What is this transistor?

[steve_rb]

I have this transistor in Motor speed control board of Beckman J21c centrifuge but couldn'
t find its datasheet. Also no trace of it. Anyone can recommend a replacement?

 

[Mattylad]

Where did you search? (or did you?)

A quick google for "RCA 40250" shows many hits.

I.E.
https://electrontubestore.com/index.php?main_page=product_info&products_id=2469
or
https://www.radiomuseum.org/tubes/tube_40250~2.html

40250 Transistor Datasheet. Parameters and Characteristics.

Type Designator: 40250

Material of transistor: Si

Polarity: NPN

Maximum collector power dissipation (Pc), W: 29

Maximum collector-base voltage |Ucb|, V: 50

Maximum collector-emitter voltage |Uce|, V: 50

Maximum emitter-base voltage |Ueb|, V: 5

Maximum collector current |Ic max|, A: 4

Maximum junction temperature (Tj), °C: 200

Transition frequency (ft), MHz:

Collector capacitance (Cc), pF:

Forward current transfer ratio (hFE), min: 25

Noise Figure, dB: -

Package of 40250 transistor: TO66

And if you enter into Google "rca 40250 equivalent" then you get results that WILL lead you to equivalents.
I.E. https://alltransistors.com/crsearch...50&ueb=5&ic=4&tj=200&ft=&cc=&hfe=25&caps=TO66 (This was the first hit)

Check out:

