3035 W/3D USA

 


Home Up 3035 W/3D USA 3045 3089PH 4019U 5088 5088 w/EM34 87 USA

 

 

 

This is a 3055 with 3D sound USA Version.  This case is in Excellent shape.  Nothing needs done with the wood finish.  The plastic parts were cleaned and treated with Glayzit.  The Dial glass cleaned and the red line on the FM indicator repainted. 

im000114.jpg (896228 bytes)Great Cabinet. im000115.jpg (721920 bytes) im000117.jpg (737266 bytes) im000118.jpg (823897 bytes) im000120.jpg (816150 bytes)
im000121.jpg (926583 bytes)The FM dipole is forced into the SW/AM antenna jack.  Rear wood frame a bit fractured.  im000127.jpg (296802 bytes)Record speaker connections. im000128.jpg (380199 bytes) im000129.jpg (349781 bytes)Remove, protect and store the dial scale glass.  It is made with "Unobtainium".  im000130.jpg (347256 bytes)Glue and clap split wood. 
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This IF has a moving coil connected to the Treble control with a dial cord. 

im000132.jpg (320982 bytes)The moving coil is stuck. im000133.jpg (695000 bytes)

There is a deposit of something hard. 

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It is functioning well after considerable work.

im000140.jpg (850164 bytes)You can see the dial cord that moves the IF plunger when the Treble control is turned. im000143.jpg (380217 bytes)The specified eye tube is an EM85.  It is quite expensive and hard to find. I could not find one that I trust to use.

 I researched a substitute based on performance specs.  The EM81 tube is a fine sub.  The pin connections are different and the electrical specs are very close.

im000144.jpg (1178550 bytes)Seal up all the alignment controls from slipping.  You can see the green candle wax and the old nail polish.   im000146.jpg (347309 bytes)To seal the trimmers use Glypt or something that cracks easily off for the next alignment. im000147.jpg (383225 bytes) This tweeter is fine.  Plays loud (for a Grundig). No repairs needed.  im000148.jpg (328675 bytes) This side speaker had some dirt creating a Buzzing/rattling.  A bit of dusting took care of that. IM000002.JPG (252905 bytes)This is an STSP toggle switch that is wired in series with the eye tube plate.  It is used to turn off or "blank" the eye tube.  Eye tubes only last for about 1000 hours then fade out.  Use of this blanking switch should extend the life of this hard to get tube. 
IM000019.JPG (400716 bytes)This brass has a classic worn look.  Some people would never modify the original finishes of an antique (100 yrs old).  That would lower  the value. And this finish is far from needing replaced.  This radio was manufactured in 1955 to 1956 time frame.  IM000020.JPG (324589 bytes) This side grill cloth can be easily replaced by removing the four grill retaining screws. IM000024.JPG (442613 bytes) The wood finish is in great shape.  A rub down of Rejuvenating oil darkened the tiny scratches and removed any old wax. The front grill looks new.  The New eye tube looks great too.  IM000025.JPG (222507 bytes) This is what it will look like when the lights are dim with a cool drink in your hands!  Happy Holidays.

The original Eye tube is an EM-85 (6DH7).  This has been replaced by an EM-81 that looks the same but with different pin outs.  The specs of both tubes closely compare.  The EM85 is hard to get and very expensive tube, if you can find one.  Both popular vintage radio vendors that I do business with do not carry it.  And I do not want to risk the likely probability of a re-marked or fake eBay purchase.  

 

This is the second of two featured 3035s.

 

3035 w/3D USA 

 

IM000102.JPG (75879 bytes) As received IM000101.JPG (74642 bytes)Look left IM000100.JPG (72284 bytes) Look right IM000099.JPG (61969 bytes) Broken Ferrite Antenna support quickly repaired with Hot Melt glue gun.  Replacing and stringing the dial cord was a different matter.   
IM000103.JPG (75529 bytes) Out of the cabinet shot.  IM000109.JPG (64857 bytes) I ALWAYS store the dial glass separately.  I do not want an accident and have to find a replacement! IM000106.JPG (84954 bytes) The blue capacitor just under the left side of the switch enclosure was shorted.  You can also see the burnt (open) 1k ohm resistors that the short took out.  IM000107.JPG (80720 bytes)The yellowed paper capacitors can be seen under side.  The blue capacitors are also paper inside.  
IM000128.JPG (305335 bytes) Restored and working.  Products on the left used to shine the knob brights and treat the plastic.  Glass cleaner took care of the dial glass.  TEST the paint before cleaning. IM000129.JPG (178357 bytes) No flash and  Light Out shot. Sorry.  I did not take a picture of the restored under chassis.  I will post one if I disassemble the unit again.  All the paper and blue capacitors have been replaced with yellow tubular caps that are considerable smaller in size but all rated at 630 volts. In the picture directly above,  between the two horizontally oriented blue caps, is a dark circle with three wires.  Two electrolytic capacitors mounted to a new terminal strip replace the chassis mounted can capacitor.  The wires were moved to the terminal strip and the can cap left in place for appearance sake.  Again sorry for not taking an after picture. See the Capacitor Page for an example. 

 

Selenium Bridge Rectifier retrofit with 1N4007.  

Selenium rectifiers loose their efficiency over the years.  It is common practice to replace them with silicon diodes of similar capabilities.  I use 1N4007 diodes with a 1000 volt PIV.  That stands up easily in a tube type radio B+.  Some applications a series resistor is added to compensate for the much lower voltage drop of the silicon junction diode.  This is to bring the B+ back down to specifications.   Below is a pictorial of how a flat bridge rectifier was retrofitted.

