EEVbog 1613 -Audiophile REPAIR: Chord Hugo DAC

[EEVblog]

Simple repair on the neighbours $4500 Audiophile Chord Hugo DAC.
Replacing the rechargeable lithium ion batteries wasn't quite as simple as expected though...
And is this thing worth $4500?

[wraper]

And still too cheap to put a battery connector.

[SiliconWizard]

Would have liked a full teardown. We don't see much of it at all, so hard to tell how it's really designed, apart from the two batteries and the Bluetooth module, which, btw, is from a (now dead) finnish company, none of this Espressif junk.
I don't know how old the design of this DAC product is though - Bluegiga has been acquired by SiLabs, and I doubt this module is still current (there's much better in the SiLabs offering directly these days, and I don't know if they still sell the legacy Bluegiga stuff).

[themadhippy]

And still too cheap to put a battery connector.

Have you seen the price of audifool grade battery connectors

[temperance]

If what you saw with the one shorted battery terminal is true, than this product has a serious flaw because the protection circuits within the batteries will open/close in a random order.

[Exosia]

And still too cheap to put a battery connector.

connectors will introduce noise 

[Samuel]

I think i know why the battery was acting weird:

You damaged the insulation on the battery negative cable close to the wifi module when you used the yellow plastic spatula at 10:20 in the video.
I have a big screen and can see individual strands of silver wire starting at 10:46.

It also looks like you damaged the insulation on the positive wire when you pinned it down with the tweezers at 11:17, i can see a silver spot in the middle of the cable at 10:22.
While doing this you might also have produced a short between the positive wire and the through hole pad below it, which would have triggered the protection circuit. After you let go of the wire the short was removed and the battery protection circuit could recover.

At 12:15 i can count three strands of wire in the negative cable, i attached a zoomed in screenshot to this post.
I can also see some silver in the red cable.

[coppice]

I think i know why the battery was acting weird:

You damaged the insulation on the battery negative cable close to the wifi module when you used the yellow plastic spatula at 10:20 in the video.
I have a big screen and can see individual strands of silver wire starting at 10:46.

It also looks like you damaged the insulation on the positive wire when you pinned it down with the tweezers at 11:17, i can see a silver spot in the middle of the cable at 10:22.
While doing this you might also have produced a short between the positive wire and the through hole pad below it, which would have triggered the protection circuit. After you let go of the wire the short was removed and the battery protection circuit could recover.

At 12:15 i can count three strands of wire in the negative cable, i attached a zoomed in screenshot to this post.
I can also see some silver in the red cable.

I was puzzled that he took out the batteries and then desoldered, but put the batteries in before soldering the contacts. I would have soldered the contacts with the batteries out, giving me lots of room, and then slipped them into place.

[wraper]

I think i know why the battery was acting weird:

You damaged the insulation on the battery negative cable close to the wifi module when you used the yellow plastic spatula at 10:20 in the video.
I have a big screen and can see individual strands of silver wire starting at 10:46.

It also looks like you damaged the insulation on the positive wire when you pinned it down with the tweezers at 11:17, i can see a silver spot in the middle of the cable at 10:22.
While doing this you might also have produced a short between the positive wire and the through hole pad below it, which would have triggered the protection circuit. After you let go of the wire the short was removed and the battery protection circuit could recover.

At 12:15 i can count three strands of wire in the negative cable, i attached a zoomed in screenshot to this post.
I can also see some silver in the red cable.

I was puzzled that he took out the batteries and then desoldered, but put the batteries in before soldering the contacts. I would have soldered the contacts with the batteries out, giving me lots of room, and then slipped them into place.

To be fair, if you solder with batteries outside, you then may find that wires are of the wrong length or you need to bend them awkwardly.

[coppice]

I think i know why the battery was acting weird:

You damaged the insulation on the battery negative cable close to the wifi module when you used the yellow plastic spatula at 10:20 in the video.
I have a big screen and can see individual strands of silver wire starting at 10:46.

It also looks like you damaged the insulation on the positive wire when you pinned it down with the tweezers at 11:17, i can see a silver spot in the middle of the cable at 10:22.
While doing this you might also have produced a short between the positive wire and the through hole pad below it, which would have triggered the protection circuit. After you let go of the wire the short was removed and the battery protection circuit could recover.

At 12:15 i can count three strands of wire in the negative cable, i attached a zoomed in screenshot to this post.
I can also see some silver in the red cable.

I was puzzled that he took out the batteries and then desoldered, but put the batteries in before soldering the contacts. I would have soldered the contacts with the batteries out, giving me lots of room, and then slipped them into place.

To be fair, if you solder with batteries outside, you then may find that wires are of the wrong length or you need to bend them awkwardly.

