How Can I check Horizontal output transistor with lcr-t4 meter? - Page 1
Forum section: electronics / beginners

author: bshi02
author_rank: Regular Contributor
timestamp: April 30, 2024, 02:04:30 am
content: I checked Horizontal output transistor with LCR-t4 meter which has been desoldered from pcb of CRT TV and It was written "C6090" on its surface.But Whenever I checked this HOT with lcr-t4 meter, it always displayed capacitor result instead of NPN transistor.I also checked spare AOD412 MOSFET with LCR-t4 meter and It displayed correct result.Is it impossible to check HOT(C6090) with LCR-t4 meter?And I followed below guide which shows how to test Horizontal transistor with analouge meter.I found that when I placed red probe to # pin2(collector) and placed black probe to pin3(emitter), Indicating needle won't move at all in x10 ohm mode.Is this HOT IC(C6090) defective and Should I purchase it in order to fix symptom of staying in Standby Non-Operaiton?

author: xvr
author_rank: Frequent Contributor
timestamp: April 30, 2024, 05:52:58 pm
content: Try pins 1 & 3 - it should be detected as diode with ~1.5V drop.

author: wasedadoc
author_rank: Super Contributor
timestamp: April 30, 2024, 07:28:06 pm
content: It's dead.

author: bshi02
author_rank: Regular Contributor
timestamp: May 01, 2024, 12:54:35 am
content: Quote from: xvr on April 30, 2024, 05:52:58 pmI set DMM to diode mode and I placed red probe on #1 pin(base) and placed black probe on #3 pin(emitter)and placed red and black probe vice versa.It get each reading of 0.523V and .0L VIs it means that this HOT(C6090) IC has been dead?

author: xvr
author_rank: Frequent Contributor
timestamp: May 01, 2024, 08:01:54 am
content: No. Base junction is alive.

author: bshi02
author_rank: Regular Contributor
timestamp: May 01, 2024, 08:24:03 am
content: But I checked #pin2,3(collector,emitter) of this HOT IC(C6090) with diode mode.I placed black probe of DMM to #pin2 (collector) of this HOT IC(C6090) and placed red probe of DMM to #pin3(emitter)and I also placed black and red probe vice versa.BUT,It displayed 0L. (V) in all of diode voltage test between #pin2 and #pin 3(collector,emitter)Is this result means HOT IC(C6090) defective?

author: xvr
author_rank: Frequent Contributor
timestamp: May 01, 2024, 08:28:43 am
content: CE should not behave as diode. So it mean nothing. In theory it should be detected as transistor by your tester, but it is a high voltage transistor so detection could fail, I can't say for sure.

author: bshi02
author_rank: Regular Contributor
timestamp: May 01, 2024, 09:55:08 am
content: I read A ebook of CRT TV Repair ,It said that "when testing H.O.T, Most have in built internal diode between collector and emitter. Therefore if you measure between these legs you will get high and low."So I think that It should get reading of some voltage and 0 voltage when I measure voltage between collector and emitter of H.O.T on diode mode.I quote below guide from ebook of CRT TV Repair-----------------------------------Little tip on how to test transistorTesing NPN transistortesting between base and collector expect high and low on your meter on diode test.testing between the base and emitter expect again high and low on your meter on diode test.Testing collector and emitter expect high both ways.Testing NPN transistor again use the same principle.Use this rule when measuring the switching transistor(S.O.T) but when testing H.O.T please note that Most have in built internal diode between collector and emitter. Therefore if you measure between these legs you will get high and low.----------------------------------

author: vk6zgo
author_rank: Super Contributor
timestamp: May 01, 2024, 11:43:59 am
content: Test between C & E with the DMM in "diode" position. using the red DMM lead for C, & the black one for E on an NPN transistor.Reverse the connections for a PNP transistor.Initially, it will be an infinity reading, or something else weird, indicating a very high resistance.Spit on your finger & use it to connect B & C.If the transistor is functional it should turn on, giving you a reading.If it has very little effect, don't give up, as power O/P transistors don't always have a lot of gain, & a "spitty" finger might be too high in resistance to bias the transistor, on so use a 4700resistor instead of the finger.If you use an analog multimeter, note that most of them have reversed polarity on the Ohms ranges, compared to a DMM.Your transistor is almost certainly a 2SC 6090 , which definitely is an NPN transistor, used in the horizontal output stages of analog TVs.

author: vk6zgo
author_rank: Super Contributor
timestamp: May 01, 2024, 11:46:52 am
content: Quote from: bshi02 on May 01, 2024, 09:55:08 am"e-books" often lead folk astray--- change "most" for "sometimes" & you will be closer to it!

author: wasedadoc
author_rank: Super Contributor
timestamp: May 01, 2024, 12:19:46 pm
content: 1. Datasheet for 2SC6090 has no mention of any collector-emitter diode.2. Is the diode range on your meter able to light a red LED? If yes, see if the transistor's base-emitter appears to be a diode and if the base-collector appears to be a diode. Unless both appear to be diodes the transistor is dead.

