I needed to reset a password on an old CISCO Catalyst 2900XL, so here is the procedure as a reference: The following should work at least on all older CISCO Catalyst series switches, in my case this is a very old 2900XL. Hook up a serial terminal Hold the MODE button pressed until the switch is booted. Now something like this should come up: C2900XL Boot Loader (C2900-HBOOT-M) Version 12.0(5.2)XU, MAINTENANCE INTERIM SOFTWARE Compiled Mon 17-Jul-00 18:19 by ayounes starting... Base ethernet MAC Address: 00:04:c1:e0:52:80 Xmodem file system is available. The system has been interrupted prior to initializing the flash filesystem. The following commands will initialize the flash filesystem, and finish loading the operating system software: flash_init load_helper boot switch: Type the flash_init command:

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I recently needed a LED light for a stereomicroscope of mine, so I quickly built one. Basically takes a C8 inlet for 230V, transformer, rectifier and current limiter using an old TO-38 package transistor. I also used an old AEG selenium rectifier (the red package) for fun. The LEDs I put two 1206 SMD LEDs into series on a lab card.

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All pictures taken with my Sony SLT-a77 with a Sony DT 18-55mm F3.5-5.6 SAM and Tamron SP AF 70-300 F/4-5.6 Di VC USD objective. Please note that we had Sahara desert dust on this day, that’s why there is a slight yellow tint everywhere.

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I needed a second 16mm spigot with a M8 thread for mounting a light on a universal clamp. Since I had some brass bar stock around I figured I just machine one quickly. Result Mine (right) and the commercially available one (left).

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Another quick build, this time I needed 24V AC for old DIN rail relays, as well as 24V DC for another DIN rail device. The solution? Both in one package. I only need a couple milliamps each AC and DC output so the small transformer is about just right for this.

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Just a quick project, a 1.5A 24VDC power supply with two ISO 4165 automotive auxiliary power sockets. The front and back panel are 3D printed.

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I recently got this Karl Klein DNG 6-22,5 blower (22 m3/min) I want to use for dust extraction. Unfortunately the seller spray painted the whole thing with zinc spray w/o telling or asking me. This is what I got out of the box: It appears that they at least stripped off parts of the old paint (maybe even sand blasted it?) but like I don’t like this look. So I gave it a quick new paint job, first I removed some of the zinc spray where it was not sticking properly. I decided to with RAL 3003 for the motor and matte black for the blower assembly.

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Disassembly Te screws of the bearing covers were completely sheared off, probably from vibrational damage. New bearings Replaced the old bearings with new SKF 6200-2RSH ones. Odd screws The screws holding the bearing cover were of an odd dimension, either imperial or something like M3.5. I decided to rethread the inner plate to M4, so I can use standard screws. To do this I used a 3.5mm reamer to clean up the hole and re-threaded it to M4.

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I got a couple older power supplies from the Voltcraft brand, so I decided to clean them up a little bit: 12V 2A - Replacing Selenium Rectifier This unregulated unit had a selenium rectifier that started smelling a bit sweetly, which is the smell of impending failure. I replaced it with a silicon rectifier and also added a short circuit current limiting resistor, as I dunno whether the transformer is short circuit proof.

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Built this the other day to have a more accessible higher voltage DC. The circuit is straight forward, a voltage multiplier giving ±340V off the 230Vac secondary of the transformer and another a half rectifier from the transformer’s 115Vac secondary to also provide 170V. I also added a small neon indicator to show whether the two main reservoir capacitors of the ±340V are still carrying a charge. The output is limited with power resistors.

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