11/45 revisited

[Christian Corti]

On Fri, 9 Mar 2007, Jay West wrote:
> I was looking at the power control board for the H742A (5409730) that is 
> supposed to be putting out my +15v. I couldn't find any schematics on this 
> board but the system engineering prints appear to indicate they should be 
> present. In the absence of schematics (and any obvious scorching) I figured

I have the complete set that came with my 11/45.  The schematics are on 
the sheet titled "POWER CONTROL BD.", number 5409730-0-1.
And I had exactly the same fault in my H742 during operation. The fan was 
stuck so the transistor and other parts got really hot...

> 1) The critter is Motorola "DEC3000" which I'm betting is a DEC house part 
> number (since ECG xref shows nothing && it starts with DEC). Can anyone clue 
> me in to what part that really is?

Both the transistor and the schematics say Motorola MJ3000.
Please also check the zener D3, a 1N5353B (16V) that is connectec between 
the base of the transistor and ground. I guess it is shorted.

> 2) Are the schematics for 5409730 around so I can try to understand it a 
> little better?

Yes, I'll try to scan it (not easy because of the paper size).

Christian