Can anyone identify this transistor !

[bloto123]

Hi,

I'm an electronic technologist and do a lots of repair as hobby. Recently, I tried to "resuscitate" an old Mastercraft 12V 10A car charger. The xfo is OK and the thermal breaker too. It uses SCR as rectifier (the board is a Tenatronics 50-115) and is quite simple. I suspect a transistor to be the problem, but couldn't identify it searching the Web. It's a Motorola TO-92 case and here is the picture of it :

It seems to be part of a loopback including a small transfo connect to one side. Any substitute will be welcome.

Please help !

 

[barry]

Hi,

I'm an electronic technologist and do a lots of repair as hobby. Recently, I tried to "resuscitate" an old Mastercraft 12V 10A car charger. The xfo is OK and the thermal breaker too. It uses SCR as rectifier (the boarvgd is a Tenatronics 50-115) and is quite simple. I suspect a transistor to be the problem, but couldn't identify it searching the Web. It's a Motorola TO-92 case and here is the picture of it :
View attachment 148758
It seems to be part of a loopback including a small transfo connect to one side. Any substitute will be welcome.

Please help !

Look at this

**broken link removed**

 

[betwixt]

It would be an MPSU316 with date code for week 39 of 1984.

After 34 years it's unlikely you will find an exact replacement but there are probably hundreds of suitable substitutes. Do you have a schematic or can you trace it out so we can see what it did and suggest a modern alternative? Note that Motorola also made SCRs in the same package although most would be marked 'MCR' around that time.

Brian.

 

[bloto123]

Thanks for the info. I tried to look in the Motorola transistor handbook suggested by Barry, using the number MPSU316 suggested by Betwixt without success....

The circuit around this "device" is a battery charger 12 volts, 10 amps. I found something similar :



But instead of a rectifier bridge, there is two SCRs, and the second transfo is connected to this device. According to this schematics, it is an UJT, but the spec of mine has to be closer to the original since it is used as an oscillator.