Incorrectly marked transistors?

[Shaun]

"Gareth Magennis" wrote in message
news:EtSdnSo9L81UrkjPnZ2dnUVZ8nednZ2d@bt.com...


"Phil Allison" <phil_a@tpg.com.au> wrote in message
news:bjkmq7Fjj6uU1@mid.individual.net...

"Gareth Magennis"
"Phil Allison"


I recently bought some TIP35C transistors from Farnell UK. Just before
I fitted one to an amplifier I thought I'd just check the pinouts.
Good job I did because instead of BCE they measured BEC.


** That is just not possible.

The middle leg is always the collector and metal tab used for
heatsinking.

FFS - get an ohmmeter and verify that simple fact.

Seems your dopey microprocessor ( ie software) based POS has gone ape
and confused Collector with Emitter.



I did suspect my dopey checker, but even with a fresh battery it ALWAYS
reads EXACTLY the same,


** ROTFL - since when is THAT any reason to trust it ?????

" It must be right cos it always tells the SAME lie "

Wot an idiot you are.


which is: 3 of them measure BEC with an Hfe of 5, the other one BCE with
an Hfe of 20.

** No fooling.

BJTs have very low Hfes if C and E are reversed.

Like 2 or 3 instead of 100 or 200.

They *also* show very low readings if the meter is no fucking good.

See how that might be confusing ???


(All tabs connect to centre pin)


** Then there is simply **NO** problem with the devices.
-------------------------------------------------------------------

YOU are the problem with your dopey meter that is not able to tests power
BJTs properly.

FYI Try it with a TV horizontal output transistor like the BU208.


The replacements I finally got from Farnell with a different batch code
measure an Hfe between 40 and 70.


** Testing the Hfe of *power transistors* is a whole DIFFERENT ball game
to small signal devices.

That is why I designed a special device just for power devices -
published as a project in Electronics Australia magazine in May 1988.

Test are done at a constant Ic of 0.6 amps instead of some fixed and way
too small Ib.

Results are spot on and match maker's data which follow the same idea.

Works fine with TV horizontal output devices, power darlingtons and any
BJT rated for high power.



I know Hfe is kind of meaningless on these types of checker voltages, but
was still wondering why the checker would give a different pinout result
rather than fail the device.

** Cos it is using the wrong approach for power BJT devices.

I suspect all 4 of the "old" transistors are faulty,

** Bollocks.

You have a **fucking useless** meter that only works with those examples
of power BJT devices that exceed maker's specs at the low end of the Ic v
Hfe range.

Take a LOOK at some ACTUAL power BJT data sheets some time !!!!!!!!!

Hfe is NOT a constant !!!!!!!!!!!!



.... Phil

Yes I know Hfe is not constant, that is why I said the reading is
meaningless on such a low voltage checker.

I do not use this device to measure Hfe, I don't usually give a fuck what
the Hfe of a transistor is, I assume all new ones I buy from Farnell are
within manufacturers spec.
I usually just want to know if a transistor is bad, what pinout it is, and
whether or not it tests on this meter in the same ballpark as a known good
one.

These 4 "faulty" transistors do NOT test in the same ballpark, they probably
DO exceed the maker's spec if they work properly at all. In that respect
the tester has done all I have asked of it.

I am not going to put one of these devices into a Power Amp (which I was
about to do before I tested them) and have it blow up in my face. Farnell
can damn well send me 4 good transistors which ARE in the right ballpark,
which is exactly what they have done, one of which went into the Power Amp
which did not blow up in my face.



Cheers,


Gareth.


The first tests to do on a suspect Transistor is using the Diode test mode
on a DMM (assuming there are no cracks in its case or plastic blown off -
that lets out the magic smoke). Start testing across two leads at a time,
go forwards (the red lead on one pin and the black on another) then reverse
polarity (black to red). Try all three variations. On a good transistor you
should get about 0.6 volts across two sets of pins, one of them being common
between the two, that is the base lead. When you reverse the leads it should
read OL on your DMM. From there you can determine if it is NPN or PNP
transistor. If one reading shows about 1.2 Volts and OL in the reverse
direction, its a working darlington transistor. If you read a short or
readings in forwards and reverse, then the transistor is NFG. Google the
part number, it is very easy - You will find pin outs, datasheets on almost
anything.

