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 20th Jul 2017, 11:14 pm   #21
Keith
Heptode
 
Keith's Avatar
 
Join Date: Jan 2003
Location: Tewkesbury, Gloucestershire, UK.
Posts: 689
Default Re: Test equipment: how much is needed?

Don't forget the humble headphone/capacitor combination. Used with the "finger" or "short wire aerial" injector, many simple radio faults can be found.
__________________
Keith Yates - G3XGW
VMARS & BVWS member http://www.tibblestone.com/oldradios/Old_Radios.htm
Keith is online now  
Old 20th Jul 2017, 11:43 pm   #22
paulsherwin
Moderator
 
paulsherwin's Avatar
 
Join Date: Jun 2003
Location: Oxford, UK
Posts: 27,783
Default Re: Test equipment: how much is needed?

It all goes back to #5. Test equipment is largely a matter of personal preference. You can get by with almost nothing and still do a good job. If you're used to using some sort of fancy kit or other, you'll feel it's practically indispensable.

Of course, there are many areas of modern electronics where it's effectively impossible to work on equipment without lots of (modern) professional workshop gear, but that's not what this forum is about.
paulsherwin is offline  
Old 21st Jul 2017, 1:15 am   #23
Argus25
No Longer a Member
 
Join Date: Oct 2016
Location: Maroochydore, Queensland, Australia.
Posts: 2,679
Default Re: Test equipment: how much is needed?

Quote:
Originally Posted by evingar View Post

1. Isolating transformer (for live chassis work)
2. DMM
2. Scope
3. Signal generator
I generally agree with this list. Though it is actually essential to have an analog multimeter too, a very good one are the Avo's or Hioki A-10. Digital meters often malfunction especially on reading the high value resistances of large inductors. For example a Fluke 75 proclaims the primary of many mains transformers open circuit, or the secondaries of ignition coils as open. Also the digital meter is not good when there is a waveform with higher frequency interference.

For the signal generator you need two basic types. One for audio frequencies and another well calibrated type for radio frequencies, which also has modulation options if you want to properly repair and re-align radios. For TV's you require pattern generators.

I have a well equipped workshop now, but when I started as a child, all I had for test apparatus were things like light bulbs, a crystal earpiece (which can resolve audio and with an added diode demodulate audio off an RF carrier) and a dodgy multi-meter. It is surprising what you can get away with. For example with a light bulb placed across a device like a car's fuel injector, you can brightness match another bulb to it from a DC source and from the DC level work out the duty cycle of the injector, just as one example.

But there is an old saying that still applies: The best piece of equipment in the workshop is the thing between the ears.
Argus25 is offline  
Old 21st Jul 2017, 4:31 am   #24
trh01uk
Octode
 
trh01uk's Avatar
 
Join Date: Nov 2010
Location: Ross-on-Wye, Herefordshire, UK.
Posts: 1,648
Default Re: Test equipment: how much is needed?

How much is needed?

To which my response is "How much is needed.....for what?

I am amused to see that virtually everyone who has replied so far has assumed that there is only one job for test gear - namely to repair some bit of faulty kit. And on this list - that will usually be a broadcast radio.

If that is the only job you want to do and you define "working" as "it makes a noise", then you can fix such radios with no more than a soldering iron and a bit of know how. You can replace the burnt out discoloured resistors, and the bulging electrolytics just by looking for them. And with some luck you then have it making a noise again without any test gear at all. You can then go on to roughly align it just using broadcast signals and a screwdriver.

That is a very long way from what I do with electronics. Firstly I define "working" as "it meets the spec". And to check that - you are usually going to need a pile of test gear. Certainly a signal generator - if it's a receiver - and probably an audio power meter to check power output. If it's hi-fi, you will probably want to check distortion levels. That's going to place a whole new set of demands on your kit. Merely "making a noise" can be a very long way from "it meets its spec."

If it's a professional communications receiver, it's liable to have specs for spurious responses, IF selectivity and the like. And for that, you will probably need quite a high spec professional signal generator - not a cheapie from Maplin. Something more like a HP8640B. If you start checking specs like 3rd order intermod, you will almost certainly need 2 generators - and possibly 3 - depending on the exact test you want to do.

