On the 22xx series of scopes this fault is related to the focus string resistors gone bad. Something similar maybe ?
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On 10 October 2018 at 11:11 "Jeff Pederson via Groups.Io" <email@example.com> wrote:
Probably obvious, but have you checked the trace find circuit, if that is an older one with tubes I have one for parts if interested.
On Wednesday, October 10, 2018, 2:38:26 AM PDT, chuck <@chuckyorbalinda> wrote:
just bought a 453 and of course there are problems. The trace is fat! Using the 1Khz internal signal when I put it on either channel the trace is out of focus and really hi intensity. The focus knob works to an extent but the intensity knob does nothing. I traced the signal thru the z amp and it behaves as it should as I adjust the knob the signal at the output stage (prior to going into the CRT control circuit) changes. I'm intimidated by the CRT circuitry and would love to get some feedback so that I'm not going in blind. The Tek troubleshooting guide talks about Typical High Voltage problems but does not really point me in a direction.
Any help would be appreciated. I have a couple of DVM's and a pocket scope (Chinese knock off) to work with.