Back in the day (I haven't looked into this topic for about 4 decades), Princeton Applied Research made fairly decent lock-in amplifiers. They seem to be running about $300, or so on eBay. If you

Moving slightly OT, I think Stanford Research are the Lock-In Amplifier people. (Among others) Talking $$$$ tho' Tim

Hi Lyle, My comments are below: 2465 schematic I found is missing proper measurement references, there is only one (REF) line. If you look at 2465B PSU schematic, which is almost identical, some

Re: Hacking a digital camera Removing the IR filter won't make much of a difference. The objects have to be *very* hot in order to have any appreciable IR emission at wavelengths short enough for a

Interleaved: Likely the best.  The 50% duty cycle is only for an HP current tracer, which detects fluxuating magnetic fields with a rather delicate and expensive hall effect sensor.  The idea is

Hi fellas, thanks for the input, it all helps. @ Harvey; Nicely outlined. You've helped clarify a few things which weren't so clear. The feeding a 50% duty cycle signal shall have to wait. My

Thank you Ozan. Please excuse my delayed response. Your whole comment was tremendously helpful. For instance,I had confused T1020 and T1050 as a single transformer, partly because they are placed

I'd thought about shrink tubing as well but if I can get appropriate DuPont holders, I'll probably to that route. I'm pretty sure the wires are color-coded such that brown is pin one, red is pin two,

I also had a blue one disintegrate to dust on my 7904. I put shrink tubing (blue) on every other pin. The wire to wire bonding in the flat cable keeps them in order but I drew a diagonal line across

Ooh, shiny!  Lock-in Amplifier (never heard it called an Analyzer before) - now I want one!  Onto the wishlist it goes.  Any recommendations for make and/or model, Ed?  Or Steve H. or anybody? 

Do you have access to a lock-in analyzer (LIA)? If so, you can force some reference current, say at 10-100 Hz, and do voltage probing. The LIA's large dynamic range allows it to work with very small

Ignacio, Thanks for that tip. I have some of the four-pin type but will be getting some of the other pin-count versions. I didn't realize those would work. Thanks, Barry - N4BUQ

If you can borrow or afford one, a true infrared camera is way faster. IR imagers are much cheaper than they were two years ago. A camera that allows the user to set the range is best

See the vintageTEK Video on attenuator repair: https://www.youtube.com/watch?v=ko_ubD_yrF4 Replacing the attenuator hybrid modules with wire jumpers will determine if the problem is the cam switch

I'll see if I can summarize the concepts that I understand. The basic concept is that you measure the voltage drop across each suspicious component and look for the lowest drop.  Another concept

Been there. You can replace the broken connectors with DuPont ones. They are cheap, widely used, i.e. in Arduino projects and in various pin counts. They are always black. Ignacio -- El software

Tom, I have to admit that I haven't looked closely at the interior of the plugin attenuators, the manual simply shows a 'black box' with a resistor to ground at the mid-point of the box and I simply

Yes, It's always the blue ones that crumble. D.

Regarding those harmonica connectors, when I pulled one of them from one of the circuit boards last night (P1306 on the A22 board), it crumbled in my fingers. Interestingly, it was a blue connector.

Swap the attenuators between the channels. If the problem follows the attenuators you have a bad one. They do fail.