 

bridge start.JPG (227543 bytes)  This is the flat pack selenium rectifier bridge removed from the radio.  A screw driver, pliers and a soft touch will slip the cover off. inspect diode.JPG (357921 bytes)  Once the cover clears the bottom metal container the top flies across the table and little square metal pieces shower back down on your bench.  Those are the selenium wafers.   Drill .JPG (58982 bytes)  Trim the contacts so one pad per solder contact remains.  Drill two holes in each to receive the 1N4007 lead wires.
lable install diods.JPG (131963 bytes)  I tapes and labeled the solder pads in accordance to the stamped terminal identifiers in the metal cover plate (the one that shot across the bench).   4 diodes.JPG (509973 bytes)  Install and solder all four diodes. bridge done.JPG (474160 bytes)  Reassemble making sure all the insulating materials are returned inside the metal enclosure or a high voltage short will occur.  That's it!

 

Also see the bottom half of the Electrostatic Tweeter page for the 3035 tweeter repair.

 

 

DIN Switchbox

I wanted to hook up some external audio sources to the Grundig.  So I took a Radio Shack switch box  modified the circuit board and added video quality dual shielded coaxial cable terminated with a three pin DIN.  It works well.  

The output of the Grundig is routed to the two RCA output jacks on the switchbox.  This provides for recoding off of the air programs on AM, FM or SW bands.  The signal seems a little weaker than standard line output so the recorder's manual gain had to be set high.

Three inputs can be selected with the three push buttons.  I have hooked up a DVD player playing Shania Twain "UP" album,  A cassette tape deck (I tested the off the air recordings) and a monaural source, my FM amateur radio transceiver.  All three sounded GREAT through the Grundig.  

Use the tape button on the front panel of the Grundig to play the source going through the switch box.

DIN switchbox.gif (4816 bytes)  Schematic Diagram. IM000151.JPG (192704 bytes)  Front view. IM000152.JPG (198152 bytes)Rear view of switch box. IM000153.JPG (192541 bytes) DIN connector in the Grundig 3035.

I was curios to the frequency response of this modification.  There are a lot of people rightfully concern with audio losses due to cable losses.  So I preformed a little test.

Unfortunately, I did not own an Audio Generator so I used the lower end of my RF generator (HP-606a) along with a 100mhz  B&K Oscilloscope and a 100k ohm termination resistor (as in the Grundig).

I found no frequency roll off between the frequencies of 56khz and 20 mhz.  Therefore, I can conclude frequencies below 56khz down to DC are also unaffected.

 

 

This is a third 3035 restored.  

It came in non functional with an open line fuse.  Putting a new fuse in and using a DBT the radio came to life.  Not much life but hearing some weak stations on all bands is a quick check of all the important parts that contain "Unobtainium"( Illusive material, substance or construction method no longer available on the planet Earth).  

 

See the photos below:

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As Received.

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As Received (the flash lightened the cabinet color. 

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Restored.

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Nice dial scale.  And sounds great too!  Trust me on this one. 

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Cleaned with Deodorized Mineral spirits to remove wax, dirt and grime. 

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Various stain pens used to darken chips and scratches.

IMG_5246.JPG (973944 bytes)

A coat of hand rubbed paste wax.... 

IMG_5248.JPG (1001705 bytes)

...and a nice buffing. 

IMG_5242.JPG (1085953 bytes)

She cleans up nicely. 

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Record the wiring point.

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Original parts

IMG_5189.JPG (1052590 bytes)

Ugh, Dirt.  

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Stuffed 1N4007 diodes inside the selenium bridge case. 

IMG_5192.JPG (833091 bytes)

All B+ voltage right on the mark with the fuse at 125vac.  No series resistor needed. 

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The moving coil on this IF can will not move. Document wire connections before removing can. 

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Yep. That's the culprit.  Simple cleaning did not work.  So it has to be repaired. 

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No luck on the chassis so off it comes.  This photo shows orientation of the transormer.  

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Those Germans sure know how to make an elegant IF transformers. 

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The rod on the right is stuck. 

IMG_5203.JPG (785013 bytes) IMG_5204.JPG (1039697 bytes)

A good flush does not work. 

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Nor does a good scrubbing. 

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Sand off the corrosion from the top of shaft, No go. 

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Now for the drill bit.  

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It scraped off some rough spots.  

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The shaft now moves easily. This is Caig Fader Lube. 

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This lube is used on slider pots.  I works great on the brass to plastic interface. 

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Just like new!

It has been re-installed and works great with the treble control. It only retracts about 1/8 inch.  

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All caps have been replaced, all resistors tested. 

FM tunerIMG_5215.JPG (882998 bytes)

All good inside.  I re-tensioned the tube socket.  The pins were loose. 

IMG_5216.JPG (930790 bytes)

Clean.  No paper caps here. All resistors test good and in tolerance. 

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This socket has been rewired to accommodate an EM80.  The EM80 has the same electrical/performance specs as the original EM85. 

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Time for a clean up!  Wipe on Clorox Clean Up.  

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This is a deep untreated scratch into the wood.  It was darkened with a stain pen.  

  The Tweeter received an internal overhaul. 

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You can't hear this picture but trust me, it sounds great!

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New plumber's washers used on the chassis retaining bolts. It isolates the metal chassis from the wood cabinet (a little bit). 

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The speaker selector needed the wiper contacts burnished.  Several on the chassis cleaning attempts did not get rid of an intermittent problem.  It is all gone now!

 

 

 

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