26 Mar
2018
26 Mar
'18
11:21 a.m.
Hello,
I'm not an absolute expert, but I successfully fixed a couple of RL02 in
the past.
Adjustment to the head is only useful for azimuth, I think. The radial
position will be adjusted continuously using the servo tracks, so there's
no absolute position adjustment at all.
If the drive fails during spinup, I would check at least the following:
- the presence of spindle sector signal after digital conversion of pulses
from analog signal coming from the pickup.
-
having disabled the servo linear motor (there's some jumper to setup,
check the maintenance manual), perform the motor spinup, then load slowly
the heads on the disk by hand, until you find the servo tracks.
- with an oscilloscope check the presence of analog signal of the servo
tracks on both heads, and it's digital counterpart after amplification and
threshold detection (expected level values in the manual). If you see
something strange, e.g missing or too short pulses, try to adjust the gain
with the trimmer on the head board
- enable again the servo, then load again
My 2 cents.
Andrea
26 Mar
26 Mar
11:59 a.m.
Hi Andrea,
Thanks for your suggestions.
Checking the amplified output from the r/w heads is one of the first
things I did. The voltages are within normal range, but only after I
push the head a bit further into the pack.
Although, I did not set the jumper to try the other head (I suppose I
was always looking at head 0), so I've just tried this now. There does
indeed appear to be servo burst data coming from both heads once I've
manually loaded them fully. So I am not sure if this is the problem. I'm
really hoping that the pack is not bad since I paid for a tested pack.
I also checked the sector transducer output last night. The individual
waves (i.e. from trough to peak) seem to be twice as fast, but the
timings between two peaks is correct.
The survo busts are correctly aligned with the sector pulses.
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.
Thanks again for your input,
Aaron.
shadoooo via cctalk writes:
Hello,
I'm not an absolute expert, but I successfully fixed a couple of RL02 in
the past.
Adjustment to the head is only useful for azimuth, I think. The radial
position will be adjusted continuously using the servo tracks, so there's
no absolute position adjustment at all.
If the drive fails during spinup, I would check at least the following:
- the presence of spindle sector signal after digital conversion of pulses
from analog signal coming from the pickup.
- having disabled the servo linear motor (there's some jumper to setup,
check the maintenance manual), perform the motor spinup, then load slowly
the heads on the disk by hand, until you find the servo tracks.
- with an oscilloscope check the presence of analog signal of the servo
tracks on both heads, and it's digital counterpart after amplification and
threshold detection (expected level values in the manual). If you see
something strange, e.g missing or too short pulses, try to adjust the gain
with the trimmer on the head board
- enable again the servo, then load again
My 2 cents.
Andrea
--
Aaron Jackson
PhD Student, Computer Vision Laboratory, Uni of Nottingham
http://aaronsplace.co.uk
12:16 p.m.
I have turned up the amplitude just a little higher than I think it
should be. Instead of going into fault mode after loading a pack, the
READY light flashes about quickly. With the scope hooked up I can see
that it hasn't managed to find the first track yet. Not really sure what
it thinks it is doing...
Aaron Jackson via cctalk writes:
Hi Andrea,
Thanks for your suggestions.
Checking the amplified output from the r/w heads is one of the first
things I did. The voltages are within normal range, but only after I
push the head a bit further into the pack.
Although, I did not set the jumper to try the other head (I suppose I
was always looking at head 0), so I've just tried this now. There does
indeed appear to be servo burst data coming from both heads once I've
manually loaded them fully. So I am not sure if this is the problem. I'm
really hoping that the pack is not bad since I paid for a tested pack.
I also checked the sector transducer output last night. The individual
waves (i.e. from trough to peak) seem to be twice as fast, but the
timings between two peaks is correct.
The survo busts are correctly aligned with the sector pulses.
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.
Thanks again for your input,
Aaron.
shadoooo via cctalk writes:
> Hello,
> I'm not an absolute expert, but I successfully fixed a couple of RL02 in
> the past.
> Adjustment to the head is only useful for azimuth, I think. The radial
> position will be adjusted continuously using the servo tracks, so there's
> no absolute position adjustment at all.
> If the drive fails during spinup, I would check at least the following:
> - the presence of spindle sector signal after digital conversion of pulses
> from analog signal coming from the pickup.
> - having disabled the servo linear motor (there's some jumper to setup,
> check the maintenance manual), perform the motor spinup, then load slowly
> the heads on the disk by hand, until you find the servo tracks.