If you then move to transmitters, you will almost certainly need a means of measuring RF level against frequency - and while you can do that with a calibrated receiver - more likely you will use a spectrum analyser, plus probably filters, dummy loads and attenuators.

Other people have mentioned scopes. I don't find them that useful for receiver work - but of course they can be used in a number of places. And they become more or less essential if you are working on things like synthesisers, or logic circuitry.

The other big differentiator is going to be design work as opposed to fixing work. One can reasonably assume something that needs fixing did actually work to spec at one point in time. And if its returned to its "as built" state with all working components it should again meet its spec. With new circuitry you have just designed there is no such certainty. You may need a raft of test gear then to work out why a circuit does not do what you thought it would. Or just to check that it meets the spec you set yourself.

So of course its a "horses for courses" sort of question. And depending on what you are doing you may need nothing at all - up to an array of kit that would normally only be found in professional labs.

Richard
trh01uk is offline  
Old 21st Jul 2017, 7:14 am   #25
Radio Wrangler
Moderator
 
Radio Wrangler's Avatar
 
Join Date: Mar 2012
Location: Fife, Scotland, UK.
Posts: 22,798
Default Re: Test equipment: how much is needed?

This is one of those bottomless discussions without any frame of reference as to what the initial question means. Rather like those school debating society "Does the end justify the means?" questions.

The replies inevitably contain information only about the reply-writers' assumptions because there was no real information in the question.

David
__________________
Can't afford the volcanic island yet, but the plans for my monorail and the goons' uniforms are done
Radio Wrangler is online now  
Old 21st Jul 2017, 8:16 am   #26
Craig Sawyers
Dekatron
 
Craig Sawyers's Avatar
 
Join Date: Nov 2010
Location: Oxford, UK.
Posts: 4,939
Default Re: Test equipment: how much is needed?

As David says, it depends on what you are doing. I have my own one-man-band business, of late mainly project management, but also analogue circuit design. As such I do a lot of component characterisation and have a large amount of equipment to that end. Also cable and connector characterisation over a range up to 20GHz - ditto.

There is something of a collector in this too - the ability to buy stuff (mainly, but not uniquely Tektronix) that I used in the lab in the 70's and 80's that were a house mortgage at the time essentially for beer money now.

But no worse than collecting valved radio sets, period TV's or wind up gramophones.

So far removed from fixing radios (although I have, and fixed, a decent RA17 rig) and TV's.

Craig
Craig Sawyers is online now  
Old 21st Jul 2017, 11:14 am   #27
karesz*
Heptode
 
Join Date: Jun 2010
Location: Zurich, Switzerland
Posts: 538
Default Re: Test equipment: how much is needed?

Jeremy wrote:
HTML Code:
So I agree that you really do need to understand the limitations of your 
test gear and any test procedures that use that piece of test gear.
I belive too; its the most important to remember in all our "allday jobs", especially if working on old radios- you need usually an 20Kohm/Volt Vmeter (or even less if apparate is older), but for working on HT/focus circuits Vmeter must have more higher input resistance. Btw; Such HV-Probes are for (old) analoge Meters, need an load i.e. 20K/V on 2/5V input or even are for moderner 10Mohm Vmeter inputs etc...
Than, RF-probes & HF oscilloscopes/probes dont have 1/10Mohm input resistance/impedance, and they will/can have a variance in frequency too!

Karl

Last edited by karesz*; 21st Jul 2017 at 11:19 am.
karesz* is offline  
Old 21st Jul 2017, 12:39 pm   #28
Skywave
Rest in Peace
 
Join Date: Jun 2006
Location: Chard, South Somerset, UK.
Posts: 7,457
Arrow Re: Test equipment: how much is needed?

Quote:
Originally Posted by Radio Wrangler View Post
This is one of those bottomless discussions without any frame of reference as to what the initial question means.
In essence, the original question simply asked "Is Mr. Scroggie's belief still applicable today? And if not in total, to what extent is it applicable?"
So, yes, it is a philosophical discussion - and like many philosophical discussions, there is no defined 'end point'.
I have read with much interest the comments made to date: my thanks to all who have contributed.

Al.
Skywave is offline  
Closed Thread

Thread Tools



All times are GMT +1. The time now is 9:46 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.