I was recently given Motorola 1951 Model # 75F31 Radio/Console as a present to restore. I replaced all the tubes. The FM reception is weak, considering the large antenna system it has for both AM/FM in the back. I did locate a wire that may have broken? I have to trace it. Also the turn table will not move, even though I hear some life in the tone arm when I touch the needle. The tone for the radio is weak too, considering the size of the speaker. Not loud and booming like other radios I own from the same period or older. I'd like to continue with the restoration. I'm having trouble locating a schematic. Any advice on moving foward?

:I was recently given Motorola 1951 Model # 75F31 Radio/Console as a present to restore. I replaced all the tubes. The FM reception is weak, considering the large antenna system it has for both AM/FM in the back. I did locate a wire that may have broken? I have to trace it. Also the turn table will not move, even though I hear some life in the tone arm when I touch the needle. The tone for the radio is weak too, considering the size of the speaker. Not loud and booming like other radios I own from the same period or older. I'd like to continue with the restoration. I'm having trouble locating a schematic. Any advice on moving foward?

Hi Peter,

There is a schematic for your radio on this site at http://www.nostalgiaair.org/Resources/234/M0012234.htm .The file is in Adobe pdf format.

Radiodoc

::I was recently given Motorola 1951 Model # 75F31 Radio/Console as a present to restore. I replaced all the tubes. The FM reception is weak, considering the large antenna system it has for both AM/FM in the back. I did locate a wire that may have broken? I have to trace it. Also the turn table will not move, even though I hear some life in the tone arm when I touch the needle. The tone for the radio is weak too, considering the size of the speaker. Not loud and booming like other radios I own from the same period or older. I'd like to continue with the restoration. I'm having trouble locating a schematic. Any advice on moving foward?
:
:Hi Peter,
:
:There is a schematic for your radio on this site at http://www.nostalgiaair.org/Resources/234/M0012234.htm .The file is in Adobe pdf format.
:
:Radiodoc
:

::I was recently given Motorola 1951 Model # 75F31 Radio/Console as a present to restore. I replaced all the tubes. The FM reception is weak, considering the large antenna system it has for both AM/FM in the back. I did locate a wire that may have broken? I have to trace it. Also the turn table will not move, even though I hear some life in the tone arm when I touch the needle. The tone for the radio is weak too, considering the size of the speaker. Not loud and booming like other radios I own from the same period or older. I'd like to continue with the restoration. I'm having trouble locating a schematic. Any advice on moving foward?
:
:Hi Peter,
:
:There is a schematic for your radio on this site at http://www.nostalgiaair.org/Resources/234/M0012234.htm .The file is in Adobe pdf format.
:
:Radiodoc

Thanks Radiodoc. This will help with reception. But I'm clueless with the turn table...
:

:::I was recently given Motorola 1951 Model # 75F31 Radio/Console as a present to restore. I replaced all the tubes. The FM reception is weak, considering the large antenna system it has for both AM/FM in the back. I did locate a wire that may have broken? I have to trace it. Also the turn table will not move, even though I hear some life in the tone arm when I touch the needle. The tone for the radio is weak too, considering the size of the speaker. Not loud and booming like other radios I own from the same period or older. I'd like to continue with the restoration. I'm having trouble locating a schematic. Any advice on moving foward?
::
::Hi Peter,
::
::There is a schematic for your radio on this site at http://www.nostalgiaair.org/Resources/234/M0012234.htm .The file is in Adobe pdf format.
::
::Radiodoc
:
:Thanks Radiodoc. This will help with reception. But I'm clueless with the turn table...
::

Peter,

The turntable mechanism will probably have to be cleaned and relubed to get it working. Hopefully the motor is good. Perhaps Thomas Dermody will see this posting and give you some pointers. He is quite knowledgeable with with about servicing phonograph turntables.

Radiodoc

I am sort-of. I've only worked on perhaps 15 or 20 turntables in my life. I've rebuilt a few idler wheels. Other than that I'm not an expert, but I do get them running.

