Joel, Did you try Bowmar? (www.bowmarcrystal.com) They claim to do custom crystals for various radios, and have at least one type that covers the 900kHz area. --John Gord

Chuck, Even on the plain 2465, most of the front panel control is still routed through the CPU. The difference is that the later scopes use incremental rather than absolute encoders on the controls. I

Harvey, For power, you might want to consider what I did: I converted the power cord storage compartment (with the little door) into a battery holder for an 18650 LiIon cell, then put a battery protec

Jeff, <A> is probably for the P6201 FET probe. --John Gord

Tom, I think the 3 meter version is only rated for 150MHz vs 300MHz for the 1.3 meter version. --John

Tom, I put schematics of the P6131 1.3 meter and 3 meter probes in the photos section, album name "P6131". The full manual is following by snail mail. https://groups.io/g/TekScopes/album?id=259558 --J

Tom, I'm happy to send the manual along. I think that the P6131 had some major changes over its production history, particularly a new comp box housing design. They show both box types in the 070-4210

Tom, How about I mail it to you? I assume the address after your signature will work. --John

Tom, Few of the probe instruction manuals I can still find have schematics. I opened up an early P6106 compensation box, and it has two unshielded inductors (ferrite rod cores?) placed close enough to

Tom, The p6131 2m and 1.3m probes used a T-coil in the compensation box. (Schematic in manual 070-4210-01) --John Gord

Jeff, According to the 1976 Tek catalog, the recommended probes for 50 ohm mode were P6056 (10x), P6057 (100x), and P6201 (FET). The P6202A (FET) would also be fine. For 1M ohm input, the recommended

Walter, I suppose it is possible that U112 has beefy input protection (diode clamps to the supplies?) that might survive enough current to burn a small 62 ohm resistor. At maximum sensitivity the atte

Oops, FT-241 --John Gord

The crystal in the unit is an FT-242 "channel" crystal. Those had a strange flex-mode crystal resonator (not the usual shear-mode). I think the 3-digit channel crystals had a fundamental frequency equ

Toby, You are right! And they are not in stock. --John Gord

I think "bulk" here refers to their packaging (they may have a bin full rather than tape-and-reel). They list a single piece price. --John Gord

Bruce, The vertical character jitter is probably due to poor thermal balance in the vertical amplifier. Driving the trace far away from center for a long time (as with a horizontal line off the top of

For relatively slow (Hz to 10s of kHz) square waves of known amplitude, you can use some paralleled beefy CMOS buffers powered by a precision supply feeding a relatively low impedance multi-tap voltag

Jim, The HP 54120A/54121A combination also gives very good sampling performance, and is sometimes easier to find at a good price. --John Gord

David, You wrote: " In TEK products high quality resistors do not go high over time!" Well, that may be true, but if so, they did not always use high quality resistors. The focus divider string in man