This baby is heavy (80 lbs), I had to take a rest when I brought it upstairs. I got this Chinese military radio receiver in NOS condition. The radio was a direct copy of Soviet design with minor modifications and was first made in 1950 with imported tubes and was supplied to Chinese troops fighting United Nations force in Korea War. Later, it was also supplied to Vietcom in Vietnam War. It should be replaced by Type 222 receiver in early 60s, however, my example was manufactured in 1974, long after the introduction of much superior Type 222 receiver.
The 7512 receiver is 12 tubes shortware receiver cover 1.5 to 25 MHz in 5 bands. It is for use in relatively fixed station. Every tube is protected by either tube shields or tube clamps. It weights 36 Kg with dimension of 520 x 320 x 370mm. It could by powered by 80, 90, 100, 110, 120, 190, 200, 210, 220 or 230 V AC consuming 90W of power. It has three types of outputs, two 4000 ohms outlets for earphones, one 600 ohms outlet for speaker in distance and 3.2 ohms outlet for local speaker. It resembles a commercial receiver in 1940s with much reinforced construction. It has an access hatch on the top, which makes replacing tubes an easy task.
I got this baby in NOS condition and it is a C type, the third production version. It came in wooden crate with manufactory sealed plastic bag. A range of accessories are included, a complete set of 12 extra tubes, 22-meter long wire antenna, a technical manual and a user manual, two sets of 4000 Ohms earphones. The serial number is 741348, and the certificate indicates this item was come out of manufactory in June 1974, and it was made in Shanghai Third Wireless Manufactory.
I anxiously opened the sealed plastic bag expecting a rusting metal box waiting inside, since 7512 has a steel construction instead of aluminum construction in later designs. What a surprise, the 7512 was so new, it is looked like it was made in 2004 not 1974 some 30 years ago. All the metal surfaces are still shinning like new. Paint is also new without any defect. All the control knobs and switches could be operated smoothly.
To restore the aged capacitors, I gradually powered it up. The rectifier tube went off during this process, and my heart went south at that moment. Luckily, it lighted up again after I firmly pushed it down to its socket. Sound immediately came out of the earphones after, what a wonderful moment. The sound is beautiful. The sound of my 239 seems little too harsh comparing to this big baby. The selection and sensitivity are on par with that of the 239 receiver. I listen to CRI regularly with this baby. I like to conclude this blog entry with a ham’s words about this baby, “It just like a large bear sitting beside me, breathing warm air to me and working hard for me.”