Duocast transistor help

[Grazza]

Hi all,

Just working on a duocast, I have sourced a transistor for the OC-71 position, accept I've never used on of these before and I don't know which way around it goes. There is a red dot on the side of it that looks like it's been drawn on. Photos attached, please help me!
Also I'm having trouble sourcing the two 120uF electrolytic Capacitors for this build. Can't seem to find any, will 100uF do the job or do I move up to 150uF? The single 330uF is also an issue, I could only get 50v or 25v and the 50 is massive, but the documentation calls for 35v.

 

[music6000]

As a Rule, the Red dot is C = Collector, Middle pin B = Base & outer pin E = Emitter.
The Red dot always looks as it was put on by hand!

 

[Grazza]

Ok, so the collector lines up with the notch/key thingy on the silk screen on the pcb?

 

[music6000]

Ok, so the collector lines up with the notch/key thingy on the silk screen on the pcb?

I have just been investigating & sometimes the Red dot can be the Emmiter also so I need to confirm all the Writing on your Transistor.
If you have a tester, put it on that & it will confirm pinout, The Tang on the PCB is Emitter!

 

[Grazza]

Thank you, I do have a little tester, I'll put it in, can work it out from the schematic from there I guess

 

[Ginsly]

If nothing else, the TC1 tester is invaluable for determining pinout- and dirt cheap. It's obviously good for more than that, though!

 

[music6000]

Thank you, I do have a little tester, I'll put it in, can work it out from the schematic from there I guess

C, B, E on the Duocast.

 

[Grazza]

Red Dot was the Collector, I should use that little tester more often!

 

[music6000]

I use a Peak DCA55 that tells me most things I want to know.
If anyone was to ask me should I get one, I would recommend the Peak DCA75, it reads jfet pinouts + more!
If your building Pedals, it should be mandantory!
ie if you put a Russian D9E diode it will tell you the Cathode line is Anode, they are back the front!
If you test a genuine 1N34A diode it will tell you Cathode is Cathode + all the forward voltages and stuff!
If you test an Led it will tell you Anode & Cathode & blink to let you know it works! + all the forward voltages and stuff!

 

[Grazza]

Thanks, I'll look it up, I've got one of those TC1 things, however I'm really enjoying the building process and will definitely be building more, it's pretty addictive. Might be time to get serious.