TRS-80 Model III - test-drb@ccmp.vtda.org

7 Aug 2002

I know that the TRS-80 Model 4P uses a PLL to do the high res video mode,
and that a common cause of crappy quality display is the setting of the VCO
cap.
My 4P was unsable until I adjusted the cap, not it is beautiful.
regards
Doug Jackson
MSS Operations Manager
Citadel Securix
(02) 6290 9011 (Ph)
(02) 6262 6215 (Fax)
(0414) 986 878 (mobile)
...
  -----Original Message-----
 From: Curt Vendel [mailto:curt@atarimuseum.com]
 Sent: Wednesday, August 07, 2002 1:43 PM
 To: cctalk(a)classiccmp.org
 Subject: Re: TRS-80 Model III
 Sellam,
    Are the boot straps on eproms on the motherboards???   You
 may be facing
 possible bitrot, that's one possibility.
 Curt
 ----- Original Message -----
 From: "Sellam Ismail" &lt;foo(a)siconic.com&gt;
 To: "Classic Computers Mailing List" &lt;cctalk(a)classiccmp.org&gt;
 Sent: Tuesday, August 06, 2002 3:31 PM
 Subject: TRS-80 Model III

 I am trying to get a TRS-80 Model III working.  When I turn   it on the disk
  drive spins for a while looking for a disk I
presume.  All   I get on the
  screen are wispish diagonal lines as if the
horizontal hold is all
 whacked.
 I managed to unstick one of the video adjustment knobs on the left
 underside but all it does is affect the brightness level.    The other one
  requires a screwdriver to move at all (shimmying
it up and   down) and does
  not seem to affect the display.  I haven't
opened it yet to see what
 adjustments are inside.  I'd rather not, but there don't   seem to be any
  adjustment pots accessible from outside the case.
 What's weird is that I have access to a bunch of TRS-80   Model 3's here at
  the ACCRC and pretty much all of the ones I have
played   with so far are
  basically "dead" in this manner.  The
one I'm working on   just came in
  today and is in the same state.  Also, the video
knobs on the left
 underside are all stuck on everyone I've tried to get   working.  What is
  the deal with that?  Do they get rusted over time
or   something?  Very
  annoying.
 The fact that the disk drive spins up when I turn it on is   a good sign I
  hope.
 Any help on this would be appreciated.  I know next to zero   about the
  TRS-80 series.
 Sellam Ismail                                          Vintage Computer
 Festival

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