1.	2N4232 	 	 Si 	 	 NPN 	 	 35 	 	 70 	 	 60 	 	 5 	 	 5 	 	 200 	 	 25 	 	 TO66
2.	2N4233 	 	 Si 	 	 NPN 	 	 35 	 	 90 	 	 80 	 	 5 	 	 5 	 	 200 	 	 25 	 	 TO66
3.	2N4233A 	 	 Si 	 	 NPN 	 	 75 	 	 80 	 	 80 	 	 5 	 	 5 	 	 200 	 	 25 	 	 TO66
4.	2N4301 	 	 Si 	 	 NPN 	 	 50 	 	 100 	 	 80 	 	 8 	 	 10 	 	 200 	 	 30 	 	 TO66
5.	2N5427 	 	 Si 	 	 NPN 	 	 40 	 	 80 	 	 80 	 	 6 	 	 7 	 	 200 	 	 30 	 	 TO66
6.	2N5428 	 	 Si 	 	 NPN 	 	 40 	 	 80 	 	 80 	 	 6 	 	 7 	 	 200 	 	 60 	 	 TO66
7.	2N5429 	 	 Si 	 	 NPN 	 	 40 	 	 100 	 	 100 	 	 6 	 	 7 	 	 200 	 	 30 	 	 TO66
8.	2N5430 	 	 Si 	 	 NPN 	 	 40 	 	 100 	 	 100 	 	 6 	 	 7 	 	 200 	 	 60 	 	 TO66
9.	2N6233 	 	 Si 	 	 NPN 	 	 50 	 	 250 	 	 225 	 	 6 	 	 5 	 	 200 	 	 25 	 	 TO66
10.	2N6234 	 	 Si 	 	 NPN 	 	 50 	 	 300 	 	 275 	 	 6 	 	 5 	 	 200 	 	 25 	 	 TO66
11.	2N6235 	 	 Si 	 	 NPN 	 	 50 	 	 350 	 	 325 	 	 6 	 	 5 	 	 200 	 	 25 	 	 TO66
12.	2N6235R 	 	 Si 	 	 NPN 	 	 50 	 	 300 	 	 275 	 	 6 	 	 5 	 	 200 	 	 25 	 	 TO66
13.	2N6261 	 	 Si 	 	 NPN 	 	 50 	 	 90 	 	 80 	 	 7 	 	 4 	 	 200 	 	 25 	 	 TO66
14.	2N6294 	 	 Si 	 	 NPN 	 	 50 	 	 60 	 	 60 	 	 5 	 	 8 	 	 200 	 	 750 	 	 TO66
15.	2N6295 	 	 Si 	 	 NPN 	 	 50 	 	 80 	 	 80 	 	 5 	 	 8 	 	 200 	 	 750 	 	 TO66
16.	2N6300 	 	 Si 	 	 NPN 	 	 75 	 	 60 	 	 60 	 	 5 	 	 8 	 	 200 	 	 750 	 	 TO66
17.	2N6301 	 	 Si 	 	 NPN 	 	 75 	 	 80 	 	 80 	 	 5 	 	 8 	 	 200 	 	 750 	 	 TO66
18.	2N6534 	 	 Si 	 	 NPN 	 	 36 	 	 80 	 	 80 	 	 5 	 	 15 	 	 200 	 	 1000 	 	 TO66
19.	2N6535 	 	 Si 	 	 NPN 	 	 36 	 	 100 	 	 100 	 	 5 	 	 15 	 	 200 	 	 500 	 	 TO66
20.	2N6536 	 	 Si 	 	 NPN 	 	 36 	 	 100 	 	 100 	 	 5 	 	 15 	 	 200 	 	 1000 	 	 TO66
21.	2N6537 	 	 Si 	 	 NPN 	 	 36 	 	 120 	 	 120 	 	 5 	 	 15 	 	 200 	 	 1000 	 	 TO66
22.	2S043 	 	 Si 	 	 NPN 	 	 35 	 	 100 	 	 80 	 	 8 	 	 5 	 	 200 	 	 30 	 	 TO66
23.	2S044 	 	 Si 	 	 NPN 	 	 35 	 	 100 	 	 80 	 	 8 	 	 5 	 	 200 	 	 60 	 	 TO66
24.	2S045 	 	 Si 	 	 NPN 	 	 35 	 	 150 	 	 120 	 	 8 	 	 5 	 	 200 	 	 30 	 	 TO66
25.	2S046 	 	 Si 	 	 NPN 	 	 35 	 	 150 	 	 120 	 	 8 	 	 5 	 	 200 	 	 60 	 	 TO66
26.	40250 	 	 Si 	 	 NPN 	 	 29 	 	 50 	 	 50 	 	 5 	 	 4 	 	 200 	 	 25 	 	 TO66
27.	BDY71 	 	 Si 	 	 NPN 	 	 29 	 	 90 	 	 55 	 	 0 	 	 4 	 	 200 	 	 80 	 	 TO66
28.	BUR10 	 	 Si 	 	 NPN 	 	 30 	 	 100 	 	 80 	 	 8 	 	 5 	 	 200 	 	 40 	 	 TO66
29.	BUT30 	 	 Si 	 	 NPN 	 	 250 	 	 200 	 	 125 	 	 0 	 	 100 	 	 200 	 	 25 	 	 TO66
30.	BUT32 	 	 Si 	 	 NPN 	 	 250 	 	 400 	 	 300 	 	 0 	 	 80 	 	 200 	 	 25 	 	 TO66
31.	BUX77 	 	 Si 	 	 NPN 	 	 40 	 	 100 	 	 80 	 	 6 	 	 5 	 	 200 	 	 50 	 	 TO66
32.	BUX77A 	 	 Si 	 	 NPN 	 	 40 	 	 100 	 	 80 	 	 6 	 	 8 	 	 200 	 	 30 	 	 TO66
33.	NTE274 	 	 Si 	 	 NPN 	 	 50 	 	 80 	 	 80 	 	 5 	 	 4 	 	  	 	 3000 	 	 TO66
34.	RCA1C05 	 	 Si 	 	 NPN 	 	 40 	 	 140 	 	 120 	 	 5 	 	 4 	 	 200 	 	 40 	 	 TO66
35.	SK3026 	 	 Si 	 	 NPN 	 	 29 	 	 90 	 	 60 	 	 7 	 	 4 	 	 200 	 	 70 	 	 TO66
36.	SK3538 	 	 Si 	 	 NPN 	 	 40 	 	 160 	 	 140 	 	 7 	 	 4 	 	 200 	 	 30 	 	 TO66