DEC 10A transistor

[Roland Huisman]

Hello,

Does anyone know the original number for the DEC 10A transistor?

Thanks!
Roland

 

[vrs42]

That's a hard one. AFAIK, the G226 is the only thing that uses it (though it seems something else must). The schematic doesn't list an EIA equivalent. The "Spare Parts List Volume II" lists the DEC 10A:
15-09650 DEC10A TIS#C1048 $2.00
So, what's a TI "C1048"?

Vince

 

[vrs42]

NTE claims the NTE128 is a cross for the 15-09650, so maybe it's nothing special?

 

[Roland Huisman]

Hi Vince,

It is a G226 indeed. One of the transistors is broken off and missing.
I checked the NTE128 and that looks like a reasonable replacement to me.
I will order one and see what it does.

Thanks a lot!

Regards, Roland

 

[Hugo Holden]

If you could post the schematic and make some remarks about the circuit application, I probably could suggest a replacement transistor in the same package that would work.

 

[daver2]

Hugo,

Here: http://svn.so-much-stuff.com/svn/trunk/Eagle/projects/DEC/Gxxx/G226/G226D.pdf

You have a Commodore PET now - are we going to get you interested in a PDP-8 next I wonder ?

Dave

 

[saipan59]

That's a hard one. AFAIK, the G226 is the only thing that uses it (though it seems something else must). The schematic doesn't list an EIA equivalent. The "Spare Parts List Volume II" lists the DEC 10A:
15-09650 DEC10A TIS#C1048 $2.00
So, what's a TI "C1048"?

Vince

One possibility is that "C1048" refers to 2SC1048 (Japanese transistor). The Japanese part markings often omit the "2S" part.

Pete

 

[Roland Huisman]

Hi Pete,

Yes, I checked that too. But I found the Ic from max 0.05A too little to be able to write in core.
Funny enough the 2SC1048 does have the right case. But I don't think is it a 2SC1048.
On the other hand, DEC used many factory selected parts and used then outside the standard specs.
And I have also seen the DEC3009 TO92 transistor in CBE and EBC. So also a standard transistor
with just a DEC number on it. This was very confusing to say the least... Until you realise it off course.

 

[Steve Toner]

You mentioned writing in core...

Just a guess, but how about 2N5189?

"the 2N5189 is a silicon NPN transistor preferred for use as core driver and line driver in data processing equipment and other critical applications"

 

[m_thompson]

I looked in the RICM's DEC field service kit, and found the same part number for the transistor.

 

[vrs42]

I looked in the RICM's DEC field service kit, and found the same part number for the transistor.

Yours are so new, they have date codes instead of batch numbers!

Vince

 

[Roland Huisman]

@ Steve
I think you are right, that one should be suitable as well

@ m_thompson
Wow, brand new These are in a DEC field service kit?
Never new DEC replaced transistors at the customers shop/factory.

 

[m_thompson]

Wow, brand new These are in a DEC field service kit?
Never new DEC replaced transistors at the customers shop/factory.

Yes, a kind donor gave the RICM a DEC field service kit. Since the "new" parts are all 50 years old they are all suspect.

 

[MattisLind]

I also have a DEC field repair kit with DEC 10A. But those are TO-18!

 

[Hugo Holden]

Hugo,

Here: http://svn.so-much-stuff.com/svn/trunk/Eagle/projects/DEC/Gxxx/G226/G226D.pdf

You have a Commodore PET now - are we going to get you interested in a PDP-8 next I wonder ?

Dave

Hmm, maybe I will.

It would be good to check the transistor's max collector current and voltage in the actually circuit, just to be sure a selected replacement is run inside those specs.

The 2N5189 is a good suggestion, probably much higher power rating than required it is a 60V rated 5W part, very similar to the more common 2N3053.

The pin out would need to be checked. But likely the it will be the same.

The original transistor will have a much lower max collector current and lower power ratings than either the 2N5189 or the 2N3053, because one of the photos shows of some in the parts box shows it has a brown resin base, these have a higher thermal resistance than the metal base types.

It pays to get original vintage ones if you can, less likely to be fakes, especially if you can find ones with old date codes and gold plated legs are often a sign they are not fakes.

