What did you use for a battery?

I was lucky that I caught the leaking NiCd battery in my 7A42 back in 2016, when it was still in the early stages. Surprisingly, the only damage was to the nearby jumper plugs, many of which had

Yes, a J310’s IDSS range is centered high for this particular circuit. The J309’s IDSS range is actually about right, as the buffer circuit aims to operate the FET at a VGS of -0.6 (to compensate

Hi Folks, The parts arrived from Mouser. I replaced U2101 (DAC), U2521 (4051) and U2420 (TL084) as well as all the 0.47uF capacitors connected to the U2521 just in case. I though I read somewhere the

Hmmmm...electrolytics? DaveD

The cleaned up 7A42 is still working OK. I'm calling this one fixed and done, ready to go back on the shelf. Hopefully it will still be good whenever I need it. Ed

Hi Nenad, Your photos encouraged me to attempt to disassemble my own res/freq knob assembly. I was hoping to be able to tell you whether my L-shaped insert also appears glued, but interestingly, I

For some reason I've been referring to the original working JFET as a J310, but looking back all the way to the OP, I'm not sure what it is - all kind of parts are floating around this thread. So

Raymond and Leo, thanks for the correction, it was ENTIRELY operator error and misunderstanding. I see that the same thing can be achieved on the 475 by selecting the B trigger source as "STARTS AFTER

Sorry I got the impression from earlier in the thread that these were a totem pole pair of fets . My bad Must be more careful to look at the manual. Regards dave ⁣Sent from BlueMail ​

Ed, I’ve analyzed the circuit. Any IDSS below about 30mA will satisfy the loop, as I’ve noted twice before. If much lower than that, dynamics may suffer, but the upshot is that there’s a very

There may be some confusion over "selecting" versus "matching," due to the different input amp topologies also included in the discussion. In this case, it's an opamp-stabilized system, with only one

Need some basic clarifications and guidance. I want to view some wave forms of a 465M scope with a 460A digital scope. The manual for the 465M tells you to run a 50 Ohm cable between the "A EXT

Hi Dave, I earlier posted that I doubt very much that any detailed selection went on, other than a crude sort for IDSS. The whole point of that design was precisely to eliminate the cost and bother

Thanks for bringing this up Ed. My pristine 7A42 had just started to show some battery leakage and was able to clean the liquid on the board. Had some green on the power supply jumper pins but it

Digging through our many parts bins, I found a stash of oddball NEW probe parts we have no use for, so they can be yours free if you can use them. This includes: 2 ea. P6040 50 ohm probes (has GR874

Hi Richard, If you are still at 2612 Virginia Rd I added you to the order list for Peter's book. If this isn't your current address please let me know. Dennis Tillman W7pF

I've been unable to find anything more than bibliography references to this document (in an ESD context). Does anyone happen to have a copy?

The 7D02 Logic Analyzer Plugin was designed to work with a dozen different microprocessors that were popular in the late 1970s to mid-1980s. In order to do that it needed a Personality Module that

Hi Dennis, Thank you so much for doing this. I appreciate the magnitude of the work that you are doing. No good deed goes unpunished! Again, I am deeply grateful! - Tim Dr. Timothy