July 2023

CMAC R2133 20.48MHz TCVCXO

I have two PCBs from a piece of defunct Nortel equipment with this oscillator. CMAC R2133 Freq 20.48 MHz. Looking at the circuitry around it, there’s a 16-bit DAC (AD7846), a 5V regulator (78L05) and a buffer (74F00). Google could not find me a datasheet, so I removed the oscillator to trace the pinouts (Nortel used the outside layers as groundplane, you will see nearly every trace goes from a component to a via. Makes it difficult).

Pin 1 is 0V, pin 2 is the output, pin 3 is 5V, and pin 16 is the control voltage from the DAC which is configured to supply 0-5V out via the 51R1 resistor R40 and a 47u capacitor C77. The output goes to pin 2 of the 74F00 via 33R2 R53.

I posted the above pic to Facebook, within an hour or two someone sent me the datasheet (well, the Nortel spec sheet, which is basically the datasheet in reverse). It is indeed a TCVCXO, pinouts as I’d already determined (pins 4-15 are N/C), giving -10 to -15 ppm with 0V on the control pin and +10 to +15 ppm with 4V on the control pin.

Stick this thing through an 11 stage binary counter and you get 10 kHz, add a PIC and a GPS and it could be the most accurate thing on your bench.

Ljubljana Invaders

I first spotted these invaders back in 2021. Apparently there were 20 installed in 2006 and a further 22 in 2020.

I found a few more but nowhere near all of them.

This one on Stari Trg.

Židovska steza.

Na Jami on my way to the Ljubljana Computer Museum.

So now I’m up to seven… out of 42… gotta go to Ljubljana again I guess.


Slovenia, 2023

We decided to take the train from Budapest to Ljubljana. Had fun finding the ticket office (can’t buy from the machine because International).

The ticket office it through that door. The one that looks like a radiation hazard.

The train trip takes all day, so pack food & drink and a book. We got to Ljubljana around 1700. It was raining. _sigh_

We didn’t feel like going far so we ended up at the wine bar next door, they’re either part of or affiliated with or VAR-ing the burger place next to them, so it was burgers and wine on the menu.

This is where we stayed in Ljubljana.

Right next to the “Erotic Shop”.

Quite a nice area, really.

No, seriously. Right next to the Dragon bridge, and despite the graffiti the place is clean (Europe in general is clean, Ljubljana very much so) and quiet and we had a river view.

(OK I’m joking about the river view. I mean, that is the river down there, technically, but…)

Same thing as in Budapest. Father went to Dachau, mother went to Auschwitz, kid died fighting. “Osvobojen” = “freed”, so amazingly both Evgen and Amalija survived the war. Or that’s how I read it.

Anyway. Not so many nice pictures of the scenery because the weather was kind of miserable.

We went up the funicular to the castle, climbed the staircase all the way to the top, then walked down the hill.

Yes, it was raining a bit.

We stopped at the Apotheka coctail bar for a beer and a hot chocolate. Excellent, recommended.

The next day the sun was out and we got a few better pictures.

We went to see the Plečnik library. For 5 euros per person, this is what you can see. The reading room, with NO BOOKS. Oh, and the staircase is also included as an attraction. NOT recommended.

Yea, we didn’t know either.

Anyway, the main point of Ljubljana was to go to the Friday market (which rained out) and to get a car. Ended up hiring a car from renti.si. They’re a bit bait and switchy in that you can’t book a car through their website, and their special (20 Euro / day for the 25 Euro / day cheapie if you take it for two weeks or more) is only available if you book it. So I ended up with the 25 Euro / day option. Which was still the best price out there.

The weather forecast told me that this Monday was going to have the best weather of the whole week, so I made a beeline to Jeruzalem, specifically lunch at the Gostišče Taverna. Recommended.

And from Jeruzalem it’s only a short trip home (where “home” = our Vikend in Globoka).

The rest of the week was kind of meh, weather-wise. We went to Varaždin for lunch and Ptuj for second-hand clothes (lots of second-hand clothes) and for the rest stayed in, made fire, cooked, and drank. Which is probably no different from what we would have done had the sun been shining.

Then for the weekend we went to Zagreb, and from there to Zadar and Pula, but that’s for a different blog post.