Component identification - British military radio gear - Page 1
Forum section: electronics / repair

author: Beno1983
author_rank: Newbie
timestamp: May 01, 2016, 09:52:53 pm
content: Hi allwould anyone happen to know where I could obtain a replacement for thecomponent that has let the magic smoke out? It's from a British military training simulator brick that does into a clansman DMU. There very hard to find and unfortunately this one is not working but I would very much like to remedy that. It appears to be an ITT 22u +16v.Any help on this would be greatly appreciatedThanksBen

author: station240
author_rank: Unknown
timestamp: May 01, 2016, 10:00:05 pm
content: It's a potted version of a tantalum capacitor.No idea who still makes them, the unpotted versions are easy to find.Beware, old tantalum capacitors are prone to catching fire sometimes.You really should replace all of them.

author: Beno1983
author_rank: Newbie
timestamp: May 01, 2016, 10:10:08 pm
content: Thanks for the very quick reply, I have limited electronics knowledge, would there be any issue with replacing them with a more modern type? Excuse my ignorance if there are lots of reasons why this is a good/bad idea.Ben

author: Ian.M
author_rank: Super Contributor
timestamp: May 01, 2016, 10:12:46 pm
content: They are capacitors, probably Tantalum, with moulded resin cases.You need to match the value (22uF) with the same or higher voltage rating. N.B. Tantalums tend to catch fire if reverse polarised or excess voltage is applied, even momentarily, so remove the faulty one and patch in a 22uF aluminium electrolytic for testing and check the voltage across the cap in question. You *MUST* get the replacement the correct way round, matching up + and -. The replacement may not have both leads marked. A resin dipped 'bead' tantalum capacitor could be substituted but is likely to cause more fire damage than the original if it fails again.For moulded Tantalums in a similar case style, look athttp://uk.farnell.com/vishay-sprague/790d226x9016b2be3/cap-tant-22uf-16v-rad/dp/1754017orhttp://uk.farnell.com/vishay/790d226x9025b2be3/cap-tant-22uf-25v-rad/dp/1754021to see which is the best match for pin spacing and other dimensions.

author: Raj
author_rank: Frequent Contributor
timestamp: May 21, 2016, 03:50:05 pm
content: maybe a polymer 2.2uF cap will do the jobjust be sure to connect the pin connecting to outermost layer to ground for minimal interference

author: TheMG
author_rank: Frequent Contributor
timestamp: May 22, 2016, 06:33:00 am
content: Note that the device will likely work just fine using a modern aluminum electrolytic capacitor as a replacement.Tantalum capacitors were commonly used in vintage military gear for their small size and greater reliability than what was available at the time in terms of electrolytics. Nowadays, electrolytic capacitors have come down in size quite a bit and capacitors from reputable manufacturers are actually very reliable. Better yet, solid aluminum polymer capacitors offer even better performance and reliability.

author: csmithdoteu
author_rank: Contributor
timestamp: May 24, 2016, 06:45:35 am
content: Looks like something Racal made. +1 for the electrolytic option. Cheap, does the job. Plus this isn't going back in military service if it's a Clansman set.Make sure you pick a voltage much higher than the listed voltage there if you go tantalum again.This is a suitable tantalum replacement if you want that:http://uk.rs-online.com/web/p/tantalum-capacitors/8310077/