Shaun

 

[Chris Jones]

On 14/01/2014 23:55, Gareth Magennis wrote:

"Phil Allison" <phil_a@tpg.com.au> wrote in message
news:bjkmq7Fjj6uU1@mid.individual.net...

"Gareth Magennis"
"Phil Allison"


I recently bought some TIP35C transistors from Farnell UK. Just before
I fitted one to an amplifier I thought I'd just check the pinouts.
Good job I did because instead of BCE they measured BEC.


** That is just not possible.

The middle leg is always the collector and metal tab used for
heatsinking.

FFS - get an ohmmeter and verify that simple fact.

Seems your dopey microprocessor ( ie software) based POS has gone ape
and confused Collector with Emitter.



I did suspect my dopey checker, but even with a fresh battery it ALWAYS
reads EXACTLY the same,


** ROTFL - since when is THAT any reason to trust it ?????

" It must be right cos it always tells the SAME lie "

Wot an idiot you are.


which is: 3 of them measure BEC with an Hfe of 5, the other one BCE with
an Hfe of 20.

** No fooling.

BJTs have very low Hfes if C and E are reversed.

Like 2 or 3 instead of 100 or 200.

They *also* show very low readings if the meter is no fucking good.

See how that might be confusing ???


(All tabs connect to centre pin)


** Then there is simply **NO** problem with the devices.
-------------------------------------------------------------------

YOU are the problem with your dopey meter that is not able to tests power
BJTs properly.

FYI Try it with a TV horizontal output transistor like the BU208.


The replacements I finally got from Farnell with a different batch code
measure an Hfe between 40 and 70.


** Testing the Hfe of *power transistors* is a whole DIFFERENT ball game
to small signal devices.

That is why I designed a special device just for power devices -
published as a project in Electronics Australia magazine in May 1988.

Test are done at a constant Ic of 0.6 amps instead of some fixed and way
too small Ib.

Results are spot on and match maker's data which follow the same idea.

Works fine with TV horizontal output devices, power darlingtons and any
BJT rated for high power.



I know Hfe is kind of meaningless on these types of checker voltages, but
was still wondering why the checker would give a different pinout result
rather than fail the device.

** Cos it is using the wrong approach for power BJT devices.

I suspect all 4 of the "old" transistors are faulty,

** Bollocks.

You have a **fucking useless** meter that only works with those examples
of power BJT devices that exceed maker's specs at the low end of the Ic v
Hfe range.

Take a LOOK at some ACTUAL power BJT data sheets some time !!!!!!!!!

Hfe is NOT a constant !!!!!!!!!!!!



.... Phil





Yes I know Hfe is not constant, that is why I said the reading is
meaningless on such a low voltage checker.

I do not use this device to measure Hfe, I don't usually give a fuck what
the Hfe of a transistor is, I assume all new ones I buy from Farnell are
within manufacturers spec.
I usually just want to know if a transistor is bad, what pinout it is, and
whether or not it tests on this meter in the same ballpark as a known good
one.

These 4 "faulty" transistors do NOT test in the same ballpark, they probably
DO exceed the maker's spec if they work properly at all. In that respect
the tester has done all I have asked of it.

I am not going to put one of these devices into a Power Amp (which I was
about to do before I tested them) and have it blow up in my face. Farnell
can damn well send me 4 good transistors which ARE in the right ballpark,
which is exactly what they have done, one of which went into the Power Amp
which did not blow up in my face.



Cheers,


Gareth.

Some transistors work surprisingly well upside-down. Not well enough to
rely upon, but well enough to confuse people.

