Author Topic: External SoundCard Repair - **FIXED!**  (Read 14917 times)

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Offline MrJoeyJoeJoe

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External SoundCard Repair - **FIXED!**
« on: April 12, 2016, 04:36:59 pm »
Hey guys!
I've been trying to fix my brother's Liquid Saffire 56 Soundcard and it's symptoms are no power on. Power gets to the powerboard from the switch but is not getting to any of the other boards - I think! - otherwise the lights would come on.




I've checked the first fuse for continuity and it's good. But then I've seen these two things;






The Green one says "WME CHJ471K"
And the Blue one says "WMR 70D471K"

I've searched Internet and can't find anything to do with those references. I'm pretty sure they're fuses no?
I checked continuity (in circuit) across the green one and that's good but the blue one hasn't got continuity!
Could this be the problem?
Are they fuses?

Thanks a lot,
Joe!

« Last Edit: June 16, 2016, 02:06:12 pm by MrJoeyJoeJoe »
 

Offline SeanB

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Re: Focusrite Liquid Saffire Repair - Help Needed!
« Reply #1 on: April 12, 2016, 05:09:48 pm »
Green is a NTC inrush limiter, and the blue one is a class Y interference supression capacitor. NTC will have a resistance of around 47ohms, and the other is a 470pF capacitor, like the 2 on the other side of the yellow common mode choke.

It is not your problem, look on the 2 heatsinks and there will be on the one a diode ( top pic the one on the left) and on the other either a power transistor or a TOPswitch device. Photo of the underside of the board will also help.

Please be careful, as this board will have high voltage on it, even after you have disconnected the power and left it alone for a while, and when in operation roughly half the board is at mains voltage.
 

Offline MrJoeyJoeJoe

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Re: Focusrite Liquid Saffire Repair - Help Needed!
« Reply #2 on: April 12, 2016, 08:50:56 pm »
Thanks a lot for your speedy reply!
Damn I was hoping the blue capacitor was actually one of these resetable fuses!;
http://d1gsvnjtkwr6dd.cloudfront.net/large/PA-PTC-1100_LRG.jpg

As you may have guessed I'm a bit of an electronics Noob! ;D
I did however make sure that scary 450v cap was pretty much drained before touching though! Thanks!
Here are some more pics.






So you think I should check what could be a TOPswitch on the left heatsink?
 

Offline MrJoeyJoeJoe

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Re: Focusrite Liquid Saffire Repair - Help Needed!
« Reply #3 on: April 13, 2016, 07:56:42 pm »
I can't see any leaking caps, suspicious or burnt out components and since SeanB mentioned the TOPSwitch I've googled around.
I've seen a troubleshooting guide here;
http://wenku.baidu.com/view/1a46d019227916888486d7a5

And it mentions that if the System has no power, it could be the TOPSwitches shutdown latch has tripped...

So my new question is; Does anyone know how to reset a TOPSwitch!?
(Is it even possible?)
 

Offline David_AVD

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Re: External SoundCard Repair - Anyone know how to reset a TOPSwitch!?
« Reply #4 on: April 13, 2016, 08:49:51 pm »
Did the unit suddenly stop during operation, or did it fail to power-up after a power interruption?

If the latter, I'd replace C5 (small electro cap on primary side) and also check all of the high value resistors on the primary side.
 

Offline janoc

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Re: External SoundCard Repair - Anyone know how to reset a TOPSwitch!?
« Reply #5 on: April 13, 2016, 09:22:58 pm »
Are you actually sure the problem is in the power supply in the first place? If you have a short downstream, the PSU may not start - most have some sort of protection circuitry (no, it may not blow the fuse on the mains side!).

Unplug the PSU and check whether or not you have a power rail shorted to ground, by chance. Then check the PSU separately - it may actually start if you unplug it from the rest of the system! If not, you may have to put some load on the rail where the feedback optocoupler is getting its power from. Also make sure to check whether or not it has a soft power on signal - you may have to ground some pin on that output connector or bring some voltage to it for it to start fully - then you should see some standby voltage on the connector already (usually 3.3 or 5V), indicating that the supply is most likely good.

If the PSU seems dead, make sure to discharge the large mains cap again and then check the electrolytic caps. They don't need to be leaking to be bad! You need an ESR meter for that, though - capacitance meter is not enough, it won't show you if the caps are dried out.

Other common problem could be blown switching transistor - check Q1 for shorts. But that is likely not the issue in your case, because if the transistors blew, it would have likely been quite a bang and also the fuse would have blown.

If all that checks out, you are getting voltage on the secondary of the transformer but you aren't getting correct voltage at the output when loaded (when unloaded the voltages could be off because the feedback loop is not yet regulating properly) -> check the voltage regulator(s), diodes, optocoupler, caps on the secondary side.

If you are not getting any voltages on the secondary side and everything above checked out, then you may need to try to reverse engineer the schematics of the board (or find it online). Then the problem could be something more complicated involving the controller IC or some other parts on the high voltage side - but that is not something I would recommend a newbie to poke fingers into.
« Last Edit: April 13, 2016, 09:25:03 pm by janoc »
 

Offline MrJoeyJoeJoe

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Re: External SoundCard Repair - Anyone know how to reset a TOPSwitch!?
« Reply #6 on: April 14, 2016, 01:54:36 pm »
Thanks David_AVD.
The unit just wouldn't turn on one day.
I'm thinking of buying an ESR... That way I could test the C5 cap in circuit no?
 

Offline MrJoeyJoeJoe

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Re: External SoundCard Repair - Anyone know how to reset a TOPSwitch!?
« Reply #7 on: April 14, 2016, 02:04:04 pm »

Thanks for your reply janoc.
I presumed it was the PSU as the full 230v are getting to it, but no power appears to be getting to the dashboard lights.

I would love to know a way to trace how far the power's getting to, but can only see GND marked on the other boards, not on the PSU so I don't know what contacts to check with the meter and am worried of shorting something out.

I want to test the optocoupler and have googled how, but it's out of circuit. Is it worth me removing it to test?
Also thinking of removing the Q1 TOPSwitch to test...


BTW I'm thinking of buying an ESR - would that help?
 

