Transistor datasheet and x-ref

Hmmm. Doing a web search on 2SC789 (without the suffix) leads to a few possibilities, including a Japanese transistor cross-reference list. This list indicates that the 2SC789 crosses to 2SD313 and

2SD526, both of which are low-frequency epitaxial NPN power transistors in TO-220 cases. 60-80 volts, 4 amps, fT around 8 MHz.

Another hit on the 2SC789 search seems to agree - TO-220 NPN, fT minimum 3 MHz, 60 volts, 4 amps, 30 watts dissipation, Vce(sat) max of

1.3 volts at a 3-ampere collector current.

I'm not sure about the -R suffix... this might indicate an Hfe gain range/binning for the part in question? The 2SC789 entry in the catalog says that Hfe ranages from a minimum of 40 to a maximum of

240, with an annotation "Hfe groups available", so I'd guess that the

-R might be a group designation.

Is there a 2SA489 nearby in the circuit? Since that's a PNP listed as being complementary to the 2SC789, it might be part of a complementary pair with the failed transistor. If so, you might be able to measure its Hfe and deduce the required gain of the 2SC789 (or substitute).

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Dave Platt                                    AE6EO
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The R gain grouping is the lowest of the three sorted groupings originally marketed for this part by Toshiba. 40-80 at 500mA Ic.

RL

On Wed, 24 Dec 2008 09:08:42 -0500, "Jeff D" put finger to keyboard and composed:

My Towers International Transistor Selector suggests that the suffix represents an Hfe grade.

Package Vcb Vce Veb Ic(max) Tj(max) Ptot Ft(min) Manuf

----------------------------------------------------------- NS TOP66 60V 60V 5V 4A 150C 30WC 3M Toshiba

Hfe (@ bias = 500mA)

-------------------------------- 2SC789 40/240 2SC789/R 40/80 2SC789/Y 120MN 2SC789/O 70/140

Suggested equivalents are BD589 and 2N6123.

- Franc Zabkar

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Thanks, Ill try the 2N6123