How to... MCI / Sony Recorder Tips

Basic MCI Transport alignments and Tips

I've just started on this page - lots more to come soon!!! !!!


The MCI JH 16  (later series with the JH 114 transport)  and all JH24 machines plus the JH110 machines
all come with basically the same Transport Card.     That's a great thing, since this
means there is basically ONE alignment you need to do no matter which MCI machine you have!!

There ARE DIFFERENCES - various resistors have different values in order to give the sufficent voltages
and current to the motors for various tape widths.     But if you look at a JH 110B Transport card
it looks EXACTLY like a JH24 transport card!  Very difficult - almost impossible to tell the difference!

  So here's how I align a MCI transport card - in this example I'll be talking about a 2 inch machine.

 
NOTE:   Always use a good condition 'scrap' reel of tape to check tensions....
a 'scrap' reel is one that isn't important and could get
damaged if something happens.   But it needs to be the same kind
of audio tape you are generally going to use on the machine.
The reel CANNOT shed at all - as this would cause drag and thus all settings
would be false.
 
If your machine's Torque Card has the 'Dreaded Red Sockets' you MUST replace them with new
'Dual Wipe' or 'Machined' IC sockets for stability... all the old Red IC sockets are bad now!!!

Step 1):   Turn OFF the machine, wait 10 seconds,
then gently grasp the edges of the transport card and remove it from the machine.
Using your favorite spray cleaner, spray ALL the molex recepticles.

  Re-insert the Transport card gently.   One of the great faults that MCI made was allowing the card to
be able to be re-inserted one pin off from the correct position - damaging the card once power
is applied... so make SURE that you've installed the card correctly BEFORE turning power back on!!!!

Tip - I look at the lower 3 pin connections to make sure I've mated the card to the pins correctly.
2nd Tip - some of the Molex connections are NOT fully pinned!   That is they are missing a pin, so this
can fool you!   Be VERY VERY CAREFUL.   Double-check that you've got it in correctly !!!


 

 Step 2): Next the most important thing is to insure that the Motor connections are good.
Go to the rear of the machine (Power 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 power Resistor 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...
Once they were cheap and easy to purchase... now they are getting hard to find!!

 
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 can be hard to set at ZERO Volts...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.

 
If you still cannot set the Reel Null to Zero Volts, you likely have a poor
Ground connection to the Torque Board... Try Grounding the Motherboard by
removing the Torque Board   - Power OFF first for 10 seconds !!! -
then finding the Ground point just below the middle Molex points to the Torque Board
on the Right Side... it should be visably labeled 'Ground'.     Solder
a wire there and run it to the Chassis Frame on the Right Side where a screw is,
soldering a Spade Lug to the end of the wire and attaching this to the screw.
This will get you a better Ground to the Torque Board, and often solves the
problem with setting the Reel Null to Zero.


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 smoothly and freely without any Jerking !!
Jerking means something is wrong - a sticky brake,
a bad Reel tach, poor Motor Drive transistors, dirty connectors...
The motors MUST turn and run freely without Jerking motoions !!
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...

 



Don't have a Tentelometer?
Best is then to hire a tech to come over to your location
and have them set up your transport for you, and then mark
the position of the swing-arm in the begining, middle and end of a full reel of tape
using a pencil, showing the correct position of the swing arm and
transport plate when the tape tension is correct.
 
PLEASE NOTE:
THIS NEXT METHOD IS A CRUDE WAY TO SET ROUGH TENSIONS
AND IS NOT VERY ACCURATE
Do NOT rely on this method.   It depends on the swing-arm being
set correctly (which it may not be!!).     But if you
cannot get a Tentelometer, this will at least get you running...
Make sure to use good quality 'scrape' tape !
 
First turn the Take-up Play tensions trimpot up enough so the
Take-up reel will take up tape in the play mode...
Set the SUPPLY side tension while in the PLAY mode so the Swing arm is
about halfway in it's swing between end stops, when in the
middle area of a full reel of tape.     Then you can set the
TAKE-Up tension so the tensions 'feel' - using your fingers - the same
on the Take-Up side of the Capstan as it does on the Supply side.
Check that the machine goes into the Play mode without any tape-jerk, and
runs smoothly.   Check at the Begining, Middle and End of a scrap reel of tape.
You WILL have to check your speed at the begining of the reel and at the end
of the reel using a 1 khz tone.   The begining and end of the reel tone
should remain constant.   Check this by recording a 1khz tone at the
begining of the reel then swapping reels play it at the end of the reel
and compare the tone to the ocillator you used....

 



   The dreaded RED SOCKETS of MCI

Go To Red Socket Hell

  If you own an MCI you HAVE to read this page !!!



 

 

    MCI Power Supplies

  Go To MCI Power Land  

  Power Supply page is now completed...


    Secret MCI Tips

  Go To MCI Secret Land  

Ah yes... the Secret Page of MCI Tips Part 1 done now... more to come soon


    Recommended MCI Spare Parts

Spare Parts

 Spare Parts page not quite ready



    HOME      CONTACT US      RESOURCES      HOW TO      Tips 'n Tricks      FAQ