Transistor BU406

[brennanlabs]

Hi, I've been working my way through an International analog board in my Mac Plus here in Australia.
I have a damaged BU406 transistor and have been trying to find a replacement on line. I can't seem to find any BU406D 's that are mentioned as an upgrade in the Dead Mac Scrolls book. But I do find the 406's. I assume replacing it with the same would be still ok?
I've changed the rifa caps and repaired dry joints around, this is the last thing to do before putting it all back together and seeing if it boots.
cheers,
Wayne

 

[Callan]

Bu406d's have a diode across the emitter and collector (inside the chip). A Bu406 is not a drop in replacement. I have found 406d's on ebay with pretty good success. Make sure not to buy from China (I got a bad batch). I just sourced a us based seller that had good feedback and seemed to be selling nos parts. I'd tell you who it was but it was a while back.

 

[Callan]

Here... Boca has been around for a while and are usually very reliable.

BU406D | eBay

Find many great new & used options and get the best deals for BU406D at the best online prices at eBay! Free shipping for many products!

www.ebay.com

Bu406d's have a diode across the emitter and collector (inside the chip). A Bu406 is not a drop in replacement. I have found 406d's on ebay with pretty good success. Make sure not to buy from China (I got a bad batch). I just sourced a us based seller that had good feedback and seemed to be selling nos parts. I'd tell you who it was but it was a while back.

 

[trag]

Dalbani used to have half a dozen BU406 choices, which left me scratching my head wondering which of them would work well. I never made the time to do the test.

In the intervening ten or fifteen years, they seem to have done away with their on-line store and moved to Ebay only. Also their BU406 have skyrocketed in price -- used to be a buck or two.

But they claim they have the original Fairchild part:

BU406 Original New Fairchild Silicon NPN Epitaxial Transistor | eBay

Parts labeled as "pulls" or "pulled" have been previously installed and are made by the original manufacturer. Let us fix the problem for you. We will do our best to get back to you as soon as possible.

www.ebay.com

I'm not sure if Macs wanted the Fairchild. Might have been Motorola.

Hmmm. These aren't the 'D' though. Does the D designate that the diode is present?

 

[Callan]

Yup.