BIC (B.I.C) T-4M Belt Change (lots of pictures)

ic-racer · Jan 30, 2008

First some background. I got this nice BIC deck in 1989 for $50 USD. It seemed to work fine, but it had been used in a doctor's office and it played the same tape over and over and over. This deck has an auto rewind function. The rubber wheel for the rewind spool was worn down and no longer made contact with the little brass wheel that spins it.

Back in 1989 I was able to just swap the two spools and that fixed the problem (due to the way the mechanism is set up, the FF spool worked just fine with a smaller diameter rubber on it.)

I used the deck for mastering from my 4 track Tascam Portastudio until about 1995 when I switched over to MiniDisk for mastering. Since 1995 the BIC deck saw almost no use. I was browsing this AudioKarma web site looking for something else and I saw mention of the BIC decks and I got mine out and found out that the belt was shot.

ic-racer · Jan 30, 2008

Here is the deck before starting. It is in very good cosmetic condition.

ic-racer · Jan 30, 2008

I could not download a shop manual for this unit so I thought I would just put up a thread that shows how to do it. Perhaps someone with a manual will post it on one of those sites that has all the other manuals.

We start by taking the two little screws off the door and removing the door. Next remove the knobs. They slide off easily.

The front plate has flat head machine screws holding it on the top side, and round head screws on the bottom. Remove all of them.

ic-racer · Jan 30, 2008

Remove the screws holding the control panel push-buttons. The aluminum trim panel comes off and there is a plastic piece that holds the plastic buttons. The actual little switches are on a PC board. That little shield was bent like that when I found it. I guess it is supposed to be like that.

ic-racer · Jan 30, 2008

Remove the 8 machine screws that hold this panel on to top of the motor mechanism.

ic-racer · Jan 30, 2008

In keeping with good signal transmission from one component to the next, there are no MOLEX connectors to make life easy for servicing this unit. Everything is soldered together. My attempt is to not have to unsolder anything. To get enough slack to get the motor assembly out, the chassis has to be loosened to make things flexible.

To get the bottom off remove the screws and the feet.

ic-racer · Jan 30, 2008

The motor assembly unit is attached to the front of the chassis by 4 screws. Remove these 4 machine screws.

ic-racer · Jan 30, 2008

So the wires don't bind on the power supply board, I removed the 2 screws that hold it to the back of the cabinet.

I removed all the screws that hold the front of the chassis in place, so that the front of the chassis can be bent forward to get the motor assembly out.

The front of the chassis wont budge unless the big main PC board screws are also loose. There are 4 of them. (I'm leaving the front of the chassis and the big PC board firmly attached to each other).

ic-racer · Jan 30, 2008

To get these little trimmers out of the way I first removed the two screws holding them to the side of the chassis. Now that the chassis is loose I pulled the front part forward to make enough room to get them out of the way.

ic-racer · Jan 30, 2008

The wires to the LED display limit the movement of the motor assembly. To get some slack, I removed the LED display and moved it to the interior of the chassis. The LED display is larger than the hole in the chassis and it is outside the hole. By wiggling it around and twisting it on its side it can be made to slide through the hole to the inside of the chassis.

The rest of the wires that go over that corner of the motor assembly can be moved out of the way now.

ic-racer · Jan 30, 2008

I wasn't shure if this control panel would have to come out attached to the motor assembly, or if it would stay with the chassis. I took it apart just so it could be moved around easier. The little plastic buttons fall out but its easy to put it back together.

ic-racer · Jan 30, 2008

The PC board on the bottom of the motor assembly comes off with 4 screws. I thought this made the motor assembly swing out easier.

ic-racer · Jan 30, 2008

The main PC board is still attached to the back of the chassis through the RCA jacks. The little plastic rivets can be removed and this frees things up more.

Also, there is a little plastic rivet that is holding the power supply board to the main board. Removing this helps free things up also.

ic-racer · Jan 30, 2008

Now the motor assembly can be gently lifted from the chassis and set down beside it. There is one little coax wire (brown one) from the chassis assembly that has the most tension. This may need to be released at the main PC board, but I was just very careful, always watching tension on that line.

With the motor assembly out you can see what is keeping the two halfs of the assembly togher. There are 3 screws on the bottom and 4 screws on the back. The 4 on the back lead to the 4 spacer rods that hold things in alignment.

Its a little tricky getting to the 4 screws on the back. I was able to lift the unit up in the air, this gave enough room to get to the 4 screws. Too bad I could not get a picture at the same time.

ic-racer · Jan 30, 2008

In addition to the screws, there are 3 other things holding this together.

1) The door motion damper string.
2) A lever from the solenoid that passes through the main belt to attach to the head assembly
3) The two belts themselves.
4) The door spring.

The door motion damper string is released by removing the little e-clip and unwinding it. It wraps around 3 times.

To release the lever you can remove its pivot pin back near the solenoid. The pin slides out easily and is held in place with a bendable tab. Just bend the tab down and the pin comes out easily. When re-assembling it, just bend the tab back up to hold the pin in position. (no pictures, as I could not get the camera back there)

The door spring removes easily, just remember where it goes.

ic-racer · Jan 30, 2008

I only opened the two parts of the motor assembly wide enough to get the old belt out and to put the new belt in place. The smaller belt can be replaced without having the two sides opened up as the pulley spindles do not span the entire distance between the two halves.

ic-racer · Jan 30, 2008

I threaded the new belt around the two large aluminum pulleys and the put the motor assembly back together. After the two halves were together I worked the new belt over the brass pully of the drive motor.

The screws were put back in place and the pin was put back in the lever off the rear solenoid. The lever has to fit in the slot in the solenoid for it to work. I pushed the solenoid up and down with my finger to check that it moves correctly before putting it all back together. (the solenoid moves the heads up and down)

ic-racer · Jan 30, 2008

The string for the door damper was looped back over the nylon axle 3 times and re-connected to the door with the e-clip. The door spring was re-attached.

ic-racer · Jan 30, 2008

Here is the new belt in place. Everything was checked for free movement. When putting the motor assembly back in place make shure stray wires don't get in the way of the door damper assembly.

ic-racer · Jan 30, 2008

The chassis was put back together in reverse order of disassembly.

Prior to putting the cosmetics in place it was tested and checked out OK.

3 3/4 IPS, Metal Tape and it's 1988 again!!

I have 3 sheets of hand written notes and diagrams that I can scan if anyone is interested.

BIC (B.I.C) T-4M Belt Change (lots of pictures)

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