Need help replacing some transistors on hafler dh220

[z-adamson]

One such transistor is 2n5550.

Readily available from mouser and I can get the data sheet to determine pinout.

Now, how do I confirm that the old 2n5550 transistors on the hafler board will be of the same pinout as the new ones I get?

Same for other transistors on the hafler dh220.....how do I confirm the pinouts?

 

[Blue Shadow]

transistor tester.

Did you find a datasheet that shows a different pinout?

I just pulled the old ones and put the new ones in using the same orientation.

 

[z-adamson]

transistor tester.

Did you find a datasheet that shows a different pinout?

I just pulled the old ones and put the new ones in using the same orientation.

Different pinout than what?

I see the old ones. I see the new ones. I am certain as to the pinout of the new ones. I am not certain as to the pinout of the old ones.

I would like to be certain. Last time I assumed that they were the same, I got bit.

 

[Blue Shadow]

Well good luck.

What bit you? There are some that have different versions and are known. I don't know that the 5550 has more than one version.

To be sure get a transistor tester.

 

[avionic]

http://audiokarma.org/forums/index.php?threads/testing-transistors.201303/#post-2369368

Test the new one and compare it to the old one. Using my guide.

 

[z-adamson]

I just pulled the old ones and put the new ones in using the same orientation.

Double checking...

You looked at the part list in the service manual, ordered on mouser/digikey by part number on the part list, looked at the part location in the manual and replaced one by one using the old transistors as a guide as to how to install the new ones. You pointed the rounded side of the body in the same direction then routed the leads in the same fashion.

Am I understanding you correctly?

 

[Blue Shadow]

yup. both the 5550 and 5401s. Both amps are working fine.

There is one transistor that is slightly different in shape the 2SC458 that has the outhouse box with the slanted face and the typical half-round as two styles. The pinout on these two is identical, but the front of the outhouse one is NOT what most folks think is the front and this leads folks to thinking the pinout is different and without looking at BOTH datasheets, these can easily be installed backwards.

I don't know a lot of transistors but if two are made in the same form they should have the same pinout.

Of course, you can do as Avionic says and test them or get a transistor tester, even the POS free HF meter which has a transistor hFe meter will let you know as it doesn't give a reading when the transistor is installed wrong in my very limited experience.

 

[2N697]

Maybe someone here has data on the old one that can help you verify? In my experience, there is a chance with some case styles that the pinout could vary. The ones I have seen, it was most common to find the C and E reversed, with the B in the middle.

 

[z-adamson]

Never used a transistor tester before.

If I hook up a transistor to a transistor tester will the tester tell me which lead is which?

 

[Blue Shadow]

Some do, others (the cheap chinese units) will tell you that the device is two diodes and show them and you will quickly near whether it is a PNP or NPN transistor and then learn how to label the pins Emitter, Base and Collector.

 

[avionic]

http://audiokarma.org/forums/index.php?threads/testing-transistors.201303/#post-2369368

Test the new one and compare it to the old one. Using my guide.

What ?.. You don't own a multimeter ? If the old part tests identical to the new part. By golly the pin out must be the same ....

 

[z-adamson]

What ?.. You don't own a multimeter ? If the old part tests identical to the new part. By golly the pin out must be the same ....

I do own a multimeter, but not a dedicated transistor tester.

 

[z-adamson]

http://audiokarma.org/forums/index.php?threads/testing-transistors.201303/#post-2369368

Test the new one and compare it to the old one. Using my guide.

Just to make sure we are on the same page.....

I read through the test procedure. Step one says...

"Photo 1
Transistor lead identification - If this is unknown you will need to find a spec sheet on the transistor under test.Sometimes it is provided on the schematics " legend" or even silkscreened on the printed circuit board."

Before one can do anything, the leads need to be identified.

What I am trying to do here is identify the leads of old transistors to make sure that I properly place the leads of the new transistors without a data sheet for the old transistors or any other means of identification.

That said, is your testing with a dmm a good way to identify the leads?

 

[avionic]

What I am trying to do here is identify the leads of old transistors

You stated you knew what the pin out was on the new part. Correct ? Assume its the same on the old part and test the old part. and compare. If the pin out is indeed different it won't check out the same as the new part.

 

[avionic]

I think you will find out that a 2N5550 is the same now as then.

 

[avionic]

One of these makes it real easy.. Hook up the three test leads to each transistor lead. Push the button. And it tells you what lead is connected to the red lead,blue lead and green lead. It then tells you if its a PNP or NPN, Silicon or Germanium, good or bad. piece of cake..

It also tells you Hfe . Will test all diodes including light emitting LED's and FET's
About the only thing it can identify on a FET is if its an N-channel or P-channel.

 

[Blue Shadow]

That said, is your testing with a dmm a good way to identify the leads?

Absolutely, but you must know something about a transistor. there will be two diodes that will only conduct a certain way and this with a knowledge of transistors such as EW's how to test a BJT will clue you up to which lead is a c v. b v. e. But this takes a couple minutes to wrap your head around and a diode function on the meter. Some can use the resistance measurement to do this test. I'm not one of them and if I was asked to determine what leads were the Base, Emitter and Collector of a transistor, I would want the diagram from EWs thread in front of me and a pencil.

 

[Blue Shadow]

http://www.audiokarma.org/forums/index.php?threads/bipolar-junction-transistor-testing-basics.43186/

But Avionic will answer some questions, EW hasn't been here in a while. Probably too busy.

 

[restorer-john]

Either buy the Peak Atlas tester (best of the little ones)

or

a cheap one like this: https://www.ebay.com.au/itm/LCR-T4-...l1313.TR12.TRC2.A0.H0.Xtranssitor+tester.TRS0

There shouldn't be a second of your time being wasted on pinouts these days with devices like these.

Before auto pinout devices, much time was spent cross-checking manufacturer-device, case and pin-out tables in transistor cross reference books. I still refer to my stack of original Japanese books with obscure devices. Think yourself lucky you can get a device for $10 or so that takes all the guesswork out.

 

[z-adamson]

Either buy the Peak Atlas tester (best of the little ones)

or

a cheap one like this: https://www.ebay.com.au/itm/LCR-T4-Transistor-Tester-Diode-Triode-Capacitance-Meter-Module-with-Acrylic-case/262662218785?hash=item3d27e36421:gykAAOSwOyJX92Os&_sacat=0&_nkw=transsitor+tester&_from=R40&rt=nc&_trksid=p2380057.m570.l1313.TR12.TRC2.A0.H0.Xtranssitor+tester.TRS0

There shouldn't be a second of your time being wasted on pinouts these days with devices like these.

Before auto pinout devices, much time was spent cross-checking manufacturer-device, case and pin-out tables in transistor cross reference books. I still refer to my stack of original Japanese books with obscure devices. Think yourself lucky you can get a device for $10 or so that takes all the guesswork out.

To be clear.....if you have no idea which pin is E, C or B on a transistor and you have one of these test tools at your disposal, you can hook up the leads of the tool to leads of the transistor in any which way, and any which order and the tool will identify the leads of the transistor. It will tell you which is E, which is C and which is B. Do I have this right?