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.

Closed Thread
 
Thread Tools
Old 1st Dec 2021, 9:03 pm   #41
Gridiron
Heptode
 
Join Date: Apr 2010
Location: West Midlands, UK.
Posts: 659
Default Re: Unidentified bits of test gear

Here's a picture of the B101 bridge I have, also has holes for a handle on top, serial number 64, so quite an early one. In working order although I have not checked accuracy.
Attached Thumbnails
Click image for larger version

Name:	Wayne Kerr Bridge 1.jpg
Views:	84
Size:	100.0 KB
ID:	247098  
Gridiron is offline  
Old 3rd Dec 2021, 4:02 pm   #42
Techman
Dekatron
 
Techman's Avatar
 
Join Date: Nov 2009
Location: Lincolnshire, UK.
Posts: 4,985
Default Re: Unidentified bits of test gear

Quote:
Originally Posted by Techman View Post
Regarding the previously shown piece of homebrew kit as mentioned and shown in posts #30 and #35.
So it turns out it's an alien detector!

I applied 9 volts and it puts out pulses of around 160KHz a little faster than once a second. It's a dirty old waveform, but seeing as I was taking it from the transformer secondary output it'll be this that's distorting the waveform, as it wouldn't be very happy at this frequency.

I can't say for certain that it came off this particular unit, but I found a bit of paper on the bench where I've had this thing and scribbled on it are the words "contact crop circles". This bit of paper has definitely dropped off one of these bits of kit that I've been playing with and I do remember seeing this label on something, but just not sure if it was on this or not. I don't know much about crop circles, other than the late Reg Presley from 60s band The Troggs was heavily into them, but perhaps the croc clips were to be connected onto metal stakes inserted into the ground to be picked up by some sort of receiver - just a thought.

There has to be an article on this thing in an old Practical Wireless magazine or similar you would have thought.

The question is, does it have any use today? I note that there are some useful parts, particularly (for me) the cosmetic centres of the terminals to replace the missing ones on the Wayne Kerr bridge - and 'Gridiron' (previous post), that certainly is an early serial number on yours. It seems that there are a few of these units about, but very few actually being used.

Below is the pulse waveform - you wouldn't believe how many snaps I had to take to capture that fraction of a second pulse (I got about three in the end and that one was the best...this is perhaps where a storage scope would have been useful:-
Attached Thumbnails
Click image for larger version

Name:	P1140914.jpg
Views:	53
Size:	40.5 KB
ID:	247204  
Techman is offline  
Old 13th Dec 2021, 12:35 am   #43
Techman
Dekatron
 
Techman's Avatar
 
Join Date: Nov 2009
Location: Lincolnshire, UK.
Posts: 4,985
Default Re: Unidentified bits of test gear

Quote:
Originally Posted by Techman View Post
Yet another item.

A Taylor 20B circuit analyser.

It's dead as a doornail. I applied the mains a few weeks ago and there was a very short burst of hash on a nearby radio that was turned on at the time, but that was that, indicating that it's probably the on-off switch o/c from being left in the 'off' position for decades. It measures o/c across the plug pins with the switch on (fuse is OK), so I strongly suspect the usual switch contact fault.
I got round to looking at this today and it turned out that I was on the right track, but wrong about the switch contacts, although one pole did have a little resistance measured across its contacts when closed compared to the other. The fault was that the three position mains voltage selector was o/c. I thought it might be just a dirty contact, but it was a bit more than that and probably a bad internal riveted contact, so I bypassed it for the time being by moving the black wire from its tag onto the tag with the green wire - back of voltage selector tag strip shown in the third photo below.

Powering on brought it to life with no dramas and the triple 20uf Hunts smoothing capacitor can stayed stone cold after several short power ups and power downs to check things, and a final longer power up to see if the unit was functioning. Hunts made some of the best electrolytic capacitors in history, so you can be pretty damn sure that when you see the name Hunts on a smoothing capacitor can that it's likely to be in good order and functioning perfectly. The poor old thing was hit with full DC at switch on from the metal bridge rectifier, but these Hunts electrolytics are more than man enough to stand this without a bang - on most occasions! However, there are a couple of black Hunts paper capacitors in there which are pretty much guaranteed to be very electrically leaky and would ideally be replaced to restore reliable functionality of the unit.

The valve line-up is the EM34 magic eye, which seemed in good working order. Also a 12AU7 and a 9D6, which is a W77 equiv. The W77 is a special valve to me, as this was the first valve I ever replaced to fix a radio as a child. It was my grandmothers HMV radio which had packed up and she had rented a replacement, giving me the old radio to play with. I was overjoyed to be given what was my first 'proper' mains radio, and I remember sitting on the floor of my grandmothers Walthamstow flat with it plugged into the mains with the back off, and while the grown ups were sitting talking and drinking tea, I was poking round inside and tapping things with a screwdriver when the set suddenly burst into life - everyone was amazed. However, this was short lived, because when I switched it off and then back on again, the set was once again dead. A bit more tapping of the valves while once again powered up, showed that it was the W77 that was at fault. I seem to remember that I probably sent off for a replacement from one of the valve sellers that advertised in Practical Wireless at the time. I still have that set and the only other part to be replaced was "that cap", grid coupling capacitor, which I did a few years ago.

