Alesis IO2 USB audio interface re-capping

[technicalspecialist]

Hi,

I am repairing a friends Alesis IO2 external USB audio interface cos he damaged the USB socket and bent 1 of the microphone XLRs. Already fixed them.
I thought I might as well replace the larger value capacitors with better quality ones while i've got it.

It has 2 purple Su'scon SL series 2200uF 6.3V caps and 3 orange Su'scon SA series 100uF 35V caps.
I think the 2200uF's are likely to be smoothing caps so I think I can safely replace these with low ESR ones.
On the Su'scon website the SL's are under standard and are general purpose but the SA series is under special. What should I replace the SA's with?

Also, there are 4 47uF 63V audio coupling caps in series with the MIC XLRs.
On channel 1 they've used Su'scon SL's. On channel 2 the manufacturer appears to be DON with the flat side of the "D" thicker than the rest.
I've never heard of this make before. What should I replace these 4 with?

I've always thought the lower the ESR, the better but since these are in the audio path, I thought maybe not. What will give the best audio quality?
New electrolytics or another capacitor type entirely?

The rest of the caps are all tiny 22uF 16V DON's.

[japlytic]

Re: Alesis IO2 USB audio interface re-capping

The Su'scon SA series are low electrical leakage units.
Is this an audophile unit? If so, I recommend audio grade capacitors for the four 47uF 63V units. Otherwise, standard units will do.

If capacitors are used for smoothing, it is safe to assume that you can use low-ESR units as replacements. They are generally better, especially in high frequency power supplies.

Do you have a picture of the internals of this audio interface (marked with capacitor values)?

[technicalspecialist]

Re: Alesis IO2 USB audio interface re-capping

i will take some pics of the internals tomorrow. Since testing it, i've found a more serious problem than just the caps. Basically i get no sound and just digital noise. When i plug the USB in, windows xp detects it properly as io2 so i know the usb interface chip is working properly. Without the schematic / service manual i can't progress further and find where the fault is. There are lots of surface mounted ics.

[Th3_uN1Qu3]

Re: Alesis IO2 USB audio interface re-capping

Digital noise points at a DAC fault. And that is going to be difficult to fix. However do try different USB ports or even a different computer, i once panicked coz the ESI Maya soundcard i borrowed from a friend would sound real bad, like 8-bit or something, then i simply plugged it in another USB port and it worked fine.

[stj]

Re: Alesis IO2 USB audio interface re-capping

digital & analog sections of the chip probably have seperate & decoupled power lines.
(atleast they should)

find a datasheet for the chip that has pinouts.

[technicalspecialist]

Re: Alesis IO2 USB audio interface re-capping

Yes, tried USB different ports on my desktop and laptop, same:

XP detects IO2 -> USB composite device -> USB Audio Device and
USB LED lights up and audio level indicator LEDs light up full.
Digital noise on headphones and main output when turned up full.

I've finally taken some pictures of the PCBs, see attachments

I did some research into the IC/chip part numbers and it uses:

TAS1020B USB controller
CS8416 SPDIF receiver
CS4265 104 dB ADDA with SPDIF Transmitter 32pin QFP
3 ON Semiconductor MC33079DG quad op-amps for analogue inputs/outputs on bottom PCB, 1 on top PCB below CH2 gain potentiometer.

When I connect the S/PDIF output to my Denon AV reciever, the "Lock" LED on the front lights up so the CS4265 is outputing something, but I don't get any sound.

The datasheet for the CS4265 says it has reset and mute pins, I'll check them if I can. Link

[technicalspecialist]

Re: Alesis IO2 USB audio interface re-capping

I emailed Alesis to ask for the service manual but got no reply. I can't see how I can progress much further without a schematic. If the CS4265 IC is broken and I could get a free sample from Cirrus Logic, it would be extremely difficult to solder those tiny contacts by hand.

[stj]

Re: Alesis IO2 USB audio interface re-capping

qfp is easy,
you use the flow method.

[technicalspecialist]

Re: Alesis IO2 USB audio interface re-capping

Just phoned the UK number for Alesis and they're gonna email me the service manual in PDF.

