levell R.C. Oscillator type TG200DM - UK Vintage Radio Repair and Restoration Discussion Forum

derek100 · 24th Sep 2019, 10:13 am

Hi,

i recently got the above oscillator. have the schematic and went through everything but seem to be over looking something. The board itself is not great so far as im not sure all the traces are correct. as i said i did compare the schematic, but just to be sure i would like to get a photo of a working circuit board so i can rule that out. any help would great, many thanks in advance

govjohn · 24th Sep 2019, 3:36 pm

Here you go. I have recently got one of these ocillators and I must say it is a big improvement on the previous Levell gear I've seen which has always seemed to be poorly assembled. I note you have the cct diags etc which are essential as the circuit is unususal. In the case of my instrument all the electrolytic capacitors had a poor tan delta so they were replaced,after this I calibrated it following the instructions although its very fiddly and it now works very well. I dont like battery opperated test equipment appart from Multimeters as the batterys allways seem to run out just when you need them. I can see the advantage regarding ground loops when connecting to a piece of earthed gear. To this end the +/- 18V power supply I've built into my oscillator is only earthed to the mains transformer body and electrostatic screen, this is probably bad practice but its better than just disconnecting the earth lead. (who hasn't done that) The other dissadvantage to battery supply's is visible in the photo of the power supply. Good luck with your oscillator, persevere and it will be worth it.
Regards, John. (I wish this forum had spell check)

G3VKM_Roger · 24th Sep 2019, 4:14 pm

QUOTE (I wish this forum had spell check)

It does, or rather your browser has if you enable it.

Cheers

Roger

derek100 · 25th Sep 2019, 11:41 am

Many thanks for that John. like the power supply, very tidy.

I also built a dual ps for mine.

24th Sep 2019, 10:13 am	#1
derek100 Retired Dormant Member Join Date: Sep 2019 Location: Dunshaughlin, County Meath, Ireland Posts: 2	levell R.C. Oscillator type TG200DM Hi, i recently got the above oscillator. have the schematic and went through everything but seem to be over looking something. The board itself is not great so far as im not sure all the traces are correct. as i said i did compare the schematic, but just to be sure i would like to get a photo of a working circuit board so i can rule that out. any help would great, many thanks in advance

24th Sep 2019, 3:36 pm	#2
govjohn Pentode Join Date: May 2011 Location: Cardigan, Ceredigion, UK. Posts: 100	Re: levell R.C. Oscillator type TG200DM Here you go. I have recently got one of these ocillators and I must say it is a big improvement on the previous Levell gear I've seen which has always seemed to be poorly assembled. I note you have the cct diags etc which are essential as the circuit is unususal. In the case of my instrument all the electrolytic capacitors had a poor tan delta so they were replaced,after this I calibrated it following the instructions although its very fiddly and it now works very well. I dont like battery opperated test equipment appart from Multimeters as the batterys allways seem to run out just when you need them. I can see the advantage regarding ground loops when connecting to a piece of earthed gear. To this end the +/- 18V power supply I've built into my oscillator is only earthed to the mains transformer body and electrostatic screen, this is probably bad practice but its better than just disconnecting the earth lead. (who hasn't done that) The other dissadvantage to battery supply's is visible in the photo of the power supply. Good luck with your oscillator, persevere and it will be worth it. Regards, John. (I wish this forum had spell check) Attached Thumbnails

24th Sep 2019, 4:14 pm	#3
G3VKM_Roger Heptode Join Date: Jun 2012 Location: Southeast Norfolk, UK. Posts: 773	Re: levell R.C. Oscillator type TG200DM QUOTE (I wish this forum had spell check) It does, or rather your browser has if you enable it. Cheers Roger

25th Sep 2019, 11:41 am	#4
derek100 Retired Dormant Member Join Date: Sep 2019 Location: Dunshaughlin, County Meath, Ireland Posts: 2	Re: levell R.C. Oscillator type TG200DM Many thanks for that John. like the power supply, very tidy. I also built a dual ps for mine.