Paul3d ago
2/ One of the curiosities on the prototype of this #tektronix plug-in is the elapsed time meter on the bottom. It is not present on the production unit. There is a note that I cannot decipher with a date or February 16 1966.
This type of indicator is a Mercury Coulometer, and shows time elapsed using a chemical reaction which moves a drop of mercury in a capillary tube slowly and linearly as chemical reaction is caused by the passage of a small, fixed current.
This unit has a large number of reed relays, which have a finite lifespan, and I wonder if this meter was there to measure usage during testing.
Show threadPaul3d ago
3/ the prototype unit also has factory modifications that seem to correlate to a later rev of the board on the production unit.
Show threadPaul
4/ The prototype unit didn’t work when I first tried it. No real troubleshooting was done
The newer unit had a resistor near the back of the unit that was hanging on by only one lead. This was R563, a 10k 8W, 1% precision resistor off the anode of a tube in the output section.
Funny enough, it wasn’t until I put the units side by side that I realized this resistor was also missing from my prototype unit. It’s kind of a flat, wide, rubberized package that’s near the plug-in connector and is prone to damage.
So that’s a smoking gun as to why my prototype unit doesn’t work.
Now to find a suitable replacement.
Apr 14 at 1:51amWeb
Show threadPaul2d ago
5/ I use brass polish to clean a lot of faceplates, mostly because I once lived in an apartment with all brass door hardware, still have the polish, and one day decided to give it a go.
I’m sure there’s a better thing to use, and someone may tell me why using it is a terrible terrible thing, but it’s doing a heck of a job getting decades of cigarette smoke off the face of this thing, even on translucent plastic.
#tektronix #electronics #vintageTech #retroTech
Show threadW6KME2d ago
@forty2 Brasso has always been my go-to plastic restorer. Love it.