[longa]

Re: Alesis IO2 USB audio interface re-capping

Hi technicalspecialist.I am not technical at all but I noticed that you might have schematics for alesis IO2.My IO2 recently died down with very similar symptoms.Friend of mine can repair it but without schm. it is very tricky.If you have schematics can you please,please,please mail it to me.Thank you very much and have a good day.Longa

[technicalspecialist]

Re: Alesis IO2 USB audio interface re-capping

Yes I managed to get the service manual emailed to me for free. I've given up trying to repair mine as the problem is likely to be the CS4265 chip, which is pretty much impossible to get just 1 or 2 of.

From the pictures, you'll see that the pins are very short and soldering by hand would probably burn it.

I uploaded the manual to to eServiceInfo and it's a 3 part .rar achive containing the PDF due to 3MB max file size upload limit. Download all 3 parts to the same folder before extracting.
Link: http://www.eserviceinfo.com/download...lesis_io2.html

[longa]

Re: Alesis IO2 USB audio interface re-capping

Thank you 123.000 times...Greetz.. Longa

[clemenslime]

Re: Alesis IO2 USB audio interface re-capping

Dear Technical Specialist,

On the one hand, I realize this is a shot into the infinite dark internet space. On the other, I've got nothing to lose and I am not a technical specialist and my USB socket on my Alesis IO2 external USB audio interface is damaged and you seem to fix those in the most nonchalant fashion. How on earth do you do that? Did you replace it? It just seems to be loose, because if i push it up and in (and hold it there), it works.
Do you have any special technical technical specialist advice?

Spank you,
Clementine

[Th3_uN1Qu3]

Re: Alesis IO2 USB audio interface re-capping

Technical specialist advice? Take the cover off, resolder the USB socket AND the metal shield surrounding it, done.

[burnt01]

Re: Alesis IO2 USB audio interface re-capping

Thought i'd join/post as i found this post quite helpful

Ive just fixed 5 of these IO2's (for a studio)
All had the problem with the signal clip being lit up as soon as you plug it in.
I found on every one, the component U9 had failed! (after 6 hours of probing)
thought id post this up as i couldn't find a fix any other place!
Checked the service manual, U9 is a:
IC VOLTAGE INVERTER CHARGE PUMP UNREG TPS60403 SOT23-5
got mine from:
http://int.rsdelivers.com/product/te...5/5171208.aspx
soldered it in and jobs a good'n

Thanks for the help/service manual!

[technicalspecialist]

Re: Alesis IO2 USB audio interface re-capping

thanks burnt01

so did you also get a buzzing digital noise and all audio level meter LEDs light up as soon as you plugged the USB in?
i've still got the IO2 in my draw of parts, PCBs and broken stuff. i'll get it out again and have a look at U9.

Since my original post i've got a proper o'scope, a digital microscope (connects to composite video input on TV or TV card) and a proper voltage/current adjustable bench PSU.

i've got a feeling i might have recycled the aluminium case though thinking it's not fixable. i've also nicked the larger caps, USB connector and 6.3mm jacks/xlrs off it for other projects.

[hopper]

Re: Alesis IO2 USB audio interface re-capping

Hi

I have exactly the same problem with a friends' io2. It seems like a very common failure. Some valuable information here on dealing with it though I am wary of soldering surface mount devices without a better soldering iron (and vision!) than I currently have.

Will see if I can get the part U9 and let you know how I get on. BTW, the way they use it in this circuit (particularly the caps around it) is rather different than recommended on the app notes. I wonder if this is contributing to the failures?

[hopper]

Re: Alesis IO2 USB audio interface re-capping

well, I did the replacement of part U9 - along with the caps around it (whilst taking care of the app note that says the flyback cap needs to have low esr) and after destroying one of the SM parts by poor soldering I got it working with the 2nd one! Certainly seems like a reliable fault on this unit.

[joshbb]

Re: Alesis IO2 USB audio interface re-capping

hi, thanks for the information relating to fixing these units.
I am just about to fix one of these. Hopper: do you have any of those TPS60403 spare I could purchase? or anyone in the UK for that matter? cheers. Josh

[markoCS]

Re: Alesis IO2 USB audio interface re-capping

Hi, have anyone measured the negative supply voltage after changing the TPS60403? It should be -4v but I'm getting -3.2v on two Alesis IO2 where I changed this IC.