14 Apr
1997
14 Apr
'97
3:04 a.m.
Well damn and double damn. My poor little TS1000 is
brain dead. I don't
get so much as a flicker on my TV out of it. Can someone suggest any
tips towards reviving it? I took it apart and the only noticeable
problem I noticed was that the keyboard connector strip was very brittle
The machine will work without the keyboard.
and broke in a couple places. I'm sure whatever
the case may be the
keyboard requires a new connector. I'm using my Atari 2600 9VDC adaptor
which should work fine. Does anyone know what voltages I should see on
Have you got the polarity correct? I _think_ (and somebody should
correct me if I'm not) that the TS1000 power jack has the tip positive.
I'd be inclined to check for +5V at the output of the 7805 regulator. The
modulator case (silver metal box) is a 0v ground. If you've got 5V, then
check for a clock waveform at pin 6 (?) of the Z80 CPU.
I assume you've tried tuning the television. The output of a TS1000 is an
RF signal, not composite video. I guess it outputs on Channel 3 or 4 in
the States - over here it's on UHF channel 36 (as are most other
computers)
the back edge connector? Should I try swapping out
the CPU? There is
also another 40-PIN chip in there (forgot what it was) and the Sinclair
The other 40 pin chip is a custom Sinclair ULA, which is almost impossible
to obtain. It's worse than the ROM in that it can't be copied. In theory,
the ROM can be replaced by an EPROM, and I believe ZX81 ROM dumps are
floating about somewhere...
ROM chip. I don't suppose I could find a
replacement for that. Judging
There should also be 1 or 2 RAM chips (4118 or 2 off 2114's I think)
from the brittleness of the keyboard connector, my
guess is that the poor
guy has been baking in the sun for years. Oh well. Guess I gotta keep
searching.
Sam
--
-tony
ard12(a)eng.cam.ac.uk
The gates in my computer are AND,OR and NOT, not Bill