Why don't you measure the breakdown voltage when you reverse-bias the
base-emitter junction and then do the same with the base-collector junction.

One of these junctions will break down at a few volts, that will be the
one with the emitter. The other one will break down at some higher
voltage and will be the collector.

This test is slightly destructive in that it can permanently worsen the
noise figure (and probably other parameters) of low-noise small-signal
transistors, especially if you don't limit the current to a very small
value, but in this case I guess you don't want the suspect transistors
any more so you might as well do this test, and see whether your meter
is right or wrong.

Also, the tab is always the collector, unless the counterfeiters went to
extreme expense to re-package exotic RF devices as some bog standard
part and sell them for a huge loss, which is the reverse of the usual
business model. The bulk of the chip of silicon (the substrate) is the
collector, and this is stuck with conductive glue, or soldered, to the
tab. Therefore unless someone put a thermally-conducting,
electrically-insulating layer in between the chip and the tab, (which is
expensive and uncommon), the tab is the collector. This applies to both
NPN and PNP transistors.

It is easy to believe that measuring instruments with a digital display
are always right but sometimes they aren't.

Chris

 

[Arfa Daily]

"William Sommerwerck" <grizzledgeezer@comcast.net> wrote in message
news:lb3cb0$4ac$1@dont-email.me...

How about phony products from China?

You should bring this to Farnell's attention.

I used to trust Farnell absolutely, but recently, I've had cause on several
occasions to be suspicious of the pedigree of some semiconductors that
they've supplied me. There seems to have been a subtle shift in their
business model from 'Lets be helpful and honest to our customers, and make
some money along the way' to 'Let's make some money ...'

Arfa

 

[Phil Allison]

"Chris Jones"

It is easy to believe that measuring instruments with a digital display
are always right but sometimes they aren't.

** I have a few TIP35Cs in stock - Motorola and ST brands.

Connected with C and E reversed, the ST brand ones show Hfes of 20 and 26.

With correct connection, the Hfe is over 200.

This is with an Ic of 0.5 amp.

Any BJT should show a much higher Hfe with C and E used the normal way -
long as Ic is within the maker's specs.

Which does not include 2mA for a 25amp BJT.


.... Phil

 

[Phil Allison]

"Arfa Daily= anonymous worm "

I used to trust Farnell absolutely, but recently, I've had cause on
several occasions to be suspicious of the pedigree of some semiconductors
that they've supplied me.

** WTF is that nonsense supposed to mean ??

Either make your complaint in plain English, with all the details or shut
the fuck up.

There seems to have been a subtle shift in their business model from 'Lets
be helpful and honest to our customers, and make some money along the way'
to 'Let's make some money ...'

** All businesses are out to make money, all the time, or they fail.

Component & test equipment warehouses like Farnell have all faced dwindling
sales and increased competition in the last few years - much of it because
of all the internet dealers, particularly eBay sellers in Asia.

However, if I want a particularly high quality component, something bit
unusual or just to be certain I am not getting supplied someone's rejects -
then I buy from Farnell ( aka " Element 14" now).


BTW:

How typical of sleazy, anonymous little worms like AD to slander people like
this.

Peeeeuuukkkkk.............



.... Phil

 

[Arfa Daily]

"Phil Allison" <phil_a@tpg.com.au> wrote in message
news:bju1lpFjg1pU1@mid.individual.net...

"Arfa Daily= anonymous worm "

Oh you juvenile sad little man ...

I used to trust Farnell absolutely, but recently, I've had cause on
several occasions to be suspicious of the pedigree of some semiconductors
that they've supplied me.


** WTF is that nonsense supposed to mean ??

Either make your complaint in plain English, with all the details or shut
the fuck up.

Was I talking to you, you fucked up Aussie twat ? Just shut the fuck up
yourself and piss off back under your rock you dopey bastard ... And that
is plain English, not the fucked-up bastardised version that you speak down
there on the bottom of the world. If you can't understand it, that's your
problem, not mine.

