Exploring a 1950s Eico oscilloscope, inside and out, with fantastic pictures.
While scanning the shelves of my secret supply of antique electronics, I noticed this beauty hiding behind a stack of silver plastic VCRs. Its gridded CRT display showed just enough to catch my eye. A brief shuffle later, the pesky video tape monsters were out of my way, and this beautiful scope was staring me in the face.
As you can see, the leather handle had rotted. It immediately snapped off in my hand. However, everything else seemed to be in decent shape, so I brought it home for an autopsy.
An interesting feature you can see is that there is a grid on the display. This model did not come with a grid on the display; someone actually added it after the fact. You can see the original without the grid here. The grid is a piece of overhead transparency with a circle of acrylic cut to fit in the rim. It is held in only by friction on the felt ring.
This device was manufactured in Brooklyn. I couldn't find a date on it, but the model 425 of this form factor was manufactured through the 1950s.
I was able to find a few other model 425 scopes on the Internet, though they had a different face plate. Judging by their lower serial numbers, I'd say this one is newer, and I'm placing it in the second half of the 1950s. The earlier models (shown in the website above) appear to have a blue front plate.
Not much is available on the rear of the unit. There is an access port that lets you get to the rear of the CRT.
Aside from the acrylic plate and grid upgrade, I can see that the power plug has been replaced. Someone cared for and used this machine. Now let's open it up and look inside.