I could kick myself. Tektronix 603a

[backflipper]

I picked up a piece of Tektronix kit today from and ignored the golden rule before powering it up. Check some numpty hasn't replaced the 600mA fuse with something stupid like a 10A slow blow.

I couldn't wait to fire up the storage monitor and when I did I got a dot on the screen and was able to shift it around so I thought "Nice" then it went dead after 5mins with a puff of smoke.

One of the Sprague 3300uF 25V caps had shorted and because it had a nail for a fuse both tracks feeding the bridge rectifier for the +20v rail instantly disintegrated. Well I can fix it but it was a reminder to do some initial checks before getting too excited.

Cheers

[MrBungle]

Easy mistake to make. I found tinfoil in a Heathkit counter fuse holder before. Usually Tek bridge rectifiers make pretty good fuses themselves (I've lost count of how many I've replaced) so that's a bit unlucky.

[evingar]

Yes. I've had a handful of Tek bridges go open circuited as well. Odd really, most other types fail short

[vinrads]

I say a lucky escape ! It could have been a lot worse , Mick.

[backflipper]

Originally Posted by MrBungle

Easy mistake to make. I found tinfoil in a Heathkit counter fuse holder before. Usually Tek bridge rectifiers make pretty good fuses themselves (I've lost count of how many I've replaced) so that's a bit unlucky.

Cheers but yes it did drive home the importance of initial checks.

Originally Posted by vinrads

I say a lucky escape ! It could have been a lot worse , Mick.

I agree. Safety 1st!

[dseymo1]

Interesting that such bodges are made by users of this sort of gear, who might be expected to know better.

[backflipper]

I think it was a reseller who replaced it thinking it would fix the no image not realising that the dot was off screen.