There seems to have been a subtle shift in their business model from
'Lets be helpful and honest to our customers, and make some money along
the way' to 'Let's make some money ...'


** All businesses are out to make money, all the time, or they fail.

You really are a dopey twat. Fuck off and get a life ...

Component & test equipment warehouses like Farnell have all faced
dwindling sales and increased competition in the last few years - much of
it because of all the internet dealers, particularly eBay sellers in Asia.

However, if I want a particularly high quality component, something bit
unusual or just to be certain I am not getting supplied someone's
ejects - then I buy from Farnell ( aka " Element 14" now).


BTW:

How typical of sleazy, anonymous little worms like AD to slander people
like this.

What, like you never do ? You hypocritical arsewipe ...

Arfa

Peeeeuuukkkkk.............



... Phil

 

[Phil Allison]

"Phil Allison"

"Arfa Daily= anonymous worm "

I used to trust Farnell absolutely, but recently, I've had cause on
several occasions to be suspicious of the pedigree of some semiconductors
that they've supplied me.

** WTF is that nonsense supposed to mean ??

Either make your complaint in plain English, with all the details or shut
the fuck up.

There seems to have been a subtle shift in their business model from 'Lets
be helpful and honest to our customers, and make some money along the way'
to 'Let's make some money ...'

** All businesses are out to make money, all the time, or they fail.

Component & test equipment warehouses like Farnell have all faced dwindling
sales and increased competition in the last few years - much of it because
of all the internet dealers, particularly eBay sellers in Asia.

However, if I want a particularly high quality component, something bit
unusual or just to be certain I am not getting supplied someone's rejects -
then I buy from Farnell ( aka " Element 14" now).


BTW:

How typical of sleazy, anonymous little cunts like AD to slander people like
this.

Peeeeuuukkkkk.............



.... Phil

 

[Arfa Daily]

"Phil Allison" <phil_a@tpg.com.au> wrote in message
news:bju49oFjvd5U1@mid.individual.net...

"Phil Allison"

"Arfa Daily= anonymous worm "


I used to trust Farnell absolutely, but recently, I've had cause on
several occasions to be suspicious of the pedigree of some semiconductors
that they've supplied me.


** WTF is that nonsense supposed to mean ??

Either make your complaint in plain English, with all the details or shut
the fuck up.


There seems to have been a subtle shift in their business model from
'Lets be helpful and honest to our customers, and make some money along
the way' to 'Let's make some money ...'


** All businesses are out to make money, all the time, or they fail.

Component & test equipment warehouses like Farnell have all faced
dwindling
sales and increased competition in the last few years - much of it
because
of all the internet dealers, particularly eBay sellers in Asia.

However, if I want a particularly high quality component, something bit
unusual or just to be certain I am not getting supplied someone's
ejects -
then I buy from Farnell ( aka " Element 14" now).

And that's what we were trying to discuss before you jumped in with your
size twelves. Gareth suspects that Farnell may - and I stress 'may' - have
unknowingly supplied him with someone else's rejects. He may be mistaken
because of the testing methods he has used, but equally, he /may/ be right.
The whole reason that I use Farnell - now much less than I used to - is the
same as you, that is to get what /should/ be a top quality certified
product. But, as you say, they have faced stiff competition recently, so
who's to say that they haven't sought alternative suppliers to try to cut
their costs, and in so doing, have inadvertently fallen foul of some dubious
trader somewhere down the line.

Things that have rung my alarm bells, have been some power transistors that
I use to repair HK powered speakers. I always stick to the same ones, and
have always bought them from Farnell for years. Over the last year, I have
had some batches where the logo doesn't look 'quite' right, and ones from
the same batch haven't been very well matched. These amplifiers are very
well behaved, and for the most part, the only problem with them is failed
output transistors, often brought on by barely adequate heatsinking, dried
out heatsink paste, and airways clogged with dead sheep. There is a very
detailed repair and checking guide produced by the manufacturer, and if all
the tests check out, they can be considered good to go. I have repaired many
of these over the years, and never had a problem with repeat failures, until
the last year, when several have returned after only a couple of weeks, with
the same set of transistors failed. After replacing them again with newly
ordered ones, and checking all the conditions and adjusting as required,
these repeat failures have gone back to work, and not returned again. It may
be coincidence, but with 45 years experience in this business, it certainly
doesn't 'feel' like it.

