HP-67 not working
#1

Hi,

My hp67 is stuck, displaying a fixed pattern and not responding to key presses.

Power cycling sometimes changes the pattern, but otherwise its stuck.

Using a digital oscilloscope I confirmed that main voltages (Vbat, Vss, Vgg are all OK: proper voltages without ripple).

Both clocks are fine as well.

SYNC looks OK (but has some ripple) as well as RCD.

However, STR is stuck high.

Should I assume that ROM0 (which generates STR) is broken and needs to be replaced, or should I be looking elsewhere?

Thanks

**vp

-----

Here is the SYNC signal:



Possibly Related Threads…
Thread Author Replies Views Last Post
  HP Prime Save Power Turn Off Not Working Timothy Roche 12 4,079 10-27-2013, 01:41 PM
Last Post: Michael de Estrada
  Temporary User Mode Key Programs not working in RPN BruceTTT 7 2,625 10-14-2013, 01:46 PM
Last Post: BruceTTT
  HP-97 suddenly not working Brad Barton 10 2,724 02-25-2013, 08:15 PM
Last Post: Brad Barton
  [41CL] Problem with PowerCL ... not working Doug (NYC) 5 1,932 01-22-2013, 07:18 PM
Last Post: Doug (NYC)
  42S exit key not working dwsmith 4 1,626 11-05-2012, 10:59 AM
Last Post: dwsmith
  HP-46 not working Ignacio Sánchez 1 995 10-24-2012, 11:17 AM
Last Post: Donald Williams
  [WP34s] last QtGui version not working fhub 8 2,448 08-31-2012, 05:08 PM
Last Post: fhub
  Modfile not working with Win 7 x64 Richard Wagoner 6 2,211 07-04-2012, 10:32 PM
Last Post: Diego Diaz.
  Working on HP's again Les Koller 49 12,651 06-20-2012, 01:29 AM
Last Post: Thomas Radtke
  held breath, found tapes & drive working Garth Wilson 9 3,039 06-12-2012, 12:52 AM
Last Post: Garth Wilson

Forum Jump: