American Dental Tech Blog

Monthly Archives: October 2009

  • Tech Tips #15: Peri Pro Transport Repairs- How to Solve the Mystery of the Missing Film

    Peri Pro Transport Repairs: How to Solve the Mystery of the Missing Film

    The Peri Pro Film processor uses a film “Transport Rack” that utilizes a system of arms and gears to push the films along eight grooves on the inside of the rack. The films will travel through the developer, fixer, and wash tubs to the dryer/heater assembly where they are dried and then deposited into a film “catcher” at the back of the machine.

    Film sizes #0, #1, #3 and #4 are placed inside a film carrier to move them through the transport and unless these films are placed inside the carriers incorrectly or there is a problem with the transport rack or processor itself, these films rarely get lost. However, the #2 films travel freely along the eight grooves without a carrier to guide them. These films will sometimes “mysteriously disappear”. In this edition of Tech Tips, we would like to help you solve the mystery.

    Reasons Why Films Sometimes Do Not Exit the Peri Pro

    REASON #1: DIRTY RACK

    One of the most common causes for lost films. Be sure to follow a regular cleaning and maintenance schedule for your Peri Pro transport rack, if you do not, chemistry can build up in the grooves causing the films to pop out of the rack.

    We suggest paying special attention to the area at the chemistry line– above and below where the smaller “L-arms” turn as the chemistry tends to dry and build up there. Use a toothbrush and thoroughly clean the grooves of your rack as well as the gears on the back of the rack. Do not use anything abrasive. There are kits available with a special brush and tub. Follow manufacturer recommendations for cleaning and maintenance.

    **A side note: It is important to not to “drop” your transport rack into chemistry tubs when placing it back into the unit or splash the chemistry when refilling the tubs as you may contaminate the chemistry. In addition, the chemistry can get up into the area where the shutter plate sits causing it to stick. Chemistry can also corrode the shutter plate extension spring causing it to snap, your shutter plate will no longer move and your films will not drop when they are supposed to. To replace the spring and clean under your shutter plate you will need to remove the three top plate pins to gain access to the shutter plate area.

    REASON #2: BROKEN GEARS

    Broken or missing teeth on the rack gears or even the Main Drive Gear, (which engages the rack) can cause it to skip and will in turn knock the films out of the rack. Make sure to check the gears on the transfer arm assemblies on the open side of the rack, as well. All of these gears can be replaced but you will have to remember that any time you remove a gear from the Peri Pro transport rack, the drive arms and timer gear will have to be realigned.

    The Main Drive Gear is located on the inside wall of the Peri Pro behind the fixer tank. This gear is held on by a 3/32” allen (hex) set screw. When replacing this gear, be sure that you get the gear that is appropriate for your Peri Pro as the gear is sized differently for each model of the Peri Pro.

    REASON #3: DRIVE ARMS OUT OF ALIGNMENT

    If your drive arms are out of alignment, you will lose your films every time you send a batch through. Realigning drive arms for the Peri Pro and Peri Pro II transport racks will be done in the same way. However, realigning the arms for the Peri Pro III will be slightly different. You will also have to be aware of where the “dot” on the Timer Gear points (gear is located on the back of the transport rack near the shutter release assembly) when realigning to make sure the shutter opens and releases films at the right time. Please see the diagram below:

    REASON #4: FILM PROBLEMS

    If your films are bent- straighten them out before feeding them into the transport. If films are jagged, try feeding the jagged side in last. Do the same thing with the small raised “dot” or “dimple” on one of the corners of #2 films, as well. Make sure to feed the #2 films into the processor with the “Film Inlet Grill” in place. The grill helps align the films with the grooves in the rack.

    REASON #5: NON-TRANSPORT RELATED PROBLEMS

    • Dryer Drive Motor not turning: If the dryer drive motor is not turning, the rollers that move the films through the dryer heater assembly will not be turning as well, the transport rack would still turn as it is driven by the Main Drive Motor. This may cause the films to fall down on to the heater assembly and in turn burn out the heater assembly. You will need to replace the dryer drive motor. If losing films in the dryer, make certain to check your heater & heater fuse (or thermostat) as well in case films have melted on the heater causing it or the thermal fuse/thermostat to burn out or blow.
    • Main Drive Motor not turning: Make sure that you have power to the unit. Is the rack sitting squarely on the drive gear? It can be easy for the fixer tub to get in the way. Is the main drive gear broken? Is the drive shaft turning? If it is not, replace the main drive motor.

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