https://www.ebay.com/itm/181633719286?epid=1723870569&_trkparms=ispr=1&hash=item2a4a369bf6:g:x20AAOxyZwpSUf10&amdata=enc:AQAGAAACkPYe5NmHp%2B2JMhMi7yxGiTJkPrKr5t53CooMSQt2orsS7UXID%2BRPOSNsnm8kYPghtK9WL47VQ1qakZDsFCZitfDHnsLOeHsyX%2BFwB%2BMohmhJ9s1bfCLNWlNGX%2BytrJKKsmb%2F9Pk4Q9PD5RQPj%2BmF40nJ%2BjcfxH1o3R3uVB9XWtJvVKNK3166Q1M11mzUqzT%2FQD2hVHTdsILgK3ZLGfvvbuvoTn5Qm%2FC8eB2gjXaBHi6KLFmtrYZRM1IS4tY8ArjlPo%2BlK%2BBqax2Jy%2FnuIw6DmPxg8fewXGIBEuvr7DjQ7zG6QfUSdd1N0MSz5QGidoD9l%2Fw5o%2FbrYH4nYJ5j4ZSJX9L%2F4biIA53YPohLUcs%2F4Rd7z%2FhpmehEcvdgS8HdauAxUE1OY7D4vjyMgqENb4H369eBO5i3DsmZQAoanRRcihFVovFJOguQDhufr4A0DgJFeqLv%2FIjDMW8Aw9SKO1TtbKT95BPL3UcV9%2FPp1u6GC6d0dLWC9ECmVv3%2BPYULr3YzFc5uG3YI8%2BJYmhA53Ol2452%2FPJujm22dYrQebHRJYqg8u6ZyCkQUZbkmcBmFOI%2B0%2Bn%2FhfxNA7DK1MVpIaWRQFOoGR3SsQrwwOMHyO%2FneH1yrOz3NGy2sSsdPA2pvkXh0gyPls3QGfbf4ydSULA4hKD2imXe0IpLiiJXiQg73twhG8bjQaqZYVUfqjIBFEmF%2FCSRyzSNxC5QgWgCVOV7GJnz%2B9KLe3KQDZHDGlNqhTVJtuAa33Zt8LjtMWhBElO%2BEuoGvNRlr86euhzFbTSV50q4Ua1%2BH5Ue0p1Frzo6ec9ZSox%2F9SUSLVQFRwzuiAvlEwi6Kg6KaD67MPhTJz%2Fbw%2Fa4%2B9j7R5sYJoFtKPmL8X%2FBX|clp:2334524|tkp:BFBMzPLNh95f

A likely very suitable transistor for the task is a 2N2222A, but it is TO-18, it is a 40V-50V , 800mA collector current rated part, with a small signal current gain typically >50 and a high transition frequency of 250 MHz, low C-E sat voltage, good for high speed switching not insignificant currents, although its called "small signal" but that underestimates it. It is a good driver. If you had a dud original DEC transistor, and you wanted to preserve the "look" you could machine the other one out on the lathe enough to expoxy resin 2N2222A inside it. If you were going to do this I would get the mil spec JANTX-2N2222A with gold plated leads, virtually guaranteed non-fake as the fakers are Gold scavengers and cannot let Gold out of their sight, like Pirates of the Caribbean:

JANTX2N2222A - GREEN BROOK ONLINE - MILSPEC TRANSISTOR - VINTAGE | eBay

Find many great new & used options and get the best deals for JANTX2N2222A - GREEN BROOK ONLINE - MILSPEC TRANSISTOR - VINTAGE at the best online prices at eBay! Free shipping for many products!

www.ebay.com

Data Sheet:

https://web.mit.edu/6.101/www/reference/2N2222A.pdf

 

[Hugo Holden]

Of course, further to the above post, if the DEC transistor really is equivalent to an NTE-128, that is a relatively high voltage video output transistor. So it is important to check what voltages are involved in the circuit.

If it is a high voltage circuit then my recommended replacement would be a BF336, BF337 or BF338, , but they might not support the collector current. And the 2N2222A might not support the collector voltage, but would likely support the current. Do we know how much is expected of it ?

transistor BF337 datasheet

the BF337 is a silicon NPN transistor preferred for use in video output stages in monochrome and color TV applications

www.web-bcs.com

Since the NTE128 part is well rated at a moderately high collector voltage and 1A collector current, probably that is the one to go for.

A 2N3439/2N3440 is a high voltage rated 1A collector current device in a suitable package:

https://www.nteinc.com/specs/original/2N3439_40.pdf

ebay:

(1 PC) RCA JAN2N3439 Bipolar Junction Transistor NPN Type TO-5 | eBay

(1 PC) RCA JAN2N3439 Bipolar Junction Transistor NPN Type TO-5 NSN# 5961-01-423-9272. ELECTRODE INTERNALLY-ELECTRICALLY CONNECTED TO CASE COLLECTOR. SEMICONDUCTOR MATERIAL SILICON.

www.ebay.com

The 2N3440 looks very good, probably ideal for the job if it is a high voltage range circuit ( I have bought lots of original NOS parts from this store, never a problem, all genuine parts):

2N3440 RCA NPN Silicon Si Transistor TO-39 - NOS Qty 2 | eBay

Qty 2 2N3440 RCA NPN Silicon Si Transistor TO-39 - NOS.

www.ebay.com