Denon X7200w - Speaker Output Issue and another question ref Front Height vs Front Dolby

[Buckster]

2 questions please:

1st off - I seem to have an issue with at least 2 terminals on my Denon X7200W - seems to be the Surround Back Right and Front Wide Left terminals - ie next to each other

over time the outputs to these speakers get lower and lower and the low frequencies reduce, if I put some slight pressure up on the terminals the sound comes back and then is good for a few weeks. I had assumed when I thought it was one terminal that it must be the soldered connection to the terminal from the board, but now I've realised it is affecting 2 outputs I'm wondering if it is some bend or loose connection on the board - does anyone know how they are connected up please ? I've looked at photos online but can't see below the HDMI board so can't see how the speaker outputs are connected

I did think maybe I could "prop" up these speaker terminals so some pressure always applied vertically rather than the weight of the speaker cables- might be a not-ideal fix, else I could go in and attempt to fix myself (out of warranty) but my electronic skills and soldering skills aren't completely good enough to not ensure I wouldn't damage the whole av receiver. Propping up and if they get worse over time I could always buy a multi-channel power amp.

2nd question I have please - is regarding Dolby vs Height speaker settings. I have KEF Q350s as rear heights and KEF Q50as as Front Upfirers, I had until this evening set the Front Upfirers also to Heights until I read a thread earlier that said Upfirers should be set to Dolby Speakers (I hadn't even realised there was a "Dolby" option tbh)

I noticed when I set the Q50as to Front Dolby that I can't EQ above 1khz (I manually EQ). What I don't understand and was hoping for some info please is whether the processing is applied differently when set to Front Height vs Front Dolby ? I thought if any HRTF was applied to Upfirers it was set in the speaker themselves within the crossover not on the amp ? If no difference in processing why would one setting not allow EQ above 1khz ? Or does it apply some form of LPF if they are set to Front Dolby ?

It had sounded very good set to Height tbh and I was able to EQ above 1khz, I've yet to try fully set to Dolby

many thanks for any info

 

[kyuu]

How is the speaker wire from those speakers connected to the terminals? Bare wire, bananas (locking/spring), spades, something else? I'm just wondering if you've eliminated the possibility that it's the speaker wire's interface to that terminal that isn't coming loose or otherwise losing good connection over time, rather than an issue with the terminals' internal connection to the board as you suspect.

 

[Buckster]

thankyou for the reply - the first one I noticed being problematic was connected via banana plugs, I replaced the banana plugs and no improvement. I then went to bare wire and whilst thought had fixed to start with the problem came back again. Apply some vertical pressure on the terminal upwards and it is "fixed".

When there is a problem the speakers still output but it is at about -10-15dB lower - ie when there is the problem there is some sound it is just very very quiet, and it seems to be not just quieter but lacking in lower frequencies - it is like there is a HPF applied as well as a reduction in gain

 

[Buckster]

I did think I could work around for at least one pair (only one of pair affected) by using the custom amplifier setting to use "Height 1 Left" and "Height 1 Right" which are further over but no matter what configuration I set I can't get the Denon to allow me to use them - haven't worked out why

as in I was hoping to use the Rear Heights - which are on the Rear Back terminal outputs, instead on the Height 1 Left/Right terminal outputs but doesn't allow me

all the other terminal outputs I can set to whatever I like - the Height 1 L/R won't allow me to assign to anything

 

[kyuu]

Sounds like you've eliminated the speaker wire connection as the culprit then. Hrm...

I can't find a good source for pictures of the internal portion of the speaker terminals on the X7200W, but all the ones I have been able to find look like this on the inside and I imagine the Denon's are similar:

It would be a relatively simple matter to see if perhaps the nut on the back of the bolt is loose on any of those. If the actual connection to the board has an issue it might be visible or might not.

 

[Doodski]

1st off - I seem to have an issue with at least 2 terminals on my Denon X7200W - seems to be the Surround Back Right and Front Wide Left terminals - ie next to each other

over time the outputs to these speakers get lower and lower and the low frequencies reduce, if I put some slight pressure up on the terminals the sound comes back and then is good for a few weeks. I had assumed when I thought it was one terminal that it must be the soldered connection to the terminal from the board, but now I've realised it is affecting 2 outputs I'm wondering if it is some bend or loose connection on the board - does anyone know how they are connected up please ? I've looked at photos online but can't see below the HDMI board so can't see how the speaker outputs are connected

I did think maybe I could "prop" up these speaker terminals so some pressure always applied vertically rather than the weight of the speaker cables- might be a not-ideal fix, else I could go in and attempt to fix myself (out of warranty) but my electronic skills and soldering skills aren't completely good enough to not ensure I wouldn't damage the whole av receiver. Propping up and if they get worse over time I could always buy a multi-channel power amp.