Offline SeanB

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Re: External SoundCard Repair - Anyone know how to reset a TOPSwitch!?
« Reply #8 on: April 14, 2016, 06:40:28 pm »
Not a TOPswitch but a high voltage MOSFET. The controller is the little 6 pin chip by your middle finger, and the resistors by the finger are the start up resistors, and are the most likely failure, along with the small electrolytic capacitor there being faulty. Resistors are possible to check in circuit using a DMM, simply measure the resistance, they should be lower than the marked value somewhat because of the surrounding components, but likely one or more has gone open circuit. If so replace all 6 with the same value.

this PSU will run unplugged ( some whil not) so simply put it back in the chassis and leave the output plug disconnected, but put all screws and plastic sheeting back on the board, and apply power. You should see some voltage on the output pins if it is working,  At least a 5V rail and some 12-18V rails both positive and negative with respect to the chassis, as the groundd of the output is connected to the chassis when it is screwed into the case.
 

Offline Rasz

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Re: External SoundCard Repair - Anyone know how to reset a TOPSwitch!?
« Reply #9 on: April 14, 2016, 08:16:35 pm »
Thanks David_AVD.
The unit just wouldn't turn on one day.
I'm thinking of buying an ESR... That way I could test the C5 cap in circuit no?

dont, cap costs $0.1, meter $30-100, unless you are planning to make a living fixing electronics for couple of years

as SeanB told you power it up unplugged and start measuring voltages, but you can check for shorts before as its very simple procedure - you dont need to desolder anything when short hunting. Start with diode and transistor (big 3 legged parts on radiators).
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Offline janoc

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Re: External SoundCard Repair - Anyone know how to reset a TOPSwitch!?
« Reply #10 on: April 15, 2016, 02:10:18 pm »

Thanks for your reply janoc.
I presumed it was the PSU as the full 230v are getting to it, but no power appears to be getting to the dashboard lights.

I would love to know a way to trace how far the power's getting to, but can only see GND marked on the other boards, not on the PSU so I don't know what contacts to check with the meter and am worried of shorting something out.


There is a connector with a ribbon cable going out of it visible on your power supply board. That's your output. The connector seems to be marked, the individual power rails are likely marked on it. Put the negative (black) lead of your meter to ground (the mass of copper going all over the secondary part of the board, I think it is connected to the second pin from the left of the connector in the photo where you are holding the bottom of the PCB. And then check the voltages on the other pins of that connector with the red lead of your meter.



I want to test the optocoupler and have googled how, but it's out of circuit. Is it worth me removing it to test?


Don't bother with the opto until you have checked the rest. Optocouplers rarely fail and you could just break stuff that is not broken yet if the problem is elsewhere. That optocoupler is part of the feedback network and the power supply must be powering up at least for it to make sense to start checking the opto. It is a LED and a phototransistor and the LED needs power from somewhere - which is the output of the PSU. If there is no power, the opto can't work and has no effect anyway, so the problem will likely be elsewhere.



Also thinking of removing the Q1 TOPSwitch to test...

I am not sure what (or why) you call that as "TOPSwitch". It is a normal transistor, most likely a MOSFET switching the power to the transformer. If you want to quickly check it, you don't need to remove it - turn everything off, make sure the big capacitor is discharged (!!) and check the transistor for shorts. If it has the pins shorted together (0 ohms on the meter) regardless of the polarity (don't forget to swap the leads), then it is certainly blown. If you get different (non zero) readings, then it is likely OK, but to be sure you would have to desolder it and check it outside of the board, otherwise you could be measuring the resistance of the transformer windings, for example.

BTW I'm thinking of buying an ESR - would that help?

ESR meter is very useful for checking electrolytic caps in these power supplies. Especially cheap poor quality caps will dry out over time thanks to the high ripple currents and temperature and their serial resistance goes up. Then you end up with bulging/leaky caps and non working power supply. The ESR meter helps to diagnose such caps that may not be bulging/leaking yet but are about to fail already.

Dave has a video on this:


Now whether or not to buy one - it depends on whether or not you are planning to do more such repairs in the future. If it is a one off and it is an older device you are repairing, you can just blindly replace the electrolytic caps as a matter of course. It is very possible the caps are bad. However, a $30 meter from eBay is not such a huge expense neither.
« Last Edit: April 15, 2016, 02:13:38 pm by janoc »
 

Offline MrJoeyJoeJoe

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Re: External SoundCard Repair - Anyone know how to reset a TOPSwitch!?
« Reply #11 on: April 15, 2016, 03:32:51 pm »

Thanks a lot for your replies and suggestions guys, I'm currently away from home but will try them out on Monday!
I'm very much an anti-planned-obsolescence kind of guy (in fact me and my brother did a music video about that!  ;D ) so I'm always trying to fix things for the sheer 'screw you consumerism' factor, just like Dave in the EEVblog video!

I've bought an ESR meter now because it's something I could be doing with more and more!
And Solder Wick! What a discovery! I had never heard of it until seeing Janoc's post! (I have a solder suction pump thingy) so I'll definitely be getting some of that!

I'll let you know how I get on!
 

Offline janoc

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Re: External SoundCard Repair - Anyone know how to reset a TOPSwitch!?
« Reply #12 on: April 15, 2016, 09:35:44 pm »
I've bought an ESR meter now because it's something I could be doing with more and more!
And Solder Wick! What a discovery! I had never heard of it until seeing Janoc's post! (I have a solder suction pump thingy) so I'll definitely be getting some of that!

I'll let you know how I get on!

Hehe, someone got bitten by the equipment bug :) Check other Dave's repair videos, there is a ton of stuff to learn from.

Good luck with the repair, but please stay safe. If you are a newbie, a switching mains power supply is a fairly dangerous item to work on. Well, it is dangerous for non-newbies too, but at least they know who or what to blame when they get their brains fried.

Remember - one hand always in  your pocket when poking around a live device so that you don't accidentally close a circuit through your body by touching the wrong things. I am sure you don't have an isolation transformer which one should use in such cases, so at least wear shoes with a thick rubber sole, in case.

 
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Offline MrJoeyJoeJoe

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Re: External SoundCard Repair - Anyone know how to reset a TOPSwitch!?
« Reply #13 on: April 22, 2016, 07:32:39 pm »
Sorry for the delay!
I've finally got round to checking the outputs of the ribbon cable. I plugged the board back in, screwed it down, attached earth cable and turned it on.
I followed Janoc's instructions, putting my meter's negative probe on pin 2 which is Ground and found it's definitely not outputting what it should be!
I have written what each pin reads on the photo - most of them apart from pin 1 fluctuate constantly.

