Tekprobe interface repair

I'd clean it with acetone and a q-tip, to see if it's worn through, or simply dirty. I'd also try cleaning it with a pencil eraser.

If it is worn through, I bet one can use silver-epoxy to attach a bit of silvered copper foil to the landing pads. Or just hot-air solder the foil down.

Joe Gwinn

And second thought - don't use tin. It is subject to fretting corrosion, and the contact point will soon fail. Tin is the worst choice for contacts. Google for a vast number of papers.

If one solders to the silvered areas, be sure to use a silver-bearing solder - 2% silver is enough.

Joe Gwinn

Looks like there was no lubricant on the switch. It won't last long.

Don't use WD-40. It is not a lubricant. Use plain unscented vaseline.

The flex part is often available on eBay.

Cheers

Phil Hobbs

Oh, and while you're got it apart, convert it to a 784A (1 GHz, 4 GS/s). It's trivial--you remove one slowdown cap on the differential outputs of each of the front ends, and remove one zero-ohm jumper so that the motherboard boots up as a 784A.

I've done both of mine, and was pleasantly surprised that there were no step response artifacts.

Pro tip: some of the directions on the web have Bad Info about the jumpers--if you remove the wrong one, you'll wind up with 1 GHz and 1 GS/s. I got one of mine for cheap because somebody had done that and panicked.

Search the SED archives for a thread from 2016 entitled, "Tek TDS 744A -> TDS 784A upgrade hack!".

Cheers

Phil Hobbs

The flex part/pogo pins is ok it seems, it has the fault on even new probes also

Cheers

Klaus

That is simply great. I knew the Rigol scope could be hacked to open up the higher frequency modes, but didn't know the mod is so simple to get at even higher performance out of the 744A

First task is to find the best way to take it apart. Guess I can find that information on Youtube or some repair manual, or proceed with care myself

For this scope I programmed an external frequency generator, to make a gain/phase /impedance analyzer. The higher frequency will mean that can perform to higher frequencies, before phase delay kicks in

(the swept analyzer is a little slow, but when it is running I normally have a parallel task to work on)

Cheers

Klaus

I don't mean the probe side. The pads on the front panel are also flex, at least on mine. I have one with a mildly damages flex on channel 1. You can get parts on eBay, anyway.

Cheers

Phil Hobbs

The one I have looks and feels like standard FR4 board

But anyway, that will become visible when I take it apart

First, I have a more critical project, doing a LISN for my lab (I work from home 75% of the time due to COVID, so I need a way to do simple conducted emission tests

Cheers

Klaus