Re: troubleshooting Tek453 Mod 210H
Hello Chuck,toggle quoted messageShow quoted text
When it comes to intensity control inoperative, and highly intense trace, I`m afraid that you're going to set your fears aside about the CRT circuit and playing around it (with all its indeed intimidating High Voltages)...
Still, a lot of those circuits can be troubleshoot on the "Low" side, and what can't, can be troubleshoot by rising one lead of the components and measuring them (with scope turned off).
The regular caution is advised though... To keep one hand in the pocket, to remember to discharge the H.V. points before poking around and, preferably, don't be isolated in the bunker with nobody around.
About the focus, I think you probably don't have a problem in that dept. The trace is fat and the focus can't tame it because it's too intense and the beam is "bloomed".
An inoperative intensity control can have many causes, from a short between grid (G1) and Cathode (K) of the CRT tube, to problems (mostly leakage currents) in the DC restorer circuitry, to defects around the CRT bias circuitry, which encompasses the Intensity control pot and the CRT bias control (usually a trimpot).
All that I`m saying above is general to CRTs and not exactly specific to the 453.
In order to get more specific, anyone in the group will ask you 2 things:
1. If you have a manual, whether in Paper or PDF form (which for the 453 vintage is simultaneously a user and service manual). Some options to download here:
2. What is the serial number? And if it's really a plain 453, or if it's a 453A.
Please let us know... and we take from there.
On Wednesday, October 10, 2018, 2:38:26 AM PDT, chuck<@chuckyorbalinda> wrote:Using the 1Khz internal signal when I put it on either channel the trace is