Not sure what this could mean, but it's definitely a problem with a powerboard component. Could it be a cap?

 

Offline SeanB

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Re: External SoundCard Repair - Anyone know how to reset a TOPSwitch!?
« Reply #14 on: April 22, 2016, 07:53:49 pm »
Stuck in startup mode, so very good. Says power switch and the little IC is still good, and that the secondary side is not totally shorted. Time to change all the secondary side electrolytics, and the little one on the primary side, and it should work properly. I would check the diode attached to pin 5 though, to see if it is not shorted. A simple diode test across it will show if it is shorted or not in circuit, and if short both ways either the diode or the capacitor is shorted.
 

Offline MrJoeyJoeJoe

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Re: External SoundCard Repair - Anyone know how to reset a TOPSwitch!?
« Reply #15 on: April 24, 2016, 10:30:14 am »
Thanks a lot! I will check that diode you mentioned, but just thinking I may as well wait for my ESR to arrive to check the caps rather than replacing them all.
Sounds like we're getting close to the problem! Cheers!
 

Offline janoc

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Re: External SoundCard Repair - Anyone know how to reset a TOPSwitch!?
« Reply #16 on: April 24, 2016, 10:11:54 pm »
Thanks a lot! I will check that diode you mentioned, but just thinking I may as well wait for my ESR to arrive to check the caps rather than replacing them all.
Sounds like we're getting close to the problem! Cheers!

That's perhaps a good idea - if nothing else, it will be an educational experience. You won't learn to use an ESR meter on good caps only :)

And yeah, as SeanB said - that you are getting some voltages on the output is very good news. That means that most of the deal is still working ok.

On the other hand, the fluctuating voltages are not right - it most likely means that the PSU is attempting to start up but fails. That could be because the caps are bad and the excessive ripple is throwing things off or simply because there is not enough load on the output and the feedback loop doesn't work right.

Check the caps, replace them if needed and if it still doesn't work, more troubleshooting can be done.
 

Offline MrJoeyJoeJoe

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Re: External SoundCard Repair - Anyone know how to reset a TOPSwitch!?
« Reply #17 on: May 14, 2016, 02:05:59 pm »
Hey guys!
My ESR finally came!
I've taken some readings and most of the caps on the power board seem fine apart from 3. Two of them give a reading as if they were resistors? And the third has a really high amount of microfarads. (It's supposed to hold 470uf but is registering at 2722uf!?)



I'm gonna replace those 3 - ordering them now!

Cheers,
Joe!
 

Offline janoc

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Re: External SoundCard Repair - Anyone know how to reset a TOPSwitch!?
« Reply #18 on: May 14, 2016, 08:51:57 pm »
Well, if that meter shows them as resistors that's odd. Is that one of those cheap component testers? Something like this: http://thumbs.ebaystatic.com/images/g/GBQAAOSwpDdVbU3S/s-l225.jpg

That's not really very good as ESR meter, btw. and measuring in-circuit will give you nonsense results with this. Instead of sending a low level high frequency signal through the cap, like a normal ESR meter will do, these testers try to charge and discharge the cap and do a lot of other things trying to identify the connected part. That is going to be affected by the other components around, you can't measure in-circuit with it.

The 470uF cap could be ok. The capacity measurement of these universal testers is very approximate for large capacitors. Moreover, there could be easily other caps in parallel with it.

If you want to be sure, you will have to desolder the caps and measure them out of circuit.
« Last Edit: May 14, 2016, 08:56:54 pm by janoc »
 

Offline Monadnock

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Re: External SoundCard Repair - Anyone know how to reset a TOPSwitch!?
« Reply #19 on: May 15, 2016, 02:42:48 pm »
Have you metered the output diodes?
 

Offline MrJoeyJoeJoe

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Re: External SoundCard Repair - Anyone know how to reset a TOPSwitch!?
« Reply #20 on: May 15, 2016, 09:41:35 pm »
Well, if that meter shows them as resistors that's odd. Is that one of those cheap component testers? Something like this: http://thumbs.ebaystatic.com/images/g/GBQAAOSwpDdVbU3S/s-l225.jpg

That's not really very good as ESR meter, btw. and measuring in-circuit will give you nonsense results with this. Instead of sending a low level high frequency signal through the cap, like a normal ESR meter will do, these testers try to charge and discharge the cap and do a lot of other things trying to identify the connected part. That is going to be affected by the other components around, you can't measure in-circuit with it.

The 470uF cap could be ok. The capacity measurement of these universal testers is very approximate for large capacitors. Moreover, there could be easily other caps in parallel with it.

If you want to be sure, you will have to desolder the caps and measure them out of circuit.

Haha, the meter I bought is EXACTLY the one you posted! One of those cheap ones, yes.
If you could recommend me one that can be used with components in circuit like in the EEVBlog, that would be awesome.
You're right about it not working in circuit - I tried the meter out on a broken tv first and it read 3 bad caps. But when I removed them only 1 of the 3 was actually bad.

I guess it's time to start removing components then!

   
 

Offline MrJoeyJoeJoe

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Re: External SoundCard Repair - Anyone know how to reset a TOPSwitch!?
« Reply #21 on: May 15, 2016, 09:49:57 pm »
Have you metered the output diodes?

Are the output diodes those two big ones to the left of the transformer?
 

Offline Monadnock

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Re: External SoundCard Repair - Anyone know how to reset a TOPSwitch!?
« Reply #22 on: May 15, 2016, 10:19:19 pm »
Have you metered the output diodes?

Are the output diodes those two big ones to the left of the transformer?

Yes, those are 2 of them, looks like D6 and D9. There is also the big TO-220 one on the heatsink, but since you got voltage on that output it is OK.

I would look at D6 since you didn't seem to get any voltage on that output.
 

Offline EPTech

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Re: External SoundCard Repair - Anyone know how to reset a TOPSwitch!?
« Reply #23 on: May 16, 2016, 08:09:15 am »
Hi There,

I agree with David. If there are some voltages present, that means the control IC is showing some startup behavior but not quite getting there. This is often caused by undervoltage on it's own supply, that comes from an auxiliary winding of the transformer on the primary side in this case. I would also replace C5.

The ESR of a capacitor is best measured outside of a circuit. The meter uses an AC voltage to measure and that will also pass through the rectifier diode (partially) and the transformer's secondary coil. So you are not just measuring a capacitor.

