On 30 Jan 99 at 23:35, R. Stricklin (kjaeros) wrote:
I finally scored a piece of disk-based software for Atari 8-bits, so I
decided today to test out my atari disk drives to see if any of them
One 1050 did.
The other 1050 doesn't run the seek test when you turn it on, and is
invisible to the computer. I removed the actual disk drive from the
cabinet and verified that it does in fact work in the other 1050 chassis.
While doing this I noticed that the non-working 1050 seemed to have had a
modification done (rather sloppily, I might add; I suspect this has
something to do with why it doesn't work properly).
There is a hand-written silver sticker over what I'm assuming is an EPROM
that reads, "Doubler". There is a second Motorola 6810 piggybacked onto
the normal 6810, and a couple of jumper wires leading off into the PCB.
What was this, and how was it done properly (so I can verify that it's
I have a Percom branded full height disk with Atari SIO connects on that
also seems to not work. I think this is because I need to decipher the
4-position DIP switch at the back panel. Any hints? As it is now, the
access light repeatedly switches on and goes off again, each accompanied
by a moderately loud click. The light is on for a second and then off for
maybe two. It doesn't ever stop doing this, and the drive is invisble to
the computer. The drive inside is full height, and made by Tandon I
From David Pattersons Atari 8-bit Hardware Upgrade FAQ
The Atari 1050 drive was brain-damaged from the
very beginning. Rather than add a few dollars worth of
parts to make a true double-density drive, Atari invented
their own format, called "dual-density", which stored
130k on a disk. ICD produced the US Doubler, a hardware
add-on that gave the 1050 true double-density. As an
added bonus, it also included UltraSpeed, which made
"the normal beep-beep of Pokey sound like staccato
machine gun fire" according to one review. A variant
was produced which added 4 to the drive number,
permitting drives to be addressed as D5:-D8:.
Likely the best place to get answers would be
naewsgroup. It is very active and they're a helpful lot.