A good source of replacement parts for test equipment is Sphere Research ( http://www.sphere.bc.ca/ ). They don't show any in stock, but you could email. NTE is a good source for replacement parts, but the NTE189 is really expensive ($26.73 from Newark and $30.59 from Mouser). For the cost of a couple of these you can get a whole 5328A (I have one or two on my shelf I'd sell for $50 if you are ever up in San Jose). I'd use a MJE171GOS-ND<http://search.digikey.com/us/en/products/MJE171G/MJE171GOS-ND/919498> or 497-4829-5-ND<http://search.digikey.com/us/en/products/2SB772/497-4829-5-ND/954133> from DigiKey (but as mentioned by others, watch the pinout, as most any power tab transistor will have the collector in the center, while the MPS-U51 is one of the few exceptions). You might also need to slim down the leads to fit the PC board.
Stan On Sun, Jan 22, 2012 at 12:34 PM, Don Latham <[email protected]> wrote: > NTE lists their equivalent as: NTE-189 See: > http://nte01.nteinc.com/nte/NTExRefSemiProd.nsf/$$Search > Newark has 262 of them :-) > Don > Chris Albertson > > I have an eBay HP5328A counter with two dead digits on the display. I > > figured out the problem was two dead transistors. I can swap > > transistors with a good digit and the problem moves. > > > > I'd not worked on LED displays before. Turns out only one digit is > > lit up at a time, they strobe the digits in sequence. The dead > > transistor is the one that controls the all the anodes in the > > 7-segment LED module. The service manual describes the transistor > > like this: "part number = 1853-0326", "description = TRANSISTOR PNP > > SI ... FT-50MHZ" > > The p/n 1853-0326 cross references to a Motorola MPS-U51. The MPS-U51 > > data sheet matches the part that fails so I'm sure I got a correct > > cross ref. > > I took a photo of the dead transistor. It is on .1" perf board for > > scale. You can read the "3-326" p/n and see the Motorola "M" logo. > > http://www.dropbox.com/gallery/28915695/1/HP5328A?h=da35c1 > > > > I look up the spec in the mps-u51 and see it is a to-220 like case and > > can handle 1W. I'm really surprised it burned out as I doubt an LED > > requires 1W even if showing an "8". Reading the mps-u51 spec sheet I > > see it has a low saturation voltage. Maybe that is why the selected > > it as it is being driven by 7400 TTL logic that goes through a > > connector and has some resistors involved. > > > > Question: These seem to be hardtop find. Can anyone suggest a good > > sub" > > > > > > > > Thanks, > > Chris Albertson > > Redondo Beach, California > > > > _______________________________________________ > > time-nuts mailing list -- [email protected] > > To unsubscribe, go to > > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > > and follow the instructions there. > > > > > -- > "Neither the voice of authority nor the weight of reason and argument > are as significant as experiment, for thence comes quiet to the mind." > R. Bacon > "If you don't know what it is, don't poke it." > Ghost in the Shell > > > Dr. Don Latham AJ7LL > Six Mile Systems LLP > 17850 Six Mile Road > POB 134 > Huson, MT, 59846 > VOX 406-626-4304 > www.lightningforensics.com > www.sixmilesystems.com > > > > _______________________________________________ > time-nuts mailing list -- [email protected] > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