Kind greetings,

Pascal.
 

Offline janoc

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Re: External SoundCard Repair - Anyone know how to reset a TOPSwitch!?
« Reply #24 on: May 17, 2016, 05:30:18 pm »
Haha, the meter I bought is EXACTLY the one you posted! One of those cheap ones, yes.
If you could recommend me one that can be used with components in circuit like in the EEVBlog, that would be awesome.

That's what I thought, I have recognized the display screenshots.

Buy something that is actually marketed as ESR meter and not a component tester. These little testers are useful for quickly identifying/checking components, but don't rely on them for getting an accurate measurement.

An actual ESR meter looks somewhat like this:

http://www.ebay.com/itm/AnaTek-Blue-ESR-Low-Ohms-Meter-Complete-Kit-for-Assembly-BESR-Kit-/181171316406?hash=item2a2ea6e6b6:g:gV4AAOSw34FVDeYt

or this

http://www.ebay.com/itm/Portable-Digital-Capacitor-ESR-Tester-Internal-Resistance-Meter-Test-In-Circuit-/322034893012?hash=item4afac680d4:g:oNQAAOSwoudW4WGt

Dave has an early video on ESR meters too, explaining how it works and how to use one. I think the Anatek one is based on the same design Dave's one is using.

The other option is to get a proper LCR meter, those often include ESR measurement for capacitors, but they tend to be (a lot) more expensive and a massive overkill if you only want to check caps for repair.

You're right about it not working in circuit - I tried the meter out on a broken tv first and it read 3 bad caps. But when I removed them only 1 of the 3 was actually bad.

I guess it's time to start removing components then!

Yep. That little tester will get confused by other components in parallel with the component you are measuring, so that is to be expected.
 

Offline MrJoeyJoeJoe

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Re: External SoundCard Repair - Anyone know how to reset a TOPSwitch!?
« Reply #25 on: May 24, 2016, 06:00:19 pm »
Hey guys!
I've desoldered a few of the caps and they all seemed okay, but on double-checking C5 (10uf) it suddenly read 9792nf! 2 out of 3 times it reads like this, so I'm going to replace and see if it works!

A strange thing to note which I've never had happen before - is that on each cap, after heating and suctioning the solder off the second leg, the cap just fell out! I've never had it so easy!!
Thanks again for all your help, I'll let y'all know how I get on.
« Last Edit: May 24, 2016, 06:03:45 pm by MrJoeyJoeJoe »
 

Offline Anks

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Re: External SoundCard Repair - Anyone know how to reset a TOPSwitch!?
« Reply #26 on: May 24, 2016, 06:57:59 pm »
9792nf Is pretty much 10uf
 

Offline PedroDaGr8

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Re: External SoundCard Repair - Anyone know how to reset a TOPSwitch!?
« Reply #27 on: May 24, 2016, 08:53:39 pm »
Hey guys!
I've desoldered a few of the caps and they all seemed okay, but on double-checking C5 (10uf) it suddenly read 9792nf! 2 out of 3 times it reads like this, so I'm going to replace and see if it works!

A strange thing to note which I've never had happen before - is that on each cap, after heating and suctioning the solder off the second leg, the cap just fell out! I've never had it so easy!!
Thanks again for all your help, I'll let y'all know how I get on.

9792nf is 9.792uF. That is actually really close for a cap. Honestly, if I were you I would replace ALL of the caps. They are cheap, otherwise you will repair, then a new cap goes bad in a year or two. Diagnose and repair again, then a year or two later. Repeat continuously. Caps are limited life devices, they just don't last forever. The electrolyte dries out and they just don't perform as well as they should.
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Offline janoc

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Re: External SoundCard Repair - Anyone know how to reset a TOPSwitch!?
« Reply #28 on: May 24, 2016, 09:00:07 pm »
Keep in mind that electrolytic caps can have tolerances from -20 to +80% of the nominal value, so for a cap of 10uF anything between 8uF to 18uF is well in spec. That cap you have measured is likely just fine as far as capacitance is concerned. Also the accuracy of your cheap meter/tester likely sucks for these large capacitance values and there will be significant errors.

Worse, measuring the capacitance won't give you an indication whether the capacitor is good or bad - you must measure ESR. A bad bulging capacitor will happily measure its nominal capacitance despite having sky-high series resistance due to dried out/boiled off electrolyte. Such capacitor is essentially completely non-functional in the power supply but if you only measure capacitance, you will never know. That is why capacitance meters are pretty much useless for repairing switch-mode power supplies unless they measure ESR as well.

BTW, am I seeing right that the caps are CapXon brand? If yes, don't even bother to measure them - just replace all of them, even the large mains rated input cap. CapXon has the nickname "crapxon" for a very good reason - those capacitors have only one thing reliable about them - they reliably die, usually right after the warranty of the item is out.

« Last Edit: May 25, 2016, 06:55:05 pm by janoc »
 

Offline MrJoeyJoeJoe

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Re: External SoundCard Repair - Anyone know how to reset a TOPSwitch!?
« Reply #29 on: May 24, 2016, 09:35:38 pm »
Hehe... 9000nf is 9.000uf?  :palm: Have I said before I'm somewhat of a noobie?
Well I guess I'm going to have to just replace all the caps then. Seeing as they're all 'Crapxon'  ;D
A proper ESR would be really handy, but $80 is about $30 more than I'd be willing to spend!
I know it would save money in the long-run though...

I'll check that D6 diode, replace all caps and check back!
 

Offline janoc

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Re: External SoundCard Repair - Anyone know how to reset a TOPSwitch!?
« Reply #30 on: May 25, 2016, 06:57:30 pm »
You don't need to spend $80 for the Anatek one. I have something like this and it works well enough for the occasional repair job:
http://www.ebay.fr/itm/Digital-Capacitor-ESR-Tester-Internal-Resistance-Meter-Test-In-Circuit-/182066050731

 

Offline MrJoeyJoeJoe

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Re: External SoundCard Repair - Anyone know how to reset a TOPSwitch!?
« Reply #31 on: May 25, 2016, 09:57:00 pm »
You don't need to spend $80 for the Anatek one. I have something like this and it works well enough for the occasional repair job:
http://www.ebay.fr/itm/Digital-Capacitor-ESR-Tester-Internal-Resistance-Meter-Test-In-Circuit-/182066050731


Awesome, that's much more within my price range!
Thanks a lot!
 

