Re: 7A16A high frequency compensation.


Ozan
 

On Sun, May 15, 2022 at 08:07 AM, unclebanjoman wrote:

...
I measured voltages in the source follower stage.
I posted a screenshot of the partial schematic with measured voltage values
written in red.
All the DC voltages look fine. Unless there is a subtle failure mechanism that doesn't show up in DC operating point JFET looks good.

If you probe left side of R132, is rising edge clean? If left side of R132 looks good R132 may have went up in value. If you don't want to lift one side of R132 to measure you can short its right side to ground and measure resistance of parallel combination of R132 and R130 =~ 320k.

Stephen's suggestion of checking caps is also good.

Ozan

Join TekScopes@groups.io to automatically receive all group messages.