"Tower" Model 6158
Geiger Counter
Complete Set
The Sears "Tower" Model 6158 Geiger Counter was sold in the mid 1950's. This model uses two 67½
volt "B" batteries and one 1½ volt "A" battery. The range is 0 - 20 MR/HR over 3 scales.
Three indicators are used, the meter, the headphones and a flashing neon bulb. There is a calibration pot
under the screw cap for the 0 - 20 MR range. This unit also has a selectable Fast / Slow response switch,
located to the right of the carry handle. The probe is shown above in the internal holder.
Dimensions: 9" long x 5½" wide x 8½" tall with handle.
The case is made of aluminum and has a rubber gasket between the top and bottom.
Shown With Geiger Mueller Tube Out Of Holder
Close-Up of Meter Face And Controls
The BNC connector is for the 900 volt probe. The screw cap covers the 0 - 20 range calibration pot.
Inside View
The three calibration pots for the 0-.2 and the 0-2 ranges and for bias are located on the left side.
Probe - Headset - Shoulder Strap - Check Source
The Geiger Mueller probe is made by Anton Electronics Labs. The G-M tube is 5¾" long, made of thin
wall stainless steel and halogen quenched, comes with a Teflon® covering to protect from electrical shock.
The probe attaches to the meter with a BNC connector. Also shown are the headphones which use a ¼"
phone jack, and are made by the E.F. Cannon Company of Springwater New York. The headphone
model number is 15 and are called " Alnico Magnetic". The radioactive check source is on a key chain
and reads 0.6 milliroentgens per hour gamma on my PDR-27T. The check source also came with a tag
on the keychain saying, " This Source is intended for use with this instrument only".
The Carry Strap is black plastic.
Teflon is a registered trademark of E.I. du Pont de Nemours and Company.
A copy of the Instruction Manual for this Geiger Counter is available here.
Inside View of Case Bottom
These units were made by the El-Tronics Company of Philadelphia, PA for Sears as shown on the
schematic. The tube shown in the lower part is the holder for the El-Tronics type 106-C Geiger Mueller
tube, made by Anton Electronics Labs. The schematics are also in the manual, available above.