My vintage BC-221C, serial number 575. The BC-221C is powered by a home made power supply inside the plastic housing below the Opto 8000 frequency counter. The BC-221C is tuned to and producing an RF output signal at 3.890Mhz as displayed on the Opto 8000 frequency counter. The calibration book has the same 575 serial number as the BC-221C has. I have a second calibration book, also with the same 575 serial number.
The newest addition to the test equipment collection is a “Still in kit form” Heathkit IO-4560 5Mhz oscilloscope. I picked up the scope kit for “$15” plus shipping!! I have not gone through the part list but I plan on doing that later on this summer. More than likely the carbon resistors will be replaced with metal film resistors. The can and other electrolytic capacitors will have to be checked with my Sprague capacitor checker to ensure they are good. I doubt the can capacitors and other electrolytic caps will need replacing.
Military AN/URM-25D RF Signal Generator. I picked this one up from Fair Radio Sales in Lima Ohio. It’s a great and stable signal generator but it must be turned on and allowed to warm up for a minimum of 15 to 30 minutes.
Simple Heathkit IG-102 RF signal generator. I changed the input and output connectors to female BNC. The audio Input/Output select knob cracked so I had to use an older Heathkit knob. When I use the IG-102 signal generator, I power it up and allow it to warm up for 15 to 30 minutes.
The row of analog VTVMS are left to right, Heathkit IM-5238 AC volt meter, Heathkit IM-5225 FET Volt meter, Heathkit IM-5218 VTVM, Eico 232 VTVM, and a Heathkit IM-21 AC volt meter. The scope is an E&L Instruments 20Mhz. The frequency counter is a Sinometer VC-2000. The Scope and the VC-2000 are displaying the audio signal from the Heathkit IG-72 audio signal generator. Note the nice clean sine wave of the IG-72 audio signal.
A few power supplies. Top left s a mid 50s Heathkit PS-3 providing 0-450VDC at 200ma. Next is a Heathkit IP-28 providing 0-30VDC up to 1 amp. Below the IP-28 is a dual output IP-2718 producing 0-20VDC at 500ma and fixed 5VDC at 1.5amps. Below left is the Heathkit IP-17 providing 0-400VDC at 100ma maximum. Bottom right is a Heathkit providing 0-50VDC at 1.5amps maximum. The frequency counter is an Opto Electronics Opto-8000 measuring frequencies from 10Hz to 600Mhz.
Two working 1962 Heathkit IM-32 VTVMs. The IM-32 on the left has a “Lectrocell” battery eliminator from Lectrotech that is powered by the 6VAC filament voltage. IT provides the 1.5VDC voltage for the Ohms measurements. The left IM-32 also didn’t work very well. The meter would peg fully to the right in AC/-DC and peg fully to the left in +DC and Ohms settings. The problem turned out to be bad 12AU7 and 6AL5 solid state replacements. Pulled those solid state tube replacements and put in actual 12AU7 and 6AL5 vacuum tubes, replaced the power supply filter capacitor and selenium rectifier with modern components and performed the alignment, works great now. The IM-32 on the right would not power up. Problem was blown 250ma fuse. I also replaced the power supply filter capacitor and selenium rectifier with modern components and put a new fuse in the fuse holder, and powered up the meter. The alignment went okay but the Ohms, when measuring any resistor, displayed the same value, approximately 1 ohm. Problem was caused by poor connections in the “C” cel battery holder. Fixed the battery holder connections and the Ohms started working as it should. I moved the AC/Ohms Banana socket wire to the tip of the 1/4″ mono socket on both VTVMs so the switchable Heathkit probe could be used. The Red banana socket on both VTVMs is not connected to anything but the Black banana socket is connected to the chassis.