First, though, is there any particularily good reason why you replaced ALL of the tubes??????? Please do not do this unless all of them are bad. This is wasteful and shortens the supply for all of us. The terrible myth that tubes are always at fault is a myth. If you are having radio trouble, you should be checking condensers for leakage, and resistors for drifting high in resistance. Then, after every faulty resistor and condenser has been replaced, you turn back on the radio and see how it plays. Even if all of the tubes are weak, it'll still usually play fairly well. If and only if you still have trouble, you TEST the tubes and replace the bad ones, or replace by substitution. If you still have trouble after this, you look for open or shorted coils and bad wiring, though actually you should look for faulty coils and wiring prior to doing anything to the tubes other than cleaning them so that they look attractive. If you wet a tube with a bakelite base, by the way, you'll have to wait a day for the water in the base to dry up. You can't use it prior to this or you will have irratic operation and possibly a short if the tube is used in a high voltage circuit.

Regarding the turntable, I do not know how your's is constructed. Where the turntable rides on the spindle, though, should be well lubricated, though not in excess. If the turntable rides on a ball bearing, grease this bearing with wheel bearing grease. Oil the bushing with a few drops of light motor oil--like 5W-30 oil. Examine the electric motor's mounting and then disassemble the mounting so that the motor may be removed. MAKE CAREFUL NOTE AS TO HOW THE MOTOR IS MOUNTED. Find a hole in each of the motor shaft bushings. If no holes are present, you'll have to disassemble the motor. Note which way the armature (rotor) is assembled in the motor, as assembling it in reverse will cause the motor to spin backwards. Mark the side of the motor which the shaft protrudes with a black marker. Place several drops of 3-IN-1 oil on the felt which surrounds the bronze bushings. Saturate the felt. Place a drop on each end of the motor shaft on the thrust washers. Re-assemble motor and wiggle shaft while tightning screws evenly. Check for free movement of the shaft. There should be absolutely no binding. If there is binding, gently loosen the screws slightly and wiggle shaft again--use force. Keep wiggling shaft and spinning shaft while gently tightning screws. This should put it in alignment.

WIPE ALL OIL FROM DRIVE SURFACE OF SHAFT!!!!!!! Wipe drive surface of shaft with alcohol and then dry with a CLEAN cloth or tissue. Remove C-clip which retains rubber drive wheel, if phonograph uses such a drive wheel. Carefully remove wheel from its shaft and keep track of the washers on either end of the shaft. Wipe a thin film of 3-IN-1 oil on the shaft and DO NOT GET ANY ON THE RUBBER AT ALL COSTS! ABSOLUTELY DO NOT OVER-OIL THIS SHAFT or oil will be spun onto the rubber, which will cause slippage. Re-assemble rubber drive wheel. Re-assemble motor to suspension. Place washers and nuts on suspension exactly as they came off.

If your rubber drive wheel is deformed and hardened severely, or is mushy, it will have to be rebuilt by www.westtech-services.com.

You may put a light film of grease on any automation gears (those which drive the automatic record changer mechanism). Put a light film on any cams and levers where contact occurs. If your phonograph uses a friction trip clutch, DO NOT GET ANY LUBRICANT OF ANY KIND ON THIS CLUTCH. You will know if it has a friction clutch because as you move your tone arm towards the center of the record, one lever will move another lever which is pressed against it on a common shaft with a spring. If you hold the other lever, you should be able to move the first lever with the tone arm, and it'll slide over the other lever without moving it. The other lever (love my terminology!) triggers a catch on the drive gear of the automation mechanism. When the tone arm moves slowly across the record, the clutch allows the two levers to slip so that the mechanism doesn't trip. If the tone arm begins moving rapidly, the first lever moves the second lever, which trips the mechanism. Too much oil will create too much slippage, and your records won't trip at the end.

Thomas