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 Post subject: Where do you get your transistors
PostPosted: Aug Sun 30, 2020 1:22 pm 
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Joined: Aug Fri 28, 2020 12:22 pm
Posts: 1
I'm new to this hobby. I'm fixing a Emerson 888 Vanguard I've got a bad transistor. The sams on it says RCA 2n408 or Raytheon 2n633. I was hoping someone could point me to a link for a modern replacement.


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 Post subject: Re: Where do you get your transistors
PostPosted: Aug Sun 30, 2020 4:16 pm 
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Joined: May Tue 30, 2006 4:46 pm
Posts: 10199
Location: Santa Rosa, CA
Those transistors are so old they are collectors items! Haven't been made in 50+ years. You might find something via an NTE distributor, like Newark Electronics.

https://www.primeirow.com/index.php?mai ... _id=364038

https://www.nteinc.com/specs/100to199/pdf/nte102a.pdf

https://www.newark.com/nte-electronics/ ... gKL9_D_BwE

Good luck.

Rich


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 Post subject: Re: Where do you get your transistors
PostPosted: Aug Sun 30, 2020 7:01 pm 
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Joined: Aug Sat 16, 2014 2:19 am
Posts: 1783
Location: Palos Verdes, CA
Since my local Radio Shack closed, I've bought components from sellers on eBay. There is a seller who has 2-2N408 for sale currently on eBay:

https://www.ebay.com/itm/LOT-OF-2-ETCO- ... Swo-5d-scE

I have also purchased NTE replacement transistors and had good success with them and the replacement for a 2N408 transistor is a NTE102a. Good luck! - Mark


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 Post subject: Re: Where do you get your transistors
PostPosted: Aug Sun 30, 2020 10:32 pm 
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Joined: Jan Thu 09, 2020 6:46 am
Posts: 79
Location: Lexington, KY, USA
For a NTE102A (A=more current capacity), Ive found the Russian GT403G transistors worked fine in the audio output of my TO 3000-1 and the betas were very consistent on my germanium capable tester. However they are big, clunky, and have odd to us pinouts. They may not fit in a tight shirtpocket radio. They are cheap and mine are date coded 1992.


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 Post subject: Re: Where do you get your transistors
PostPosted: Aug Mon 31, 2020 2:19 am 
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Joined: Jan Tue 31, 2012 1:55 am
Posts: 14325
Location: Mountains of Mourne. Ireland.
Whatever transistors you are replacing...
alltransistors.com will list many Equivalent Substitutes - via their... Cross-Reference Search.
https://alltransistors.com/

------------

A Guide to Making Transistor Substitutions.
Bookhttps://www.americanradiohistory.com/BO ... k-1963.pdf
Image

Greg.


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 Post subject: Re: Where do you get your transistors
PostPosted: Aug Mon 31, 2020 3:34 am 
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Joined: Sep Tue 30, 2014 6:08 am
Posts: 5936
Location: Norfolk, VA
Me, for subs, I trust two things more than all else - D.A.T.A. manuals, and pre-1998 substitution guides from RCA and ECG. Pre-1998 because of the China dump of questionable transistors (and the later Russian transistors of unknown origin - factory rejects, seconds, remarked, who knows?). YMMV, but I'll stick to known source stuff.

DATA manuals list the transistors in an electrical specification order, meaning you can generally find acceptable subs on the same page (10 lines up, 10 lines down....)

https://archive.org/search.php?query=da ... transistor

ECG replacement Guide - note that NTE bought ECG from Philips, and dumped the quality ECG stuff, opting to procure as they always had.

https://archive.org/details/EcgSemicond ... tGuide1989

As to where I get my transistors for repair, well, I pretty much stocked up back when transistors became passe' - GC, Workman, Motorola HEP, RCA SK, GE, and Raytheon replacement types, and a bunch of bargain bin types at the local distributor, mostly from GC's Calectro line. I added a bunch of MIL-packed stuff when eBay came along, easy enough to cross that 2N408 to a dozen or more part numbers from others, and all nicely NSN coded for searching. I've also got heaps of old boards full of transistors of all kinds, culled from a lifetime of junking stuff.

All too many websites will list a transistor sub that is unobtainable today (and even back then - an in-house development type, or a quickly obsoleted part, for the benefit of a preferred, better, suffixed device (2SC1172 vs 2SC1172B, for example). They list these types not out of malice, but ignorance. And ignorance is far short of authority when it comes to subs.

_________________
Brian
"Capacitor Cosmetologist since 1979"
USN Retired 1984-2006 (Avionics/Cal)


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 Post subject: Re: Where do you get your transistors
PostPosted: Aug Mon 31, 2020 3:51 am 
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Joined: Sep Tue 30, 2014 6:08 am
Posts: 5936
Location: Norfolk, VA
egg wrote:
Whatever transistors you are replacing...
alltransistors.com will list many Equivalent Substitutes - via their... Cross-Reference Search.
https://alltransistors.com/

------------

A Guide to Making Transistor Substitutions.
Bookhttps://www.americanradiohistory.com/BO ... k-1963.pdf
Image

Greg.


Sorry Greg, but a bone to pick with the Sams sub guide. It ignores Ft of a transistor - completely.

2N2369, a UHF transistor, typically good to over 300MHz operation (I've seen it used as a doubler-amp in 270MHz range stuff). What does Sams sub? A 2N1566A, a transistor that, besides being a physically larger device, tops out with an Ft of just 100MHz or so.

Attachment:
SamsSubGuide.jpg
SamsSubGuide.jpg [ 117.33 KiB | Viewed 550 times ]


I'm sure there are other "fails" but that one just pops out.

