Powered by Invision Power Board


Forum Rules Forum Rules (Please read before posting)!
  Reply to this topicStart new topicStart Poll

> 123AP transistor
evildragon
Posted: April 28, 2007 04:50 pm
Reply to this postQuote Post


Forum Addict ++
*******

Group: Trusted Members
Posts: 5,566
Member No.: 6,862
Joined: October 27, 2006




What does the 123AP transistor do? I have an old RCA TV (ehh, 1995 actually), and it died within 5 years of owning it, and only recently I took it apart..

I could turn the TV on, if I dropped it from 1 foot. And the thing is, it would stay on.. Once you turned it off, it wouldn't turn on till you tried dropping it again..

I found those EXACT symptoms online, and it was a bad transistor at spot TP-15...

It says to replace with transistor 123AP (which oddly isn't the original part number on the TV)... So, what does the 123AP transistor do?


--------------------
Brandon
PM
Top
Sch3mat1c
Posted: April 28, 2007 05:24 pm
Reply to this postQuote Post


Forum Addict ++
Group Icon

Group: Moderators
Posts: 19,366
Member No.: 73
Joined: July 24, 2002




ECG123AP is an all-purpose transistor (as you might've guessed), comparable to 2N2222, 2N4401, etc., and BC something or other that I don't care about because I'm not British.

Tim


--------------------
Answering questions is a tricky subject to practice. Not due to the difficulty of formulating or locating answers, but due to the human inability of asking the right questions; a skill that, were one to possess, would put them in the "answering" category.
PMEmail PosterUsers Website
Top
tekwiz
Posted: April 28, 2007 06:24 pm
Reply to this postQuote Post


Forum Addict ++
Group Icon

Group: Moderators
Posts: 28,711
Member No.: 5,746
Joined: July 24, 2006




You can use any general purpose NPN transistor in that application, as long as the collector current rating is at least 1A. I wonder if that one had been replaced before, as ECG transistors are used as replacements, not as OEM installed. cool.gif


--------------------
Trouble rather the tiger in his lair, than the sage among his books.
For to you, kings & armies are things mighty & enduring.
To him, mere toys of the moment, to be overturned at the flick of a finger.

Fortuna favet fortibus.
PMEmail Poster
Top
evildragon
Posted: April 28, 2007 08:53 pm
Reply to this postQuote Post


Forum Addict ++
*******

Group: Trusted Members
Posts: 5,566
Member No.: 6,862
Joined: October 27, 2006




The TV never had it's original transistor replaced.. Actually only has the TV ever been taken apart..

The old transistor left a big burn spot on the TVs motherboard, where it was..

So this new transistor should work then, right?

(because it seems all the transistor does is turn the TV on, and that's it, like a starter..)

also, are the pinouts the same? (meaning, I just match the pins like the old transistor?)


--------------------
Brandon
PM
Top
MacFromOK
Posted: April 29, 2007 12:22 am
Reply to this postQuote Post


Forum Addict ++
*******

Group: Spamminator Taskforce
Posts: 13,939
Member No.: 5,314
Joined: June 04, 2006




QUOTE (evildragon)
I could turn the TV on, if I dropped it from 1 foot. And the thing is, it would stay on.. Once you turned it off, it wouldn't turn on till you tried dropping it again..

Lol, I've heard of "jump start" and "kick start"... but this is my first for a "drop start". laugh.gif

Mac


--------------------
Mac *

"Basic research is what I'm doing when I don't know what I'm doing." [Wernher Von Braun]

* is not responsible for errors, consequential damage, or... anything.
PMEmail Poster
Top
evildragon
Posted: April 29, 2007 06:38 pm
Reply to this postQuote Post


Forum Addict ++
*******

Group: Trusted Members
Posts: 5,566
Member No.: 6,862
Joined: October 27, 2006




k, i installed the 123AP, and it WORKED.. the TV turned on...

the old part was 3214, T335...

I noticed that the replacement had to be installed backwards.. i hope that's normal wacko.gif


--------------------
Brandon
PM
Top
tekwiz
Posted: April 29, 2007 06:45 pm
Reply to this postQuote Post


Forum Addict ++
Group Icon

Group: Moderators
Posts: 28,711
Member No.: 5,746
Joined: July 24, 2006




You have to compare a pinout from the old transistor to that from the new one to make sure, but physically reversing a transistor to get the right basing is not unusual. cool.gif


--------------------
Trouble rather the tiger in his lair, than the sage among his books.
For to you, kings & armies are things mighty & enduring.
To him, mere toys of the moment, to be overturned at the flick of a finger.

Fortuna favet fortibus.
PMEmail Poster
Top
evildragon
Posted: April 29, 2007 06:51 pm
Reply to this postQuote Post


Forum Addict ++
*******

Group: Trusted Members
Posts: 5,566
Member No.: 6,862
Joined: October 27, 2006




QUOTE (tekwiz @ Apr 29 2007, 01:45 PM)
You have to compare a pinout from the old transistor to that from the new one to make sure, but physically reversing a transistor to get the right basing is not unusual. cool.gif

yea, i made sure to match "E, B, C", but the physical structure looked backwards...

what would happen if i accidentally reversed the pinout?


--------------------
Brandon
PM
Top
evildragon
Posted: April 29, 2007 09:20 pm
Reply to this postQuote Post


Forum Addict ++
*******

Group: Trusted Members
Posts: 5,566
Member No.: 6,862
Joined: October 27, 2006




here's the stuff..

http://blackevilweredragon.spymac.com/old.jpg

that was the offending part..

here's a comparision of the two.. the LEFT one is the old and dead one, where the one on the right is the new and working one.. Notice how while physically in the same position, the E, B, and C are backwards..

http://blackevilweredragon.spymac.com/transistor.png


--------------------
Brandon
PM
Top
tekwiz
Posted: April 30, 2007 07:43 pm
Reply to this postQuote Post


Forum Addict ++
Group Icon

Group: Moderators
Posts: 28,711
Member No.: 5,746
Joined: July 24, 2006




If the transistor was installed with the E & C reversed, it may or may not work, or may work improperly. Most BJTs will amplify somewhat with E & C reversed, a property which has driven many a transistor tester designer nuts. If the B was wrong, the results range from nothing to a blown transistor & possible other damage to the TVs circuitry. cool.gif


--------------------
Trouble rather the tiger in his lair, than the sage among his books.
For to you, kings & armies are things mighty & enduring.
To him, mere toys of the moment, to be overturned at the flick of a finger.

Fortuna favet fortibus.
PMEmail Poster
Top
evildragon
Posted: April 30, 2007 07:44 pm
Reply to this postQuote Post


Forum Addict ++
*******

Group: Trusted Members
Posts: 5,566
Member No.: 6,862
Joined: October 27, 2006




ahh ok.. so im safe then, cause the TV works.. tongue.gif


--------------------
Brandon
PM
Top
tekwiz
Posted: May 01, 2007 06:45 pm
Reply to this postQuote Post


Forum Addict ++
Group Icon

Group: Moderators
Posts: 28,711
Member No.: 5,746
Joined: July 24, 2006




Yeah, that is a good sign. cool.gif


--------------------
Trouble rather the tiger in his lair, than the sage among his books.
For to you, kings & armies are things mighty & enduring.
To him, mere toys of the moment, to be overturned at the flick of a finger.

Fortuna favet fortibus.
PMEmail Poster
Top
0 User(s) are reading this topic (0 Guests and 0 Anonymous Users)
0 Members:

Topic Options Reply to this topicStart new topicStart Poll

 


:: support us ::




ElectronicsSkin by DutchDork & The-Force