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The tape tensioning roller is not that critical as long as it spins freely. It should be approximately 7-8mm high and 19mm in diameter.
The rubber pinch roller/wheel is very important! I usually remove the roller and rub it's surface on 120 emery paper finishing on 80. Hold the roller between your index finger and thumb and let it abrade on the emery paper, don't hold it to tight as you will introduce flat spots. After I am satisfied with this procedure I give it a coat of "renue" and let that sit for a day or so. Sometimes I have to do it all again two or three times. BE CAREFUL WITH THE RENUE IT IS HIGHLY CARCINOGENIC!
My next step is to remove the steel pinch roller support and check this to ensure it is perfectly flat. All rubbing areas are smoothed with emery paper and I do this to keep the wheel perfectly flat against the motor shaft. Failure to do this can cause the tape to wrinkle, the tape to ride up or down on the shaft and increase wow.
The 47uf capacitor does not give to many problems, in my 50 years of echolette repairs I have possibly only found one faulty one. The capacitor is a motor start capacitor and if it increases in value it would make the motor turn a little faster, no big deal!
The bridge rectifier can be replaced with numerous options as long as it has at least 400PIV at 200mA rating. I have not used a voltage drop resistor but that is your choice.
At the risk of being repetitive check the heads all should measure 1.2K ohms, replace all the coupling and bypass capacitors, check the valves/tubes and if all has been done then move on to the mechanical overhaul.
The rubber pinch roller/wheel is very important! I usually remove the roller and rub it's surface on 120 emery paper finishing on 80. Hold the roller between your index finger and thumb and let it abrade on the emery paper, don't hold it to tight as you will introduce flat spots. After I am satisfied with this procedure I give it a coat of "renue" and let that sit for a day or so. Sometimes I have to do it all again two or three times. BE CAREFUL WITH THE RENUE IT IS HIGHLY CARCINOGENIC!
My next step is to remove the steel pinch roller support and check this to ensure it is perfectly flat. All rubbing areas are smoothed with emery paper and I do this to keep the wheel perfectly flat against the motor shaft. Failure to do this can cause the tape to wrinkle, the tape to ride up or down on the shaft and increase wow.
The 47uf capacitor does not give to many problems, in my 50 years of echolette repairs I have possibly only found one faulty one. The capacitor is a motor start capacitor and if it increases in value it would make the motor turn a little faster, no big deal!
The bridge rectifier can be replaced with numerous options as long as it has at least 400PIV at 200mA rating. I have not used a voltage drop resistor but that is your choice.
At the risk of being repetitive check the heads all should measure 1.2K ohms, replace all the coupling and bypass capacitors, check the valves/tubes and if all has been done then move on to the mechanical overhaul.
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