Max, Some plugins of that era had small ceramic trimmers that went open circuit. See if one of the trimmers does not seem to have the effect implied by the calibration procedure. --John Gord

Barry, There are two serious limitations to the 7704A XY mode at higher frequencies: The Y path includes the delay line. The X path (horizontal) has limited bandwidth (a couple MHz or so). In the mid

Roy, I described a modification to use a lithium-ion 18650 cell plus a boost converter in an earlier message: https://groups.io/g/TekScopes/message/165764 --John Gord

Stephen, Back in the dark ages they used chart recorders. --John Gord

Dan, If I remember correctly, the knob and shaft are a single plastic part. The shaft can probably be just pulled out, and the whole knob/shaft piece replaced without changing the attenuator. --John G

The main boards for the TDS30xx 4 channel units are different from the 2 channel units. I don't think there is any (practical) way to convert a TDS3012 to a TDS3014 without a total main board transpla

Sean, If those are the tiny ceramic trimmer capacitors like I had in some 7A26 units, yes I have seen multiple failures on the same board. --John Gord

William, See if the channel 2 "spiking" occurs at all Volts/div settings, or only some of them. If it is only present at some settings, suspect the attenuators or possibly the switches. The attenuator

Joel, Bomar claims to still make custom crystals. This model seems to cover the proper frequency range: http://bomarcrystal.com/hc_51Ucrystal.html --John Gord

The main feature of the Tektronix 067-1338-0x is the step rise time of under 20ps. The 33120A arbitrary waveform generator is much, much slower. --John Gord

I would guess that this contains one of the TDR generator hybrids used in the SD-24. The same hybrid is used as the (very fast) calibrator on some Tek sampling scope mainframes. I bought a "parts" SD-

Note that the 1DP11 has a much lower filament power than some of the other 1 inch CRTs. Most of them were 600mA, 6.3V. I think the NLS mini-scopes had a low power (directly heated?) filament. --John G

Andy, The 2465B uses the same A5 board, I think. Tekwiki has the service manual, which includes high serial number versions: https://w140.com/tekwiki/images/7/79/070-6863-01.pdf --John Gord

Barry, If you are willing to modify your 2445, you could patch one of the rear panel BNC connectors to the Line trigger input of U500 (pin 28), with appropriate precautions, of course. I don't know ho

David, Take a look at the EEVBLOG two-part video at: https://www.youtube.com/watch?v=leC-zSMbtfg Dave tries to fix a TDS3054 with a single bad channel that has problems at the same sample rate breakpo

David, The TDS3000 series scopes have a fast-in, slow-out chip that is used for the higher sample rates. Apparently that chip is enabled for sample rates above 2.5 million samp/sec, but a normal ADC i

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