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yup... can't view the schematic with anything but your link (doesn't load anything in Altium 365, or directly on the Kicanvas Webpage.)

There is no mouse.? There is only a touchpad.? Yes, you can zoom in, but it's a bit tricky. I did look.? I'm not sure about the power supply, I'd be tempted to perhaps do it differently.? You can

Are you using Kicanvas? then... CTRL down... and use the wheel (on your mouse) to zoom in out. wheel to scroll up and down SHIFT down... and use the wheel to scroll left and right

Hello again, I have made good progress on the "drastic change" option, i.e. replacing the original PCB with a homebrew version which is immune to the flaws we discussed in previous messages. In the

Interesting project. For this function, I would use a Tek 7000 series mainframe withe 7A13 OR 7A22, although neither would go to 100 MHz. Seems to me that if the Offset pot is towards either extreme

Hi, Harvey, try pressing CTRL and use the mouse wheel to zoom. The offset pot needs to be in this position to be able to adjust the input to the first op-amp close to 0V. Patrick, I'm no expert in low

Hi, this is a pretty neato thing, if you commercialize your design I'd be interested in buying one! tx! J Patrick Coleman wrote:

Well, I tried looking at the schematic you supplied, and I can't zoom in on it.? I did look at the original design, and I have at least one question.? The offset voltage is applied to the gain

I've spent the last couple of weekends working on an open-hardware power rail oscilloscope probe: connect it to a low-impedance source via a 50Ω cable/termination and it applies an adjustable offset,

Hi PeterS, That's a terrific solution and I'm most impressed. I don't want to modify my TF1245A so won't go down that path, at least not yet! You mentioned in a previous post that you were not able to

TF1245A injection transformer update The wet weather of the last few weeks persuaded me to bring forward my transformer injection experiments mentioned in post #1703. The FT50-43 and 15mm copper pipe

Be aware that using any switch or relay contacts in a “dry” circuit (one with vanishingly small current) has a certain risk. Namely, there’s insufficient wetting current to break through any

I just looked at a Bourns cermet trimpot list, and it looks like they are all around +/-100 ppm/C, which is pretty decent - not as good as WW, but probably OK for this in reasonable lab environment.

Joel, it seems weird that the 200 ohm pots are not wirewound - the parts list says R113-R119 are all 200R, 10%, 5W, "WWVar." Maybe they changed them in the later years of product life, but I'd find it

Folks, Thank you for your responses. I am, at the same time, grateful and impressed after seeing additional expertise ! Your various messages helped me better understand the weaknesses in the original

Unfortunately, you're kind of stuck with it, without doing drastic changes. The range switch contacts should not be too much trouble (you should treat them with Deoxit if not already done). The real

What kind of switches and wafers on the switches? What kind of pots? Multi turn Bourns or Clarostat?For this vintage of instruments I would expect open wafer switches with silver plated contacts -

Maybe some newer tighter tolerance high ohm resistors and make the pots an even smaller change in the total resistance? Tight tolerance low PPM resistors won't be cheap, of course. Steve Greenfield

Try shorting the arm of the pot to the unused end.? That way, if the arm bounces, it only bounces to the maximum resistance and not a? complete open. Harvey

Hi Gary, Quite a good point. Actually, the adjustment range of the pot is quite large (approximately +/- 15% of nominal output), because it has to match the wide tolerance of the high-megohm