Skip to main content


Showing posts from May, 2019

Bell & Howell Oscilloscope Model 34 DeVry Tech

The Bell & Howell Oscilloscope Model 34 was purchased at an auction and then give to me. It was made by Heathkit for DeVry Tech (DeVry University). Below is a photo of the front after I finished electronically going through it. There was nothing interesting that came up while working on it. Below you can see some before and after of the underside. Below is the top side. The 2 filter cans were 4 sections of 20mfd for a total of eight 20mfd capacitors.  Below is the solution I came up with to replace them. It consists of eight 22 mfd on a PCB that is zipped tied to the bottom of the chassis.   Overall this is a simple oscilloscope and was a simple electronic restore.  Here is the schematic.

1960 Curtis Mathes Television 1121, 2121, 3121A, 5521A

I purchased this set around Christmas of 2018 for $2.50. As you can see below the socket was broken off of the picture tube. The set was also dirty. Below you can see before and after of the RF section of the TV. Notice all the black capacitors in the first photo. Below is the power supply section. Here is the tv back working again.