flavio@... wrote:
I am sourcing the components for the Z80MC, which have brought me to a halt trying to find the pre-biased transistors Q1-Q5 used on the front panel (FJN3303R, FJN4303R) and even their equivalents (NTE2358, NTE2357).? The TO92 versions all seem to be out of production... Are there any other equivalents that could be used instead? Glad if anybody could point me in the right direction.
These "pre-biased" transistors with internal resistors have been around for decades, and there are hundreds of part numbers. When I designed them into the Z80MC, all the major distributors stocked them for a few cents each.
I buy my PC boards and parts to go on them in batches; so I still have enough of the FJN3303R and FJN4303R transistors for kits, and to supply customers who bought the bare boards from me. If that's the case, let me know. :-)
But the age of through-hole parts is coming to an end. Surface-mount parts are everywhere; but through-hole versions of the same parts are disappearing. Digikey and Mouser sold their remaining inventories to Rochester Electronics. Rochester is a good outfit; but they have a $250 minimum order. For a 3-cent part, that means buying >10,000!
I added the NTE equivalents to my manual. NTE has long been a supplier of replacement parts for service and repair. They buy a standard part, add their own part#, and jack up the price. They maintain inventory, which costs money. So if you only need one, and don't care what it costs, they've got it!
It doesn't help that manufacturers don't use generic 2Nxxx or 2SBxxx numbers any more; they hide them with their own "house" numbers, so you can't easily cross-reference them to other parts. When searching, use the term "pre-biased transistors" to find them. There are *lots* of equivalents (especially surface-mount); but they've made them hard to find.
Octopart.com is a free search engine for electronic components. They'll show who has (or says they have) stock on parts such as these. At the moment, they list:
NTE2357 NPN $1.20 each
NTE2358 PNP $0.78 each
--
A designer knows he has achieved perfection not when there is
nothing left to add, but when there is nothing left to take away.
-- Antoine de Saint Exupery
--
Lee Hart, 814 8th Ave N, Sartell MN 56377, www.sunrise-ev.com
--
This email has been checked for viruses by Avast antivirus software.
Lee Hart