Offline MrJoeyJoeJoe

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Re: External SoundCard Repair - Anyone know how to reset a TOPSwitch!?
« Reply #32 on: May 26, 2016, 02:17:32 pm »
Hey chaps!
I've taken out all of the caps, and also took out the D5, D6, D8 and D9 diodes which people suggested. On testing the two big diodes with the diode tester on my DMM the D8 one appears to be shorted! It reads 0.00 in both directions!
I'm starting to get that tingling feeling... Could this be it?

 

Offline Mephitus

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Re: External SoundCard Repair - Anyone know how to reset a TOPSwitch!?
« Reply #33 on: May 26, 2016, 04:12:58 pm »
Your last photo of the back of the board, maybe its nothing, but check R31. It looks like it may be damaged. But I admit it could just be nothing.  :-//
A true gentleman must be prepared for anything. - Pepe le' Pew
 

Offline janoc

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Re: External SoundCard Repair - Anyone know how to reset a TOPSwitch!?
« Reply #34 on: May 26, 2016, 10:39:31 pm »
Well, if the diode on the secondary went poof, that certainly wouldn't help things. It is possible that that voltage regulator on the heatsink may need replacing too now.
 

Offline EPTech

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Re: External SoundCard Repair - Anyone know how to reset a TOPSwitch!?
« Reply #35 on: May 27, 2016, 12:58:23 pm »
Hi there,

Did you check that diode while the board was disconnected? If so, it is definitely broken and needs to be replaced. I have had schottky diodes die on me before without any apparent reason. Hey, sometimes they do. I hope for you none of the other circuits died from getting semi-rectified switch mode AC.  :o

The component on the heat sink may also be a double schottky rectifier. So check the part number before assuming it is a voltage regulator and measuring it as such.

Happy hunting, almost there.
Kind greetings,

Pascal.
 

Offline MrJoeyJoeJoe

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Re: External SoundCard Repair - Anyone know how to reset a TOPSwitch!?
« Reply #36 on: May 27, 2016, 03:23:58 pm »
Your last photo of the back of the board, maybe its nothing, but check R31. It looks like it may be damaged. But I admit it could just be nothing.  :-//
Just checked R31 with a better light. Looks ok, thanks!  ;D
 

Offline MrJoeyJoeJoe

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Re: External SoundCard Repair - Anyone know how to reset a TOPSwitch!?
« Reply #37 on: May 27, 2016, 03:31:05 pm »
Hi there,

Did you check that diode while the board was disconnected? If so, it is definitely broken and needs to be replaced. I have had schottky diodes die on me before without any apparent reason. Hey, sometimes they do. I hope for you none of the other circuits died from getting semi-rectified switch mode AC.  :o

The component on the heat sink may also be a double schottky rectifier. So check the part number before assuming it is a voltage regulator and measuring it as such.

Happy hunting, almost there.

Hi Pascal,
Yes the diode testing I did out of circuit. D5,6,8+9.

According to the part number on the heatsink next to the shorted D8 is a Dual Common Cathode High Voltage Schottky Rectifier.
How would one go about testing this? I presume out of circuit?
I have a DMM and a very cheap component tester/ESR.

 

Offline janoc

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Re: External SoundCard Repair - Anyone know how to reset a TOPSwitch!?
« Reply #38 on: May 27, 2016, 07:51:56 pm »
According to the part number on the heatsink next to the shorted D8 is a Dual Common Cathode High Voltage Schottky Rectifier.
How would one go about testing this? I presume out of circuit?
I have a DMM and a very cheap component tester/ESR.

It is nothing special - those are just two diodes connected together by their cathodes and put in a single package. So you test it the same way as you would test a PNP transistor (treat the the common cathode as "base" and the the two anodes as "collector" and "emitter") using the diode test mode on a multimeter. You will just have to desolder it. Even your component tester should be able to test it - it should indicate it is a dual diode.
 

Offline MrJoeyJoeJoe

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Re: External SoundCard Repair - Anyone know how to reset a TOPSwitch!?
« Reply #39 on: May 27, 2016, 10:18:10 pm »
It is nothing special - those are just two diodes connected together by their cathodes and put in a single package. So you test it the same way as you would test a PNP transistor (treat the the common cathode as "base" and the the two anodes as "collector" and "emitter") using the diode test mode on a multimeter. You will just have to desolder it. Even your component tester should be able to test it - it should indicate it is a dual diode.

Awesome, thanks for that. I'll check it out tomorrow.
Cheers.
 

Offline MrJoeyJoeJoe

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Re: External SoundCard Repair - Anyone know how to reset a TOPSwitch!?
« Reply #40 on: May 28, 2016, 11:58:17 am »
Okay the double-diode appears to be good. It's reading O.L in the NPN position and then each diode reads about 0.300 in PNP.
Also my cheap-o tester recognized it as a 2xdiode with 340uf on each  :D

So I guess that's ok.
As you can see the board is looking pretty bare!

 

Offline janoc

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Re: External SoundCard Repair - Anyone know how to reset a TOPSwitch!?
« Reply #41 on: May 28, 2016, 01:45:46 pm »
Okay the double-diode appears to be good. It's reading O.L in the NPN position and then each diode reads about 0.300 in PNP.
Also my cheap-o tester recognized it as a 2xdiode with 340uf on each  :D

I assume that was 0.3V (or 300mV) - that would be about correct forward voltage for a schottky diode (that's what the meter indicates in diode test mode). Or did you literally stick it into the transistor test socket that some cheap multimeters have?

So I guess that's ok.
As you can see the board is looking pretty bare!



Heh. I do hope you are taking notes where goes what and in what orientation/polarity, though. The board seems to be well labeled, but still. There is nothing dumber than to buy a bunch of new parts and have them release the magic smoke only because I was an idiot and have put something backwards or in a wrong place. A capacitor installed backwards exploding in your face is not fun.

When I am doing repair like this, I usually snap a few pictures using my phone for documentation and then label the caps and such over it on my PC. Or print it out and write it in by hand using a pen. That makes it easy to make sure that I am not messing something up during re-assembly.

I think the only thing that remains now is to replace the components with known good parts and see whether that has fixed it.
 

