CT-F900 transportation torque fix.
I am looking at the CT-F900 service manual that I own. At the back of it there is a "Service Information" bulletin stapled to it. It came from US Pioneer Electronics Corp and distributed to the repair shops. It says as follows [Items between brackets and in italics are my own:]
Open Quote
Model: CT-F900, CT-F800
Subject: Low Tape Transportation Torque.
Since the CT-F900 was introduced back in May 1978 several changes have been made to improve the transportation torque.
This information is to introduce a very easy, very effective, efficient and therefore, economic method that has proven to be reliable by our New Jersey branch repair department's two year experience.
In New Jersey, more than 95 percent of the CT-F900's torque problem has been solved by this very simple method.
Here is it's know how:
1. Preparation:
A. Permatex Belt Dressing (part number 120DA)
Made by Permatex Company, Inc.
[Permatex Belt Dressing (or equivalent) is still available today from auto parts supply stores.]
The Permatex Belt Dressing, originally in a spray can, must be transferred to another container so that a proper amount can be supplied to the proper part.
B. Remove top cover and front panel and also remove the half holder (RNK-556) and brake plate so that the work can be done properly.
[Then drawings of the brake plate and the half holder follow. For those who don't know what the half holder is: It's a plastic part that is curved and that is placed right above where the cassette to be played is inserted. It has a spring attached to it to keep it down. You feel the spring when you insert the cassette and have to push up against the half holder to get it in place.]
2. Before applying the belt dressing:
Clean idler (RNK-561,) take-up pully assembly (RXA-998,) and both supply and take-up reel bases with 91% isopropil alcohol "Rite Aid" (See Fig.2)
[Then follows a drawing of the transport assembly, front view, with arrows pointing to the Supply reel, the take-up reel and the idler.]
Scrape any contamination off from the take-up pully assembly.
3. Apply a small amount of Permatex Belt Dressing to:
Idler (RNK-561,) TU belt (REB-271,) sensing belt (REB-272) (See Fig. 3.)
[Figure 3 is an exploded view of the transport assembly taken from the service manual and where these belts and pulley are highlighted.]
Do not apply to to capstan belt (REB-270) or sub-belt (REB-289) (See Fig. 4.)
[Figure 4 is an exploded view of the transport assembly taken from the manual and where the capstan belt and the belt between the two flywheels are highlighted.]
Above procedure should be effective to restore proper amount of torque on most of the CT-F900's.
Here is some additional information worth noting:
1. Excessive wow-flutter may be caused by accumulation of Powdered Plastic Deposits on the felt pads in the reel base assembly, (RXB-001, RXA-999.)
In such a case, take reel base assembly apart and clean the deposits off.
A very similar case is also possible with the felt pad in the idler arm full assembly.
2. Permatex Belt Dressing is effective not only with CT-F900, but also many other cassette decks.
Caution:
Pioneer cassette decks, CT-F4141, 5151, 6161, 7171 and 2121 that use "Idler A assembly" may require a minor spring adjustment when belt dressing is applied. The spring for rewind lever, RBH-189 must be extended to reduce the spring tension. Due to, too strong a grab of the idler A stored by belt dressing, idler A may jam itself in if it is not reduced and will cause a slow FF and RW.
If reducing the tension is not enough, replace the idler, it may be worn down.
End Quote.
In another service bulletin thay say the belt dressing should be applied with a small brush or the tip of a flat blade screwdriver but never sprayed on.
Now, remember the above info was distributed in the late 70's and all belts were practically new then. Now we're almost forty years later and I recommend that you change all your belts first. Then, if you still have problems, you may look at this service bulletin. I tried it about three months ago and it worked great for me!
Hope this helps.
Olivier.
:tresbon:
