Paul, Can you track down what is feeding the display its power? There may be something kaflooey in the PS. No doubt another cap, but check the PS out or something between the PS and the display.
~Carl On Sat, Dec 18, 2021 at 3:02 PM The MacDougals via TriEmbed < [email protected]> wrote: > I replaced the transistor with an exact match from ebay and a couple of > electrolytic caps (at Carl’s suggestion). > > The display is still dim. Oh well. > > > > ---> Paul > > > > > > *From:* TriEmbed <[email protected]> *On Behalf Of *The > MacDougals via TriEmbed > *Sent:* Friday, November 26, 2021 9:11 PM > *To:* [email protected] > *Subject:* [TriEmbed] Substitute transistor > > > > My microwave display suddenly went very dim. I opened it up and found a > discolored > > spot on a circuit board feeding the display (see attached image). That > component is > > marked B1238, so I assume it is a 2SB1238, which is obsolete. > > > > > https://www.digikey.com/en/products/base-product/rohm-semiconductor/846/2SB1238/30307 > > Medium power transistor( 80V, 0.7A) 2SB1189 / 2SB1238 Features 1) High > breakdown voltage, BVCEO= 80V, and high current, IC= 0.7A. > > 2) Complements the 2SD1767 / 2SD1859. Absolute maximum ratings (Ta=25C) > Parameter Symbol Limits Collector-base voltage VCBO −80 Collector-emitter > voltage VCEO −80 Emitter-base voltage VEB O −5 Collector current IC −0.7 C. > > > > Anyone want to help me find a replacement? > > I dug through my Dad’s stash of old electronics and found a TIP30B, which > looks like it might work. > > > > > > ---> Paul > > > _______________________________________________ > Triangle, NC Embedded Computing mailing list > > To post message: [email protected] > List info: http://mail.triembed.org/mailman/listinfo/triembed_triembed.org > TriEmbed web site: https://TriEmbed.org > To unsubscribe, click link and send a blank message: mailto: > [email protected]?subject=unsubscribe > Searchable email archive available at > https://www.mail-archive.com/[email protected]/ > > -- -------------------------------------------------------------- Carl J. Nobile (Software Engineer/API Design) [email protected] --------------------------------------------------------------
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