Offline MrJoeyJoeJoe

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Re: External SoundCard Repair - Anyone know how to reset a TOPSwitch!?
« Reply #42 on: May 28, 2016, 03:42:03 pm »
I did plug it straight into the cheap-o tester  ;D and it gave me 369mv on each side and my DMM gave me 0.308 (volts?) so they're pretty similar results no?
Heh I'm not a stranger to that 'magic smoke' you talked about!  :-DD But I've learnt a lot from many of my mistakes and am more methodical now - I've also taken lots of photos with my phone  ;)

Just waiting for the replacement parts!
Thanks for all your help!
 

Offline janoc

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Re: External SoundCard Repair - Anyone know how to reset a TOPSwitch!?
« Reply #43 on: May 28, 2016, 09:25:28 pm »
I did plug it straight into the cheap-o tester  ;D and it gave me 369mv on each side and my DMM gave me 0.308 (volts?) so they're pretty similar results no?

Yep, that's pretty much the same thing - the tester is not very accurate, so a bit of difference is to be expected.


Heh I'm not a stranger to that 'magic smoke' you talked about!  :-DD But I've learnt a lot from many of my mistakes and am more methodical now - I've also taken lots of photos with my phone  ;)

Well, the best way to learn :)

Just waiting for the replacement parts!
Thanks for all your help!

Hopefully it will work now!

 

Offline MrJoeyJoeJoe

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Re: External SoundCard Repair - Anyone know how to reset a TOPSwitch!?
« Reply #44 on: June 16, 2016, 02:05:16 pm »
 :o :o :o :o :o IT'S ALLIIIVVVVEEE!!!  :o :o :o :o :o :o 8)



I replaced all the caps and the faulty diode:




BEFORE:



AFTER:



My brother has already plugged it back into his studio and it all works fine again!




Thanks to all of you who have helped! Together we stuck it to the Man! (in this case the man being Consumerism)
Excellent result, and I've learned so much! ;D

Many thanks for the help!
Until next time!
Joe!
 

Offline janoc

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Re: External SoundCard Repair - **FIXED!**
« Reply #45 on: June 16, 2016, 07:39:18 pm »
Congrats!

I am sure you have learned quite a bit more than you have expected too :) And saved a nice piece of gear from the bin in the progress.
Btw, any particular reason why did you leave the diodes so high above the board? Having components flush is usually better for mechanical reason and there is less chance for something to short on the exposed leads too.

Just one tip - you want to get a better multimeter, especially if poking around mains powered gear. Those cheapies are OKayish to use in a car, but not safe to use  with mains voltages.
 

Offline macboy

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Re: External SoundCard Repair - **FIXED!**
« Reply #46 on: June 17, 2016, 01:55:00 pm »
Just one tip - you want to get a better multimeter, especially if poking around mains powered gear. Those cheapies are OKayish to use in a car, but not safe to use  with mains voltages.
I agree. When repairing any SMPS like this, you might be measuring voltages on the primary side. It is not uncommon for these to have a voltage-doubler circuit for 120 V use. So whether on 120 or 240 V mains, you can have 340 V or more on the capacitors. That much voltage on a cap is an explosion waiting to happen if something goes wrong. I would not trust any cheap meter to measure that. Cheap meters are best used when there is a risk of damage to the meter, such as measuring high-ish current on a low voltage circuit. For that you just don't use your Fluke(etc.) and risk blowing that $30 HRC fuse. You use the cheapy that has a $0.50 glass fuse (if any at all). Your best expensive meter is used when there is risk of damage to you, such as measuring lethal voltages on a capacitor.
 

Offline MrJoeyJoeJoe

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Re: External SoundCard Repair - **FIXED!**
« Reply #47 on: July 04, 2016, 03:23:57 pm »
Thanks guys, yes I guess it's time to look for a new DMM!
Janoc: I put the diodes back how I found them! :D I think they were that high off the board to better dissipate the heat?
Thanks again for all your help!

 

Offline David_AVD

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Re: External SoundCard Repair - **FIXED!**
« Reply #48 on: July 04, 2016, 09:25:00 pm »
Good to hear you got it fixed.  :)

Mounting of diodes and resistors up off the board is commonplace and can aid heat dissipation.
 

Offline janoc

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Re: External SoundCard Repair - **FIXED!**
« Reply #49 on: July 04, 2016, 09:44:33 pm »
Thanks guys, yes I guess it's time to look for a new DMM!
Janoc: I put the diodes back how I found them! :D I think they were that high off the board to better dissipate the heat?
Thanks again for all your help!

Heat dissipation, sure, but I doubt those diodes get significantly hot. If they did, they would have been on a heatsink. When I see parts mounted like this I am immediately thinking vibration and the forces the long leads transfer to the pads and solder joints. The former could peel off the board and the later crack.
 

Offline AMPLent

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Re: External SoundCard Repair - **FIXED!**
« Reply #50 on: March 26, 2018, 08:23:56 pm »
Hello I haven't read the full forum, but I would like to ask a question.

I just purchased a liquid saffire 56, before I had a digi 003. Now when I had the digi 003 and recording a vocal, i would have to bring the gain knob between 1-2 O'clock, for example 1-10 around 6-7. i would have a great signal, Since I do not have a vocal booth, I would be able to hear the background etc. The Artists could be 6-12 inches away and it would still capture the artists at a good level, the closer well you know. Now with the liquid saffire 56 i find my self raising the knob to 34-5 O'clock, 1-10 9-10 and still the level is extremely low. I called focusrite etc, I decided to look online a came upon this forum. I see that that the liquid saffire 56 has fuses, Are you ale to tell me what voltage/ratings etc those fuses are? I would like to re[lace any replaceable parts/components my self and save money. For example anything that doesn't need to be soldered.
 

Offline The Soulman

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Re: External SoundCard Repair - **FIXED!**
« Reply #51 on: March 26, 2018, 08:37:08 pm »
Hello I haven't read the full forum, but I would like to ask a question.

I just purchased a liquid saffire 56, before I had a digi 003. Now when I had the digi 003 and recording a vocal, i would have to bring the gain knob between 1-2 O'clock, for example 1-10 around 6-7. i would have a great signal, Since I do not have a vocal booth, I would be able to hear the background etc. The Artists could be 6-12 inches away and it would still capture the artists at a good level, the closer well you know. Now with the liquid saffire 56 i find my self raising the knob to 34-5 O'clock, 1-10 9-10 and still the level is extremely low. I called focusrite etc, I decided to look online a came upon this forum. I see that that the liquid saffire 56 has fuses, Are you ale to tell me what voltage/ratings etc those fuses are? I would like to re[lace any replaceable parts/components my self and save money. For example anything that doesn't need to be soldered.

