REP: Calibrating Pioneer RT-909 torgue

I calibrated the tension and backtension of a Pioneer RT-909 some months ago but I didn't remember that I had uploaded two videos about it.

The first shows the problem, only present in RWD mode:




This can be produced by you if you just play with the internal pots without knowing exactly what are you doing and without having the correct tools to calibrate the tension:

- The service manual where is described the procedure to follow and the order in which is needed to do it.

- A spring gauge, or even better, a tentelometer.

Notice that even when the tension is not correct in one transport function and rest seems to work OK, all the entire calibration is needed because the values of the rest impact in the other tensions.

This is the result after some time calibrating the pots until getting the correct readings in the tentelometer:

AN: More photographies

They were shot two days ago.

AN: Photographies

I know that in the last weeks I didn't update the blog, but I've been busy with lot of work during week and most of the remaining time has been spent in my hobbies. Also here is very very hot and sunny, during the day it's 30 ºC (measured in shadow) and my home is most of the time shot by the sun.

I finally bought some tools to help me to repair and calibrate reel to reel decks, including scopemeter, millivoltmeter, tentelometer and digital weight scale. Soon I want to write a complete article about all the DIN plugs of the Uher 4400 Report Monitor. I made most of of the adapters for my unit and I'll share all the info I've got, including about the Z124 charger.

But until that day, I'll put here some pics shot during these days.

My second Pioneer RT-707 with ReVox 7" metal blue reels




Uher 4400 Report Monitor






Recording trains into the Uher 4400 Report Monitor






Two Pioneer RT-909