Cavro XL-3000 Syringe Pump – How to Control the 8 Port Valve

Even found a manual on the web, thanks to, who recently has torn the pump apart a bit. But still no idea how to control the 8 port distributing valve that it came with. The pump has no NVRAM where settings may be stored (in contrast to the VersaPumps), so it’s either hard coded in the firmware EPROM (a 27C256, it contains a string that there should be an 8 port valve) or this information is mechanically stored in the optical encoder wheel that it attached to the valve axis and read upon initialization.

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Hacked! The Ultrospec 1100 pro Admin Password

IMAG0883_part_half_size Case report: Got a used Ultrospec1100pro UV/Vis spectrophotometer. Of course, it came without logs and docs. It seems to be fully functional, as expected and as promised. But as usual, the Devil was hiding in the Details, despite finding the manual on the web was no problem:

To access the setup menu and to tweak options like if the (expensive, ~ 0.5USD per hour) deuterium lamp (which is required to record UV spectra between 200nm and 340nm. For longer wavelengths, a rather cheap halogen bulb is doing the job) should automatically be fired upon booting the instrument or not, one needs to enter the admin pass code which has some default value which is documented in the manual. Of course, it had been changed by the previous owner who I don’t know. Murphy’s Laws always apply.

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Uvicord II


The Uvicord II has a pretty fascinating way of running the UV lamp: The light source is a sealed quartz glass tube with a little zinc or mercury in it (depending on the desired spectrum), but it has no leads! Instead, it is externally heated at one end (see below) and the energy is transferred by high frequency capacitive coupling into the tube. Like when you bring a fluorescent lamp into a microwave oven or similar if you move it close to a charged old fashioned CRT :

Gas at low pressure + alternating high strength electric field -> ionized gas -> light!


Fig. 1: The PCB

Fig. 3 shows the reconstructed schematic of the lamp driver: It generates a high frequency signal which is capacitively coupled into the light source tube. The power is supplied through P1 and the HF current is coupled into the gas tube with metal rings connected to the ends of the coil (depicted as P2), they are located at the reverse side of the PCB (Fig. 2).


Fig. 3: The reconstructed driver schematic

The easyeda file: uv-driver_easyeda

The NPN transistor, originally a BSX53 (30V, 100mA, 130V, 300MHz, Ic/Ib=75..750, of which it was quite difficult to find a datasheet, the PCB is from 1987, almost 30 years ago and the board still reads “LKB”) was supposedly and apparently dead (I tried to measure its hfe with my DVM, it turned out to be 0, i.e. no response). So I replaced it with a 2N2219A which has similar electrical characteristics (UCE 50V, 800mA, 0.8W, 300MHz) and the same case (TO-39, to re-use the heat sink).

The gas tube is heated at one end by a BD179 transistor (30W, UCE 80V, IC 3A, IB 1A) mounted to the lamp holder as heat sink.

Notes & Acknowledgements:

The schematic was created with the free SAS online editor at

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Taiwan TaKeDa and Mobile Data Access

This is how I spent a week-end without having much fun: Making Taiwan TaKeDa mobile Network APN work on an unbranded Dumbphone!

Opted for a data plan. Got even a call that it had been activated on August 1st after lunchtime. Of course, didn’t work: Got a “wrong APN settings” error message. Went to one of their shops. They concluded my mobile (a HTC one plus, obtained from SingTel as a “free” gift to our communication package there in 2012) had a problem. So went home again and finally found an excuse to transplant the working mainboard from a HTC Sensation XE (but a broken screen) to a HTC sensation XE with a working screen (but a broken mainboard). Sometimes it makes sense when you and your TaiTai have the same models of hand phone, this really may save you money if you are able to perform micro surgery on micro electronics! The two phones had been bought without contract in Taiwan some years ago. Finally, I got another perfectly working Dumbphone, but still the mobile network still would not work.

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Resurrecting a VWR Galaxy 14D Benchtop Centrifuge


VWR Galaxy 14D, back alive!

It had been advertised as “does not power on” and I got it pretty cheap on eBay, below 100USD including shipping from the U.S. to this beautiful country.  Assuming the usual culprits for a “complete failure”, when the cosmetics are fine: a broken switch or a blown fuse, it should have been an easy fix and a good bargain for a used item sold new for 1400USD.

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C++: Outputting a string as hexadecimal characters…

… is easy with the boost format library:

Digging the net for examples was not very productive, so I started my own approach:

The trick is the “%x” which will output the numerical value (uint)s[i] as hexadecimal value.

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OsziFox / ProbeScope in Xubuntu 14.04 LTS

2014-07-01_21-02-19_CH1On my system, it runs with wine and a USB to serial adapter and the FoxiOsz program (originally for WinXP), by Michael Butschkau, to be found here: Thanks and Kudos to Michael for this! The site offers 3 versions, just get the latest one (v1.1 at the time of writing).

You probably have to tell wine to use /dev/ttyUSB0 (or whichever number) as COM1 (or whichever number) and make sure that your humble userness has the right to access it: Make yourself member of the group “dialout” and add a symbolic link in ~/.wine/dosdevices:

ln -s /dev/ttyUSB0 com1 (or whatever)

If in doubt where your USB2Serial device might show up, you may check it with “ls /dev/ttyUSB*”.




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