on the Front Board - and thus on the small VAUX Board. So there was no option but to replace it.
The 'up-side' of this will be for me to experiment in finding a better method of stripping the 'printed side' off one of these ribbon cables and I have a notion of using your suggestion of heat, Tha fios agaibh. But I shall not use a paint-stripper type but, since I have one, an 858D hot air solder gun. I shall experiment for optimum heat setting so as not get into the realms of the dread Mozzarella Cheese syndrome.
Symbols: On the top Right of page 126 in the AVR-1912 E2/EA Service Manual, C799 in-line capacitor on the ADINR rail. Looked at closely there are lines between the two parallel lines which depict 'Capacitor' - do you or anyone reading this know what this means? It is important to know because this SM Capacitor was broken off when separating the HDMI_B'D from the SIDE_CONNECTOR (page 111) and I had to replace it. For this I used an ordinary radial electrolytic 10mF 50Vdc capacitor. But the burning question is what do those lines between indicate!? Michael 12:43 GMT

 

[Tha fios agaibh]

C799 in-line capacitor on the ADINR rail. Looked at closely there are lines between the two parallel lines which depict 'Capacitor' - do you or anyone reading this know what this means? It is important to know because this SM Capacitor was broken off when separating the HDMI_B'D from the SIDE_CONNECTOR (page 111) and I had to replace it. For this I used an ordinary radial electrolytic 10mF 50Vdc capacitor. But the burning question is what do those lines between indicate!? Michael 12:43 GMT

The lines in between indicate a liquid or gel dielectric inside the capacitor. Meaning it's an electrolytic capacitor.

 

[Michael Studio1]

The CX4 ffc ribbon has arrived. I have checked it for continuity: OK. Also checked when inserted in its 'socket' on the Front_B'D for continuity from its 'open' end to the solder tags of CX4 on the Front B'D.= OK. Then inserted the CX4 into its 'socket' on the HDMI_B'D and checked continuity from the solder contacts on HDMI to the same on the Front_B'D.= OK: Powered up the AVR-1912 = OK. Checked the voltages at: (page 111 Service Manual) CN14 pin 14 = +8.156V ref. AGND. (same as CP13A pin 7 for these are duplicated as <73's ed Edd> says.)
Next checked CP13A pin 6 ref. AGND = -7.824V. OK.
Next: moved on to page 110 in the AVR-1912 Service Manual. REGULATOR B'D
Checked: CN101 pin 1. +14.2V ref. AGND.
Test Tones: I have injected 700Hz. 2V. into AUXR and 500Hz. 2V. into VAUXL. Only the Right Channel Tone is getting through to the SPKR terminal. The Left Channel Tone is getting through the IC801 (page 114) pin 84 (VAUX_L) to pin 54 (A/D_L) and the last I hear it is on page 126 on pin 2 (AINL) of IC30.
Where it goes from here I cannot trace for I believe IC30 is an A/D converter and I can only trace Analog Tones. - or can I?? How are Digitized tones traced?? Michael Studio1. UK 13:02GMT

 

[Tha fios agaibh]

Yes, ic30 is a AK5358BET adc.
I'd believe you'd want to read the digital output stream of pin 9 with a scope.
Hopefully one of the more knowledgeable guys will chime in here.

 

[Michael Studio1]

Yes, ic30 is a AK5358BET adc.
I'd believe you'd want to read the digital output stream of pin 9 with a scope.
Hopefully one of the more knowledgeable guys will chime in here.

Thanks for the suggestion Tha fios agaibh. I have only a rudimentary 'scope - a pocket battery powered one named DS201PRO - whether it is suitable I don't know. It is 'Open Source' 200Khz Bandwidth, 1Ms/s sample rate. It's very small, measuring only 3 1/2" x 2 1/2" x 1/2" thick. Screen-size: 2 3/4" diagonally. I've used it but once - so shall have to learn how to use it all over again! Advice please!! like: where to stick the probes etc! Michael Studio1. 18:00GMT

 

[Michael Studio1]

Yes, of course - you said pin 9. Michael. UK

 

[Michael Studio1]

A large deviation incurred by recapitulation of an old Voltage problem. IC801 (page 114) reads +3.581V at pin 80 - it should read +7V. (reference AGND) Measuring +V. at CN/CP pins 15 & 14 gives +8.154V. Obviously, then, things are not as they should be and the Oscilloscope cannot be used until this is corrected. There's precious little on the Cct.Diag. between CP14 pins 14 & 15 and IC801 pin 80 but Diode D800 (IN4007) which isn't in the Parts List among the Schottky Diodes on page 190. The IN4007 DATA sheet gives it as having a Peak Repetitive Voltage of 1000V, Non-Repetitive = 1200V. RMS Reverse Voltage = 700V. Also Average Recified Forward Current = 1Amp. I have measured the Voltages either side of this Diode = +7V on the CP114 side and +3.5V. on the IC801 side. So what is causing the Voltage Drain? In the Cct. Diag. there's an electrolytic Cap/GND (C808/100mF,16V) which, according to Parts List on page 194 isn't an electrolytic, but one of a bunch of ceramic 1000pfd would you believe it? The +7V. rail (actual +3.5V) then goes on to supply IC800 - an 8 pin IC which I couldn't find so maybe this is another 'Option' which doesn't exist on this AVR E2/EA). It all ends at Jack 102 - a Phono type labelled 'SUBWOOFER PRE OUT' on the chassis back panel. So I'm enjoying my research but getting no-where really. Any suggestions please? Michael Studio1 UK. 13:54GMT

 

[Tha fios agaibh]

Don't get discouraged. It sounds like your narrowing in on things.

Obviously pull D800 to make sure its ok. I'd look at C808 and C823 for possible short circuits. Also try pulling R871 out to isolate that that npn transistor isn't pulling the voltage down.
If all checks out ok, it may be that power supply side is the problem, where it's unable to deliver the current.
If that's the case, you could isolate the downstream loads by pulling D800 and temporarily hook up a dummy load such as a flashlight (torch) lamp to determine if its capable of delivering the required current at 7 volts.

 

[Michael Studio1]

Don't get discouraged. It sounds like your narrowing in on things.

Obviously pull D800 to make sure its ok. I'd look at C808 and C823 for possible short circuits. Also try pulling R871 out to isolate that that npn transistor isn't pulling the voltage down.
If all checks out ok, it may be that power supply side is the problem, where it's unable to deliver the current.
If that's the case, you could isolate the downstream loads by pulling D800 and temporarily hook up a dummy load such as a flashlight (torch) lamp to determine if its capable of delivering the required current at 7 volts.

Thanks for your encouragement Tha fios agaibh. It needs 'resolution' and reasoning to get me to pull components - and I see your reasoning. Re: D800,C808,C823 & R871 if I pull the 'drop' end of these in turn I should be able to resolve those points. Thanks for the suggestions. Michael Studio1. UK 17:56GMT

 

[Michael Studio1]

later . . . .
RE: D800. diode showing open in both directions. I couldn't believe it - so I removed the HDMI_B'D to gain better access to D800 for the dvm probes. Yet that's exactly what showed. No dvm Ω reading in either direction. Michael Studio1 UK.19:23GMT

 

[Michael Studio1]

I have removed D800 entirely and rechecked the Ω readings. Just as well, for there is a reading in one direction: With the (+) probe on the 'gold' end it reads: 'open' = 0 MΩ.
With the (+) probe on the 'black' end it reads: 162MΩ and falling.
Michael Studio1 UK 20:05GMT