Components that underachieved.

[G4_Pete]

I guess for completeness we must add the AF11x series.

Although not all bad news when I consider the sets I obtained at jumble sales and boot sales years back thrown out as "Not Working"
Pete

[Jon_G4MDC]

Another vote for Tantalum capacitors - I think of the solid variety but I can stand correction.

My Pye Whitehall W20AM/FM did many years of sterling service in the back of my car.
The car was T-boned and written off in 2014. I got the Whitehall out but since then it has sat dormant for 4-5 years.

On the first turn on, a week ago, it emitted a vast cloud of very smelly smoke from a cremating 22uF Tant (one of two in parallel).
Meanwhile it's parallel mate survived untouched.

Now I look around I can see other Tant smoke bombs which have gone off inside while it was under the car seat and I knew nothing about them.

Horrors!

[G6Tanuki]

In the transistor world as well as whiskery AF11x series I'd nominate the fragile AD161/162 complementary Germanium pair. They were ubiquitous in 1970s/early-1980s cheap unit-audio and car stereo radio/cassette-players and had an innate tendency to thermal-runaway, specially if installed where the air-circulation to the back of the equipment was poor and the owner liked his music TURNED UP TO ELEVEN!!!

I replaced plenty of these back in my student-days. A good source of 'beer-money' for me!

[Julesomega]

Originally Posted by Julesomega

snip.. enclosures which were used for Lab-assembled and small production-run test equipment. Front and rear panels were joined together by lengths of extrusion, and the case sides, top and bottom were attached to the extrusions by M3 screws fitted into square nuts which floated up and down channels in the extrusions. All very nice if there were any provision for fixing the locations of the nuts, but there was none and they would all relocate to the ends of the channels while you try to screw the panels on..snip

I've just found a precedent for this form of construction, used properly by Siemens Instruments. They used rubber bar to secure the nuts against sliding

[Hartley118]

Originally Posted by Julesomega

If we are not limited to devices, I'd like to rant against a series of equipment enclosures which were used for Lab-assembled and small production-run test equipment. Front and rear panels were joined together by lengths of extrusion, and the case sides, top and bottom were attached to the extrusions by M3 screws fitted into square nuts which floated up and down channels in the extrusions. All very nice if there were any provision for fixing the locations of the nuts, but there was none and they would all relocate to the ends of the channels while you try to screw the panels on. As the panels were pre-drilled, you'd think they could have drilled the extrusions or solid bars to suit.

have added a blob of glue to the nuts here in the hope they will retain the nuts next time I open up the case.

That looks like the wonderfully flexible STC/ITT 'ISEP' equipment practice, though the use of square nuts instead of the more usual tapped strip is certainly penny-pinching, suffering from the snag you so clearly describe. If the tapped strip is slightly shorter than the extrusion in which it slides, then modules and panels can be precisely aligned and there are no nuts to slide around inconveniently.

There many are robust mixing consoles in studios around the world built on the ISEP system: the extruded rails are usually mounted between profiled vertical aluminium 'end cheeks', making a very stiff structure to carry the various plug-in channel strip modules, faders, and their respective back connectors.

Surprisingly, ISEP components are still available. See https://www.srs-products.co.uk/the-isep-range/ . I guess there's still a legacy demand for building and rebuilding ISEP-based equipment.

Martin

[Julesomega]

The ISEP sockets look particularly useful

[Electronpusher0]

Originally Posted by G6Tanuki

Another component that had promise but turned out to be a real problem: tantalum capacitors. Whether the 'wet' type in sealed metal cans as found in things like Clansman radios and 1970s oscilloscopes, or the blue resin-encapsulated 'bead' types, they always seem to be the cause of issues a few years down the line. I guess you could consider them the 'waxies' of the late 20-th-century.

When I was working in electronic design we used Tantalum capacitors but ALWAYS doubled the voltage rating to what we needed as they were known to fail early if run anywhere near their rated voltage.

I still have some new old stock "tants", anyone?

Peter

[short wave]

Surprised no ones mentioned "Rifa capacitors" (gets my vote).

[ekjdm14]

Yep, RIFA smoke bombs, and the TDA2020 audio IC's used in B&O TVs too.

[Maarten]

RIFA paper caps are not really a component but a running gag in my opinion For all we know, their sales team made (and won) a bet with the WIMA sales team who could convince most customers to buy these craps.

[dglcomp]

Originally Posted by Julesomega

If we are not limited to devices, I'd like to rant against a series of equipment enclosures which were used for Lab-assembled and small production-run test equipment. Front and rear panels were joined together by lengths of extrusion, and the case sides, top and bottom were attached to the extrusions by M3 screws fitted into square nuts which floated up and down channels in the extrusions. All very nice if there were any provision for fixing the locations of the nuts, but there was none and they would all relocate to the ends of the channels while you try to screw the panels on. As the panels were pre-drilled, you'd think they could have drilled the extrusions or solid bars to suit.

have added a blob of glue to the nuts here in the hope they will retain the nuts next time I open up the case.

Behringer synth modules do this and it's a pain when you want to take them a part (which as they are eurorack compatible is not unexpected). I feel for their factory workers, esp. as these are not some low run specialist units but mass produced modules.

[ekjdm14]

Originally Posted by Maarten

RIFA paper caps are not really a component but a running gag in my opinion For all we know, their sales team made (and won) a bet with the WIMA sales team who could convince most customers to buy these craps.

Personally, I think their popularity over WIMA equivalents is purely down to people seeing the humour in something called a RIFA that tends to emit acrid smoke & speccing the part for a laugh... RIFA madness?

Another disappointing cap is the surface-mount electrolytics that came in around the early '90s. They almost universally leak after >15 years and eat away their pads/tracks to make replacement all the more difficult.

[G6Tanuki]

Originally Posted by ekjdm14

Another disappointing cap is the surface-mount electrolytics that came in around the early '90s. They almost universally leak after >15 years and eat away their pads/tracks to make replacement all the more difficult.

Yes I've seen a few of the little Sony "World band" radios that have been BER because the SMD electrolytics have oozed and the electrolyte's eaten away the PCB tracks/leadouts-to-some-semiconductors.

Another underachieving component: first-generation LCDs from the 80s/early-90s which inevitably develop black staining and/or have segments become unreadable. Particularly annoying when it happens on top-spec communications-receivers or test-gear.

[ekjdm14]

Funny you mention LCDs, as the worst example of SMD cap leakage I've seen has been on the main board of a VA0 Sega Game Gear, the first (commercially successful at least, the Atari Lynx was true first) full colour LCD handheld games system, the screens of both the above being notorious for failed bonding, failed driver chips (embedded on the flat-flex) and dead pixels.