Transistor question?

[kdschmidt]

First time post - long time lurker
i have a general question about transistors (BJT type). I'm a novice, currently refurbishing a Pioneer SX-9930 i picked up at a yard sale. i' m clear on the NPN/PNP, post order, etc. I was searching fora source for 2SC2240 transistors, i was under the impression that the suffix letters just described the way they were merchandised. is that the case?
i found a source, but they had two products; 2SC2240 GR (@ .94) and 2SC2240 BL (@ 1.98) ???
what do the suffixes mean that make
such a difference in price?
thanks!!

 

[dlucy]

Not exactly answering your question, but there is good info is this thread: http://audiokarma.org/forums/index.php?threads/counterfeit-2sc2240.285234/

 

[sregor]

The codes are hfe ranges. GR is hfe (current gain) 200-400. BL is hfe 350-700.
I'm not a sure but I'm guessing BL's are slightly harder to make, but mainly more preferred and less common.

 

[slimecity]

If you find and download the datasheet for the transistor you are after, there is usually a grid showing the variants and the hFE gain for each variant.

If you refer to the original service manual for your machine, it will tell you the gain ("type") of your original transistor used in the machine, it may even tell you what other grades could be used for replacement parts.

 

[kdschmidt]

Thanks for the replies!
I had already gotten some of the 2SC2240s off a seller on ebay but I wasnt sure about them. I'm replacing the 2SC1313s on the EQ amp board (as well as the 2SA725s). That thread you gave me the link to has me a little nervous!
The BLs sound good to use but $1.98 each seems a bit steep, I think I'll keep looking, or just get the GRs.
I got some KSA992s for the 725 replacements from a different seller on ebay. The printing looks good on both (the 2240s were advertised as Toshiba and the 992s as Fairchilds), they are, of course, to-92 but they are somewhat smaller than the original transistors. Is that normal for the newer transistors to be smaller than the old ones?

 

[Freddymac2]

I am not as trusting as you, I do not buy off EBAY!!!!!

 

[Hyperion]

Is that normal for the newer transistors to be smaller than the old ones?

No, and this is exactly the reason why people should not buy semiconductors from auction sites - there is too much risk of receiving counterfeit, or substandard items.

 

[kdschmidt]

Well, several of the caps I got from Mouser were smaller than the originals, so I reasoned that new transistors are smaller these days as well.
Not true?

 

[DaveVoorhis]

Well, several of the caps I got from Mouser were smaller than the originals, so I reasoned that new transistors are smaller these days as well.
Not true?

It's true, but buying transistors on eBay is risky. Counterfeits, substandard copies, and discards abound. Best to stick to Mouser, Farnell, RS, etc.

 

[ghazzer]

Think about it!

Is it better to save a few $$$s on an order, knowing that there is a significant probability you will have to repeat the order (& maybe more) if the cheaper parts don't work, or if they cause a failure in ancillary parts. How much are your time & effort worth?

 

[kdschmidt]

Thanks for the replies (and scoldings
I understand the "ebay risk". I sold on ebay for many years, vintage and antique stuff, since 1999. I considered myself a supremely honest and forthright seller. There's only one like me for every 10 or 15 schmucks on there.
Never sold any delicate vintage audio though. Too risky to ship and the potential for selling it to a dishonest idiot or a novice who hooks it up wrong and fries something is too high for me. But I have a nice collection of music and I regularly pick up lots of great audio equipment. I think I have about 25 turntables at the moment.
Anyway, I bought the transistors on ebay because I couldn't find them anywhere else. Stumbled onto the referred supplier via a thread here on AK.
The transistors I got look pretty good, printing is sharp. The alleged Toshiba's say; "C2240 / GR 3C" vertically on the flat, and the Fairchild's say; "A992 / FCG48" horizontally (is FCG appropriate ?). They are both just smaller than the old ones.
Maybe I'll pick up the 2240 BL range trannies for this receiver as I'm keeping this Unit for myself. It's a very rare Pioneer, I picked it up for $20 bucks. They said it died after a lightning strike. I first replaced the transformer ($40 on ebay from an SX-939) based on probability. That wasn't it, so after poking around I found the 250V Cap that links between the AC line as it enters the unit and the variable voltage fuse holder had blown up inside it's plastic cover. ¢.51 later, It fired right up, everything working and in EX++ condition. Oh, I put the old variable voltage transformer back in it, so if anyone needs a transformer from an SX-939 let me know!