I didn't do much in the way of testing on the Taylor 20B, other than to note that the signal tracer part was working and producing audio from the probe through to loudspeaker. The speaker and its small transformer look to be ideal replacements for battery powered valve radios and I've got one right now with an o/c transformer, but this unit is in such good condition and very clean inside that it would be a great shame to break it for parts, so I probably wont be doing that any time soon. On removing the two valve 'hats' to inspect the valves, the one on the 9D6 split straight in half, so I popped a bit of tape round it for the time being, although I think I've got a replacement of the same type for it in a box up in the loft.

So that's it, it's alive, but will need a couple or three capacitors replacing and voltages checking etc. Pictures (which I don't think so far that there are any of the innards of this particular unit on the forum) below:-
Attached Thumbnails
Click image for larger version

Name:	P1140928.jpg
Views:	124
Size:	137.6 KB
ID:	247780   Click image for larger version

Name:	P1140931.jpg
Views:	120
Size:	105.5 KB
ID:	247781   Click image for larger version

Name:	P1140932.jpg
Views:	113
Size:	110.6 KB
ID:	247782   Click image for larger version

Name:	P1140934.jpg
Views:	112
Size:	131.2 KB
ID:	247783   Click image for larger version

Name:	P1140935.jpg
Views:	111
Size:	82.7 KB
ID:	247784  

Techman is offline  
Old 14th Dec 2021, 2:06 pm   #44
Andrewausfa
Octode
 
Andrewausfa's Avatar
 
Join Date: Dec 2010
Location: St Ives, Cambridgeshire, UK.
Posts: 1,180
Default Re: Unidentified bits of test gear

I acquired one of these at the recent RWB meet for not very much. It was in a bit of a state so I wasn't expecting too much. However, it seems to power up fine and just needs a check of internal C&Rs, a good clean and a cabinet respray. What I didn't realise with this particular version is that it has a germanium diode in the probe as opposed to its predecessors valve diode. Anyway, I have all three versions now, the early one, the 'A' and the 'B'.

Andrew
__________________
Invisible airwaves crackle with life. Or they should do.
BVWS Member
Andrewausfa is offline  
Old 15th May 2022, 3:52 pm   #45
glowinganode
Octode
 
glowinganode's Avatar
 
Join Date: Apr 2009
Location: Aylesbury, Buckinghamshire, UK.
Posts: 1,522
Default Re: Unidentified bits of test gear

Quote:
Originally Posted by Techman View Post

Something goes in that socket/hole in the top, but what?
As already mentioned, this is a proving unit for a high voltage voltmeter / potential indicator, manufactured by Edgcumbe Peebles of Glasgow.
It is standard procedure to confirm correct operation immediately before and after use, especially when proving dead.

The probe of the tester fits into the hole, contacting the leaf contacts connected to the hv secondary winding of the unit.

Reference the wooden test lamp, the disc on the base of the unit was to access a spare fuse for the fused test leads which is replaced by unscrewing the tip.

Cheers.
Attached Thumbnails
Click image for larger version

Name:	20220515_145208.jpg
Views:	81
Size:	96.1 KB
ID:	257237   Click image for larger version

Name:	20220515_145323.jpg
Views:	74
Size:	91.5 KB
ID:	257238  
__________________
We have done so much, for so long, with so little, we are now qualified to do anything with nothing.
glowinganode is offline  
Old 15th May 2022, 4:18 pm   #46
Techman
Dekatron
 
Techman's Avatar
 
Join Date: Nov 2009
Location: Lincolnshire, UK.
Posts: 4,985
Default Re: Unidentified bits of test gear

Quote:
Originally Posted by glowinganode View Post
Cheers.
Thanks for the additional information
Techman is offline  
Old 20th May 2022, 7:52 pm   #47
its ur aerial
Hexode
 
its ur aerial's Avatar
 
Join Date: May 2009
Location: Ryde, Isle of Wight, UK.
Posts: 418
Default Re: Unidentified bits of test gear

Pictures 7 and 8, GEC Phase rotation meter, used to check a three phase supply that was then, Red Blue and yellow were are in the correct order, before connecting to a motor.
The clamp meter, pic 10 is clipped on to the phase or phases in turn to measure the current being drawn .

Ken G6HZG
__________________
Life is not Hollywood, life is Cricklewood.
its ur aerial is offline  
Closed Thread

Thread Tools



All times are GMT +1. The time now is 8:42 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 - 2024, vBulletin Solutions, Inc.
Copyright ©2002 - 2023, Paul Stenning.