+95V is generated from HV transformer. If you observe TP+95V in sheet <2> (CRT & Z Axis sheet), does it stay regulated or does it change with intensity? Ozan

Schematic says nominal is 52.2V, measured voltage looks reasonable. Ozan

In most analog meters input impedance changes with the range. Picture of 269 says 5k-ohm/V in AC, you are changing the shunting impedance as well when you are changing the range. Ozan

This is a real puzzle. In the pictures there is a metal connection between attenuator and the amplifier, roughly between CR130 and CR507 (CR507 shows up in board layout but not in schematic). Probably

In this context it is one of the ESD discharge models: Charged-Device Model. Board may have charge on it because it is not grounded, when a ground potential connector (e.g. soldering iron) touches the

With the board floating only concern is CDM as Ross mentioned. Touch the ground of the board with tip of the soldering iron (i.e. ground it) before touching any internal traces. Ozan

5mV and 10mV are the only settings in which there is a direct path from gate of the source follower to BNC. Probably this says something is happening at or to the left side of switch 5. Did AC/GND/DC

Congratulations for the fix. Ozan

Very impressive setup. On similar cam based switches sliding a thick paper soaked in IPA between the contacts worked well. I believe this is also what Tek recommends. Ozan

In the first picture you are in 50-ohm mode but in later pictures you are in 1M-ohm DC mode. In 50-ohm mode I tested frequency measurement function up to 650MHz on a 2467B, which is very similar to 24

Because of C132 high frequencies (or faster edges) will see a lower impedance. However, it should still be relatively higher impedance than the 50-ohm source. Do you put the attenuator at source side

In the error light pattern are Ch1-4 lights off? If you push delta-V/delta-T/slope buttons all at once you will enter the test menu. Then if you push "Trigger coupling" up button scope should run a sm

Waveforms look like reflections coming from the cable between signal source and the plugin. If you double the length of the coax you use, does the place where first step happens in the middle picture

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

There is some chemistry reasons (I don't remember the details) for some deposits not dissolving in alcohol. I also found these boards to have so much electrolyte residue it was difficult to completely

C000 EPROM looks correct with code 1626-04 and start address of C000. All the data bits are exercised too (bitwise or gives 0xff), only remaining unexercised connection is the address bus. Perhaps one

Hi Luca, I saw the other post, it looks like you are indeed getting a EPROM checksum error. I was thinking it is a parity error, which happens for calibration memory. Since you are seeing correct cont

Congratulations for the PSU fix. Service manual Exercise 02 can give more clues about the parity error. Ozan

Hi Ralph, This is most likely because of a leakage path from U1101 input to negative supply. Did you wash the board after unsoldering bad caps? Everyone has their own recipe but 50% vinegar-water solu

Hi Ralph, My comments are below. This may be another open trace or control voltage issue. Interpolator makes heavy use of calibration voltages. I had similar errors on TDS520’s that cleared up once re