Here is the PCB that you are flexing and where the apparent issue is located. The odds are that the solder at a speaker connector(s) is cracked. There may be a chassis bottom plate/cover that is removable and if you are lucky the speakers solder terminals can be accessed. I downloaded a service manual although it has block diagrams not schematics so I was unable to 100% confirmed bleeder resistors used for discharging the power supply big capacitors when the unit is unplugged. That means you need to manually discharge the power supply before working on this unit. Otherwise you could get shocked with DC voltage and or cause damage to the unit if you short stuff out accidentally. If you do not have good mechanical and mechanical reasoning skills as well as poor solder skills then it would be best to get a qualified tech or engineer to service the unit for you because this is a very complex model and it would be very upsetting if you break connectors etc while disassembling the unit in order to access the speaker terminals solder joints.
Here is the PCB where the speaker terminals are located.

 

[Doodski]

Sounds like you've eliminated the speaker wire connection as the culprit then. Hrm...

I can't find a good source for pictures of the internal portion of the speaker terminals on the X7200W, but all the ones I have been able to find look like this on the inside and I imagine the Denon's are similar:

View attachment 386910

It would be a relatively simple matter to see if perhaps the nut on the back of the bolt is loose on any of those. If the actual connection to the board has an issue it might be visible or might not.

The speaker terminals are soldered to the PCB. There are no bolts/nuts.

 

[Buckster]

thanks very much Doodski and kyuu for the equivalent photo and the schematics

It is odd that the 2 terminals affected are next or near to each other which made me wonder if was further up the chain than just the immediate connection to the board

but I guess maybe both could have been knocked at same time and caused a physical issue at the soldering joint

I am an Electronic Engineer by trade, but not hands-on these days my failure finding logic and thought process is normally pretty good but my soldering skills and patience with fiddly connectors less so !! so as an expensive item I probably would not attempt myself

looking at the schematic it does look like the terminals are individually soldered and pretty stand-alone but maybe if there is an issue with the board (maybe a small bend that might have happened in transit or something) maybe it could affect the on-board traces for more than one terminal

 

[Doodski]

It is odd that the 2 terminals affected are next or near to each other which made me wonder if was further up the chain than just the immediate connection to the board

Good point and you are 100% correct in your thinking. Expect anything to be the culprit and keep in mind that the speaker terminals flex a lot and that does cause cracked joints so you can firstly go to that stuff and then look further on that PCB that I posted images of in this thread.

ooking at the schematic it does look like the terminals are individually soldered and pretty stand-alone but maybe if there is an issue with the board (maybe a small bend that might have happened in transit or something) maybe it could affect the on-board traces for more than one terminal

Again you are 100% correct. Divide and conquer is the methodology with this specific fault.

 

[Buckster]

thankyou

I did think an alternative "solution" (pretty rubbish one but might work) would be to attach the 2 sets of speaker cables connected to the problematic terminals to the cabinet above under vertical tension

bit like some people do with heavy graphics cards in PCs to combat "droop"

 

[kyuu]

The speaker terminals are soldered to the PCB. There are no bolts/nuts.

There has to be some mechanism holding the speaker terminals to the back plate of the AVR. They can't just be floating there anchored by nothing but a spot of solder. Though I suppose if they aren't held securely to the back plate, that would explain an issue with solder cracking...

 

[Doodski]

thankyou

I did think an alternative "solution" (pretty rubbish one but might work) would be to attach the 2 sets of speaker cables connected to the problematic terminals to the cabinet above under vertical tension

bit like some people do with heavy graphics cards in PCs to combat "droop"

If that works for you then that works. There is a chance the fault will escalate in the future so it might work long terms and it might go intermittent again with the flex causing further breakage of terminals.

 

[Doodski]

There has to be some mechanism holding the speaker terminals to the back plate of the AVR. They can't just be floating there anchored by nothing but a spot of solder. Though I suppose if they aren't held securely to the back plate, that would explain an issue with solder cracking...

There is one screw affixing the plastic terminal(s) @ the rear chassis plate. This is normal.