27 Mar
2018
27 Mar
'18
4:19 p.m.
There's another option if you're near Manassas VA (roughly DC area):
https://www.ebay.com/itm/VINTAGE-Digital-DEC-RL02-A-Rack-Mount-PDP-11-Disk-…
Look at the pictures. It's in sad shape but if you look closely it looks
like the heads are locked in place for shipping. He's down to $16.49 (+199
shipping). If you can arrange local pickup it would probably be worth
risking 3 big Macs just for the parts.
Marc
On Tue, Mar 27, 2018 at 6:26 AM, Jay Jaeger via cctech <
cctech at classiccmp.org> wrote:
My inventory indicates that I have a pair of lower
("UP") heads, part
number 70-15637 for an RL02. (I don't have any spare "DOWN" heads as
far as I can tell). I think they might even be new old stock, as they
are marked "NEW" in my inventory. So maybe we could work something out.
You might suggest a price, and we can take it from there. Once we get
agreement, I'll open up the box they are in (in my garage) and confirm
my inventory.
JRJ
On 3/27/2018 4:34 AM, Aaron Jackson via cctech wrote:
Thanks for the suggestions, Allison.
Given that the pack was tested before it was shipped, I am beginning to
come to the conclusion that the heads are bad. I can see the servo burst
data if I push the heads on a few mm further into pack, but perhaps the
heads produce noise which confuse the logic upon load.
Heads are more expensive than what I'd like, from what I have seen on
eBay.
I believe I have a "working" (i.e. non-crashing) down head (as in the
one on top). If this is head 0 (anyone know?) then I might have a chance
of getting it working without spending anymore money. Let's see.
Thanks again,
Aaron.
> On 03/26/2018 04:08 PM, Aaron Jackson via
cctalk wrote:
>>>> So, from what I can see, the drive should spin up correctly, but for
>>>> some reason it goes into fault mode. I am right in thinking that upon
>>>> load, the heads should continue moving forward until the first track
is
>>>> found, right? I should not have
to perform a seek manually from the
PDP?
>>>> If this is not the case, perhaps
there is something else wrong.
>>> I?m not an RL02 hardware expert at all, just a daily user back in the
>>> day. I?m reading this assuming that at all times the drive is
>>> correctly hooked up to an RLV12 in a running PDP with the correct
>>> cable and termination present on the drive? If it isn?t you?ll get a
>>> fault condition instead of ready after spin up.
>>>
>>> A
>> No worries, your input has been valuable, so thank you.
>>
>> For anyone else who might have an idea:
> ON fault the heads are retracted and will not load till cleared.
> Least mine behaves that way.
>
> Most common problems are wrong drive address, cable issues, no
terminator.
> Others include head lock not removed or the
auto unlock style of
> headlock has
> the tab broken.
>
>> It seems to be hooked up correctly. When it is in the weird flashing
>> ready state, the boot loader says "Read error" or "Device
error"
>> randomly. The heads oscillate back and forth very slightly as if it is
>> trying to align itself better on the first track, which doesn't exist
>> because it hasn't moved far enough into the pack.
> IF in fault its resetting to retracted on every try.
> If not something else is wrong.
>
>> I'm beginning to think the heads are bad which will be far too
expensive
so I may end up giving up.
Heads are not that expensive... However you could have a wrong pack
or one that has been erased and has no servo tracks. You must start with
a known good pack and cleaned heads.
Allison