Motorola VIP1225 - (AT&T Uverse)

[USchabon]

So based on another thread I understand there may be a super easy mod that might result in slightly better (and hopefully noticeable) audio improvement out of the RCA output from this older DVR/main TV box.

I can record the signal so I will be able to do a comparison using the same audio for a fair and objective comparison, so let's find out! I mean, why not! heheh

I don't know what I am doing, so pls help me by literally telling me what to replace, hopefully STJ will chime in here as he is to blame for giving me this idea

PLS NOTE:
On the last photo (#6), I drew the traces that I THINK I saw on the far left side, yup, I closed it all up without confirming, but some of the other photos do show the second trace from the left and it seems that the furthest to the left has a similar configuration, so I figured you guys might be able to tell whether it makes sense or not and hopefully I won't have to open the whole thing back up (yet) until I get the components

[USchabon]

Re: Motorola VIP1225 - (AT&T Uverse)

IGNORE THIS POST UNLESS YOU HAVE DONE THIS BEFORE, OR HAVE AN AMAZING SOURCE TO LINK TO:

[going off on a tangent]

If anyone knows how to clone the contents of the drive (without losing the recordings) into a larger drive, please share that here, that way we add all interesting mods to the same device in one thread

Personally, I am not concerned with this larger HDD mod. I am just putting it out there in case someone knows exactly how to do it, since this is a very popular modification to DVRs, so there might be a BadCaps member that already did this and might be able to post a step by step guide.

[/going off on a tangent]

If someone does I will edit this post and copy the step-by-step here, or post the link to the existing step-by-step in this post.

[stj]

Re: Motorola VIP1225 - (AT&T Uverse)

looks like they arent using electrolytics to filter the audio.
they could be using ceramics but it's risky to try to remove those.

[budm]

Re: Motorola VIP1225 - (AT&T Uverse)

http://www.dslreports.com/forum/r281...the-recordings

[budm]

Re: Motorola VIP1225 - (AT&T Uverse)

https://www.badcaps.net/forum/attach...9&d=1466192358

Is U6 a dual op-amp?
Cap C221, 229 connected to the U6 pins? They may be audio output coupling caps.
Q6, 7 may be for Audio Mute function.
BTW, using the scope to trace out the unknown circuit for audio will be much simpler.

[USchabon]

Re: Motorola VIP1225 - (AT&T Uverse)

Awesome! HDD upgrade case: CLOSED. Bdum, that link is exactly what I was hoping to have linked to this thread. Thanks!

Here are some photos of those components.

What is a scope?

[budm]

Re: Motorola VIP1225 - (AT&T Uverse)

U6: WM8521 DAC


Pin 6: analog output Right channel.
Pin 10: analog output Left channel.
So you can trace those two pins to see where they go to, C229, C221?
See spec sheet on how the outputs are coupling to the DC blocking caps.

[Khron]

Re: Motorola VIP1225 - (AT&T Uverse)

That would make a certain amount of sense. And the audio signal's quite likely buffered by Q6/7, then put through an RC low-pass before the RCA outputs.

[USchabon]

Re: Motorola VIP1225 - (AT&T Uverse)

I am just nodding my head and pretending to understand

[budm]

Re: Motorola VIP1225 - (AT&T Uverse)

'What is a scope?'

https://en.wikipedia.org/wiki/Oscilloscope

[USchabon]

Re: Motorola VIP1225 - (AT&T Uverse)

'What is a scope?'

https://en.wikipedia.org/wiki/Oscilloscope

Yea... I don't have one of those


So does it look like there could be an audio quality gain with a simple mod?

[stj]

Re: Motorola VIP1225 - (AT&T Uverse)

what are c229 and c221? make & series?
value?

[budm]

Re: Motorola VIP1225 - (AT&T Uverse)

If they use ceramic caps for audio coupling then you may able to change them to other type of caps, you MAY notice the difference.
Read some of these links:
https://ez.analog.com/thread/3465
http://sound.westhost.com/articles/coupling-caps.htm

[budm]

Re: Motorola VIP1225 - (AT&T Uverse)

what are c229 and c221? make & series?
value?

They are MLCC, no marking.