How to... MCI / Sony Recorder Tips

Basic MCI Transport alignments and Tips

 Step 2): Next the most important thing is to insure that the Motor connections are good.
Go to the rear of the machine (it's still OFF), find the Molex connector that goes to one of the
reel motors (a 2 pin molex as I recall...)   and spray clean this connector for EACH reel motor!

 
  Step 3):   Next find the wire that goes from the Reel Motor Tach
(which is mounted just below the motor) and follow that wire down to the
molex connector that goes into the large Mother Board.
Pull the connector away from the mother board and spray clean it,
then re-insert it.... double checking your connections !!!
Do this for each Reel Motor Tach.
 

Step 4):   Open up the Transport Power Supply.
Take out the Driver Card and visually check for cold solder joints at the Molex Pins.   If you
even suspect one, resolder it.   IF the card has the 'dreaded Red Sockets', you MUST replace them now!
Check the resistance of EACH high power resistor.   These are usually .39 ohms so will almost measure
as a short.   If you find one that is open - i.e. a high value, replace it and test all the motor drive
transistors !!!
 

Step 5):   It is ESSENTIAL that ALL your Power Supply fans are working in top condition.
If they are still Original, they're going to go bad soon, so replace them.   This is the cheapest
insurance policy you can have in keeping your MCI running well, so check your fans often !!!
 

Step 5):   It is ESSENTIAL that the +15 volt and -15 volt power to the transport card
be within .2 volts or closer... check the voltages on the card, and if there is more than
a .2 volt difference between the Positive and Negative basic 15 volt voltages -
say one is +14.9 and the other -15.6 volts   you MUST change the voltage regulators
at the back of the Transport Power Supply.  
 
NOTE:   These are 340-15 and 320-15 and/or 7815 and 7915 regulators... cheap and easy to purchase.
 
NOTE:   There is about 20 volts on one of the Regulator cases!     Make SURE to replace
the plastic cover over each of the Regulators - or if you've lost them, use electrical tape
and cover the body of each regulator IC.   !!!
 
Since you must set the Reel Tach Null to 'Zero volts' with no reel movement,
which is the exact mid-point voltage between +15 and -15 volts,
you need the proper rail voltages.     If the voltages are off
then the DC Null has to be set at something other than zero, which isn't correct and makes the
transport alignment difficult or impossible to do easily.
 
If you cannot set the Reel Tach Null to Zero volts
and have checked that your +/- 15 volts are correct, and the reels are not moving,
then you should replace the 3 LM741cn IC's #4 and #10 and #11.

Step 7):   Once you can set the Reel Null to Zero Volts,
the next step is to Set the STOP tensions.     You do this
by blocking the Tape-Break Sensor with a piece of paper, then
without any reels on the machine, and in the STOP mode,
set each IDLE (stop) Trim Pot so each reel turns slowly and about one
complete revolution every two to three seconds.
It's very important that the reels turn constantly and freely without any
jerking.   Remove the paper used to block the tape-break sensor.

Step 8):   Next put on a full reel of good quality
'scrap' tape (a reel of tape that can be damaged) and a take-up reel.
Hit PLAY and turn the Take-UP PLAY trimpot so tape is taken up onto the
Take-up reel.   Turn the SUPPLY PLAY Trimpot so there is some hold-back tension.
Note you may have to use your hand to apply some hold-back tension at first
if the tensions are way off of normal.
Now you will need to use a Tentelometer and set the proper PLAY tensions
as indicated in your manual.
If you do NOT have access to a Tentelometer
see the notes at the end of this page...

Step 9):   Once you have set the correct tensions in the PLAY mode
use a pencil and make a small mark on the swing arm and the transport
just below it while in the PLAY mode.   This now gives you a quick
and easy indication if the tension is close to correct or not.
Do this with a full reel of tape and do it close to the middle of the tape,
with equal tape pack on both reels.

Step 10):   Learn to 'feel' the tape in the PLAY
and WIND modes... do this by pressing your finger to the tape will running.
You want to be able to 'feel' if the tensions are close to correct or not...
and thus know if something is not working correctly.

Step 11):   To help make fast and easy tensions adjustments
Put a 'S' or 'I' on the Idle (stop) tension adjust trimpots and a 'P'
on the Play tension trimpots using a Magic Marker

Step 12):   A good test of a correctly tensioned MCI deck
is to play a 1 khz tone and push the Pinch Roller away from the Capstan
while still in the play mode.... the pitch of the tone should remain nearly
constant even without the pinch roller engaged.

Step 13):   Next you want to check the Stop (Idle) tensions at the begining, middle and end of the tape.
If the tape starts moving slowly in any direction when in the Stop Mode
adjust the Stop (Idle) tensions a bit to stop any tape creeping.
Check again at various points in the reel.
You can set the Stop (Idle) tensions higher than what the manual
specs out with if you want....

Step 14):   Finally you want to insure that the tape
starts playing and comes up to speed quickly at various points in the reel.
there should be no tape-jerking, just a nice smooth operation...