Help identifying a 1383 transistor - Page 1
Forum section: electronics / repair

author: sausage
author_rank: Regular Contributor
timestamp: March 16, 2022, 09:23:23 pm
content: I had a newish phone base station blow during a storm. Looking at the TO92 transistor near the RJ45 socket, it took the brunt of the impact and parts of the transistor blew off along with some of the numbering.The parts I can still read are:*R*941383Things I have done:1. Tried to duckduck 1383 but all results come back with C1383 and I am not sure if this is a similar part.2. Usedhttps://alltransistors.com/search.php?search=1383to find an alternative part for a 1384 TO92 (avoiding the C1383 entries in the list)I end up with no definitive result.Would anyone have any ideas here?

author: wraper
author_rank: Unknown
timestamp: March 16, 2022, 09:29:54 pm
content: May be some clone of MPSA94. However normally there should be a quite high voltage present to justify its use.

author: sausage
author_rank: Regular Contributor
timestamp: March 16, 2022, 10:12:37 pm
content: Thanks, wraper. A possible justification could be for lightning strikes that come up the phone line? We lose a phone or modem a year out here. Would that provide some protection at that rating?

author: fzabkar
author_rank: Super Contributor
timestamp: March 16, 2022, 11:42:30 pm
content: Trace the circuit in the vicinity. That will at least tell you if it is NPN or PNP.

author: abdulbadii
author_rank: Frequent Contributor
timestamp: March 17, 2022, 12:02:49 pm
content: might do hard works- desolder it- meter it to determine E C B- then determine polar type, npn or pnp- reverse engineer the area close to Q schema- thence might conclude the Q function/characteristic

author: PKTKS
author_rank: Super Contributor
timestamp: March 17, 2022, 02:26:50 pm
content: Quote from: wraper on March 16, 2022, 09:29:54 pmMPSA94 is vintage Motorola plastic case.. for Darlingtons and some mid power typesThe best clue is the "R" above which should be a manuf. indicator..Unfortunately there are way too much combinations for the last 2 digits..with 3 or 4 numbers... 4 would be a guess for a 2N class.and 3 if so there is the missing letter to the JIS - best shot if PNP/NPN AB/CD..( 2SAxxx or 2SCxxx )any case just the lasting 2 numbers are not enough for a wild guess...Paul

author: Haenk
author_rank: Super Contributor
timestamp: March 17, 2022, 02:31:58 pm
content: Honestly, at that position I don't think it has any critical specs to be met (other than voltage).

author: SoundTech-LG
author_rank: Frequent Contributor
timestamp: March 17, 2022, 02:52:56 pm
content: 2SC1383 was an extremely popular JIS transistor late 70s through the 90s. Note the larger case though. Not sure if they also produced some in the smaller TO-92 style cases.

author: PKTKS
author_rank: Super Contributor
timestamp: March 17, 2022, 03:03:13 pm
content: Quote from: SoundTech-LG on March 17, 2022, 02:52:56 pmThat makes sense... for such a vintage MitsubishiTHE "R" suffix for the JIS is the tolerance class...R - redO - OrangeB - Blueusually hfe and other stuff

author: BrokenYugo
author_rank: Super Contributor
timestamp: March 17, 2022, 11:53:02 pm
content: MPSA94 makes some sense, telephone dialing is is the suggested use on the first datasheet I found. Reverse engineer enough to see if a PNP with EBC pinout makes sense there.

author: sausage
author_rank: Regular Contributor
timestamp: March 17, 2022, 11:56:30 pm
content: Thanks everyone for your insight. Clearly a multimeter test is too late for this poor little transistor, but I am tracing the area on the board (a mud map) and will post up.

author: Jeff eelcr
author_rank: Frequent Contributor
timestamp: March 18, 2022, 02:24:38 am
content: The letter code following the part number on all japanise transistors is the gain group. It makes matching transistors in audio equipment easy (just by looking). An A with no space after the part number is a part revision, not a gain group which would have a space after the A most will be like Q, R, S and T. I do not remember the hfe these equeate to, it may be different for different transistors. I have never seen a 2SC1383 in a TO-92 case style.Jeff

author: Wallace Gasiewicz
author_rank: Super Contributor
timestamp: March 18, 2022, 02:40:47 pm
content: How about this:Assume it is an ECB pinout transistorTurn the unit onTest the pins with a voltmeterIf pin #1 is positive, it is a PNPIf pin #3 is pos it is an NPNProbably just a switching or low freq transistor. Put one in and see if it works.

author: DavidAlfa
author_rank: Super Contributor
timestamp: March 19, 2022, 07:21:15 am
content: Quote from: abdulbadii on March 17, 2022, 12:02:49 pmReally? How to you measure a blown transistor?

author: wraper
author_rank: Unknown
timestamp: March 19, 2022, 11:38:50 am
content: Quote from: DavidAlfa on March 19, 2022, 07:21:15 amIf its not totally destroyed (probably it is due to explosion), one of the junctions may still measure fine and you could determine if its npn or pnp.

author: DavidAlfa
author_rank: Super Contributor
timestamp: March 19, 2022, 01:43:29 pm
content: Have you seen the 1st post picture?

author: SpecialK
author_rank: Regular Contributor
timestamp: March 19, 2022, 02:16:01 pm
content: KSP94 - 400V PNP?

author: wraper
author_rank: Unknown
timestamp: March 19, 2022, 03:10:39 pm
content: Quote from: DavidAlfa on March 19, 2022, 01:43:29 pmAre you able to actually read the post?Quote from: wraper on March 19, 2022, 11:38:50 am