18 Jan
2015
18 Jan
'15
4:05 p.m.
Does anyone know the whereabouts of an online copy of the field maintenance print set for
the VT101? It's part number is MP-01066.
-----Original Message-----
From: cctalk [mailto:cctalk-bounces at classiccmp.org] On Behalf Of Johnny
Billquist
Sent: 18 January 2015 22:53
To: cctalk at classiccmp.org
Subject: Re: VT101 8085 CPU Fault
On 2015-01-18 23:04, Diane Bruce wrote:
A remote possibility is the boot ROM is b0rked and it's simply running
around like a chicken without a head.
That is something a good logic analyser could tell you.
If the RD pin never gets active, the contents of the ROM will not even be
presented to the CPU, so while it's possible the ROM is borked, that is not the
problem we're trying to fix right now.
Johnny
--
Johnny Billquist || "I'm on a bus
|| on a psychedelic trip
email: bqt at softjar.se || Reading murder books
pdp is alive! || tryin' to stay hip" - B. Idol
On Sun, Jan 18, 2015 at 09:47:35PM -0000, Robert
Jarratt wrote:
...
>> you more. Nice sharp edges to signals when they shift. Times that
>> look reasonable... Steady levels, and correct levels.
> It will never be steady with a scope
because the address lines won't be a
regular waveform. That said they looked
very different on the faulty board to
how they looked on the good board.