Fixing a Soviet Space heater Луч

Banner
I recently got this old 1.2kW soviet made space heater of type “Луч”. The heating resistors/spirals are fine, but the fan was making loud noises. This usually indicates a bad bearing somewhere. Furthermore the heater had a unearthed East-German/Soviet type Schutzkontaktstecker compatible plug, which I was going to swap out to an earthed plug (and also a respective line cable with earth wire). The inner workings are fairly simple: There is a thermal cutoff, then a rotary switch selects which of the heating spirals get supplied and also powers the synchronous motor.

Read More

Microscopy Insights #7

Banner
Pictures taken with a Sony SLT-a37 on my MBS-10 (МБС-10) with the МФУ tube. Porous Concrete Exploded X2 Class Capacitor This capacitor was from my HP 8112A pulse generator, it had a catastrophic failure. I removed it and replaced it with a new one, the pulse generator is working again, albeit it is still somewhat stinky. Moth An unspecified type of moth, I’m not quite sure about the species. Anyone any idea?

Read More

Funkwerk Erfurt 8600a Stelltrafo

Banner
I recently got this east German Funkwerk Erfurt Stelltransformator 8600a, which is a 250VA step transformer with 14 steps and a ratio display. Picture taken after the fixes outlined in this article First thing I saw broken was the plug. The original one out of bakelite broke in an unrepairable manner. I replaced it with another bakelite plug I had sitting around. Cleaning the inside In order to cleanup the inside I completely disassembled and reassembled the unit.

Read More

Magnetic Stirrer Maintenance

Banner
I recently got this magnetic stirrer labeled “Fisherbrand Agitateur Magnétique 10510”. It had remains of silicone on the top. It had some problems with the motor starting at low speeds, so I figured let’s check it out and try to fix it. The circuit is unimpressive, it’s a small transformer, discrete bridge rectifier and a BD681 NPN transistor controlled by a potentiometer to regulate the motor speed. However the advantage here being, that is super simple to troubleshoot and repair.

Read More

Quick Restoration: Theatrical Light

Banner
I recently acquired this rusty theatrical spot light. It looked like, someone already repainted the thing at some point and as can be clearly seen on the second picture above evidently someone put a bulb of a too high wattage in it. I removed the remains of the paint and applied new high-temperature paint. The fixture uses a GY9.5 socket, which in by itself does not really help in figuring out the rating of the light.

Read More

Mettler K7T

Banner
My other laboratory scales and balances: Mettler B5, Mettler P1210, Sauter L10 I recently obtained this Mettler K7T laboratory scale from the late 1950s to early 1960s. It has a resolution of 100mg with a capacity of 800g. Cleaning The internal mirror was fairly dirty, so I gave it a clean with isopropanol. The case didn’t actually have any normal rust spots, this looks more like some corrosive chemical spilled onto there at some point.

Read More

Stereomicroscope Ringlight Supply

Banner
As mentioned on my MBS-10 post the power supply of the ringlight I have for the former isn’t quite up the the safety standards I’d like. It was one of the cheaptest I could get and the quality of the power supply matches that. So I decided to built myself a new one! It’s an unregulated 12-15V power supply with an adjustable current limiter consisting of a TIP41C transistor. I used a lot of hot glue to secure the front panel components, as they wouldn’t probably hold on the plastic panel.

Read More

SUN Netra X1 Capacitor Replacement

Banner
For the keen observer, the picture on my last post about the SUN Netra X1 showed a couple suspicious capacitors around the processor. Two of them already started venting, so I figured to replace them before the short out and damage the mainboard. I also examined all other capacitors, including in the power supply and those all still looked fine. The broken capacitors in question are SANYO 1500uF/6.3V I replaced them with Würth 1500uF/10V capacitors (WCAP-ATUL 860040275011) which happen to have the same via spacing and diameter.

Read More