We need more info, what microphone do you use and is there noise or distortion in the recording?

Is the PAD button pressed?
 
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Offline AMPLent

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Re: External SoundCard Repair - **FIXED!**
« Reply #52 on: March 27, 2018, 09:40:53 pm »
Sorry about that, in my first reply I stated that the Focusrite Rep said should instead of shouldn't, sorry for the typo.

Original message

No the pad is not on, I'm not a newbee. but i understand why one has to ask these questions.

I've worked with several interfaces, such as UAD, Avid, etc. I've used Nuemann, shure, rodes, etc.

In this case for my home studio I have 2 MXL Mics one is V69ME, THE OTHER IS MXL 990HE, Both have the Capsules upgraded.

Now before upgrading to the Focusrite Liquid saffire 56 I had a Digi 003 W/same mics.

With the Digi 003 my gain knob was always at 1-2 O'clock example (1-10) around 6-7.

Now with the Liquid Saffire 56 I have to turn the gain knob to example 1-10 between 9-10, which is crazy.

i called Focusrite , the first rep gave me some B/S like trying to compare apples to oranges etc.

So I decided to call back, got a different rep, i explained the same thing, he agreed that it should not have to be turned that far for a decent level.

He stated since my interface out of warranty i would have to pay out of pocket, but if the fuses shown in the other pics posted by MrJoeyJoeJoe
could be the issue, then I can replace those myself and save some money. The cost just to ship and evaluate will be about $100.00,

Can anyone tell me the voltage/values etc. of each of those fuses (all the fuses) in the Liquid Saffire 56 ?

Very much appreciated.


P.S.

I use Pro Tools 10.3.10, The Pro Tools Meter DbFS, with the Digi 003 danced around -10-14, and peaked around -6 and thats with the gain knob  example 1-10, around 6-7, With the Focusrite Liquid Saffire 56 going to into Pro Tools, It Dances way below -18db and peaked around -10.

I do understand that in the digital world there is no need for hot signals, I understand that. I just would like to replace fuses myslef, run tests and if it still happens then I'll send in to repair. So please can anyone help me ?

Modify message
 

Offline AMPLent

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Re: External SoundCard Repair - **FIXED!**
« Reply #53 on: March 27, 2018, 09:43:20 pm »
Hey, how many fuses does the Liquid Saffire 56 has in total? I mean the glass fuses, shown in your pics. Also what are the Voltage etc. of those fuses so I can purchase them myself and install them? can you recommend where I can purchase them?

Hey guys!
I've been trying to fix my brother's Liquid Saffire 56 Soundcard and it's symptoms are no power on. Power gets to the powerboard from the switch but is not getting to any of the other boards - I think! - otherwise the lights would come on.




I've checked the first fuse for continuity and it's good. But then I've seen these two things;






The Green one says "WME CHJ471K"
And the Blue one says "WMR 70D471K"

I've searched Internet and can't find anything to do with those references. I'm pretty sure they're fuses no?
I checked continuity (in circuit) across the green one and that's good but the blue one hasn't got continuity!
Could this be the problem?
Are they fuses?

Thanks a lot,
Joe!
 

Offline AMPLent

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Re: External SoundCard Repair - **FIXED!**
« Reply #54 on: March 28, 2018, 09:32:25 pm »
Sorry about that, in my first reply I stated that the Focusrite Rep said should instead of shouldn't, sorry for the typo.

Original message

No the pad is not on, I'm not a newbee. but i understand why one has to ask these questions.

I've worked with several interfaces, such as UAD, Avid, etc. I've used Nuemann, shure, rodes, etc.

In this case for my home studio I have 2 MXL Mics one is V69ME, THE OTHER IS MXL 990HE, Both have the Capsules upgraded.

Now before upgrading to the Focusrite Liquid saffire 56 I had a Digi 003 W/same mics.

With the Digi 003 my gain knob was always at 1-2 O'clock example (1-10) around 6-7.

Now with the Liquid Saffire 56 I have to turn the gain knob to example 1-10 between 9-10, which is crazy.

i called Focusrite , the first rep gave me some B/S like trying to compare apples to oranges etc.

So I decided to call back, got a different rep, i explained the same thing, he agreed that it should not have to be turned that far for a decent level.

He stated since my interface out of warranty i would have to pay out of pocket, but if the fuses shown in the other pics posted by MrJoeyJoeJoe
could be the issue, then I can replace those myself and save some money. The cost just to ship and evaluate will be about $100.00,

Can anyone tell me the voltage/values etc. of each of those fuses (all the fuses) in the Liquid Saffire 56 ?

Very much appreciated.


P.S.
I use Pro Tools 10.3.10, The Pro Tools Meter DbFS, with the Digi 003 danced around -10-14, and peaked around -6 and thats with the gain knob  example 1-10, around 6-7, With the Focusrite Liquid Saffire 56 going to into Pro Tools, It Dances way below -18db and peaked around -10.

I do understand that in the digital world there is no need for hot signals, I understand that. I just would like to replace fuses myslef, run tests and if it still happens then I'll send in to repair. So please can anyone help me ?


Hello I haven't read the full forum, but I would like to ask a question.

I just purchased a liquid saffire 56, before I had a digi 003. Now when I had the digi 003 and recording a vocal, i would have to bring the gain knob between 1-2 O'clock, for example 1-10 around 6-7. i would have a great signal, Since I do not have a vocal booth, I would be able to hear the background etc. The Artists could be 6-12 inches away and it would still capture the artists at a good level, the closer well you know. Now with the liquid saffire 56 i find my self raising the knob to 34-5 O'clock, 1-10 9-10 and still the level is extremely low. I called focusrite etc, I decided to look online a came upon this forum. I see that that the liquid saffire 56 has fuses, Are you ale to tell me what voltage/ratings etc those fuses are? I would like to re[lace any replaceable parts/components my self and save money. For example anything that doesn't need to be soldered.

We need more info, what microphone do you use and is there noise or distortion in the recording?

Is the PAD button pressed?
 

Offline KhronX

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Re: External SoundCard Repair - **FIXED!**
« Reply #55 on: March 28, 2018, 11:35:02 pm »
Especially with stuff more complicated than lightbulbs and such, you most definitely do NOT want to be just replacing fuses willy-nilly, without determining / knowing WHY a / the fuse blew in the first place. Otherwise, you just run the risk of causing even more damage downstream, than what caused the fuse to blow in the first place.