There. Detailed enough for you ?

As to Farnell needing to make money, of course they do. But as ever, you
missed the point I was making as you rushed to dive down my throat with your
usual bucket-mouthed diatribe. Farnell have done themselves no favours with
their loyal customers, by starting to levy delivery charges on what they
consider to be 'small' orders. They built their business on the loyalty of
small customers, and have now kicked us all in the teeth by levying these
additional charges. I could maybe accept it if their prices weren't a
premium in the first place, or the postage charges weren't unrealistic, and
if they stopped sending everything by UPS. I don't care how good a deal they
get from UPS, it is not going to be cheaper than a Jiffy bag through Royal
Mail. Also, UPS vary their delivery route "for security reasons" so you
never know what time you are going to get stuff fro 8 am to 6 pm, and it' a
different driver every time, so they never get to learn where stuff can be
left, or who with if you're not in. Also, a lot of stuff is now shipped from
their Belgian warehouse. This can't be cheap, and on more than one occasion
recently, the stuff hasn't made it to me by the next day.

These are some of the main reasons that they have gone from being my
supplier of choice to my supplier of need, and talking to colleagues in the
trade, I am by no means alone in this. I expect that some kid fresh out of
university, has done some kind of study of their costings, without taking in
the broader picture, or their customer demographic, and come up with this
new business model, which must be losing them small customers in droves.
Alternatively, maybe they have just looked at their customer base and
decided fuck the small boys, we only want big corporate customers ...

For non-critical components, I now buy almost all everything from a couple
of eBay suppliers that for the moment I trust. So far, I have had no
problems with anything that I have bought. These suppliers both have very
reasonable prices, and ship by Royal Mail First Class, for free. One of them
will even do his best to source stuff for you.

Arfa

 

[Phil Allison]

"Arfa Daily = pommy cunthead "

( snip paranoid rave )


How typical of sleazy, anonymous pommy cunts like AD to slander
honest people like this.

Including me.

Peeeeuuukkkkkeeee .............

Hope his fucking cat dies.




..... Phil

 

[Arfa Daily]

"Phil Allison" <phil_a@tpg.com.au> wrote in message
news:bjvc9fFrijbU1@mid.individual.net...

"Arfa Daily = pommy cunthead "

( snip paranoid rave )


How typical of sleazy, anonymous pommy cunts like AD to slander
honest people like this.

Including me.

You ??!! Honest ??!! What an arrogant dickhead you are. 40 years ago, you
would have got banged up in an asylum, you wobble-eyed lunatic, and it would
have been the best place for you. They would have kept you dosed up on horse
tranquilizers, and you would have never seen the light of day again, which
would have been a result for the whole world.

You asked for reasons why I commented on Farnell's recent performance. I
gave them, but dopey shithead that you are, you just come back with more of
your worthless bucket-mouthed crap, because you are clinically incapable of
rational thought.

I am sick and tired of you hijacking every fuckin thread on here trying to
show how superior you think you are. You are actually a low-life twat, who
deserves to get a serious kicking from someone to put you in your place. You
are not clever or even remotely interesting. Everybody on here, without
exception, thinks that you are a stupid bastard, and about the worst advert
for the Australian nation, that there could possibly be.

Now do us all a favour and fuck off and get some help before you hurt
yourself, and if you can't do that, get back in your darkened room, and
don't come out until I tell you you can.

Fucking arsehole

Peeeeuuukkkkkeeee .............

Hope his fucking cat dies.

You sad, sad mental deficient ...

Arfa

.... Phil

 

[Gareth Magennis]

I have had a few alarm bells from Farnell recently.

