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Emud Model 196 JuniorThe Emud is a little Grundig dated back to about 1960 as determined by the Sam's photofact pages. It has a great tube line up with a ECC85, EZ80, ECH81, EBF89, EAA91 and a ECL82. All the tubes tested good in this unit. The cabinet is in great shape. A little cleaning, Teak oil and some paste wax will shine up the finish. There is an oval dynamic speaker and a ceramic high impedance electrostatic tweeter. These can be seen in the pictures below. The dark brown round unit on the inside cabinet picture, to the right of the oval speaker is the electrostatic tweeter.
Electronic RestorationRestoration is in progress at this time. So far I have found several bad components that would prohibit the unit from functioning. R27, 1000 ohm 5 watt resistor that supplies B+ to all but the Audio output tube was open. The open resistor was rated at 2 watts (the gray/black powered tube to the right of the big power transformer. However, the Sam's schematic lists it as a 5 watt. It has been replaced with a 10 watt resistor. The new resistor should run nice and cool. Since the original resistor was open the radio should have been rendered non-functional or dead except for the audio output tube and the dial lamps. I do not power up radios until after component restoration (replacement of electrolytic filter capacitors, wax/paper caps and out of tolerance resistors). Vintage radios can have multiple problems that may just ruin good components like a power transformer or burn up a rectifier tube. Some components are just not available unless one is lucky enough to find a donor chassis. The other most visually obvious failed component is capacitor C10 in the FM RF section. It looked like it was calcified and covered in some sort of powdery deposits. And not just a light dusting. But it looked as though it grew crystals out of it. That cap was replaced by a dipped silver mica rated at 600 volts. I speculate the capacitor had failed from either humidity, a manufacturing flaw or an over voltage condition. There are four electrolytic capacitors including the dual section filter cap. All were way out of tolerance. All were replaced. You can see two of them on the right side of the underside chassis picture near the out put transformer. They are yellow/green in color. You can see two white covered paper capacitors in the middle of the chassis. These are all over the unit. These types of caps crumbled in my fingers when removed. And tested way out of tolerance. I check all removed components for value. I do not reinstall components that happen to be in tolerance. My experiences have shown these caps and some resistors (power, carbon composition) go bad shortly after power is restored. It may take a month or two or six. But you will be back in there finding the failed part if you leave them in. All replacement components were checked appropriately (capacitance meter(s) and ohm meters) for proper value and tolerance. There are some capacitors seemingly specified, some within, 2.5% of value and others at 5%. I specifically pulled and matched capacitors with in those marked tolerances. AlignmentI performed the first full alignment tonight (September 15). It is a real thrill when the sensitivity of a radio climes and climes while adjusting the tuning slugs. A before and after alignment listening test is quite impressive. The radio adjusted in easily with no problems. The only exception being the travel of the frequency indicator does not travel to the lower extreme of the dial (88Mhz/515Khz). There is a mechanical limit to the actual travel of the dial cord, tuning gang and main pulley attached to the tuning gang. However, this does not stop the radio from covering the designed frequency coverage. You will notice the dial glass has been removed. This is intentional and is done to protect it from damage. It will be reinstalled when the radio is complete and ready to return to operational display. I will perform another full alignment and recheck all voltage reference points (B+, Grid voltages, Screen voltages and any documented reference voltage) after a 24 hour burn in period. I will also sag or dip the line voltage to ensure acceptable performance over a "relatively" wide range of line voltages. This is more critical with short wave radio oscillators and battery powered radios on the higher frequencies around 15 to 20 Mhz. All bias voltages checked good, with in tolerances and proportional to documented numbers. The radio was operated in a sag line voltage condition at 90 volts. The internal oscillator kept working on both bands (AM, FM) up and down the scale. A bit down on the volume but still operational. (Do not sag the voltage of solid state (transistor) gear. The transistors do not like (too much current) when this happens, get hot and let the magic smoke out. Some units may have power supplies that compensate but most do not.) This test is most significant with Transoceanic restorations. It ensures the selenium to silicon diode replacement was properly calculated. Dial Scale BackgroundThe Dial scale background metal had rusted, thus blistering the paint. This was color matched at the local hobby shop with Testor spray paint. The ladies at the hobby shop recommended a shade of olive drab. It looks quite good. See below.
Electrostatic Speaker
Emud 60 Senior Rekord (American version)The Model 60 is a larger model of table radios. It has two electrostatic speakers and a separate mid range. There is also a tuning EM80 tuning eye. Restoration was similar to the above model. There are some differences in the circuits between the 106 and the 60. There are three tone controls. One bass one treble and a set of three buttons. The AM tuner has a separate control from the FM tuner. Bands include AM broadcast, FM broadcast and Short Wave.
I had a small bit of trouble with the alignment. Since the chassis are very similar between the 60 Senior and the 196 junior the alignment procedure is the same. The numbering of the IF transformer slugs, variable coils and caps are different. But they act and adjust identically. The test points are the same functionally but are identified differently. Hans at Radiomuseum.org helped out with the proper test points. Once identified the FM section aligned per specs.
Emud Record 176This is nice little 1958 Bakelite unit with several bands including FM AM Broadcast and SW. It also has a phono input. This unit receives well on all bands. An external antenna improves reception considerably on the AM bands. A dipole needs to be attached to receive reliable FM signals. There are six tubes in this unit. But only a filament transformer. I must caution any owner of this unit that one side of the line cord (mains) is connected to the metal chassis within. If the line cord is plugged in the so the chassis is connected to "Hot" instead of "Neutral" then serious currents could flow. I have installed a UL rated safety capacitor for the RF bypass positions (from hot to chassis). But this is no guarantee of protection. It is my understanding from the gentlemen at Radio Museum.org that this is acceptable engineering for this period radio. Further comments on Radio Museum.org state that an "Isolated" turntable or phono should be used. See the conversation here. The schematic posted on the web site does not represent what I observed in the chassis. The Rekord 176 (note the spelling) schematic has the circuit ground connected to the chassis through a 5nF cap. The actual radio, Record 176, has rivets on the chassis with numerous component wires soldered to them. An ohm meter proved a closed circuit from the power plug to the chassis. I would recommend that an isolation transformer be used on this radio. Especially if you should have intensions to connect a turntable or other input. Restoration particulars include all paper caps replaced, one cathode resistor was burned. That lead me to a intermittently (flick it with you finger and the short would go away for a while) shorted ECL82. I replaced the burned 1w, 320 ohm resistor with a two 1w resistors in parallel for 2 watts of dissipation. When I looked up the max cathode current in the RCA tube manual I calculated about 0.85 watts. I did not like the power margin. All other tubes tested strong on the Heathkit emissions tester. All of the other resistors tested good. Usually I replace resistors like capacitors. However, I have found the foreign German radios use a coated resistor of apparently higher quality. They stay stable and in tolerance. Cosmetically a new dial cord was needed, the plastic dial scale took some TLC to clean and preserve, and the dial indicator got a shot of Clorox Clean up along with the dial scale background. The Bakelite case was cleaned with Clorox Cleanup and numerous Q-tip swabs. Stray strands of the speaker grill were pushed back into the weave with a dentil pick and/or clipped off and a few spots cleaned. The knobs and buttons took a soak in Clorox Cleanup and were scrubbed with a tooth brush. Round felts were used under the knobs. I hate that scraping feeling when a knob contact something hard. The bakelite case, buttons and dial scale got a healthy dose of Magnolia's Glazit. The only thing left to do is add a polarize plug so the chassis is connected to the neutral side of the line. Enjoy the pictures below.
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