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Newly acquired 11/23+

glitch said:
Nice work!

On the stuck RL02, the pin on the slide latch is probably out of its groove in the release mechanism. You can line them back up and get it back in by having the slide lock halfway over and the lever halfway up, then releasing them (slide lock to spring driven resting position, lever down). It takes some fiddling.

Be sure to replace the cooling air intake filter behind the fronts of the drives -- 10 years ago, mine were fine, but when I opened them for servicing this year, the foam was turning to chunks and dust!

Getting the DLV11-J going is definitely not critical with the KDF11-B in there, you get console + SLU0 for TU58 emulation onboard.
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"Be sure to replace the cooling air intake filter behind the fronts of the drives."

I know I'm sounding like a broken record (not going to explain that to the younger folks) but replace them with what? I have a suspicion that any NOS filters laying about might be as degraded as the ones in the drive. Ditto for any filters pulled from a parts donor drive. Any new info on a source for new(ish) filters? Has anyone taken a crack at a DIY solution?
 
DDS said:
For sealing/resealing engine parts, I'd use some flavor of RTV silicone. But they tend to release acidic vapor when curing and afterwards whereas aquarium glue does not. Anything here to be concerned about when choosing what to use to reseal those tubes?
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I use 3M Polygun adhesive, which is industrial hot glue. I would definitely be concerned about the acetic acid released as RTV cures. The brown stuff DEC used melts if you get the Polygun hot end against it, so it's probably some similar hot melt.

DDS said:
"Be sure to replace the cooling air intake filter behind the fronts of the drives."

I know I'm sounding like a broken record (not going to explain that to the younger folks) but replace them with what? I have a suspicion that any NOS filters laying about might be as degraded as the ones in the drive. Ditto for any filters pulled from a parts donor drive. Any new info on a source for new(ish) filters? Has anyone taken a crack at a DIY solution?
Click to expand...

I used this:


One package is less than $4 USD and contains enough for a pile of RL drives! It is about the same thickness as the original, and probably close on density. Since it's just a coarse filter for cooling air, it doesn't need to be an exact match. I've used similar product on e.g. the foam cooling air filters on test equipment, the kind with the snap-on plastic grille that goes on an 80mm or 120mm fan.
 
I spent time cleaning both the RL02 mechanism and the RL02 packs themselves. For the drives, everything looked pretty good, and the heads were clean when I cleaned them. I followed glitch's RL02 cleaning outline. There was no indication of head crashes or other surface damage. I heard no unusual noises when I powered up, and the first drive went ready.

Booting didn't work. I have three packs and two drives, and all of them give me a halt shortly after typing DL0 or DL1 at the boot prompt. I messed around with a few things. I tried using PDP11GUI (brilliant program) to dump the drives, but _every single sector_ gave read errors. This happened on both drives, all three packs.

I had a hard time loading the XXDP module for the RLV12 controller via PDP11GUI, as I did not know the starting address (the comments on starting at 200 didn't work), so I used TU58EM (another brilliant program), and booted XXDP modules from here (https://ak6dn.github.io/PDP-11/TU58/).

I started with VRLB, a diskless controller test (identified as 11XX_5 in the site above), and when I ran it, I got tons of errors. I do not know how to interpret these errors, so I've attached the console log in the hopes that some may give me direction. At the end of the console log is a boot attempt showing the halt.
 

Attachments

  • xxdp-log.txt
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Having skimmed the test output, it looks like you probably have a fault somewhere in the serialization datapath or in the CRC generation circuits. You're getting all the way to test #026 so basic QBus data and address paths, address decoding, etc. are probably not fragged, and it attempts to boot instead of telling you there's no such device, which is further suggestion that the basics of the controller interface are functioning.

For future notes, XXDP controllerless tests are definitely the place to start, running through the diagnostics will avoid stomping on good data. Always start with the write protect switch engaged, and don't release it until you have good reason to do so. I have no experience with PDP11GUI other than fixing problems other hobbyists insisted couldn't exist because "PDP11GUI said it was OK" (it's my impression that's not really "how it works"), but running off @AK6DN tu58em and premade images is an excellent path forward, until you get your RLs working.
 
glitch said:
I use 3M Polygun adhesive, which is industrial hot glue. I would definitely be concerned about the acetic acid released as RTV cures.
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There is RTV silicon that doesn't release acetic acid during cure. If its labeled electronics grade or neutral cure should be safe.
 
glitch said:
Having skimmed the test output, it looks like you probably have a fault somewhere in the serialization datapath or in the CRC generation circuits. You're getting all the way to test #026 so basic QBus data and address paths, address decoding, etc. are probably not fragged, and it attempts to boot instead of telling you there's no such device, which is further suggestion that the basics of the controller interface are functioning.
Click to expand...

While digging thru the documentation, including the service prints, that leads me to two more questions:

#1 - since I'll need to scope out signals, is there any way to acquire a q-bus extender, so I can bring the RLV12 out of the cage to test things?
#2 - is the source for the VRLBC diagnostics available anywhere?

I've searched around for both, but not much luck. An older thread (~2018) referred to Douglas as a possible supplier for q-bus extenders, but the URL provided is now some scammy looking site.
 
Douglas Electronics is indeed the correct place to buy an extender. This is the quad height extender:

Douglas Electronics Inc || 6-DE-8

The 6-DE-8 is a quad-width, dual-height DEC compatible extender board with 144 contacts (72/side) on .125" centers on 4 tabs. It is available as a bare board or with 72-125C-EL connectors installed (6-DE-8-C option). <p>Height 8.43" Width 10.436"
www.douglaspcb.com www.douglaspcb.com

You can order that, or two dual extenders (listed elsewhere on their site). I've bought from them since 2018 and had no problems.

The source for the diagnostic is probably going to be on microfiche, some of which has been scanned and is on Bitsavers, etc. It is seemingly not well indexed, so you will likely have to dig through directories.
 
ftcnet said:
I don't think there's an extender that's specific to the QBus, but if you want the option to build your own set of DEC extenders Todd Goodman has the parts.
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I can second Todd Goodman. I bought a quad extended (5mm longer) and a dual extended board and connectors from him in 2021 and have no complaints. I emailed him, he responded, I replied and I had the board i just a couple days. The worst part was soldering all the connections. 🤪 (Even that wasn't that bad).

The board inventory is here: https://retrobrewcomputers.org/doku.php?id=boardinventory

Scroll down to near the bottom.

Funny coincidence, I was just looking at the emails and the website wondering if I should order a few more connectors and boards. Is one quad and one dual extender enough?
 
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