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**lpbkdotnet** @lpbkdotnet@mstdn.social · Feb 24

Ok #vintageElectronics nerds! tell me about these things…

The “MR” designation denotes some kind of diode (it stands for Metal Rectifier, a notation hangover from before silicon/germanium diodes) and they’re obviously arranged as full bridge rectifiers

They’re in a PSU made for the British Post Office in 1972

The brown stripe seems to denote the + end, but what does the other stripe mean?

A brown pcb with 4 small diodes labelled MR14 to MR17, clearly arranged as a bridge rectifier. The diodes are marked with brown and orange stripes.

A brown pcb with 4 small diodes labelled MR8 to MR11, clearly arranged as a bridge rectifier. The diodes are marked with brown and blue stripes.

#Electronics #TelephoneExchange #Telephone

**lpbkdotnet** @lpbkdotnet@mstdn.social · Feb 16

Feb 16

lpbkdotnet @lpbkdotnet@mstdn.social

Welcome to the #TelephoneExchange shed my new beepyboopy friend!

This is a “GPO Modem 2B” - a #dialup #modem… phone line in, RS232 out at a whopping 300bps!

It’s all discrete components (no ICs here!) and beautifully built with all the diodes/resistors mounted on little plastic carriers.

The modulator, demodulator etc are on separate, pull-out cards

It’s a gorgeous chunk of engineering, that I’ll be carefully powering up over the next few weeks!

Thanks for the swap @anachrocomputer

A large, brownish grey box (about 17” wide, 6” tall) with a black rectangular GPO label on one rnd

Lifting the front panel reveals four removable modules that slide into the chassis. They’re light straw coloured (a yellowish cream) and from left to right are labelled power supply, control unit, modulator and demodulator. There are various indicators, controls, and test points available

Same view again, but with a hand pulling one of the modules forwards out of the chassis

A close up of a brown PCB adorned with transistors, resistors, diodes etc all mounted in little clear plastic carriers

**This Is My Glasgow** @thisismyglasgow@mastodon.scot · Jan 26

Jan 26

This Is My Glasgow @thisismyglasgow@mastodon.scot

I love the granduer of this Neo-Baroque style 1930s telephone exchange in the Tradeston area of Glasgow. I'm sure there are many uses it could be put to, but instead it's been left empty and decaying for years.

A large red brick and stone former 1930s telephobe exchange which lies empty and decaying.

#glasgow #architecture #glasgowbuildings

**This Is My Glasgow** @thisismyglasgow@mastodon.scot · Jul 25, 2024

Jul 25, 2024

This Is My Glasgow @thisismyglasgow@mastodon.scot

The former Tradeston Telephone Exchange. Designed in a Neo-Baroque style, it was built around 1935. Due to changes in telecommunications technology, it became vacant in the 1970s, and despite a number of attempts to rejuvinate it over the years, it has lain pretty much abandoned and decaying ever since.