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Question on finding RF power transistors....

guitar_199

Sr. Member
Mar 8, 2011
896
1,173
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Deer Park, TX
First off, I understand the idea of parts sources being a "dear thing"! If nobody answers .... I'll understand!!!!

So let's say I have a radio and it needs a driver and a final.

For the driver, SAMS says: 2SC1957 or 2SC2314 or 2SC1678

and, for the final SAMS says: 2SC 2078 or 2SC1306.

So I go over to rfparts and, great! They have 2SC1957 in stock.

but when I try the 2SC2078 or 2SC1306........ NOTHING FOUND!!!!!

So, if I go Googling out in the wild wasteland......

2SC2078's pop up in Ebay and on Amazon! Oddly.... only a VERY FEW hits show up from electronics businesses carrying them. The problem here...... for YEARS I have seen cautionary tales about the landscape of RF power transistors on Ebay/Amazon. GREAT risk of "fake parts".

Now the question.... kind of complex but still a question.....

How in the Hell do you find them?

Do you take a risk on some of the Amazon parts?

Are there RF (particularly Cb radio parts) sources that I just have not found yet??

Do you just grab the data sheets and start hunting for one with:
1) proper specs,
2) proper case,
3) proper lead arrangement
and hope for the best???

I am really interested in how THIS part of the puzzle gets solved!

Thanks in advance for any tips... they are much appreciated!

Bob
 

You have to understand that many electronic manufacturers - not distributors, will NOT post there stuff out here anymore.

You need to be part of the supply link chain to have access to much of the parts still present in the system.

There are plenty of distributors - but to locate a "fresh" 2078, you need to be a part of that link.

It's worse than the "dark web" - much of the dialogue, documentation, fabrication - are done overseas on intra-web not internet...
 
Absolutely DO NOT trust any eBay or amazon sellers when buying any rf transistors.
Im sure folks will chime in with known reputable sources. The basics are Mouser and RF Parts though ill say their 6lf6 tubes are used up junk but they dont tell you that before you buy them, just when they arrive with shitty test numbers. I ate $200 worth of weak tubes. They'll make good .22 targets i guess.
 
I am thinking this does not bode well for my plans.

Handy Andy, if I am reading you right.... you have to be a "commercial business" or you can't get the parts. That kind of works against the hobbyist.

So I guess just trying to cross-reference is the only way. Kind of saddens me that it works this way but..... oh well.
 
Hahahah...
you say DON'T go by their data sheet???

It just sounds odd.....but I know that you know what you are talking about!!!!

But dont expect them to be direct replacements. Dont go by hg data sheets. You may need to tweak a little to get the best results. Hg makes a decent product.
 
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@guitar_199 - the Market for RF Transistors isn't what it used to be.

The CB - in perspective, what is the first thing they do?

"Oh, it's using the 2078 - we'll swap it out and put in a BIGGER RF transistor for you."

Thats' the shop - half this CB forum is about 'eeking more out of the radio and what to make it do more of that it didn't come with in the first place...I could say more...

But I won't...

The 2078 is a Unique to the device and application, the demand is not there anymore - it's why we see IRF520 and other MOSFET replacing them. No one does the Linear Mode anymore - you're hard pressed to find QUALITY discretes that aren't dirty or house-numbered and offer Hfe's worth a darn.

Oops, I said I won't - so to keep from Derailing this thread -

You want to know where to find Fresh, the problem is, they are in-house units and most of them are kept for the application of and FOR - the Factory, even the Radio Manufacturer like Dynascan no longer can provide many of the parts they can list in their Schematics, Seems they gave up trying to offer inventory of spares. They just aren't there. No one likes old inventory that holds up office space they could lease to someone else.

To Add, I got interrupted...

The common, if not only, solution for this is to cannibalize the older radios that are in Garages, Basements, Junk Bins and such so you can obtain the parts for your patient. It seems odd to say that, but the ability of the radio to keep going versus under the hands of an abuser, your choices for new and donor parts are limited to the older technology that was left behind when China took over this mess we created.

Else you may wind up having to do up that which CB Tricks did up for the EN-369 1230 series...by hand for the newer MOSFET that is now replacing the Bipolar.
 
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That seems particularly interesting because (I only took a QUICK look but) I didn't think that they were very expensive at all. At least didn't seem like it.

$2.80 for a 2SC1969
$0.80 for a 2SC2078?

From the outside just seems suspicious....
But at that price..... almost worth a try.

I personally have good luck with the HG transistors. I usually even see more power out of them.
 
That seems particularly interesting because (I only took a QUICK look but) I didn't think that they were very expensive at all. At least didn't seem like it.

$2.80 for a 2SC1969
$0.80 for a 2SC2078?

From the outside just seems suspicious....
But at that price..... almost worth a try.
So far i havent heard any complaints on their smaller transistors. Just be ready with a couple trusty transistor testers just to make sure of the numbers.
 
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