He did have a role model for lengths that would work well in the batteries he took out.

[elektryk]

Bluetooth module, which, btw, is from a (now dead) finnish company, none of this Espressif junk.

I was also sceptical about ESP32 but it turned out that running BT I2S sink was so easy with open source libraries.
There are modules dedicated strictly for BT audio such as QCCxxxx but without public documentation and SDK...

[golden_labels]

How did the neighbour react to being considered an audiofool?

[jnissen]

How did the neighbour react to being considered an audiofool?

 

I'm sure Dave will have to live that down later!

[syzygy]

I'd guess the battery can is actually shorting to the product's case (and not a reliable short).

Keep in mind, this uses 2 batteries for a reason - bi-polar rails (quiet ones)
Both batteries have a negative can (I think), and the obvious connection for the batterie is spilt around common.
So, one battery may be allowed to touch the case but not BOTH.... and if the case isn't 'floating', then even one battery touching the case will be as short circuit.

-it may come back, and soon.

intermittent faults can cause confusion

[EEVblog]

How did the neighbour react to being considered an audiofool?

He also thinks they are stupidly expensive, hence why he got it cheap 2nd hand.

[EEVblog]

I think i know why the battery was acting weird:

You damaged the insulation on the battery negative cable close to the wifi module when you used the yellow plastic spatula at 10:20 in the video.
I have a big screen and can see individual strands of silver wire starting at 10:46.

It also looks like you damaged the insulation on the positive wire when you pinned it down with the tweezers at 11:17, i can see a silver spot in the middle of the cable at 10:22.
While doing this you might also have produced a short between the positive wire and the through hole pad below it, which would have triggered the protection circuit. After you let go of the wire the short was removed and the battery protection circuit could recover.

At 12:15 i can count three strands of wire in the negative cable, i attached a zoomed in screenshot to this post.
I can also see some silver in the red cable.

I was puzzled that he took out the batteries and then desoldered, but put the batteries in before soldering the contacts. I would have soldered the contacts with the batteries out, giving me lots of room, and then slipped them into place.

To be fair, if you solder with batteries outside, you then may find that wires are of the wrong length or you need to bend them awkwardly.

Correct. I've bene burned by this too many times, so it's just a habbit to fit first then solder.

[Greybeard]

Dave, I'm quite sure that you can do it much better than here in the video (soldering).

Sorry... 

[EEVblog]

Dave, I'm quite sure that you can do it much better than here in the video (soldering).
Sorry... 

What was wrong with the solder joints?

[rsjsouza]

To me the PCB design has the plus and minus pads so close to each other that it is a major fail - a catastrophe waiting to happen.

[EEVblog]

To me the PCB design has the plus and minus pads so close to each other that it is a major fail - a catastrophe waiting to happen.

It's certainly not ideal. But once carefully soldered in place it's no problem really. Also the proximity to the metal case above, not much clearance. I put some tape over the connections just in case.

[Greybeard]

Dave, I'm quite sure that you can do it much better than here in the video (soldering).
Sorry... 

What was wrong with the solder joints?

Come on... you know it.
I think just a bit too little solder, too many attempts with too little flux, not enough "shine"...
Don't the joints look a bit ugly?

[syzygy]

To me the PCB design has the plus and minus pads so close to each other that it is a major fail - a catastrophe waiting to happen.

... I put some tape over the connections just in case.

You should have put tape over where the battery wrapper got cut.

I know you said that the battery cases are negative, but NOT IN THIS SITUATION!  With a dual-rail derived from 2 batteries, the CASE on ONE of those batteries is going to ACTUALLY be the -3.3V rail for the circuit.
-and if THAT battery's case touches the aluminum housing (like that one did when it got sliced) you will have a short circuit.

I'm suggesting THAT is what might have happened with the fault you saw.

[thm_w]

You should have put tape over where the battery wrapper got cut.

Agree you'd have a short if it cut through fully, though, the battery wrapper is: a sticker, heatshrink outer layer, and another heatshrink inner layer. Unlikely you'd cut through all of those layers without decent force. When he inserts the battery at 11:30 and pushed it in, there was still voltage on it, indicating no short had been made.

Come on... you know it.
I think just a bit too little solder, too many attempts with too little flux, not enough "shine"...
Don't the joints look a bit ugly?

Looks good enough to me. No shine is due to lead-free solder.

[SiliconWizard]

In french, we call that "inspecteur des travaux finis". There's always a herd of them on social media.

[EEVblog]

Come on... you know it.
I think just a bit too little solder, too many attempts with too little flux, not enough "shine"...
Don't the joints look a bit ugly?

Nope, they are fine.
Lead free solder, lighting and camera exposure can make anything look like anything.