Zenith 8-S-563

Zenith 8-S-563

Manufacturer: Zenith, USA
Model: 8-S-563 (8A02 chassis)
Approximate Date Of Manufacture: 1940 (1941 model year)
Type: 8-tube Superheterodyne AM BC/SW band console radio
Tube lineup: 1232, 6A8G, 6K7G, 6J5G, 6F5G, 6P5G, 6AC5G, 6X6G
Status: working, restored
Where purchased: private sale, March 2005

Introduction

In my teens I was given an old Zenith console radio. The case was rotten, having been stored in a barn for years, and had to be thrown out. I kept the chassis, which worked after a few simple repairs. That radio was my introduction to shortwave listening and I spent many evenings listening to it. I remember many cold winter nights spent standing over the radio listening to short wave stations around the world and being warmed by the glowing tubes. Years later the chassis was damaged in flooded basement and no longer worked. I was no longer actively interested in radios and due to lack of space I gave it to a friend who collected old radios. Year later, when my interest in old radios had been rekindled, I started looking for a radio of the same model. I was able to identify that it was a Zenith model 8S563 (or 8-S-563) with an 8a02 chassis. I kept a lookout for this radio on ebay to see one could be obtained at a reasonable cost, including shipping.

In March 2005 a seller with an 8S563 contacted me and we were able to agree on a price and arrange to have it shipped to me. It was shipped from Syracuse New York, along with a spare chassis. There was some damage in shipping but with the spare parts I was able to restore it without any problems.

About This Model

The is an 8-tube console made for the 1941 model year. It has AM broadcast as well as two shortwave bands covering 1.5 to 5.2 MHz (indicated as Police) and 5.2 to 18.3 MHz (indicated as Shortwave). It has 6 station presets that are tuned to specific AM broadcast stations. There tone control provides 6 switches labelled Low Bass, Treble, Voice, Normal, Alto, and Bass (offering a total of 64 different combinations of tone settings). It has a 10 inch field coil type loudspeaker, and a built in rotating "wavemagnet" antenna as well as external antenna connections. Power consumption is 65 watts and audio power output is 6 watts. It has the famous Zenith black dial with shutter indicators showing which band is selected. Power, volume, tuning, and band selection are all controlled by 3 knobs on the same shaft.

I found this radio has good performance on shortwave, even using the built-in wavemagnet (which in itself is bigger than most radios). The large dial and heavy flywheel make it quite easy to tune. The audio quality is excellent with good bass and treble performance. Initially I thought there was a problem with shortwave reception at the high end of the band but found the same problem with other shortwave receivers in my house. I have 5 computers in the house connected on a LAN which produces a lot of interference. It seems to have become worse after I recently upgraded the network switch to support 100mbps speeds. The LAN cables run right above my radio workshop in the basement.

It has 8 tubes, consisting of 1232 (or 7G7) RF Amp, 6A8G Converter, 6K7G IF amp, 6F5G 1st AF amp, 6P5G 2nd AF amp, 6AC5G power amp, and 6X5G rectifier. The tubes include ST type (with and without grid cap), GT type, and one loktal type. The IF frequency is 455 KHz. Schematics can be found in Beitman's, Rider's, and the Zenith repair manuals. Slusser's price guide lists a value of $250-$300. The same chassis was used in models 8-S-531 (table model) and 8-S-548 (chair side). There was an 8a03 chassis that was almost identical except for a phono input. Note that there is one quirk in the schematics which is typical of radios of the era but can be confusing: the suffix "M" indicates thousands, not millions. So, for example, a "10M OHM" resistors is 10,000 ohms, not 10 megohms.

Restoration

After locating the schematic and alignment info and doing a general inspection, I started a full restoration.

The entire chassis was given a good cleaning and I took many pictures with my digital camera to aid in reassembly or troubleshooting any problems later.

All tubes were tested using my EICO 666 tube tester and appeared good. So did the tubes with the spare chassis. All resistors were measured for values being within tolerance. All paper caps were replaced with new modern units. The 3 in 1 electrolytic caps were replaced, with the new ones stuffed into the original can. I replaced the line cord with a new one. The line bypass capacitor was replaced with a Y2 type safety cap. The 6X5G rectifier is notorious for shorting and destroying the power transformer; I added a circuit breaker to protect it (I would have used a fuse but I had a suitable breaker handy). All controls were cleaned with contact cleaner.

The wavemagnet was damaged in shipping. I carefully reglued the many broken pieces until it looked presentable again.

The other major damage in shipping was the tuning shaft, which had become badly bent. I replaced it and the associated parts using the spares from the extra chassis. The leather tuning belt was still in good enough shape to use. I also had to fix a cracked dial pointer.

This is one of the models of chassis that used rubber wiring that has now become cracked and brittle with age. It is believed that they used inferior quality rubber due to wartime shortages. The insulation now falls off as soon as it is touched. Most of the wiring was replaced. I left a few pieces which I did not need to move or touch. I was careful to ensure the replacement wires were the same colour as the originals.

I tested all voltages against the values listed in the documentation (some were not readable, at least not the decimal points). I adjusted the tuning presets. I performed an alignment as per the 10 steps in the documentation using a signal generator.

The cabinet had some damage in shipping, mostly old joints coming apart. I reglued them and touched up some scratches with wood stain before giving it a couple of coats of wax.

I ordered a replacement grille cloth from grilleclothe.com and installed it. Finally, I ran the radio for several hours of "burn-in" testing.

The spare chassis is complete except for speaker. I put in all the tubes, hooked up a PM speaker with a power resistor in place of the speaker field coil, and powered is up slowly with a variac. I was able to pick up stations, so it is functional. It has the same crumbling wire and the chassis is a little rusted.

Due to limited space I decided some time ago I only had room for one console radio in the house. It is fitting that this would be the one, as it is the model that was my main radio during my youth.

Pictures