I receives this Extreme Networks Summit 200-24 switch a while back. It an early 2000s managed switch with 24x 10/100Mbit and two dual personality Gigabit/SFP ports.
When powering it on I smelled capacitor electrolyte coming out of it despite it working. Since this is an early 2000s gear it seems to have either struggled with the usual capacitor plague from this time or it was in operation in a fairly hot location for an excess amount of time.
Landsweiler-Reden January 2026
All pictures taken either with my Sony SLT-a77 with a Sony DT 18-55mm F3.5-5.6 SAM.
Precision 10V, 0...10V and 0...10mA Reference
Built this precision voltage and current reference the other day to calibrate some multimeters of mine. It features a ADR01B reference, which has an initial accuracy of 0.05% and a temperature drift of 1 to 4 ppm/degC.
Construction is fairly simple: 10V is output directly on two pins and buffered by an opamp, the opamp output is fed through a precision potentiometer, whose center tap is the 0..10V output and also fed into another opamp which generates the variable current source based on the adjustable voltage. The ADR01 is short circuit proof, so I didn’t bother to buffer its output further. There is a linear power supply for a ~12Vdc supply, a DC/DC converter to generate ±15V for some operational amplifiers. That’s the general overview.
Fixing a Victron Pico 102 and Micro 104
I recently got those two UPSes. The Victron Pico 102 is a mid-80s/early 90s 200VA backup-ups i.e. it switches the load with a relay to the inverter when primary power fails. The Micro 104 is a 400VA online-ups, that is it generates the output AC from an internal DC bus that is jointly supplied by the battery and line voltage. So it doesn’t have a switchover period, at the compromise of a higher-standby usage and inverter reliability.
Replacing a loud fan in a Cisco switch
I have this Cisco ME 3400EG-2CS metro ethernet switch which has quite a loud fan so I figured to replace it with a more silent Noctua fan.
The ME 3400EG-2CS takes around 10W of power with two ports being active, which is similar to a Catalyst 2940 I have, which doesn’t has a fan. So I figure the fan in this unit is mostly to support the extended operating temperatures required for metropolitan equipment.
Maintaining Strand/IANIRO QuartzColor Daylight 575W HMIs
Strand Sirio 575W HMIs I recently got two Strand Sirio 575W HMIs, which are actually rebranded IANIRO HMIs.
Mine are using the GTV standard which I think is pretty exclusive to Europe. Its basically the same as the normal standard but instead of bayonet connectors “VEAM”, these use are screw connectors “GTV” by the company Schaltbau.
I immediately spotted two issues on the ballasts, aside from each having a differently rated circuit breaker (10A and the other 5(6)A), both had circuit breaker with an interruption capacity of only 3kA. In Germany the minimum permissible is 6kA for domestic applications, however in this case since these are device breakers and not for a fixed installation wire you could argue that its probably fine. However I opted to replace them with proper 6kA breakers regardless and also have both be the same (type C4).
Quickie: Hertel Reuss STE 2B & CN-hF Fixes
Hertel & Reuss STE 2B base The base of my Hertel und Reuss STE 2B microscope had what looks like it chemical burns on it from the previous owner. I do not think those rust spots happened naturally. To fix this I first used my Proxxon tool to grind the rust off and then filled the spots with 2K resin. Afterwards I gave it a new spray paint job with the proper hammer effect silver color.
12V 100mA Plugpack Power Supply
I needed a 100mA 12V plug-pack power supply with a linear regulator. So I just built one real quick in 20min.
It’s basically just a fuse, MOV and transformer on the primary side and on the secondary side a bridge rectifier, reservoir capacitor, 7812 regulator, output smoothing capacitor and I threw in a TVS diode to clamp the output voltage in case something fails.
Repairing a Sartorius 1003
In line with my Mettler PC440 repair the other day I also finally came around to look at my Sartorius 1003 scale. This one is quite simple, it uses a strain gauge.
No calibration trim done yet, that’s why it is off slightly.
Power Supply The power supply (12V/100mA) is simply a small transformer with a thermal fuse, a couple diodes, resistors a capacitor and a LM317.
The capacitor was way out of spec from what was probably decades of being plugged in. I replaced it with one from Frolyt I had in the component box, the latter also having a higher temperature rating (105C) than the old capacitor (85C).
Repairing a Mettler PC440
After having a small collection of various old Mettler scales, I recently decided to get this Mettler PC440 DeltaRange series scale that was declared broken.
It didn’t turn on, but I could hear humming out of the case. After leaving it running for a bit and warm up it suddenly started working. So clearly whatever the issue is, it solves itself with temperature or power-on time - intriguing.