Here's one - I had an old Lexicon 224 reverb to repair that had a problem
with the crowbar circuitry on the 5v line.
It used a 6vsomething Zener and a Triac to short out said line should it
rise above 6vsomethingelse volts.
Which it was doing on an extremely intermittent basis. Hard to determine if
the problem was the supply or the protection.


Anyway, after days of testing and discovering it was the protection, I
ordered the appropriate 6vsomthing zeners from Farnell.

Fortunately for me, I decided to construct a quick test rig just to make
sure the new Zener and Triac did indeed go short at the required
overvoltage.

Well it didn't.


It turned out these 6vsomething zeners were nothing of the sort. I couldn't
make them breakdown with my bench supply at 30v. It was not possible to
tell from the markings what they were.

I got these replaced with proper Zeners, and then the rig tripped out at the
less than 7 volts it was supposed to do.


Had I just fitted this zener without checking it was what it said it was,
the 224 would have been vulnerable to the 5v line going hugely overvoltage
and taking out every single digital IC in the unit. (100's of them)


This is, in fact, the VERY reason I chose to try and test the TIP35C
transistors before installing them in the Power Amp.



With regards me testing these TIP's with my dodgy tester, I may well be
wrong about them being dodgy, I understand fully what Phil has been saying,
and it is entirely possible he has been correct all along. Thing is I
reacted to the way he was reacting, maybe that wasn't the smartest thing to
do, I can normally tolerate him a lot better.
I apologise for that, Phil, it shouldn't really have gone that way.

I stated from the very outset that I knew a Hfe reading from this tester on
a Power Transistor was "meaningless", but this seems to have been largely
ignored.
In fact the reason I knew of this was because of previous posts by Phil
probably a couple of years ago now on this thread.

Thing is though, all 4 replacements read OK at a healthy Hfe of 60 - 70,
where all 4 of the other batch read pretty much zero, most probably because
of a confused pinout diagnosis from the tester, or maybe because they really
are dodgy at the lower extremities of operation, where they would not be
operated anyway.

I did later construct a quick test rig on 2 of these old "dodgy" TIP35C's
which showed, at around 0.5A collector current, an Hfe of around 49, and the
correct pinout.
I suspect the other 2 will be similar, but I will not be putting any of
these into a Power Amp.
At less than Ł1 each I think Farnell can afford another 4 my dodgy old
tester doesn't have a problem with.



Cheers,


Gareth.

 

[Phil Allison]

"Gareth Magennis"

With regards me testing these TIP's with my dodgy tester, I may well be
wrong about them being dodgy, I understand fully what Phil has been
saying, and it is entirely possible he has been correct all along. Thing
is I reacted to the way he was reacting, maybe that wasn't the smartest
thing to do, I can normally tolerate him a lot better.
I apologise for that, Phil, it shouldn't really have gone that way.

** OK.

I stated from the very outset that I knew a Hfe reading from this tester
on a Power Transistor was "meaningless", but this seems to have been
largely ignored.

** As I explained repeatedly, the Peak meter uses Hfe readings to determine
C and E.

So if it *cannot read Hfe reliably* for a particular BJT - then it CANNOT
always get C and E right.

There is no magic way to determine C and E with certainty other than break
down voltage tests ( the CE junction should go at about 12V while the CB
one ought to be higher) - with only an internal 5V supply, the Peak tester
cannot do this test.

In fact the reason I knew of this was because of previous posts by Phil
probably a couple of years ago now on this thread.

Thing is though, all 4 replacements read OK at a healthy Hfe of 60 - 70,
where all 4 of the other batch read pretty much zero, most probably
because of a confused pinout diagnosis from the tester, or maybe because
they really are dodgy at the lower extremities of operation, where they
would not be operated anyway.

I did later construct a quick test rig on 2 of these old "dodgy" TIP35C's
which showed, at around 0.5A collector current, an Hfe of around 49, and
the correct pinout.

** Halleluiah.


..... Phil