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catman

How often does this happen....or am I just cursed?

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G'day all, I think that I must be!  For the last few days I've been trying to build another simple phono stage using two NE5534 op amps.  On power up only channel worked and the other channel was completely dead, and by the way the op amps were brand new and unused straight out of their supplied container. 

 

So I thought well I've made a wiring or soldering error, and I spent the next three days looking for it!  In the end I needn't have bothered as the cause turned out to be one faulty NE5534 op amp.  Simple substitution proved it, and yes by the way I had used high quality 8 pin IC  sockets.  I think that it is time to give up!  Regards, Felix. 

Edited by catman
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You didn't give up for three days Felix , why start now ?

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G'day mate, I'm starting to lose faith in certain things!  I have better things to waste time on, to be completely frank!  Regards, Felix. 

 

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20 minutes ago, catman said:

G'day all, I think that I must be!  For the last few days I've been trying to build another simple phono stage using two NE5534 op amps.  On power up only channel worked and the other channel was completely dead, and by the way the op amps were brand new and unused straight out of their supplied container. 

 

So I thought well I've made a wiring or soldering error, and I spent the next three days looking for it!  In the end I needn't have bothered as the cause turned out to be one faulty NE5534 op amp.  Simple substitution proved it, and yes by the way I had used high quality 8 pin IC  sockets.  I think that it is time to give up!  Regards, Felix. 

 

Felix, in terms of diagnosis - given you soldered in the IC sockets, so that opamps could be rolled - I would've thought that trying the 'working' NE5534 in the 'non-working' socket would've been your first step?  If that channel suddenly sprang into life ... then the problem was obviously a dead opamp; if it was still dead then, bcoz it had been working in the other channel ... shirley, you must have a wiring difference in the 'dead' channel?

 

I decided earlier this year I didn't want the problem of soldering in 'dead' semiconductor devices ... so I bought myself a Peak DCA75 that someone mentioned in an SNA thread.  Is there a similar device for opamps?

 

Andy

 

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G'day mate, well you are perfectly right but in my general sense of trustfulness, I honestly didn't think that a brand new op amp would be faulty, but obviously I was wrong!  Regards, Felix.

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Guest Muon N'

Where do you purchase ya' op amps from, Felix?

 

Maybe try a different supplier, maybe RS Components.

 

I either get them from RS here in Aus' or from Partsconnxion in Canada.

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32 minutes ago, elcamry said:

You didn't give up for three days Felix , why start now ?

It’s called fault finding, part of fault finding is process of elimination....this takes time....  especially when everything is solder in.....Good on ya @catman for not giving up.  Never had a op amp to be faulty,   the only faulty opamp are me being over confident and not checking after plug in and stuffing the orientation up!   Only happens once, teaches you a very memorable lesson.....never again!

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32 minutes ago, andyr said:

I decided earlier this year I didn't want the problem of soldering in 'dead' semiconductor devices ... so I bought myself a Peak DCA75 that someone mentioned in an SNA thread.  Is there a similar device for opamps?

 

Andy

 

A Peak DCA75 are only tests for discrete semiconductors, they do not test Opamps.  Opamps are complete amplifier circuits that can have multi discrete devices and are usually 8pin...

http://www.ti.com/lit/ds/symlink/ne5534.pdf

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G'day all, I normally purchase from Element 14, but I have used RS at times.  I am pretty sure that those NE5534's were purchased from Element 14.  Oh well, &%it happens at times!  Regards, Felix. 

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1 minute ago, catman said:

G'day all, I normally purchase from Element 14, but I have used RS at times.  I am pretty sure that those NE5534's were purchased from Element 14.  Oh well, &%it happens at times!  Regards, Felix. 

Sh|t happens,  

 

imaginging powering up a 30A 3 phase device and the power supply goes “bang”.  You’re there for the next for days fault finding to discover you need to replace 2 out of 6 power supply that cost $1000s together to resolve the fault,   And this is stuff that’s made in Japan...... or made in Sweden! 

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Guest iant

Felix,do you use an antistatic wrist strap?

It's easy enough to kill an opamp with the odd stray "zap".

As a Telstra tech we had it drummed into us "use antistatic precautions" especially when handling CMOS boards.

I cringe when I see the local Jaycar staff handling semis without any consideration for antistatic measures.If it doesn't kill the device straight away it may well shorten it's lifespan long term.

Edited by iant

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Guest Muon N'
6 minutes ago, iant said:

Felix,do you use an antistatic wrist strap?

It's easy enough to kill an opamp with the odd stray "zap".

As a Telstra tech we had it drummed into us "use antistatic precautions" especially when handling CMOS boards.

ESD protection is a must with IC's :thumb:

 

ES Damage is cumulative also as we know, and may not kill straight away, but a fault develops down the track instead.

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G'day all, as a former Telstra tech myself I also know the importance of a wrist strap with CMOS stuff but as far as I know the NE5534 is not CMOS, and isn't particularly static sensitive!  Regards, Felix.  

