unitrazakl: UNITRA RMS-451 - Motor speed stabilization

From the UNITRA service manual it seems that there is one additional IC used for motor speed stabilization  besides the four other IC's used on the receiver section.

This is the UNITRA UL1901, installed on a small PCB attached to the motor case. It is still possible to find the datasheet for the UL1901 in the Internet, but could not find any equivalents.

I do not have this radio model, but would like to have some additional information from owners of this model concerning the motor driver. 

Thank you.

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According to the 1991 issue of the ECA "vrt" cross reference table, the UL1901 is equivalent to ESM227 , apparently a Thomson (later ST Microelectronics) part.

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It might be the same or very similar to the TDA1040, or maybe the TDA1041

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