Repurposing transformer from Tandberg - UK Vintage Radio Repair and Restoration Discussion Forum

Richardgr · 25th Dec 2025, 8:56 pm

I am looking for a suitable project for a transformer from a Tandberg 64 tape recorder.

As can be seen from the portion of the schematic, the secondary provides the 250V for the motor as well as being rectified for the needs of the plethora of double triodes.

I have no idea what power a motor for a tape recorder consumes. Standard equipment is a Papst HSZ 32.50-4-440 250V or Engel ES5030/4S 250V. The power demand for the unit is 65W, and at least 40W would seems to be needed for heaters, with some inefficiencies due to rectified AC, so could the 260V secondary be able to supply 100mA?

paulsherwin · 26th Dec 2025, 11:08 pm

Probably. You need to load it and measure the output voltage with various currents while monitoring the temperature. If it doesn't get hot and the voltage holds up then it's OK.

Ed_Dinning · 28th Dec 2025, 8:56 am

Note that even if the transformer is good for your application you should expect, say 5% regulation on voltages between no load and full load.
Temperature rise is the best indicator

Ed

25th Dec 2025, 8:56 pm	#1
Richardgr Octode Join Date: Oct 2019 Location: Täby, Sweden Posts: 1,177	Repurposing transformer from Tandberg I am looking for a suitable project for a transformer from a Tandberg 64 tape recorder. As can be seen from the portion of the schematic, the secondary provides the 250V for the motor as well as being rectified for the needs of the plethora of double triodes. I have no idea what power a motor for a tape recorder consumes. Standard equipment is a Papst HSZ 32.50-4-440 250V or Engel ES5030/4S 250V. The power demand for the unit is 65W, and at least 40W would seems to be needed for heaters, with some inefficiencies due to rectified AC, so could the 260V secondary be able to supply 100mA? Attached Thumbnails

26th Dec 2025, 11:08 pm	#2
paulsherwin Moderator Join Date: Jun 2003 Location: Oxford, UK Posts: 30,573	Re: Repurposing transformer from Tandberg Probably. You need to load it and measure the output voltage with various currents while monitoring the temperature. If it doesn't get hot and the voltage holds up then it's OK.

28th Dec 2025, 8:56 am	#3
Ed_Dinning Dekatron Join Date: Jan 2004 Location: Newcastle upon Tyne, Tyne & Wear, UK. Posts: 8,939	Re: Repurposing transformer from Tandberg Note that even if the transformer is good for your application you should expect, say 5% regulation on voltages between no load and full load. Temperature rise is the best indicator Ed