And anyway, had you looked a bit more carefully at those big photos, you might've(?) been able to notice that, at least in the power supply, the fuse ratings are quite clearly silkscreened on the circuit board.

PS: Is that "low gain" symptom the case on all eight inputs? And/or do you have any of the emulations enabled for ch1/2?

PS2: Your Saffire 56 works, and has low gain, but still works with (at least) one blown fuse? Or...?  :wtf:
« Last Edit: March 28, 2018, 11:37:56 pm by KhronX »
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Offline AMPLent

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Re: External SoundCard Repair - **FIXED!**
« Reply #56 on: April 04, 2018, 02:48:18 am »
No the pad is not on, there is no distortion or noise.

My issue is that in order for me to get a decent level I have to crank the gain knob of the liquid saffire 56 to 9-10 just to get a level and thats me being 3 inches away from the mic.

The type of mic I am using is a MXL 990 modified. It has the Mod Kit from Microphone parts.com as well as capsule. There is no issue with the mic as I tested on my friends interface which is a UAD Apollo Twin. The gain knob of the apollo Twin is at lets say 1-10 about 5-6 with great level and thats me being 10 inches away from the mic.

I believe there is something wrong with the Preamps of the liquid 56
 

Offline KhronX

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Re: External SoundCard Repair - **FIXED!**
« Reply #57 on: April 05, 2018, 05:58:15 pm »
What about some of the questions i posed?  ???
Khron's Cave - Electronics - Audio - Teardowns - Mods - Repairs - Projects - Music - Rants - Shenanigans
 

Offline AMPLent

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Re: External SoundCard Repair - **FIXED!**
« Reply #58 on: April 10, 2018, 11:36:44 pm »
What about some of the questions i posed?  ???



Sorry didn't see your questions, I assumed it was the fuse, but the fuse in the unit is perfect. This is the issue in all channels the level are extremely low, I have disabled the transformer in mix control, I set first channel at flat and then checked all settings/presets. As for the rest of the channels 3-8 Same thing.
When I opened the unit all i did was dust it, Thats all.

https://youtu.be/IfnvA_Jya78

I have made sure the pad is off, i mean the whole nine yards. I did a screen recording here is the link I posted on youtube,

At the time I did not have the UAD Twin available, when I did screen recording.

On the 56 the gain knob is at 6-7 and the level is so low and thats me being 10 inches away from mic, (Yes I have phantom power on, I've checked connections etc.) Now on the UAD, Digi 003 the level would be perfect at that gain level of 6-7, actually on the UAD Twin 5-6 is a great level.

Usually at that level and since I do not have a booth, I am able to hear background noise, such as TV, air conditioner or fan etc. Which of course when recording a vocal one wants to avoid all that stuff, I understand that.

Now if I turn gain knob of 56 to 8.5-10 I get a level that I should be receiving at 6-7.


Another thing, I do mic mods and the mic I'm using which is the mxl 910. I have upgraded, the capsule, and the circuit. Now when I connect the mic to the preamp of 56, I turn down volume when checking voltage with a multimeter. So the levels should read 55-60v, but it doesnt. Now there is nothing wrong with mic as I tested the mic on the UAD Twin I mentioned earlier. When I checked the voltage it read 63v, which then I had to tweak the mic untill the multimeter read 60v.

So maybe there is something wrong with the phantom power of the saffire 56.


If this helps and answers your question please let me know. It looks like I will have to ship interface to be fixed, but after reading a few forums and blogs I have learned that Focusrite or the third part who fixes their product have shipped back interfaces and the issue continues which they claim they couldn't find anything wrong with units.

I have been experiencing horrible costumer service from focusrite, I am starting to regret ever buying one of their products.


Is there away I can test the voltage of phantom power with a multimetter, to see if that is the issue?



in a different forum one individual stated this

"If it was a phantom power problem you would have normal levels with a dynamic mic (you should test it) if it's the case, check the caps in the AC input area.
I doubt we experience the same problem. On my unit it would record fine for a minute or 2 and then drop levels. Then I i put the gain to maximum and back where it was, levels would be normal again."

Where would I find the caps hat he is speaking of ?

do you have an image of what he is speaking of ?
 

Offline AMPLent

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Re: External SoundCard Repair - **FIXED!**
« Reply #59 on: April 11, 2018, 07:14:21 am »
So I have actually tested the xlr's of the 56 with a multimeter, turned on phantom power and they all read 48.0, so what could be the problem ?
 

Offline KhronX

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Re: External SoundCard Repair - **FIXED!**
« Reply #60 on: April 11, 2018, 10:10:51 pm »
It's a reasonably well-known(?) thing that, in Focusrite interfaces, the gain ramps up in a big hurry only towards the end (the upper 25% or so) of the gain pot travel. That in itself isn't a fault, only a design choice.

You didn't say what voltage reading the capsule bias voltage was while connected to the Saffire (only that it was 63v on the UAD, unless i horribly misunderstood something).

The AC-coupling caps for the XLR inputs are easily determined. First of all, they'll be rated at 50v or 63v, most likely 47uF. And if you can't follow the PCB traces, you can stick one multimeter probe on pin 2 of the XLR and beep out the cap for the "hot" input, then the same on XLR pin 3 for the "cold" input.

So the "fault" you're encountering is... that your Saffire doesn't have the same gain taper that units from other manufacturers do?  :-// Or is the maximum gain available, somehow not enough for your application?

If it's not loud enough - turn it up, it's dead-simple. Isn't that what the knob's there for? Who cares what setting the gain knob's at, as long as you get the levels you need to into your DAW?

I've personally had positively wonderful experience with Focusrite support. A couple years ago i bought a dead Scarlett 18i8, that had its USB connector ripped out (i had some bodging to do on the board), was missing a bunch of screws and one of the "halos" from the gain knobs. Apart from the connector (which i already had), the support staff was kind enough to mail me a replacement "halo" along with the missing screws - FOR FREE  ;D
In a similar case last year, i landed a "comatose" 18i20. After some troubleshooting, i contacted the support department again, and they mailed me a pre-programmed SPI flash chip with the firmware for the thing (once again, for no charge), which brought it back to life.

So i'm afraid i must ask - what IS the actual problem, in case there really is one?
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