Osborne monitor service information ?

From: Dave Dunfield <dave04a_at_dunfield.com>
Date: Sat Nov 6 13:39:32 2004

Hi Guys,

I have an Osborne-1 with a bad monitor - I have the technical
manual, which gives schematics for the main logic board and
the disk board, but NOT the monitor.

The monitor is a: Zenith model DS5NF3

Symptoms are:

  Its Powered through a single +12v line on the connector,
  filiment lights, which suggests power is present.

  Horizontal drive, vertical drive and video signals are all
  present on the monitor connector.

  No light at all, no "buzz" typical of flyback transformer.

  Looks like horizontal/high-voltage circuit is dead.

Unfortunately I have no schematic - At least the only IC on
the board is a 555 - hopefully no unobtainium used in this
one (unless it's the flyback :-(

anyone got diagrams or other service information on a
"Zenith DS5NF3" monitor.

Suggestions/debug hints welcome - I'm guessing horizontal
output transistor or flyback ...

[and before anyone asks - yes, this is the one which was
 missing it's monitor plug, however I have borrowed the plug
 from a working machine and verified that the signals are
 getting to the monitor]

dave04a (at)    Dave Dunfield
dunfield (dot)  Firmware development services & tools: www.dunfield.com
com             Vintage computing equipment collector.
Received on Sat Nov 06 2004 - 13:39:32 GMT

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