UK Vintage Radio Repair and Restoration Discussion Forum - View Single Post - Tektronix 2211 scope short-circuited

MrBungle · 15th Apr 2019, 10:21 pm

You're lucky it didn't catch fire! Those RIFAs tend to go incendiary.

C904 has to be a Y2 class capacitor as it's between mains and earth - can't just use any film capacitor here. C903 is supposed to be the same capacitor but it looks like it has been changed before, probably explaining the last person's attack on the scope. 250V is fine. Basically these capacitors go short temporarily if there is a spike on the mains to stop it blowing up the scope.

Value isn't that important for these. They are between Live/neutral and ground and eat up noise and spikes and that's it. The manual specifies 0.022uF (2.2nF). I replaced the last scope with KEMET PME271Y422MR30. You can get these from RS locally to you: https://benl.rs-online.com/web/p/pap...itors/0210572/ (pack of 5). Replace C903 and C904 at same time.

2n5401 I'd probably hit ebay for.

15th Apr 2019, 10:21 pm	#15
MrBungle Dekatron Join Date: Jun 2016 Location: London, UK. Posts: 3,687	Re: Tektronix 2211 scope short-circuited You're lucky it didn't catch fire! Those RIFAs tend to go incendiary. C904 has to be a Y2 class capacitor as it's between mains and earth - can't just use any film capacitor here. C903 is supposed to be the same capacitor but it looks like it has been changed before, probably explaining the last person's attack on the scope. 250V is fine. Basically these capacitors go short temporarily if there is a spike on the mains to stop it blowing up the scope. Value isn't that important for these. They are between Live/neutral and ground and eat up noise and spikes and that's it. The manual specifies 0.022uF (2.2nF). I replaced the last scope with KEMET PME271Y422MR30. You can get these from RS locally to you: https://benl.rs-online.com/web/p/pap...itors/0210572/ (pack of 5). Replace C903 and C904 at same time. 2n5401 I'd probably hit ebay for.