I am not sure that removing the brake will help.
I once heard the following rumour:
the brake in combination with the 'heavy' motor
makes sure that the disk platters always rotate
in the same direction, never for a short instance
in the other direction (vibration, power flutter,
whatever reason). Rotation in the opposite direction,
for any short moment, will cause the air on which the
r/w head fly to disappear and result in an immediate
head crash ...
As I said, it is a rumour I once heard a few years ago.
Has anybody heard of this too?
gd luck with your drive,
- Henk, PA8PDP
> -----Original Message-----
> From: Brad Parker [mailto:brad@heeltoe.com]
> Sent: dinsdag 9 maart 2004 2:50
> To: General Discussion: On-Topic and Off-Topic Posts
> Subject: Re: R80/RA81 diagnostic experience?
>
>
> >Tony Duell wrote:
> >>
> >>IIRC there's a microswitch which detects that the tensioner
> >>lever is in the 'tensioned' position, but nothing more. Of
> >>course the drive does check that the spindle is rotating at
> >>the right speed when it's spun up.
>
> I pulled the HDA - the belt tension switch was fine.
>
> I found, however, the electric brake was *extremely* tight. So much
> friction that I doubt very much the motor could spin at all.
> I removed it (I'll sand down the 'brake pad' later).
>
> Hoping for a small miracle I fired it back up but still no joy - the
> motor (now free) refused to spin up.
>
> [a side note: the unit does not seem to reset no power up -
> it comes up with all lights on until I click the reset manually.
> sometime tells me this is a symptom]
>
> I need some prints so I can trace the motor power back to the micro...
>
> Any have prints for an R80 (or RA80/RB80/RM80). Or an RA81?
> I suspect they are similar in terms of motor drive...
>
> -brad
I just got a call from a friend of mine who has a number of NOS
Panasonic LDV-1000 Video Disk Players. These are the type that were used
in some of the early video games like Cinamatronics Space Ace. Is there
any interest in them from list members? Apparently the only thing wrong
is that the boxes got damaged but the units themselves are fine. Let me
know via email if you are interested.
After wanting a Commodore 64 SX for such a long time, a kind man
finally gave me one. (it was
the victim of a garage-clean out. I got it back home and it worked fine
for a while. later
that night I was writing basic programs and this strange color washed
over it's little screen
then it went blank.
Cycling power did not restore any picture.
I left it unplugged overnight, (thinking the problem may have been heat
related)
but it's still in the same state this morning.
Any one have any knowledge? Is it really dead? Is there anything I can
do?
A little info can be found here:
www.pdp-11.nl/peripherals/disk/ra81-info.html
According to the table, when the rightmost light [B]
stays on (and the FAULT light of course), it would mean
you have spin-up problems. Did you tension the belt with
the lever at the right-hand side (at least there it is
in an RA81 drive)?
success,
- Henk, PA8PDP
> -----Original Message-----
> From: Brad Parker [mailto:brad@heeltoe.com]
> Sent: maandag 8 maart 2004 15:50
> To: General Discussion: On-Topic and Off-Topic Posts
> Subject: R80/RA81 diagnostic experience?
>
>
>
> [resend - looks like original got lost this weekend]
>
> Hi,
>
> If anyone has diagnostic experience with an R80 or RA81, I'd like to
> pick your brain a little...
>
> If this is better done off line, email is fine. I suspect
> not everyone
> is interested on how to revive an R80 :-)
>
> (why *I* find it infinitely fascinating is something I'll
> never understand)
>
> I have an R80 which does not spin up or come ready:
>
> - All of the voltages are good (all the ones I checked anyway).
> - The drive belt had come off but I managed to get it back on
> - I can't seem to get it into diagnostic mode; the 8 leds' on the
> bottom pcb show 0101 0101 (hex 55).
> - When it powers up all of the external lights go on and stay on.
> - if I reset (click the switch ont the pcb to "R", the lights go out
> - if I then push the run/start it lights and after about 5 seconds
> the fault light comes on and run/start goes out.
> - if I push the fault light all lights go on and then the right most
> one stays on
> - push fault again and they all go out (I can then repeat the
> run/start sequence)
>
> I'm guessing the above behavior means the micro is operating,
> but then I set the rotaries to "FF" and hit 'enter' (i.e. put the
> toggle to 'E') the led's don't change at all. The manual says they
> should flash and change as a I enter diag mode. I wanted to use
> diag more to force a spin up but no joy.
>
> Does the unit have to be connected to a controller to go into
> diag mode?
> I have an RB730 which this connects to. Connecting is does
> not seem to really change it's behavior.
>
> -brad
Ive got well over 50 SONY QW5122F tapes brand new still wrapped up. 200/420M
capacity. Not sure what they work on though. .25 cents each.
Also have other QIC80 tapes, but no MC3020 anymore. Inquire for others.
--
On Mon, 8 Mar 2004 Brad Parker <brad(a)heeltoe.com> wrote:
> Gooijen H wrote:
> >A little info can be found here:
> >www.pdp-11.nl/peripherals/disk/ra81-info.html
>
> thanks!
>
> >Did you tension the belt with the lever at the right-hand side (at
> >least there it is in an RA81 drive)?
>
> I did, and it seems to be right, but who knows. Is there any sort of
> lock out or micro switch which senses proper belt tension?
Yes, I think so. Also, there is a transport safety for the heads. It's a
lever on the HDA, which you should turn to unlocked.
Does the R80 have the terminal interface on one card like the RA8x drives
do? If so, plug a terminal in there and talk with the drive. 1200 bps I
think, though it could be 300. 8N1.
> This is an R80 drive, btw. I'm assuming the RA80, RB80 and RM80 are all
> very similar at the drive end (not the controller end - which is very
> different).
Yes, it's the same HDA.
Johnny
Johnny Billquist || "I'm on a bus
|| on a psychedelic trip
email: bqt(a)update.uu.se || Reading murder books
pdp is alive! || tryin' to stay hip" - B. Idol
TSIA
Not sure if I posted this already. I was wondering if anyone has an extra
original manual for the HP 10529A logic comparator.
Thanks!
Jay West
---
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