All:
If some of you, like me, are forever messing about with vintage/obsolete so lid-state equipment, here is a handy website to find out equivalencies for obsolete semi-conductors, that also includes my latest search. Put in what you have on top, and it spits out equivalencies below.
I am sure most of you have this tool already, or something similar, but for the one-or-two otherwise, there it is.
Peter Wieck Melrose Park, PA
solid-state equipment, here is a handy website to find out equivalencies f or obsolete semi-conductors, that also includes my latest search. Put in wh at you have on top, and it spits out equivalencies below.
TO3
or the one-or-two otherwise, there it is.
I tried searching for geraniums just to see if it worked ok, and a couple o f surprises turned up:
2N671 Veb 40v 2N675 Veb 70v T1393 Veb 40v T1656 Veb 70v NTE105 fT 0.1MHzNT
I generally seek out the actual spec sheet on what I need to replace. I hav e seen NTE, ECG and SK books to be wrong.
I consider many things when choosing a replacement. If it is a switcher the n I look at the turnoff time mainly if it runs into an inductive load. If i t is analog I look at a few other things.
It seems like some of these "resources" do noyt consider all the parameters . They for example had a replacement for an RCA 164589 diode which is a hig h speed rectifier. I told the boss "This is not going to work", he ordered me to put it in anyway and it lasted less than a minute. That was straight out of the ECG book, and NTE is a cheap knockoff on ECG. It is Nutone, ECG was Sylvania, SK is/was RCA.
The only way I'll take the word of a cross reference guide is if I got the JEDEC or JANTX numbers for the parts and can see the whole datasheet. those engineers don't waste money on a transistor when they could have used the old dime a dozen 2N3055. They get paid to save money, not to spend it.
So when you see a transistor that only has 50 volts across it and passes 2 amps, that doesn't mean that any transistor will work if it meets those spe cs.
For example, in a Zenith TV many years ago it had a funny looking picture. I found that in the IF module someone had replaced a video amp transistor w ith an RF power transistor. "WOW, this one'll do 50 MHZ, it must work !". Y eah, it worked but the picture looked like a cartoon because it was not lin ear in its gain. It was designed for use in a class C RF power output or dr iver circuit, not a linear amp.
Anyway, I trust nobody when it comes to replacements. If that thing breaks again it comes back on ME, and since the world is not really all that toler ant of my mistakes, I will do unto others.
Here's a project to test out this cross reference : change the outputs and drivers in a Marantz 1152DC. There's a test because you have to consider th e Vbe before a transistor turns on and the Vcesat of the predrivers. The bi as is not adjustable.
Who do you want picking your replacements then ?
At any time you can make a post here about a replacement and I will probabl y respond. Take advantage of that before something or someone kills me.
2N671 Veb 40v 2N675 Veb 70v T1393 Veb 40v T1656 Veb 70v "
Really ? Seventy frikken volts ? That is phenomenal.
What can I do with that ?
(probably nothing but it's nice to know)
Well, it is spring time. Who knows what might spring up whe you plant and water the geraniums.
-- Jeff Liebermann jeffl@cruzio.com 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558
te solid-state equipment, here is a handy website to find out equivalencie s for obsolete semi-conductors, that also includes my latest search. Put in what you have on top, and it spits out equivalencies below.
=TO3
t for the one-or-two otherwise, there it is.
e of surprises turned up:
hopefully the result will be a gain. At least if you overcome your resistan ce to do it. Just don't plant them in a silly cone shape.
NT
No gain. I planted the germaniums according to the instructions, with the three roots pointing downward. I then watered them but they wouldn't grow or gain biomass. I'll try another batch, hopefully with less leakage so the water doesn't leak out of the planter box.
Is "solid state" the same as "ossified" where everything looks and acts like a rock?
-- Jeff Liebermann jeffl@cruzio.com 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558
the roots act as collector & base. The emitter is the top.
geraniums are a form of wet solid state. But they also love growing in a glass belljar, occupying a vacuum where no other plant is present.
NT
The tool allows the user to put in the parameters, and then returns part nu mbers that meet those parameters. Meaning: It's a start.
I have quite a number of things that use parts, including transistors, no l onger in production, and with part-numbers that have no listed equivalents. So, I can take the data sheet from the obsolete parts, insert the paramete rs into the tool and get a list of other part numbers that meet those param eters. And, then, maybe, I, can, find, a, part, to, try.
And, maybe I then do not have to go to eBay looking for a Chinese knock-off that *might* work. Or not.
Peter Wieck Melrose Park, PA
The obvious case is some kinds of one-transistor oscillators that reverse the base bias (a class C oscillator, obviously).
It's an artifact of Ge alloy transistor construction, the emitter was a plated-on metal that (when heated) diffused in. The collector was the same thing, from the other side of the Ge slab. And the slab itself, the 'base' was the third contact. So, the B-E and B-C breakdowns weren't very different.
numbers that meet those parameters. Meaning: It's a start.
longer in production, and with part-numbers that have no listed equivalent s. So, I can take the data sheet from the obsolete parts, insert the parame ters into the tool and get a list of other part numbers that meet those par ameters. And, then, maybe, I, can, find, a, part, to, try.
ff that *might* work. Or not.
Better to feed in the values used in circuit plus a suitable margin. Many t imes I used beefier trannies than required because they were cheaper. TIPs in particular.
NT
Ya think? Yeah, I try to reduce the issue of future failures by using replacement parts that are stronger/better than OEM. Except in the case of some resistors and diodes that seem to have a fuse function.
Peter Wieck Melrose Park, PA
** I have often used TIP3055ts and TIP2955ts to replace a host of Asian TO220 types ( 2SA... 2SB...etc) found in low powered stereo amps and receivers.
The basic specs ( 70V, 15A, 90W) are well ahead of what was originally fitted and I not come across compatibility issues.
I also like the TIP35C and 36C very much as subs for larger flat paks.
.... Phil
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