> - with an oscilloscope check the presence of analog signal of the servo
> tracks on both heads, and it's digital counterpart after amplification and
> threshold detection (expected level values in the manual). If you see
> something strange, e.g missing or too short pulses, try to adjust the gain
> with the trimmer on the head board
> - enable again the servo, then load again
>
> My 2 cents.
> Andrea
--
Aaron Jackson
PhD Student, Computer Vision Laboratory, Uni of Nottingham
http://aaronsplace.co.uk
12:37 p.m.
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
1:08 p.m.
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 
1:17 p.m.
On 03/26/2018 04:08 PM, Aaron Jackson via cctalk wrote:
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.
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 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
27 Mar
27 Mar
2:34 a.m.
On 03/26/2018 04:08 PM, Aaron Jackson via cctalk
wrote:
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.
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.
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 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
5:32 a.m.
On 03/27/2018 05:34 AM, Aaron Jackson wrote:
Did it
survive shipment?? Common problem.
On 03/26/2018
04:08 PM, Aaron Jackson via cctalk wrote:
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.
Thanks for the suggestions, Allison.
Given that the pack was tested before it was shipped, I am beginning to > 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: 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 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.
Not likely the heads produce
noise they are passive.? If there is a loose
or broken wire maybe and thats easily checked with an ohm meter.
However... If you push the heads in you see servo burst that suggests a
alignment or servo system problem.? Its supposed to seek and find the
servo info.
Heads fail only a few ways.? Broken wires, crashed with mechanical damage,
and open windings.? They are remarkably simple other than mechanically
precise.
Heads are more expensive than what I'd like, from
what I have seen on
eBay.
Cant help that.
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.
I'd have
to read the RL02 service docs to remember what head is which.
I'
d suggest diagnosing the problem to see if its a servo/mechanical
alignment issue.
Long short story.? I got my RL02 directly through DEC while I was a
engineer there.
It was a pile of parts in the back lab.? The story was it was pulled
from a customer
site as FS could not make it work
at install.? Seems despite being new
just about
everything that could be swapped apparently was and no one could get it
to spin
up. ? So I made a deal if I get it working its mine (ok, to be part of
the 11/23 in my
office, which later would become mine).?? After assembling it and
testing it sure
enough it didn't spin and would turn slowly for a few moments and quit.
? Drag
out the meter and start testing voltages.? I found the motor starting
cap (known
new) had odd voltages.?? A bit of ohming out later it was the crimped
faston
connector at the end of the power line going to the capacitor.?? What
was wrong
was crimped but the wire was never stripped so there was no connection.?
The
only thing never swapped was the power wiring harness.? The pile of swapped
boards and even heads was impressive.? I got the drive and word got around
that it was me that solved the riddle.? I troubleshot the problem, and
didn't
swap it to death.
Before you swap out a part that is expensive or unobtainium check to be
sure its the problem.
Allison
6:26 a.m.
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:
On 03/26/2018
04:08 PM, Aaron Jackson via cctalk wrote:
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.
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.
> 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: 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 
9:19 a.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
12:22 p.m.
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 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
1:54 p.m.
On 03/27/2018 03:22 PM, Aaron Jackson wrote:
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.
Well, I replaced the DOWN head and adjusted the amplitude on the r/w
board. The drive now stays in READY without the FAULT lamp coming on, so
this is promising. The heads load onto the first track.
Without any r/w operations, should the READY light flash? Mine is
flashing a little but not too rapidly. I am guessing this is while it
tries to keep the heads positioned over the track. Yes, normal read/write/seek
activity causes that.
> 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: 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 When I try to boot using the MXV11-BF boot roms, it
says:
MXV-11 boot is not very chatty or informative.
]] ?BOOTROM-F- DL 0 read error
The alignment between the two heads looks okay also.
Any ideas, anyone?
Is the OS on it?? IF RT-11 is it configured to boot from DL-nn?
IF you have OS on floppy can your do a dir of the devices it knows of?
Allison
Thanks,
Aaron.
2:04 p.m.
>> 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 When I try to boot using the MXV11-BF boot roms,
it says:
MXV-11 boot is not very chatty or informative.
]] ?BOOTROM-F- DL 0 read error
The alignment between the two heads looks okay also.
Any ideas, anyone?
Is the OS on it? IF RT-11 is it configured to boot from DL-nn?
IF you have OS on floppy can your do a dir of the devices it knows of?
2238
days inactive
2239
days old
12 comments
6 participants
participants (6)
-
aaron＠aaronsplace.co.uk -
allisonportable＠gmail.com -
binarydinosaurs＠gmail.com -
cramcram＠gmail.com -
cube1＠charter.net -
shadoooo＠gmail.com