Replacing Toshiba outputs with On-semis, confused with pinouts from datasheets

[Gobstopper]

Hi everyone, brief question, I'm replacing the outputs transistors on my SA-7100(going with MJ2119XG for the 2sd and 2sbs as suggested) In any event, I hadn't run across any mentions of "WATCH PIN OUT" in the BOMs on this forum that I've seen from time to time for 3 leg transistors, but thought to double check. I compared the pinout for the 2sd371 that I found online against the datasheet for the MJ21194. I went in assuming the pinouts were the same, but don't know based on the sheets if they actually are; there doesn't seem to a clear reference point like on the other 3 lead transistors. Can anyone confirm that I should match the pins (slightly above the midline) between the two sets? It's possible they only go in one way, but just wanted to double check before screwing anything up.

Thanks

 

[markthefixer]

They only go in one way. In this case (TO-3 and variants) they are the same.

 

[Gobstopper]

Thanks Mark! Hoping these output transistors will take care of my ongoing issues with the unit.

 

[larryderouin]

If you look somewhat closely the 2 pins on the bottom are OFFSET from Center toward one end. They can only go in one way and then able to be tightened down. You MUST use either a Mica insulator AND Heatsink Grease (plain old white stuff), OR the NEWER Silicon Insulator Pad's. I prefer the Mica's, although some guys prefer the Sil-PAds.

 

[Gobstopper]

Hi Larry, the two pins being offset from top-bottom center made sense, and I lined up relative to the old ones, and it was also my hunch that they could only go in one way for connecting to the recieving plate, but I was just a bit nervous since I couldn't fully confirm the orientation based on the datasheets. I used heatsink grease and mica sheets. I'll have to look into the Sil-PAds for future projects.. Now I'm kind of nervous to turn on unit due to concerns over the trim pots values changing due to new output transistors

 

[Willy6]

Hi Larry, the two pins being offset from top-bottom center made sense, and I lined up relative to the old ones, and it was also my hunch that they could only go in one way for connecting to the recieving plate, but I was just a bit nervous since I couldn't fully confirm the orientation based on the datasheets. I used heatsink grease and mica sheets. I'll have to look into the Sil-PAds for future projects.. Now I'm kind of nervous to turn on unit due to concerns over the trim pots values changing due to new output transistors

Plug it in to a dim bulb tester before you power up..If the bulb glows bright you have a problem if the relay clicks and the bulb slowly go's dim then your good to go..you can Google dim bulb tester and find out how to make one fairly cheap.

 

[Gobstopper]

You read my mind Willy! Hoping to make it to the hardware store this weekend.