Re: How do you properly check a darlington driver?
- From: Golf <stokesb@xxxxxxx>
- Date: Thu, 12 Jul 2007 17:55:16 -0700
On Jul 12, 4:56 pm, Udo Piechottka <ifmd.messdatensyst...@xxxxxxxxxxx>
wrote:
Golf schrieb:
This component crosses to an NTE 2547, which says it's an NPN and PNP
complementary transistor darlington driver. This component is in the B
The NTE 2547 is an NPN darlington transistor, the complementary one
would be the NET 2548 PNP darlington...
+ section of this TV set. I have 160V on collector, 120V on base and
emitter. There is an external didoe between base and emitter. The
emitter is connected to the flyback/collector of the HOT. I'm only
You're sure it is connected in this manner? In must HO stages you'll
find pulses with about 1,2kV peak voltage on the collector against Gnd.
May be the NTE switches the B+ in respect of standby/on.
getting 120V on collector of the HOT with B+ adjusted all the way up.
I can adjust the B+ and vary the darlington collector voltage OK. I
have a 40V voltage drop between the collector and emitter/base. This
is why I suspect the darlington is bad. I"m just not sure how to
confirm this. Anyone have some insight on how to determine if this
component is working properly? Thanks once again group.
It isn't clear what function this transistor has in this circuitry...
You have schematics?
- Udo
Not yet. I am trying to repair without the added cost of this. Yes, it
is connected like this, almost. I left out a few low ohm resistors, a
diode and the flyback between the emitter and the Hot collector. I'm
not sure of this transistors function either, but the Hot collector
voltage is supplied from this transistor from what I have seen and
tested so far. I'm not sure how this transistor is supposed to be
biased for least amount of resistance between the emitter and
collector. One thing I should mention - the voltages I have taken are
with this power board out of the set. I didn't think this would change
the voltage readings I am getting at the Hot collector. I am going to
remove the transistor from the circuit and test it's function. Until
then maybe someone knows how this thing functions. Thanks.
.
- References:
- How do you properly check a darlington driver?
- From: Golf
- Re: How do you properly check a darlington driver?
- From: Udo Piechottka
- How do you properly check a darlington driver?
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