Osborne Vixen - Zenith 7" display t-shooting issues

[Chuck Guzis]

On 11/07/2014 12:41 PM, tony duell wrote:

>, I would want to reduce the number of variables. If it doesn't work
> with an MJE13007, then what? Is it that this transistor is not suitable, or is there some other
> fault?

That's why god made oscilloscopes, Tony :)  But really, a well-designed 
circuit will work with a wide variety of devices, as the two enemies of 
humanity--purchasing managers and device tolerances--will always be 
there to bedevil us.

If an MJE13007 doesn't work, try another.  If not that, try, say, a 
BU406.  I seem to recall that some early Macs would work with an 
MJE13007 just fine, but others of the same model required the BU406.

Personally, I don't think that Zenith would ever make the mistake of 
requiring selected semiconductors on what is essentially the video 
section of a TV set, something that they made in the millions.  The 
service manual for the DT2 certainly makes no mention of it.

In any case, the monitor itself is not in any particular danger of being 
destroyed by an out-of-spec HOT, so there's little risk involved.

--Chuck