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Restoring a Pioneer RT-909 Reel-to-Reel

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Limit the use of Pro-Gold to connector contacts. DeOxit should be enough for pots and switches. Measure contact resistance of each switch, if consistently less than 1 ohm when switching multiple times, the switch does not need to be cleaned. Monitor varying resistance as pots are slowly rotated. If resistance changes smoothly, as the pot rotation is changed, the pot does not need to be cleaned. Do these measurements while disassembled and power is removed.

Rich P
 
pustelniakr said:
Limit the use of Pro-Gold to connector contacts. DeOxit should be enough for pots and switches. Measure contact resistance of each switch, if consistently less than 1 ohm when switching multiple times, the switch does not need to be cleaned. Monitor varying resistance as pots are slowly rotated. If resistance changes smoothly, as the pot rotation is changed, the pot does not need to be cleaned. Do these measurements while disassembled and power is removed.

Rich P
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I have just completed recapping my RT-909. I have confusion RT-909 SM. Page 24 Take up torque adjustment FF as per manual measure in D direction at FF mode 440 - 460g and adjust VR205 I have done up to this step, next in C direction what mode? VR206 is it for REW Take up Torque? SM not mention REW take up torque ! Thanks Rajkumar
 

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It is inferred by the wording that brackets around VR206 ( this { VR206 } ) means you are measuring/adjusting the REWind motor tension. After the F-Forward tension/pot is set properly, the Rewind motor is then activated. Pull the string/ scale combo in the direction it tells you to. Position the string and scale properly to adjust the REWind tension pot. Make sure both of the reels you are using have the same diameter (where the string winds around the hub) the hub diameter specified in the service manual.

Always make sure the buttons for reel tension, tape speed, and reel size are set according the the manual for each measurement. Using smaller or larger than specified hub diameters or mixed different diameter hubs/reels will negatively affect the final measured torques, and though the torques will measure correctly, they will be wrong.

IIRC, you will use 7 and 10 inch reels of specified diameters when making torque measurements and setting the different tension pots. Reel size and speed switch positions are specified for each measurement, and must be followed to the letter.

Do not stall the fast wind motors (meaning do not measure the tensions with the motor activated and not turning) for any longer than absolutely necessary while adjusting the tension pots. Stalling the motors for too long can cause heating of drive transistors and subsequent failure, along with their other associated components as well. Just ask me how I know !

Hope this helps you or someone else, even it is a little late.
 
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