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Diabolical Artificer · 27th Jan 2019, 2:39 pm

A few days ago the above turned off/stopped working. I found the mains fuse blown, so after checking the mains tfmr, and a thorough visual check inside and a quick check of the main filter caps I powered it up with a lower value mains fuse in - 1A fast type instead of 4A slo blo, smoke issued, SW off. R670 was toast, looked for shorts, found C671 shorted, replaced both, these on the +100v rail.

Scope now powers up but as soon as the delay period is over, EG 30 seconds and K601 latches, fuse blows. Have checked every rail for shorts, checked R's in V dividers as per Tek manual, checked res to ground of rails, checked the cap across K601 and K601 coil res, checked the voltage regulator valve for short and checked all big smoothing caps. Removed plugin. Checked all diodes.

Stumped, any ideas? Andy.

27th Jan 2019, 2:39 pm	#1
Diabolical Artificer Dekatron Join Date: Jul 2009 Location: Sleaford, Lincs. UK. Posts: 7,658	Tektronix 585A issues. A few days ago the above turned off/stopped working. I found the mains fuse blown, so after checking the mains tfmr, and a thorough visual check inside and a quick check of the main filter caps I powered it up with a lower value mains fuse in - 1A fast type instead of 4A slo blo, smoke issued, SW off. R670 was toast, looked for shorts, found C671 shorted, replaced both, these on the +100v rail. Scope now powers up but as soon as the delay period is over, EG 30 seconds and K601 latches, fuse blows. Have checked every rail for shorts, checked R's in V dividers as per Tek manual, checked res to ground of rails, checked the cap across K601 and K601 coil res, checked the voltage regulator valve for short and checked all big smoothing caps. Removed plugin. Checked all diodes. Stumped, any ideas? Andy. Attached Thumbnails __________________ Curiosity hasn't killed this cat...so far.