UK Vintage Radio Repair and Restoration Powered By Google Custom Search Vintage Radio and TV Service Data

Go Back   UK Vintage Radio Repair and Restoration Discussion Forum > General Vintage Technology > Success Stories

Notices

Success Stories If you have successfully repaired or restored a piece of equipment, why not write up what you did and post details here. Particularly if it was interesting, unusual or challenging. PLEASE DO NOT POST REQUESTS FOR HELP HERE!

Reply
 
Thread Tools
Old 12th Oct 2022, 11:07 am   #1
nigelr2000
Heptode
 
nigelr2000's Avatar
 
Join Date: Nov 2008
Location: North Walsham, Norfolk, UK.
Posts: 846
Default Stroboconn 6T5 Tuning Unit

I have never seen one of these before and probably won't again. It came my way from Pete the guy who does musical instruments on the repair shop.
It was made in the early sixties but the original design was alleged to be from the 1936 and is used to tune instruments.
It has 2 units, the bottom one is a frequency clock to run the motor unit and consists of an excited tuning fork tuned to exactly 55 Hz which locks the motor to this frequency and runs via precision gears several strobe discs in the upper unit. It has an oscillator section and an output stage using 4x 6V6 valves in push pull.
The upper unit contains an amplifier which instead of running a speaker runs a huge U shaped neon lamp to illuminate the strobes flashing at whatever frequency the microphone is picking up again a 6V6 in push pull is used.
It can then show the note and all harmonics as well.

It required a lot of work to bring it back to life including the main rectifier in the lower unit, 5U4G which showed it's demise with a big burn on the side of the valve and lots of mica rattling around in it. I changed all the coupling capacitors and the electrolytic's in the top unit, the lower unit had new ones fitted fairly recently. A first run of the motor showed it was making nasty noises, this was the start up cap (3.5 F ac) cleverly hidden behind the original big can one which had been replaced with an ordinary 10F 400V DC one which unsurprisingly had blown out leaving a mess on the bottom of the case.

After this it ran fine and the neon lit up once the amplifier warmed up. I then plugged in the lower unit and after a while the pilot neon lit meaning it was running. I threw the switch from warm up to run and the motor locked to 55Hz, success. I then hummed various nots into the microphone and was rewarded with various strobe line dependant on frequency.

Overall it was fun to do and an ingenious device using electronics and precision engineering to give a simple but precise frequency measurement.

I have a link to all the pictures and a video of it running here https://photos.app.goo.gl/vPpkbushmstg3pb96
Attached Thumbnails
Click image for larger version

Name:	20221012_111507.jpg
Views:	73
Size:	49.5 KB
ID:	265998   Click image for larger version

Name:	20220921_104204.jpg
Views:	60
Size:	94.0 KB
ID:	265999   Click image for larger version

Name:	20220921_104134.jpg
Views:	57
Size:	63.1 KB
ID:	266000   Click image for larger version

Name:	20220921_104213.jpg
Views:	57
Size:	68.4 KB
ID:	266001  
Attached Files
File Type: pdf Stroboconn_20221012_0001.pdf (3.10 MB, 18 views)

Last edited by nigelr2000; 12th Oct 2022 at 11:16 am.
nigelr2000 is offline   Reply With Quote
Old 12th Oct 2022, 7:06 pm   #2
Andrewausfa
Octode
 
Andrewausfa's Avatar
 
Join Date: Dec 2010
Location: St Ives, Cambridgeshire, UK.
Posts: 1,160
Default Re: Stroboconn 6T5 Tuning Unit

Conn Strobo tuner, very nice and lovely to watch!

Out of interest and size comparison, here's my modern Peterson version, Peterson started making strobe tuners back in the late 1960s.

Andrew
Attached Thumbnails
Click image for larger version

Name:	20221012_195911.jpg
Views:	41
Size:	65.7 KB
ID:	266025  
__________________
Invisible airwaves crackle with life. Or they should do.
BVWS Member
Andrewausfa is offline   Reply With Quote
Old 12th Oct 2022, 9:07 pm   #3
nigelr2000
Heptode
 
nigelr2000's Avatar
 
Join Date: Nov 2008
Location: North Walsham, Norfolk, UK.
Posts: 846
Default Re: Stroboconn 6T5 Tuning Unit

Quote:
Originally Posted by Andrewausfa View Post
Conn Strobo tuner, very nice and lovely to watch!

Out of interest and size comparison, here's my modern Peterson version, Peterson started making strobe tuners back in the late 1960s.

Andrew
At least it's a lot more portable the Conn is a real lump
nigelr2000 is offline   Reply With Quote
Reply

Thread Tools



All times are GMT. The time now is 7:34 am.


All information and advice on this forum is subject to the WARNING AND DISCLAIMER located at https://www.vintage-radio.net/rules.html.
Failure to heed this warning may result in death or serious injury to yourself and/or others.


Powered by vBulletin®
Copyright ©2000 - 2023, vBulletin Solutions, Inc.
Copyright ©2002 - 2023, Paul Stenning.