Home |
Search |
Today's Posts |
|
Electronics Repair (sci.electronics.repair) Discussion of repairing electronic equipment. Topics include requests for assistance, where to obtain servicing information and parts, techniques for diagnosis and repair, and annecdotes about success, failures and problems. |
Reply |
|
LinkBack | Thread Tools | Display Modes |
#1
Posted to sci.electronics.repair
|
|||
|
|||
How do you properly check a darlington driver?
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 + 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 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. |
#2
Posted to sci.electronics.repair
|
|||
|
|||
How do you properly check a darlington driver?
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 |
#3
Posted to sci.electronics.repair
|
|||
|
|||
How do you properly check a darlington driver?
On Jul 12, 4:56 pm, Udo Piechottka
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. |
Reply |
Thread Tools | Search this Thread |
Display Modes | |
|
|
Similar Threads | ||||
Thread | Forum | |||
Repair an old board with BUT 33 power darlington transistor | Electronics Repair | |||
EKG equivalent for Motorola darlington | Electronics Repair | |||
Furnace not functioning properly | Home Repair | |||
TV tunes all channels but not properly. | Electronics Repair | |||
drill-driver vs magazine driver £200 budget | UK diy |