2465B/Repairs
Failed (leaking) SMD Capacitors on the A5 board
The 2465Bs are notorious for leaking SMD electrolytics on the A5 board.
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Electrolyte leak
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Electrolyte leak
When this happens, the electrolyte tends to damage the DAC reference, leading to TEST 05 failures. Because everything in these scopes is drive-by-wire from the DAC output, this can also lead to kinds of other problems, including no traces, and no on-screen display.
Note that the DAC reference is a current, so it's impossible to measure it directly without lifting a pin on the DAC or breaking traces. A quick and easy indirect assessment of the state of the DACs reference is to locate and measure the 1.36V and -1.25V reference voltages on the A5 board. Make sure J504 is in the normal position (bridging pins 1 and 2), and if the reference voltages measure OK, then the DAC reference is OK.