Reply With QuoteI couldn't find a supplier in Australia, but you might be able to cross-reference a substitute by checking the specs. using
WES are worth trying.
Can't find transistor
I'm looking for a few transistors 2SC3623A-LK.
Can't find an Aust supplier.
According to Mr Google it's an epitaxial. Never knowingly had any relations with one of them before so unfamiliar with that variety.
Last edited by loopyloo; 06-06-18 at 12:21 PM.
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I couldn't find a supplier in Australia, but you might be able to cross-reference a substitute by checking the specs. using
WES are worth trying.
loopyloo (06-06-18)
LOL, when I was young (and a bit naughty) I often made fun with the people who brought me stuff to fix and told them that their 'NPN silicon epitaxial planar transistor' was faulty!
Many were shocked and concerned how much that would cost and then I confided that it was actually pretty much run of the mill stuff, it just sounded so cool to say that.
Epitaxial (thin overlay of silicon) is a process used to make transistors more efficient (faster switching, better heat dissipation) from the 1960s on. Even the good old 2N3055 is an epitaxial transistor (with some variations).
From the specs
you are looking for a small signal NPN darlington, pretty much general purpose.
However it has an unusually high Emitter-Base voltage though: 15V, which seems to be the special feature of the A-version.
RS-Australia seems to have the SMD version listed which you might manage to solder on the copper side: 2SC3624A
however that says back order.
What is the application? Why does it need such a high Veb?
Update: A deletion of features that work well and ain't broke but are deemed outdated in order to add things that are up to date and broken.
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loopyloo (06-06-18)
According to my substitution bookOriginally Posted by loopyloo
2SC3330, 2SC3327,2SD1424,2SC2603.
loopyloo (06-06-18)
Yeah I don't think I've seen transistors referred to as epitaxial before. A bit I read said something about them being of similar design to the first transistor invented.
The item I'm looking at was started back in this thread.
I put it away until yesterday, but decided I would get it out and have another go at fixing it after I accidentally came across a fix for it on the net.
It appears these units are known to blow those transistors, which causes it to lose output channels.
You can see them here on page 9 and 10, and also page 11.....
They don't appear as darlington on the schematic but they don't always show those details. I've got a stack of BC337's, it's a shame the specs are a bit off for using them here.
Last edited by loopyloo; 06-06-18 at 08:17 PM.
WES has the 2SC2603 but unfortunately the gain is a long way out.
Couldn't find any of the others.
Where in the circuit does it appear ?
2N5962 May suit depending where in circuit.
page 10, there's 10 of them bottom half of schematic, and also another 2 on page 11 at K-18
Damn !
Leave the A off the number and they show up on ebay. Just put 2SC3623
Found that out accidentally too...lol
Nope, I would not do that.
Look at the circuit page 10 where there are 8 of them, biased mostly with -12.2V.
It may not sound like much but the 2SC3623 can only handle -12V. Hence the use of the A-typ that could handle down to -15V in this circuit.
This is a totally pathetic design if you ask me. They are just activating a mute. Why do things simple when you can go overboard complicated. Why on the earth use -12V when you could use -5V that almost any transistor can handle? Why even negative bias an NPN transistor at all just to switch a simple audio signal? That is almost always a recipe for disaster, espcially with a high impedance darlington input.
Anyhow you are stuck with these and unless you want to keep replacing them you got to find a darlington that can handle a safety margin over 12V for Vbe, so more like 15V.
Last edited by Uncle Fester; 06-06-18 at 11:28 PM.
Update: A deletion of features that work well and ain't broke but are deemed outdated in order to add things that are up to date and broken.
Compatibility: A word soon to be deleted from our dictionaries as it is outdated.
Humans: Entities that are not only outdated but broken... AI-self-learning-update-error...terminate...terminate...
loopyloo (06-06-18)
Ok ta, I'll keep looking then.
Rang Sony today.
They said 2SC3623A is not available any more and they've been replaced with KTC2874. They want $4.50ea for them.
I'd rather get them cheaper than that..
Has anyone used this supplier ?
After looking at the circuit, they are not Darlington.
Any small signal NPN will do the job.
Beta (hfe) is not important. The collector is at 0v and is turned on by taking the base negative.
The emitter is connected to a non DC line. When the Mute is on collector 0v, base -12.2 and emitter .65V lower.
When Mute is off collector and base both 0v so no reverse bias.
Should have used FETS.
loopyloo (08-06-18)
Nope!
Look a bit closer at Q403 and Q453. Their emitter are directly connected to GND and base is -12V
On every other transistor in question there is a pointer to their emitter with a 0. If you trace their emitter connection properly you will find that they are all DC connected with a resistor to GND.
Beta may or may not be important in this circuit but a standard small signal transistor can usually only handle a Vbe of around 5V.
Update: A deletion of features that work well and ain't broke but are deemed outdated in order to add things that are up to date and broken.
Compatibility: A word soon to be deleted from our dictionaries as it is outdated.
Humans: Entities that are not only outdated but broken... AI-self-learning-update-error...terminate...terminate...
loopyloo (08-06-18)
How about this one then ? ... Looks good to me.
Ideal price too.
Last edited by loopyloo; 08-06-18 at 01:14 PM.
Yep. Would look good to me but it says back order.
Bit pricy on Ebay.
Well the German vendor might be OK for a Euro each. Probably quicker than waiting for the backorder.
LOL, I used to live in Kerpen. I drove almost every day past where Schumacher's Brother lived. Michael had already moved out.
Last edited by Uncle Fester; 08-06-18 at 07:55 PM.
Update: A deletion of features that work well and ain't broke but are deemed outdated in order to add things that are up to date and broken.
Compatibility: A word soon to be deleted from our dictionaries as it is outdated.
Humans: Entities that are not only outdated but broken... AI-self-learning-update-error...terminate...terminate...
loopyloo (08-06-18)
Looks like WES has these for $1.09ea. Plus post of course.
I might give RS a call on Monday to find out how long back order on them is. Else I'll just get them from WES.
In the mean time I've got the weekend to pull the lid off the unit and check em out.
Last edited by loopyloo; 08-06-18 at 11:53 PM.
What's the go with these connectors ?
How do I separate it ?
From memory, they swing but it's been so long since I've seen one I've forgotten.
Do I simply lift the tab to unplug it ?
Oh and what are they called ?
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