I urgently need help with the transistors SJ2517 and SJ2518

Hello,
I absolutely need data on the following transistors. SJ2517 / SJ2518
Does anyone have a data sheet, specifications and/or can tell me replacement types available from Distrelec, Mouser or others? Because MJ21193 / MJ21194 would fit (as claimed in another forum) I can only get them from Chinese dealers.
Thank you very much in advance and kind regards from Germany
 
Motorola house numbers never correspond with Jap numbers. And you can’t get data sheets for them.

if they are a complementary TO-3 pair the OP’s information and instincts are probably correct. Studying the circuit would tell you for sure. The only way it wouldn’t work would be if the originals happened to be darlingtons. Again, studying the circuit would tell you for sure (in that case drivers would be omitted).
 
Jan, the SJ2517/18 are different animals as wg_ski pointed out. But I agree that they are tricky numbers 🙂

@op:

Only buy from reliable sources. MJ21195G/96G is still available at Mouser but as said above, a schematic would help.

Hugo
sj2517.jpg
 
Last edited:
A big thank you to everyone who took the trouble to offer some help. Well, unfortunately the SJ is not comparable to the 2SC type... otherwise the reference to the data sheets would have helped me 😉👍
In my case, the replacement types are to be used in a Marantz 2270. I wanted to stay as close as possible to the specification regarding HFE and the associated operating point of the characteristic. But as I now realize after hours of searching, the only option left is solid improvisation. If anyone else has some help to offer, I would definitely be happy!!!
 
Special in house number for otherwise basic TO3 transistor.

Be the usual 100 volt / 200 watt / 25 to 100 HFE
Ft not much more than 2 or 3 MHz

2270 is 70 watts 8 ohms.

And have seen cross reference to MJ802/4502
and NTE cross reference basically same old thing.

Otherwise MJ15003/15004
Same old thing as well.
Soa likely slightly higher.
140 volt compared to 100 volt
240 watts instead of 200 watts
gain 25 to 150

TO3 packages still in production.
But not 3 million options like back in the day

Because the basic 150 to 250 watt 2 to 3 MHz devices
with 25 to 100 gain are easily replaced with single device.

15003/15004 can be bought new from On Semi / Mouser
for likely 8 to 12 dollars American.

Or plenty of stock piles of NOS devices for 3 or 5 bucks

If Marantz used any fancy transistors, no special house number.
be marked Toshiba or Sanken

Otherwise plain old Motorola's with remarked numbers.
 
Last edited:
Me again....
While searching, I became aware of a change in a Marantz service bulletin. It was recommended to replace the SJ2517 / 18 with SJ2515 / 16. In a crossreference I then turned to the types 2N3055 / MJ2955 (audio transistors from the first hour of poweraplification). Do you think I can use these, or is there anything complicated with it? As far as I can see, they would fit perfectly into the circuit....!?
 
@WhiteDragon
Our contribution overlapped and now I have enough options. Even though I still have a few 2N3055 and MJ2955 from Motorola in my drawer, I would probably prefer to go with your suggestions with the higher voltage rating, because then the transistors won't be put under as much strain. I'll shop around a bit with the well-known distributors later.
 
also depends on the circuit
Some PNP/NPN TO3 pairs aren't well matched
either the PNP or NPN will be faster
And the amplifier schematic might hint at it if gracious amount
of capacitor compensation is placed around one or the other.

Otherwise if relatively well matched.
And if higher powered MJ15003/15004
works fine for most applications.

3055/2955 not well matched and
Safe operating area likely borderline
for 2270 could work could cause problems.

Gain and SOA much better with 15003/15004
better matched pair.
Becoming my favorite.
People usually toss 21195/96 at everything.
Dont care for the high prices/ and or stability issues.

Stick with 15003/4
Same old 2/3 MHz devices
and slightly better gain and slightly better SOA
than original being said 802/ 4502
 
Date codes are 1974. They may have even predated the MJ802/4502, which is what a manufacturer making these would have used (They were considered game-changing when they came out). They probably HAD to be selected just to get enough SOA and gain for a GOOD 70WPC amp. Selected 3055’s could be made to work, but their gain is crapola and THD would likely suffer. My GUESS is they are more like 2N5879/81, or perhaps 2N5630/6030. A quick look-see inside, and I could tell you die wattage, and whether they are from the high voltage (100-140V) family or the low volt (40-80V). The latter can be selected to run up at 100V.

They certainly predated ANY of the 1500x, 1502x, or 2119x. Any of those would work. The 15003/4 would be the closest match since they are a direct derivative of the 2N5631/6031. And they look identical when you pop the tops off of them.
 
The transistors arrived yesterday and I have now installed them and adjusted the power amplifiers. The previous measurement showed that all 4 transistors had pretty much the same gain (145, 146,145, 143). I wouldn't have expected this.
I've been listening to the 2270 for about an hour now (quite loud after a warm-up phase) and I'm absolutely satisfied with the sound. Tight bass, very well-resolved midrange, and silky but clearly defined highs. So I can recommend the transistors as a replacement for now. If there is any error during the long-term test, I will report it.
 
  • Like
Reactions: Netlist