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Need a bit of help resurrecting my PDP-11/73

Wednesday's update. I found a tutorial on unsticking the RD53 drives. Was able to free up the heads after going through that. Still, DU0 reports as Not ready.

I really wish there was some visual indication that it's getting any signals from the controller. Unfortunately on the RQDX3 controller there are no lights, nor are there any on the drive itself. So I can't see (and I can't hear) that it's attempting to do anything. The only thing I know is that the controller seems to see the drive, since if I unplug it it reports Non-existent drive. I just can't get it to read from the drive (or so it seems).
 
I seem to remember (back when I was trying to create a bootable drive for my 11/84) that "Disk not Ready" could indicate it's not finding anything bootable on the drive. Can you hook the drive up to a power supply and listen to it spin up? You should be able to hear that and the heads mounting.
 
tradde said:
I seem to remember (back when I was trying to create a bootable drive for my 11/84) that "Disk not Ready" could indicate it's not finding anything bootable on the drive. Can you hook the drive up to a power supply and listen to it spin up? You should be able to hear that and the heads mounting.
Click to expand...

I don't have a separate power supply to use. I slid the drive out a bit, and removed the TK50 (to cut down on the noise). Listened and didn't hear much. However, two things have changed:
1. The rear end of the drive is now getting warm, so it seems to be doing something
2. On one startup attempt, I got this far... after it entered dialog mode,I got this:

Testing

Boot in progress - Please wait - Type CTRL C to exit

But it just sat there. I will reseat the cables on the drive end again in case something is loose.
 
Ok, that seems to indicate the drive does have something bootable on it. Maybe it's gotten corrupted though and still can't boot. Yes, having a separate power supply is a good thing at times. I have several older SCSI drives I am trying to determine whether are useable. First test is the "do they spin up test". :) Could the TK50 somehow be interfering with the hard drive? I don't know how that would be but you never know. Just kinda weird that once you removed it the drive went further on booting. Keep at it and you'll get it sorted out.
 
Well, it only got to that point once. After reseating the cables again on the frontplane, it's back to where it was before.

I have some Deoxit coming Friday and will take the cards out one by one (documenting where each one goes for sure) and cleaning the edge connectors. There's a lot of dust in the sockets on the entire machine that I'll use a gentle brush to remove and then vacuum.

I wish I knew what the LEDs indicate on the back of the CPU. Generally I have (from the top down) 2 small red LEDs lit, then a large green lit, then another small red lit. This is after it fails to boot. I did some searching online but can't seem to find what those LEDs indicate.

Also wish I knew what the Continuous Self Test (in Dialog mode) is actually testing. I have let it run several times for say 10-20 minutes, then Ctrl-Z out. Every time it reports some number of Passes and Errors. Errors are always zero.
 
Well, reading from my 11/84 manuals and the 11/84 is a M8190 board. There should be 6 red LEDs. 3 before the green and 3 after. The green indicates DC Ok. The 6 red leds should be the same as the octal number on the front panel. They are read from the back of the unit forward looking from the back side of the CPU card.
 
Well, my guess is your drive is toast. I have one of the Dave Gesswin MFM readers and spent a lot of time this fall hooking up old drives including some RD53's. If you really want to you can send it to me and I'll see what (if anything) is on it. I have a couple of RD53's but I keep them around for my Pro/380's to consume.

What do you want to do with this thing? Play games? Hack?
 
There are some DEC people in that area. If I still lived there I'd offer my machine to help you out. It is likely your HD is toast though being an RD53.
 
czunit said:
What do you want to do with this thing? Play games? Hack?
Click to expand...

Just hack a bit, I suppose. The allure of running something that I set up 30+ years ago.

There's nothing on it that's critical, of course, just old files and my company's old programming to reminisce on.

I've been mulling around the idea of stripping the guts out and mounting a Raspberry pi running simh in it. Could be fun to do a little custom wiring to get some of the original lights and power switch to function with the new "engine" inside. Also rework the rear distribution panel to accommodate USB and other modern-day ports.

This weekend I'm going to pull all the cards out and clean everything well and see if that makes any difference. I'll give it a few more tries before calling it a day.
 
You could also buy one of Dave's boards and configure it to be an RD54. Then plug it into the MFM cables and load whatever OS you want on the Beaglebone. Or multiple different OSes. It's not too expensive and would solve your problem once again.
 
Noooo. Don’t Pi it!

The LED status and boot codes (including what they test (i.e. the firmware tests) are all documented in the bitsaver’s archive. Navigate to the DEC PDP11 11/73 directory.

