Re: TDS540B Power On Self Test Pass, but changing results from SPC
On Wed, 31 Jan 2018 at 17:33 satbeginner <@satbeginner> wrote:
I read something about the attenuators being/getting iffy, or at least theHey Leo,
a common problem with these scopes is that the relays on the attenuator
hybrids become high resistance or even open contact. You can see what the
attenuators look like here <
and it's the cluster of four yellow relays that often fail. On my TDS784D
this caused SPC failures, but by measuring the relay contact resistance, I
was able to identify the culprits. After replacing them, my scope's worked
like clockwork ever since. The relays a readily available, I bought mine
from DigiKey, though I couldn't find the part number readily.
Be careful when you handle and reinstall the hybrids, it's easy to
mis-position them and to crack and destroy them on reinstallation.