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38 minutes ago, Addicted to music said:

A Peak DCA75 are only tests for discrete semiconductors, they do not test Opamps.  Opamps are complete amplifier circuits that can have multi discrete devices and are usually 8pin...

http://www.ti.com/lit/ds/symlink/ne5534.pdf

 

I'm well aware of all you said, Peter - that's why I asked "is there a similar device for opamps?"  :hmm:

 

Andy

 

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Guest iant
9 minutes ago, catman said:

G'day all, as a former Telstra tech myself I also know the importance of a wrist strap with CMOS stuff but as far as I know the NE5534 is not CMOS, and isn't particularly static sensitive!  Regards, Felix.  

My experience is that it's best to err on the side of caution and regard all semiconductors as ESD sensitive.

 

To stay ESD aware, here’s a quick list of some of the most sensitive electronic devices in use that is susceptible to damage:

  • Microwave devices like Schottky barrier diodes and point contact diodes
  • Discrete MOSFET devices
  • Junction field effect transistors (JFETs)
  • Charged coupled devices (CCDs)
  • Precision voltage regulator diodes
  • Operational amplifiers (Op Amps)
  • Thin film resistors
  • Integrated circuits
  • Very high speed integrated circuits (VHSIC)
  • Laser diodes
  • Silicon controlled rectifiers (SCRs)
Edited by iant

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3 minutes ago, iant said:

My experience is that it's best to err on the side of caution and regard all semiconductors as ESD sensitive.

 

^^^ yes, absolutely!  :thumb:

 

Andy

 

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Just now, andyr said:

 

I'm well aware of all you said, Peter - that's why I asked "is there a similar device for opamps?"  :hmm:

 

Andy

 

No there isn’t, 

 

the best thing to do before plugging it in is to ensure with a multimeter that no DC is present at the output before you go plugging it in to anything else.   Then if you have a scope and a generator you can work out the gain.  Usually inverted Opamps gain is usually RF/Rin.   Non inverted gain is 1+ Rf/Rin.   

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1 hour ago, catman said:

G'day mate, well you are perfectly right but in my general sense of trustfulness, I honestly didn't think that a brand new op amp would be faulty, but obviously I was wrong!  Regards, Felix.

Correct, there are no CMOS in an NE5534. It’s all BJTs see PDF in my above post.

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27 minutes ago, iant said:

Felix,do you use an antistatic wrist strap?

It's easy enough to kill an opamp with the odd stray "zap".

As a Telstra tech we had it drummed into us "use antistatic precautions" especially when handling CMOS boards.

I cringe when I see the local Jaycar staff handling semis without any consideration for antistatic measures.If it doesn't kill the device straight away it may well shorten it's lifespan long term.

Before you go around recommending anti static straps or any thing anti static,  never trust them!   Meter it out on a MM and you’ll be surprised that even some are not what they seem to be....  Never use an anti static strap or anything suggesting that’s it is anti static until you have meter it out, test the anti static claims 1st before you go trusting it. some are BS even from places like E14 or RS or Digikey. 

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Guest iant
8 minutes ago, Addicted to music said:

Before you go around recommending anti static straps or any thing anti static,  never trust them!   Meter it out on a MM and you’ll be surprised that even some are not what they seem to be....  Never use an anti static strap or anything suggesting that’s it is anti static until you have meter it out, test the anti static claims 1st before you go trusting it. some are BS even from places like E14 or RS or Digikey. 

Radio Parts  actually sells a Wrist Strap Checker.Recommended resistance for a properly functional wrist strap is 750Kohm-9Mohm.

 Low ~750kΩ; Good 750kΩ~9MΩ; High 9MΩ~

Edited by iant

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17 minutes ago, iant said:

Radio Parts  actually sells a Wrist Strap Checker.Recommended resistance for a properly functional wrist strap is 750Kohm-9Mohm.

 Low ~750kΩ; Good 750kΩ~9MΩ; High 9MΩ~

If me, I’d be still metering it out to ensure that they do what they are intended to do....like I said never trust them.

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Guest Muon N'

After building PC's for years, I very quickly learned about ESD early on, walk out of a few stores after seeing CPU's and RAM sticks and other hardware handled incorrectly.


Edit: wasn't going to buy something for it only to fail after 1 week, 1 month or 1 year down the track due to incorrect handling in the store.

Edited by Muon N'

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Guest iant
22 minutes ago, Addicted to music said:

If me, I’d be still metering it out to ensure that they do what they are intended to do....like I said never trust them.

Fair enough and I've just listed the recommended values,anything up to 9Mohm.

Edited by iant

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7 minutes ago, iant said:

Fair enough and I've just listed the recommended values.Not sure what your problem is?

The problem is obvious,  they don’t measure what they say they do, some I have tested to be full open even with a MM that has a 20M range....  just be careful when you use them, take my approach and never trust them especially with your own gear not so much on the stuff at work but that’s where I discover that a lot of these antistatic straps work was providing do not work as claim. I actually discharge myself with ground b4 I go handling pcb..  I don’t even take the pcb out of that antistatic wrap, I place the package so it’s grounded too before I pull the pcb out b4 installation...  

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Guest iant

 

3 minutes ago, Addicted to music said:

  I don’t even take the pcb out of that antistatic wrap, I place the package so it’s grounded too before I pull the pcb out b4 installation...  

Yep that's good policy.I always work with a properly grounded antistatic mat on the workbench as an extra ESD precaution.

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