You could also see if you can locate a suitable RX33 5 1/4” floppy as a test. Another option is a SCSI card and a SCSI to SD card adapter.

See how much of the existing cards are working (after you have cleaned them) and then run the XXDP diagnostics to see if the RQDX3 controller itself appears OK.

Dave
 
Yeah, I'm sitting tight until the anti-static kit and Deoxit arrive. Then I"ll do a good cleaning.

I did read over the the info on bitsaver's yesterday, thanks for that, and it appears the CPU lights are indicating thumb's up.

I had to pull the cover off the TK50 drive; after I tried loading an xxdp tape the other day it had problems ejecting the tape. I got the tape out (no damage) but then the drive was making one heck of a racket. Turns out the (I'm sure this isn't the correct term) lead-in (the piece of flexible stuff that leads from the center of the drive wheel and catches the end of the removable tape) had come off of the "catcher arm" and was just flopping around in there. I cleaned the head and drive wheels, and rethreaded the lead-in thingy back through and hooked it on the catcher arm. I haven't tried loading another tape. If I install a tape with xxdp on it, and attempt to boot from it, how long should I expect it'll take (and should I see activity on either the green light at the bottom of the drive or the red pushbutton) to boot? I recollect that it's pretty time-consuming.

Is the RD53 a SCSI drive, meaning if the drive turns out to be bad, can I remove it and replace it with a scsi2sd adapter and sd card, and load a virgin RSX-11M distribution on it? That seems too simple to be possible but if it is, that would eliminate a major risk of mechanical failure. Of course, that would require that the RQDX3 is operating ok.

I really appreciate all the help folks! Thank you.
 
czunit said:
You could also buy one of Dave's boards and configure it to be an RD54. Then plug it into the MFM cables and load whatever OS you want on the Beaglebone. Or multiple different OSes. It's not too expensive and would solve your problem once again.
Click to expand...

Or one of Joerg's QBone boards and emulate any of RK05, RL01/2, any MSCP disk. I have one in my PDP-11/53 and it works well.

Info here: http://www.retrocmp.com/projects/qbone

North American distribution here: https://decromancer.ooo/qbone/ - At $495 Cad ($390.29 US currently) assembled it's not cheap, but it's a great piece of kit.
 
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reinhardtjh said:
Or one of Joerg's QBone boards and emulate any of RK05, RL01/2, any MSCP disk. I have one in my PDP-11/53 and it works well.

Info here: http://www.retrocmp.com/projects/qbone

North American distribution here: https://decromancer.ooo/qbone/ - At $495 Cad ($390.29 US currently) assembled it's not cheap, but it's a great piece of kit.
Click to expand...

Yes, I came across QBone yesterday while doing some research. As I understand it, QBone is very flexible and can be also used as a single-board replacement (i.e. remove all old cards and just install the QBone, along with a new drive)? I think I'd consider using an SD card formatted as two RDxx drives (one to run on, one for backups). Is what I'm thinking possible with the QBone?
 
>>> Is the RD53 a SCSI drive.

Afraid not. It has an ST506 interface.

You will need a different controller (e.g. CMD).

Dave
 
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That reader/emulator looks pretty neat - apparently it can read existing MFM drives (so there's a chance I could read my existing drive and save it to the BeagleBoard storage) as well as emulate a drive. I'm not quite sure I understand though (where's it's emulating a drive) what does it use for storage? In the picture (one attached) I see where the original control and power cables connect to it, and then they show ribbon cables going off to the left - are they going to other (new scsi) drives? In other words, where are the disk images stored when using one of these? Click image for larger version Name: MFM Reader Emulator.jpeg Views: 0 Size: 205.6 KB ID: 1235450
 
Ok. So if I cannot get the existing RD53 disk and/or RQDX3 controller to work or I find other problems such as a CPU issue, one option is to install the QBone to replace all of the existing cards in the QBUS. That gives me much better CPU performance, memory, diagnostic LEDs, ethernet, and modern I/O ports (I am not sure what the QBone comes with for ports, such as USB). Of course, then I'm running RSX11M on a simulator rather than directly on DEC hardware.

Anyhow, with this configuration, am I understanding correctly that my two storage options would be like this:
  1. QBONE ==> RQDX3 ==> MFM EMULATOR ==> Back to storage on the BeagleBoard SD CARD
  2. QBONE ==> Storage on the BeagleBoard SD CARD directly
If this is correct, is there any reason not to just go with Option #2 (other than I would have one less original DEC board in the QBUS)?
 
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