On Thu, Apr 21, 2022 at 09:50 PM, diyguitarist wrote:
, TP485 should be +12.5V and measures -0.32V & TP494 should be -0.98V and it
measures +11.42V.
1. Those voltages are correct if you measure when the sweep is trigggered. They revert to the schematic values with a free-runing trace.
2. On my 453 (c 1970) the ripple & noise on the +12V and -12V rails, measured in the B trigger area (R667 and R636) relative to the local ground is in both cases around 3mV p-p.
3. There are two X-Y modes, not sure which you're using?
4. In both X-Y modes, the horizontal x10 Mag switch should not do anything as it is shorted out by the wafer 2R switch (shown on the X amp schematic 13).
John
John Sykes