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 > Specific Vintage Equipment > Vintage Test Gear and Workshop Equipment

Notices

Vintage Test Gear and Workshop Equipment For discussions about vintage test gear and workshop equipment such as coil winders.

Reply
 
Thread Tools
Old 26th Nov 2022, 9:44 pm   #1
hunts_joe
Diode
 
Join Date: Nov 2022
Location: Huntingdon, Cambridgeshire, UK.
Posts: 3
Default Looking for info on British National Radio and Electronics kit oscilloscope

Searching the forum, I see that several people have one of these little kit scopes.

I built the valve version of this scope some 40+ years ago; and I still have it, and it served me pretty well for a number of years.

My late brother had built the same scope some 10 years before me and when I was clearing out his workshop last year, I stumbled across what I thought was that scope, only to find out it had transistors in it. I'd assumed he'd just tried to rebuild it with transistors as a project, but after reading the threads here I see they released a transistor version, and I would love to return this scope to working order. I'm assuming at this stage that he purchased a faulty unit from somewhere quite recently with the intention of repairing it. Does anybody know where I can find the technical information for this scope please?

I'm hoping to make this my Christmas project... if I can find the information and replacement parts.

Kind regards,
Joe
hunts_joe is offline   Reply With Quote
Old 26th Nov 2022, 10:58 pm   #2
David G4EBT
Dekatron
 
David G4EBT's Avatar
 
Join Date: Feb 2003
Location: Cottingham, East Yorkshire, UK.
Posts: 5,145
Default Re: Looking for info on British National Radio and Electronics kit oscilloscope

The transistorised one was the MK2, known as the 'Lernkit'.

Forum member Chris55000 kindly posted the first five parts of the manual at post #6 in the thread here:

https://www.vintage-radio.net/forum/...d.php?t=179656

This might also be of passing interest concerning the MK1 valved version:

https://www.youtube.com/watch?v=HzhJKE9vzMM

Hope that helps.
__________________
David.
BVWS Member.
G-QRP Club member 1339.
David G4EBT is online now   Reply With Quote
Old 29th Nov 2022, 4:52 pm   #3
hunts_joe
Diode
 
Join Date: Nov 2022
Location: Huntingdon, Cambridgeshire, UK.
Posts: 3
Default Re: Looking for info on British National Radio and Electronics kit oscilloscope

Thanks David... I'll have a read.

Regards,
Joe
hunts_joe is offline   Reply With Quote
Old 1st Dec 2022, 4:20 pm   #4
Chris55000
Nonode
 
Join Date: Aug 2007
Location: Walsall Wood, Aldridge, Walsall, UK.
Posts: 2,347
Default Re: Looking for info on British National Radio and Electronics kit oscilloscope

I do still have the rest of these instructions and diagrams for Steps 9 to 12 of the Mk 2 "Learnakit" and will get them scanned and uploaded as soon as my spare time permits!

Chris Williams
__________________
It's an enigma, that's what it is! This thing's not fixed because it doesn't want to be fixed!
Chris55000 is offline   Reply With Quote
Old 4th Jan 2023, 9:33 am   #5
hunts_joe
Diode
 
Join Date: Nov 2022
Location: Huntingdon, Cambridgeshire, UK.
Posts: 3
Default Re: Looking for info on British National Radio and Electronics kit oscilloscope

As my Christmas project I decided to try getting the MK2 I have working. I've no idea where it originally came from as I found it when clearing out my late brothers workshop. I know he didn't built it; both he and I built the original valve versions 8+ years apart and he had already moved onto a proper scope by the time I started my kit and anyway, the build quality is pretty poor.
I spent some time redoing some of the connections that had or were about to come lose, tidied up around the mains wiring which to be frank was a death trap, and fixed a couple of bad/loose joints on the circuit board and it now partially works.
Next I went though all the related documentation from this site and tried to recreate the documentation pack. Unfortunately some of the key diagrams are missing and there's no circuit diagram. I have a single PDF document containing everything I have all oriented correctly and in the (hopefully) correct sequence for anybody that wants a copy.
The main circuit board is a piece of matrix perf board with components being soldered to vero pins on the top side, and all the interlinking wire on the underside. To be frank it's a mess. I was scared to remove the board to look at the underside as most of the wires to the board are way too short and the wiring won't survive the removal process. So, going though the documentation I have, I attempted to reconstructed the board diagram. I did this by following the build steps in the documentation (which look to be complete). By following these I managed to place all the pins in the correct place and solder in the jumper wires. The build instructions then say which components to solder between which pins. Again these seem to be complete.
Following all these instructions it took a while but I managed to recreate the board layout. I'm now in the process of reverse engineering the board to try and create a schematic.
For those that are interested I've attached the board layout.
I actually drew it in a PCB package and I may get a PCB made based on the design but has an edge connector so it can be easily removed from the scope. Maybe... One day...
There are lots of components that don't appear to be connected on one side and typically these are connected to wires that connect to the scope controls.
Now the board is done I need to sit down with the actual scope and trace the wiring without dislodging anything.
I'm working on the assumption that the scope did work at some point so is built correctly and I just have a lose wire/joint or faulty component(s) somewhere. If the scope never actually worked then I'm probably flogging a dead project without more documentation... time will tell.
It does partially work. It displays a trace so it looks like the PSU section and timebase are working. There seems to be a fault around the Y axis and amplifier as you cannot adjust the Y position (just a very slight shudder when you move the control) and it won't display an input signal. There's also a possible fault around the two test voltage output jacks as they are reading way too low.
I'm guessing the CRT is a DG7-31 or equiv as there are no useful markings on the tube itself. However, looking though the Philips CRT catalogue they give pictures of the tube and the gun assembly and I think I managed to identify the CRT tube and it's operating voltages seem about right.
If nothing else it's amusing me until something more interesting comes along.
Joe
Attached Thumbnails
Click image for larger version

Name:	scopeboard.jpg
Views:	46
Size:	89.2 KB
ID:	270872  
hunts_joe is offline   Reply With Quote
Reply

Thread Tools



All times are GMT. The time now is 10:45 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.