Test Equipment

This page lists some vintage test equipment I own.

Precision E-200-C Signal Generator

Manufacturer: Precision Apparatus, Chicago, Illinois
Model: E-200-C
Approximate Date Of Manufacture: 1940s
Type: RF Signal Generator
Tube lineup: 5Y3GT, 6SJ7, 6J5GT
Status: working, restored
Where purchased: Given to me as a teenager

Description

This is a vintage RF signal generator. It covers from 88 KHz to 110 MHz in 8 ranges and up to 440 MHz using harmonics. It also has a 400 Hz audio output, and adjustable DC AVC voltage output. For it's time it was a high quality model with precision parts and heavy duty case, power supply, etc. It seems to have been a popular model and units appear occasionally on EBay.

The Precision Apparatus Company still exists under the name B&K Precision.

According to a label on the chassis the 6J5GT tube should be a 6C5.

The AVC voltage output is used for an alignment technique suggested by Precision which used the signal generator to drive the AVC line of the receiver. I think this was unique to this manufacturer.

I found on the Internet a complete manual and schematic for a newer but similar version of this signal generator with different tubes. Strangely, it is also called model E-200-C. Apparently there was an E-200-D which was solid state. After posting a query to a vintage radios forum, a fellow collector sent me the correct schematic for this model.

I modified the unit to use modern BNC type connectors for the RF output rather than the older amphenol microphone connectors. I've used the signal generator to align a number of receivers. It is not very accurate, so I use a shortwave radio with digital readout to set the frequency.

EICO 666 Tube Tester

Manufacturer: Electronic Instruments Corporation
Model: 666
Approximate Date Of Manufacture: 1950s
Type: Tube Tester
Tube lineup: none
Status: working, restored
Where purchased: Bought on eBay in June 2004

Description

This is one of the popular models of tube testers made by EICO. It tests virtually all tubes, including picture tubes with an optional adaptor. After deciding to buy a tube tester and doing some research, I chose this model based on its popularity, capabilities, and availability of manuals.

As received it was in pretty good shape with all parts. The roll chart version is not the latest (666-06) but more up to date than most. It also came with a supplement. I obtained the operation and construction manuals from BAMA.

Someone had obviously repainted the case a reddish-brown hammertone colour (the originals seem to be grey). I gave it a thorough cleaning, replaced the line cord, plate cap wire, a rubber grommet, and fixed a cracked knob. The "plate" rheostat was worn and dropped out in some positions so I replaced it. I calibrated it following the instructions in the manual. All of the features seemed to check out okay. I've used it to test many tubes.

Pictures

Heathkit IM-18 VTVM

Manufacturer: Heathkit
Model: IM-18
Approximate Date Of Manufacture: 1950-70s
Type: VTVM
Tube lineup: 6AL5, 12AU7
Status: working, restored
Where purchased: Bought on eBay in July 2005

Description

This unit is a Vacuum Tube Voltmeter (VTVM), one of several similar models made by Heathkit over the years. It can measure AC and DC voltage and resistance over 7 ranges. While not as accurate as a modern Digital Multimeter (DMM), the VTVM still offers a number of advantages:

more convenient when adjusting for maximum or minimum (e.g. during receiver alignment)
high input impedance (11 megohms on DC)
can measure DC in the presence of AC
accurate up to 1 MHz
can be calibrated and repaired by the user
has scales for peak to peak and dB measurements
less prone to erroneous readings due to noise, leakage, etc.
looks great on a bench when working on vintage radio equipment

I have a partial copy of the manual which includes specs, operation, and calibration instructions as well as a schematic. After receiving the unit purchased on ebay, I only needed to tighten the hardware, clean it, put in a new battery, and perform the calibration procedure.

This was one of the last VTVMs made by Heathkit. Years ago I had a similar, but larger, model which was almost electrically identical.

Pictures

Cap Tester

Manufacturer: homebrew
Model: n/a
Approximate Date Of Manufacture: 2005
Tube lineup: none
Status: working

Description

This is a very simple capacitor leakage tester I built from junk parts. It applies about 350 volts to the unit under test and shows the leakage current. Good capacitors should have negligible leakage. Many old paper caps show significant leakage. It is a simplified version of a circuit from the Alan Douglas book Tube Testers and Classic Electronic Test Gear. Full scale current is 1 mA and is adjusted via the pot so that a short reads full scale.

Pictures

EICO 377 Audio Generator

Manufacturer: EICO
Model: 377
Approximate Date Of Manufacture: early 1960s
Tube lineup: 6S7J, 6BQ5, 6FQ7, 6AQ5
Status: working

Description

This is an audio sine/square wave generator made by EICO, a well-known maker of test equipment and electronic kits in the 1950s and 60s. It produces sine and square waves from 20 to 20,000 Hertz in four bands.