Oh, a disclosure - we sold the Sams library at Cain Electronics back in the 80s. We also had a full file drawer of errata sheets that were to accompany the books when sold. For the transistor specifications (not the sub manual as you listed) it was .....ahem.....38 pages (single sided) of errors, probably 350 or more. Many were simply typos, but a few were transposition with a device on another line or page. Hence my questioning any Sams transistor manual. As WRH has no errata sheets or mention of such......

_________________
Brian
"Capacitor Cosmetologist since 1979"
USN Retired 1984-2006 (Avionics/Cal)


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 Post subject: Re: Where do you get your transistors
PostPosted: Aug Mon 31, 2020 3:58 am 
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Joined: Sep Tue 30, 2014 6:08 am
Posts: 5936
Location: Norfolk, VA
Oh, and germane to the topic of substitutions, there are a couple of the Sony Semiconductor Guides on eBay......cheap. Cheaper than I got mine for, and far cheaper than Sony charged for them. I have no connection to either of the ones listed. The fifth edition is full of good info:

https://www.ebay.com/itm/Sony-Semicondu ... SwrjZa86LL

That'll list the subs for EIAJ 2SA, 2SB, 2SC, 2SD, 2SJ, 2SK, 2SF and other devices, as used by Sony. Typically, they take an older part and list a newer, more contemporary (for the 1980s) part. Same for diodes, chips, and oddball types too.

Again, no affiliation, I don't know the seller(s), but do have a history of using the Sony Guides with success.

_________________
Brian
"Capacitor Cosmetologist since 1979"
USN Retired 1984-2006 (Avionics/Cal)


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 Post subject: Re: Where do you get your transistors
PostPosted: Aug Mon 31, 2020 4:33 am 
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Joined: Oct Thu 18, 2007 11:34 am
Posts: 3764
Location: Port Orchard, Wa 98366
For your Information Sams Transistor Substitution is searchable.

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http://antique-radio-lab.forumotion.com/
I was smokinradios Long time ago (2004)


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 Post subject: Re: Where do you get your transistors
PostPosted: Aug Mon 31, 2020 2:11 pm 
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Joined: Sep Tue 30, 2014 6:08 am
Posts: 5936
Location: Norfolk, VA
Radiosmoker wrote:
For your Information Sams Transistor Substitution is searchable.


Great. You can search to find an unusable sub. :mrgreen:

_________________
Brian
"Capacitor Cosmetologist since 1979"
USN Retired 1984-2006 (Avionics/Cal)


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 Post subject: Re: Where do you get your transistors
PostPosted: Aug Mon 31, 2020 6:42 pm 
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Joined: Oct Thu 18, 2007 11:34 am
Posts: 3764
Location: Port Orchard, Wa 98366
I would say most radio repair persons don't need or want to know every detail about a tube. They just get what they need from their stock as a replacement.
You have both ends of the spectrum Perfectionist and businesses or hobbyists that only needs minimum info to get the radio operating.
I remember a guy down at long Beach Naval Shipyard, He was brilliant in electronics, but His downfall was that he analyzed UHF Transceivers circuitry to the point of not being productive to meet Deadlines or to get them repaired and calibrated. (I think He only lasted a year, and He was fired.)

In other words Sam's, in their effort at publishing, has no value? :shock: Or do they use more than one source if necessary?
I guess Sam's just hoodwinked every one! :(

As a leader once said, Trust but Verify!

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 Post subject: Re: Where do you get your transistors
PostPosted: Sep Tue 01, 2020 5:56 pm 
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Joined: Jan Thu 09, 2020 6:46 am
Posts: 79
Location: Lexington, KY, USA
"...and the later Russian transistors of unknown origin - factory rejects, seconds, remarked, who knows?"

Many of the Russian transistors on eBay are their version of mil-spec, which was comparable to (i.e., lifted from) our mil-spec. Some, but not all of these, can be found with a small Soviet star on them. I have many Nixie tubes with these markings.

I have a feeling that what little "consumer goods" (i.e., transistor radios) the USSR made were built with MIL-SPEC dropouts!


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 Post subject: Re: Where do you get your transistors
PostPosted: Sep Tue 01, 2020 6:36 pm 
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Joined: Jan Thu 01, 1970 1:00 am
Posts: 11023
Location: Omak,wa,usa
Hello Guys,
getting some of these transistors are getting harder and will just get hard ever year and finding IC chips is getting the same way,
Ebay is a good source if you find trustworthy seller that's not selling fake parts .

I have a couple the ECG books also SK and radioshack great source material


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 Post subject: Re: Where do you get your transistors
PostPosted: Sep Tue 01, 2020 10:34 pm 
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Joined: Jan Thu 01, 1970 1:00 am
Posts: 543
Location: moreno valley
I bought an old one the other day still sealed in the original pack, dead as a doornail. I hate when that happens.


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 Post subject: Re: Where do you get your transistors
PostPosted: Sep Sun 06, 2020 3:40 pm 
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Joined: Jan Thu 09, 2020 6:46 am
Posts: 79
Location: Lexington, KY, USA
[quote="radiorich"]Hello Guys,
getting some of these transistors are getting harder and will just get hard ever year and finding IC chips is getting the same way,
/quote]

I remember in the 70’s that when plastic chip packaging became common(as opposed to ceramic), the thinking was that plastic packaged chips would last only 20-30 years due to moisture migration up the tinned chip legs and into the die. The military would buy only ceramic chips for this reason. This MAY be happening bit it isn’t widespread. I have machines with 100 or so TTL/MOS plastic chips in them from the early 70’s, and I’d say that only 1% went bad.


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