Levell R.C. Oscillator Type TG150D - UK Vintage Radio Repair and Restoration Discussion Forum

FERNSEH · 13th Nov 2022, 4:42 pm

Picked up this instrument from Mickey405's recent event.
Seems I've got lucky with this one. After connecting it up to an 18volt power source it didn't take much effort to get it going.
A squirt of RS Components switch cleaner on the two-gang frequency fine adjustment potentiometers was all that was needed to achieve the results as shown on the attachments.
Instrument set to 10Khz. Output set to -20db.
Oscilloscope TB speed set to 20microseconds per division.
Because the current demand is so low it should be possible to power the instrument from two high quality PP3 batteries.
A "power on" LED to remind one to switch it off when not in use?

DFWB.

newlite4 · 13th Nov 2022, 6:04 pm

I can remember using these at tech college in the late '70s. I remember the bounce in the output amplitude when varying the frequency or changing the ranges. I suppose being a wien oscillator circuit it needed settling time after a change in parameters. Very accurate once stabilised.
Neil

jimmc101 · 13th Nov 2022, 10:37 pm

Manual available on the forum here
Jim

FERNSEH · 14th Nov 2022, 11:40 am

Hi Jim,
many thanks for the link to an earlier topic about this instrument.
The manual has been printed out.

DFWB.

FERNSEH · 16th Nov 2022, 11:32 am

Current consumption is 14mA on sine waves and 20mA on square waves.
For the time being I'm using two alkaline PP3 batteries. A holder for the PP3 is available from RS components under the part number: 489-611.

DFWB.

13th Nov 2022, 4:42 pm	#1
FERNSEH Dekatron Join Date: Mar 2005 Location: Gateshead, Tyne and Wear, UK. Posts: 7,444	Levell R.C. Oscillator Type TG150D Picked up this instrument from Mickey405's recent event. Seems I've got lucky with this one. After connecting it up to an 18volt power source it didn't take much effort to get it going. A squirt of RS Components switch cleaner on the two-gang frequency fine adjustment potentiometers was all that was needed to achieve the results as shown on the attachments. Instrument set to 10Khz. Output set to -20db. Oscilloscope TB speed set to 20microseconds per division. Because the current demand is so low it should be possible to power the instrument from two high quality PP3 batteries. A "power on" LED to remind one to switch it off when not in use? DFWB. Attached Thumbnails

13th Nov 2022, 6:04 pm	#2
newlite4 Octode Join Date: Nov 2003 Location: Bath, Somerset, UK. Posts: 1,805	Re: Levell R.C. Oscillator Type TG150D I can remember using these at tech college in the late '70s. I remember the bounce in the output amplitude when varying the frequency or changing the ranges. I suppose being a wien oscillator circuit it needed settling time after a change in parameters. Very accurate once stabilised. Neil __________________ preserving the recent past, for the distant future.

13th Nov 2022, 10:37 pm	#3
jimmc101 Heptode Join Date: Mar 2009 Location: Portsmouth, Hampshire, UK. Posts: 674	Re: Levell R.C. Oscillator Type TG150D Manual available on the forum here Jim

14th Nov 2022, 11:40 am	#4
FERNSEH Dekatron Join Date: Mar 2005 Location: Gateshead, Tyne and Wear, UK. Posts: 7,444	Re: Levell R.C. Oscillator Type TG150D Hi Jim, many thanks for the link to an earlier topic about this instrument. The manual has been printed out. DFWB.

16th Nov 2022, 11:32 am	#5
FERNSEH Dekatron Join Date: Mar 2005 Location: Gateshead, Tyne and Wear, UK. Posts: 7,444	Re: Levell R.C. Oscillator Type TG150D Current consumption is 14mA on sine waves and 20mA on square waves. For the time being I'm using two alkaline PP3 batteries. A holder for the PP3 is available from RS components under the part number: 489-611. DFWB.