As received it was in very good cosmetic and electrical condition. All functions were working, the sine and square wave outputs were very clean and the calibration was accurate. It came with the original manual including the warranty card and service info. This unit appears to be the factory assembled version.

An original ad for this generator can be found at this site.

Pictures

Heathkit TS-3 Television Alignment Generator

Manufacturer: Heathkit
Model: TS-3
Approximate Date Of Manufacture: early 1960s?
Tube lineup: 12AT7 (2), 12AU7, 6AQ5, 6AU6, 0A2, 6X5
Status: not working, being restored

Description

This is a sweep/marker generator made by Heathkit. It is used for aligning televisions and FM radios. A catalogue from the time described it as follows:

TS-3 TV Sweep Generator. Fundamentals from 4 MHz to 220 MHz with output well over 100,000 microvolts. Automatic blanking and wide-range phasing. Triple marker ranges from 19 MHz to 180 MHz using a Colpitts oscillator plus the 4.5 MHz crystal-controlled oscillator for check points. Provisions for external marker. Sweep system uses the Increductor controllable inductor. Sweep width variable from 0 to 12 MHz at the lower RF frequencies, increasing to 0 to 50 MHz at the highest frequencies. Regulated power supply, constant RF output level, independent marker and RF output control circuits, low-impedance output and properly terminated output cables.

18 lbs.
1953 price: $44.50.

As received it apparently had some damage in shipping. Various modifications were made by the previous owner:

6X5 rectifier replaced with 5Y3GT and required accordingly
power transformer replaced (this one has a 5 volt filament winding needed by the 5Y3)
filter choke added to power supply
internal connection between marker and sweep circuit disconnected and replaced with external connectors
hole drilled in front panel to get at inductor for marker oscillator (presumably for calibrating it without opening the case)

If I had to guess I would theorize that at some time the rectifier tube shorted, overheated the transformer, and turned much of the chassis black. It was then rewired with a 5Y3GT tube (less prone to shorting) and new transformer.

I scanned the manual and uploaded the PDF file to BAMA.

15-Jan-2006 Update:

I gave the unit a good cleaning, measured part values and voltages. A broken knob was replaced. Some bad and intermittent connections were found and the power supply choke that had come loose was reinstalled. I replaced the connectors with more modern BNC types. I replaced the two wax caps. I made a cable to connect the marker output to the sweep circuit (which gets around one of the modifications made). It seems to be working more or less within spec. I'm waiting for replacements for two bad pots that have to be replaced. I also need one more BNC connector (local store only had 3 in stock).

The image shows the waveform at the output of the discriminator of an FM receiver when connected to the sweep generator.

Pictures

EMC801 Resistance Capacitance Comparator Bridge / In Circuit Cap Tester

Manufacturer: Electronic Measurements Corp, New York, N.Y.
Model: EMC801
Approximate Date Of Manufacture: late 1950s
Tube lineup: EZ81, 1629
Status: working, restored

Description

This is a cap tester and RC bridge. It can checks caps for open and leakage and measure resistance and capacitance. It can also test caps at voltage and make comparative measurements. It uses an eye tube.

I have an assembly manual but no schematic or operating instructions.

EMC802 Signal Tracer and Generator

Manufacturer: Electronic Measurements Corp, New York, N.Y.
Model: EMC802
Approximate Date Of Manufacture: 1959
Tube lineup:EZ81, 6AB4, 12AX7, EL84, 1629
Status: working, restored

Description

This is a multi-function device that includes the following functions:

audio signal tracer
RF signal tracer
455 KHz signal generator for IF and RF testing
audio oscillator
test speaker and output transformer

It has an RF probe which has a diode demodulator. In addition to the speaker, an eye tube indicates output level. The eye tube is extremely dim. The RF oscillator is is fixed at 455KHz for IF testing and can also be used for broadcast band alignment at the 910KHz harmonic. The audio oscillator is fixed and uses a neon lamp relaxation oscillator. I have a schematic and operation manual.

Heathkit IG-57A TV Post-Marker Sweep Generator

Manufacturer: Heathkit
Model: IG-57A
Approximate Date Of Manufacture: 1970
Tube lineup:n/a (solid state)
Status: working, restored

Description

This is a solid state TV marker and sweep generator. It has 15 crystals for various frequencies. Compared to my TS-3 model it is very advanced but still uses a controllable inductor for sweep generation.

It got this item at a low price but it was missing the cables and attenuator box. I have a full manual which was downloaded from BAMA.