E 52-b2

(Köln)

1944

1480-3020kHz
2980-6040kHz
5975-10050kHz
9950-17700kHz
17600-25200kHz

2

None

Outside

Super-heterodyne. IF frequency is 1 MHz

110-230VAC 50-60Hz, or 12VDC

NA

 

CW and voice

The E52 when I received it

 

 

Another photo.

 

 

Front cover is off.

 

 

Modules are removed - the motherboard is clearly visible in the back.

 

 

The LF and Oscillator compartment.

 

 

Commartment for the HF and IF stage modules.

 

 

The tuning mechanism.

 

 

Power supply with cover. The power supply is very heavy and is a substantial percentage of the entire receiver's weight. There are 30 screws that keep the cover attached to the power supply, and takes about 30 minutes to remove all the screws. The cover itself is very solid and heavy.

 

 

The power supply with the cover removed.

 

 

The modules.

 

 

Front cover and knobs.

 

 

 

 

Vlad Dvorkin measuring AC component of the DC anode output.

 

 

Testing RG 12 D 60 rectifier tubes - they tested fine.

 

 

Since there was a 2 Volt 60 Hz noise in the Anode chain, I wanted to see if it was coming from the power supply. I put a 4.2 kΩ 30 Watt resistor on the Anode output to measure the AC component coming from the power supply.

 

 

Closeup of the resistors. I loaded both the filament and anode outputs.

 

 

I also wanted to see what the screen grid potential did.

 

 

This is the main power supply output connector. The connected ternini are the primary ones that the (non-motor) E52 needs to operate.

 

 

120 VAC, 400 mA

 

 

This is the achieved anode voltage.

 

 

This is the AC component - 202 mA - definitely within acceptable boundaries. This means that the power supply is working very well and filtering the unwanted AC.

 

 

Testing the AF block - it tested great.

Testing one of the IF stages.

 

 

Testing another IF stage.

 

 

Intermediate frequency is 1000 Hz. Signal can be clearly heard from the IF stages at 100 uV

 

 

This is the oscillator stage removed from the chassis. Usually the green Darolwid resistors are bad. Several of mine showed signs of cracking around the contact rings. Sometimes with these resistors, only the paint keeps them in place. Mine measured within 10% of specs, so I will not touch them (for now).

 

 

The oscillator section from the bottom. Note the elaborate contact system. Also note that only one of the two screw attachment holes is grounded. German engineers were masters at grounding equipment properly.

 

 

The contacts for the oscillator module. The ones in the back are spring-loaded balls!

 

 

Cable I made to troubleshoot the IF module outside the E52.

 

 

The IF module. The receiver serial number (2041) is written in pencil on the front. This is how these modules are marked.

 

 

Female contacts in the rear.

 

 

The portion of the mother board for the IF module. The pins that are seen on the left are for the direction-finding add-on to the E52.

 

 

Top of the IF module

 

 

Front of the IF module with the cover off.

 

 

Left side

 

 

Rear of the IF module. Note the placement of the two quarz crystals used for the legendary "constant-K" variable bandwidth control mechanism.

 

 

Right side of the IF module.

 

 

IF module being tested outside the E52.

 

 

Inside of case