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.

Regards,

Roger Evans

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