Supply and Take-Up reel motors for Pioneer RT-707

[Trevor White]

Hi All,

Can anyone tell me what the run voltage is for the Supply and Take-Up reel motors on an RT-707. The motors are RXM-032 and RXM-034. I can't seem to find what their specs are.

The reason I am asking is that my machine is a 240v 50Hz version (multi-voltage) and if I was to buy a pair of spare motors from an American 120v 60Hz machine, would there be an issue with the motors in my machine?

I suspect that they will not be input voltage sensitive, otherwise there would surely be multiple part numbers. But I would like to be certain.

Cheers.

 

[dhnash]

I can't tell you for certain Trevor since I don't own an RT-707 but typically a unit designed for general export or use in countries where the line voltage is 220/240VAC has a power transformer that is configured or can be configured to provide voltages on its secondary windings that are similar to those in units intended for use in countries that have 120VAC line voltage. If the part numbers for the motors in your unit match those in the parts list for the 120VAC model, I think that would support this. You may also want to check the values of the capacitors connected to the supply and take-up motor windings. If these are different from the values shown in the schematic for the 120VAC model, this may provide further indication that the motors are are the same in both models because these capacitance values should be different for operation at 50Hz versus 60Hz if the same motors are used in both models.

 

[Trevor White]

I can't tell you for certain Trevor since I don't own an RT-707 but typically a unit designed for general export or use in countries where the line voltage is 220/240VAC has a power transformer that is configured or can be configured to provide voltages on its secondary windings that are similar to those in units intended for use in countries that have 120VAC line voltage. If the part numbers for the motors in your unit match those in the parts list for the 120VAC model, I think that would support this. You may also want to check the values of the capacitors connected to the supply and take-up motor windings. If these are different from the values shown in the schematic for the 120VAC model, this may provide further indication that the motors are are the same in both models because these capacitance values should be different for operation at 50Hz versus 60Hz if the same motors are used in both models.

Thanks mate.

My feeling also was that they were likely to be the same part running at some voltage provided by the transformer that would be the same irrespective of the actual line voltage.

Looking at the 120VAC circuit diagrams in the Service Manual I can see that the Supply Reel Motor capacitor is 5.5uF 250V, whilst the Take Up Reel Motor capacitor is 4uF 250V.

I'll have a look at those run capacitors in my machine and see what they are.

Cheers.

 

[Trevor White]

So, the plot thickens in regard to these Reel Motors.

My machine is a RT-707 'Improved' version. It is Multi Voltage (120, 220 and 240VAC 50/60Hz). The two big Metallized Paper motor run capacitors are actually 6.8uF 125WVAC, and 2.5 250VAC. So right away that does not match the circuit diagrams.

Anyway, I remembered seeing another thread by @smurfer77 when he rebuilt his RT-707 that included pictures of these two caps from his machine. Smurfers machine was a 120VAC 60Hz version. And surprise, surprise, the run capacitors are exactly the same as those in my machine which runs at 240VAC 50Hz. Ie: 6.8uF 125WVAC and 2.5uF 250VAC. See pictures here and here. (Scroll down a bit to see the images of the run caps)

So, does that means that Pioneer have engineered the motor circuits to be the same between versions and therefore the Supply and Take Up Reel motors are likely to be the same part between the two types?

Cheers.

 

[GPS16]

Hi Trevor,

the motor voltage is from a winding on the mains transformer. For fast wind it is 100 VAC for the lower torque play tensions, a 70 VAC tapping is used from the same winding via the large green dropper resistors. The voltage of the motors should not really change from any of the variants. There may be a small shift in motor capacitors to deal with 60 and 50 Hertz mains frequencies.

I would expect the motors to be the same in any model. I have seen differences as not all the motors have the small hole to lubricate the sleeve bearings.

I don't foresee problems with with motors from a US spec machine to the Euro spec of your machine.

Keep us posted on this one!!! Interesting point!!

Cheers

GPS16

 

[Trevor White]

Hi Trevor,

the motor voltage is from a winding on the mains transformer. For fast wind it is 100 VAC for the lower torque play tensions, a 70 VAC tapping is used from the same winding via the large green dropper resistors. The voltage of the motors should not really change from any of the variants. There may be a small shift in motor capacitors to deal with 60 and 50 Hertz mains frequencies.

I would expect the motors to be the same in any model. I have seen differences as not all the motors have the small hole to lubricate the sleeve bearings.

I don't foresee problems with with motors from a US spec machine to the Euro spec of your machine.

Keep us posted on this one!!! Interesting point!!

Cheers

GPS16

Hi there GPS, thanks for responding.

It turns out that the motors I was looking at are from a Multi-voltage machine anyway, despite being from the US, so they should be AOK

I'll know in a couple of weeks.

Cheers mate,
Trevor

 

[Trevor White]

OK, so I identified those run capacitors completely incorrectly

The 6.8uF 125WVAC and 2.5 250VAC caps are actually the run caps for the Capstan Motor!!!!!

Further searching inside my machine and I found the big boy's responsible for running the Supply and Take Up reel motors. They are mounted beneath the top switch circuit board that has the On/Off and Tape Speed switches etc. On my machine these two large capacitors are 4uF 250VAC and 5.5uF 250VAC, which does match what I found on the circuit diagrams. The caps are labelled as SH-MP types, which I think means they are Metallized Paper. Both of mine are actually date coded as April 1981. I presume that this type of capacitor does not degrade like Electrolytics can?

So, those caps are the same as those in a 120VAC 60Hz machine anyway, I'm pretty sure the motors are the same between the different machines.

Cheers.