author: bshi02
author_rank: Regular Contributor
timestamp: May 01, 2024, 12:37:43 pm
content: Quote from: vk6zgo on May 01, 2024, 11:43:59 amI followed your instructions(set DMM to "diode" position. using the red DMM lead for C, & the black one for E. then put some water on one of my finger ,and placed it to pin of Base & Collector.)And I found that It displayed 3.290-3.250V in DMM.But I stumbled onto below youtube video which demonstrated How to check transistor horizontal c6090 with analogue meter.It seem that He use YX-360TRD analogue meter for checking c6090 and set it to x10 ohm.And I clearly saw that Around 1:25, this YX-360TRD meter displayed low ohm when He placed red probe to #2 pin of collector and placed black probe to #3 pin of emitter which is not able to do with c6090 IC currently I have.

author: xvr
author_rank: Frequent Contributor
timestamp: May 01, 2024, 01:04:02 pm
content: Analog meter and DMM are quite different things when it comes to meter resistance of sonethig, that much more nonlinear than plain resistor. And transistor (especially high voltage) definitely not a simple resistor. So experience with analog meter could be not relevant to DMM one

author: coromonadalix
author_rank: Super Contributor
timestamp: May 01, 2024, 01:25:20 pm
content: same tought herepart testers can be good, but when you deal with high voltage part(s) the junction voltages can play trickshigh voltage diode tooanalogue meter even if they measure voltages don't have the same working principle than new dmm, their impedance too are not the samethat's why some people doe dielectric tests with analogue meter instead of digital ones ...for theses high voltage transistors i search the datasheet (for the emitter collector diode who play tricks) i use diode tests and ohms tests

author: madires
author_rank: Super Contributor
timestamp: May 01, 2024, 01:36:08 pm
content: Quote from: bshi02 on April 30, 2024, 02:04:30 amThe T4 Transistortester clone should be able to check that BJT. If it has a genuine ATmega you can flash a current OSHW frimware (k or m) to improve component detection and to also get more features.BTW, detection of a BU508 (similar HOT) works fine.

author: vk6zgo
author_rank: Super Contributor
timestamp: May 02, 2024, 02:05:44 am
content: Quote from: xvr on May 01, 2024, 01:04:02 pmAnalog meters typically use higher test voltages on the resistance ranges than DMMs & are capable of turning transistor junctions on.In normal probing of circuitry, this is a disadvantage, so the DMMs are designed to not turn them on, by using a lower test voltages.This necessitates a special "diode test" setting on the DMM (sometimes combined with the "continuity" function, as with my Fluke 77.The "spitty finger" trick always works, except as previously noted, when the device is a bit lacking in gain, as can happen with power devices.In that instance, a more formal biasing resistor does the trick.

author: vk6zgo
author_rank: Super Contributor
timestamp: May 02, 2024, 02:54:46 am
content: Quote from: bshi02 on May 01, 2024, 12:37:43 pmWhat did it read, without the finger between base & collector?It should be close to an open circuitAs a double check, just go back & check between base & collector, then base & emitteron the Ohms range--- it should be close to an open circuit in each case.Now, using thediode mode, check between the same points (with the red DMM lead on the base) ---you should see a turned on junction in each case.As to the video, unfortunately I don't understand Indonesian, so his commentary is lost on me, & I think I would find it essential to follow the action, as he moves a bit too fast for me.

author: bshi02
author_rank: Regular Contributor
timestamp: May 02, 2024, 02:01:02 pm
content: I checked #pin2,3(collector,emitter) of this HOT IC(C6090) without the finger between #pin1(base) & #pin2(collector) in diode modeI placed black probe of DMM to #pin2 (collector) of this HOT IC(C6090) and placed red probe of DMM to #pin3(emitter)and I also placed black and red probe vice versa.It displayed 0L. (V) in all of diode voltage testI checked between #pin1(base) & #pin2(collector), with DMM on the Ohms rangeIt displayed 1.03M ohm and 66.5M ohmand I checked between #pin1(base) & #pin3(emitter), with DMM on the Ohms rangeIt displayed 1.04M ohm and 68.5M ohmI check between the same points on diode modeWhen I placed the red DMM lead on the #pin1(base) and placed black DMM lead on #pin2(collector),It displayed 0.491VWhen I placed the red DMM lead on the #pin1(base) and placed black DMM lead on #pin3(emitter),It displayed 0.522VAlthough,I also unable to understand Indonesian,BUt It is possible to auto-translate indonesian subtitle to english subtitle in youtube setting menu.I also followed this youtube video tutorial and I found that when I mesaure resistance between #pin2 and #pin3 with analogue meter on x10 ohm range, Indicating needle won't move at all in x10 ohm range.But in this youtube video analogue meter displayed low ohm when He placed red probe to #2 pin (collector) and placed black probe to #3 pin(emitter) around 1:25.