Re: help tek 475 power supply

Roger Evans

Can you explain what you mean when you say 'after a few minutes it turns off'? Do you mean that initially there is a trace on the CRT but after a few minutes it disappears? The 475 should show a light behind the V/div knob of the vertical channel that is selected - does this light stay on when the scope 'turns off'?

Can you measure the voltages on the low voltage DC supplies, +50V, +15V, +5V, -8V, -15V and also '+15 unregulated'. Do any of these these change between first turning the scope on and the 'turn off'? If the only problem is with the regulated +15V then we can trace the voltages through the regulator.

Measuring Q1446 in circuit may be misleading since there are many parallel components.


Roger Evans

Join to automatically receive all group messages.