Re: Tech: Can I Test a TIP640 ?

OK. I don't believe anybody makes TIP640's anymore.
Looking at an old Texas Instruments data sheet -- this says this transistor should be a TO-3 (metal can) package and not a TO-218.

Looking at NTE cross reference - this says the transistor should be a TO-218 package.
I have serious doubts about nearly everything that NTE says are subs.

If it's in the TO-3 package -- this is VERY similar to the often used in power supply 2N6057/2N6059.

If it's in the TO-218 package -- this is VERY similar to the not very often used but easier to find TIP142.

-- Ed




<biscuitbecks@xxxxxxxxxxxx> wrote in message news:bfb1bfd1-c7ac-4a24-a9c8-8b5230cd2f2d@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
On Apr 13, 9:13 am, Scott <eag...@xxxxxxxxxxxxxxxx> wrote:
Thanks for the replay. I tested the transistor with my DMM on diode
mode and got:

Collector to Emitter = 124
Emitter to Collector = 124
Base to Emitter = 770
Base to Collector = 680

So would this indicate that the transistor was bad because the
readings from C to E and E to C were the same? Would this cause the
voltage in this small circuit to be raised from 25vdc to 39vdc ?

Thanks for the help,
Scott

Hi Scott,

thanks for the data points. What were the units being displayed on
your meter? Like Ed says, the values should be anywhere from 0.6
volts to 1.2 volts. You see these types of numbers when you test the
Darlingtons on a System 80 driver board. A cursory glance at GPE's
website did not show a Darlington in the TO-218 package with the
capacities you would need; hopefully Ed K. can help you out.

Would it be possible for you to send me the schematic for the Volcano
sound board power supply? Curiosity is getting to me...

Regards,
Dan

.

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