Test Equipment Anonymous (TEA) group therapy thread

[Specmaster]

So do you think that I fit into the TEA category or not, I certainly need help 

No, you're not there yet: while the hp1740a is a good start, you are missing Tek scopes, analogue storage scopes, signal generators, spectrum analysers, network analysers, PSUs, voltage and resistance references.

PM me if you want me to help rectify those discrepancies 

What do you mean analogue storage scopes, what's the Hameg HM 408-1A then? Admittedly, it doesn't have a lot of storage but it does have some. 

Tek scopes I've steered clear of them as for the most part they seem to use a lot of custom chips, especially those god awful, expensive and hard to find hybrid chips that I keep hearing people moan about. They have to be fed with forced air cooling all the time and is even more difficult to do when you have the chassis out on the bench.

Spectrum analysers, network analysers, precision PSU's, voltage and resistances references I cannot see me ever getting those as they don't fulfill any useful purpose for me. I tend to look at items that I can see could be very useful for me once fixed etc rather than fixing them for the sake of fixing them.

Signal generators, yes, especially ones that cover the normal domestic wavebands of MW/LW and FM to assist in the restoration of radios. All of the ones I have seen so far are way out of my reach on a pension. The Sharetree Type 450 does that very nicely if ever I can get it to work, struggling to obtain a manual for it so I can start the restoration process 

[tautech]

There are a few private auctions here in the UK I've scored on. I was in money making mode at the time so I didn't keep any of it. This was before TEA

The one thing I regret selling is the Tek 7613 and 7L12 spectrum analyser which still had a calibration certificate. I kept the Tek 475 I had in that lot for a bit but had a stupid moment of "100MHz is enough" and got rid of it.

My wife keeps asking me when I'm selling the HP 1740A I just restored. She doesn't get the idea of never!

I cannot remove the knob for the timebase on my 1740A, 1 grub screw is undone but the other.. it does not seem to fit properly with any of my allen keys, they just slip round inside of the head  So it justs sits here on the floor by my desk waiting for me resolve the issue. I looked useing stud / screw extractors none of the ones I've ever come across are small enough to pass through the opening on the knob let alone fit the grub screw 

Yep, they can be bloody tight. Get the right key. 

[Specmaster]

Well there's two options:

1. Buy an 0.05" hex key (I got a few of them from RS when I was repairing Tek stuff - same size!)
2. Buy another HP 1740A: http://www.ebay.co.uk/itm/122697662787

 

Well I can report that it certainly isn't 0.05" as I have that size already in a large set I purchased in an effort to find one that fitted (a draper metric/imperial 30 piece set). I have removed all the other knobs with problems using the 0.05" key but this one grub screw just will not budge.

I suppose the option of buying another 1740A is a partial solution and then keeping this one as a donor machine for the future maybe? Perhaps I could sell my Rapid 25Mhz scope (my most modern one with only a few hours use on it) to fund the purchase.....

[bd139]

The Rapid 25MHz one won't be much of a return on your investment even if it's relatively new. They are unfortunately quite low demand. I'd consider keeping it to fix the other stuff if it goes wrong

Just a heads up: the 1740A has two nasty looking hybrids in it as well. I am going to grab a donor machine (not that one as I can't be bothered to go to Kent to get it) when I see one so I am covered for any failures.

If you want something infinitely repairable, look out for a Tek 453. That is if you have a supply of tunnel diodes. I think I paid £5 for my last one. Someone had dumped it off at the tip. Smelled a bit funny but worked fine. Added feature is it keeps the house warm when it gets to winter

Heathkit RF-1U seem to go for around £30 on eBay. They're not terrible RF generators. Easy to fix. Certainly better than the cheap Chinese ones.

[tautech]

Well there's two options:

1. Buy an 0.05" hex key (I got a few of them from RS when I was repairing Tek stuff - same size!)
2. Buy another HP 1740A: http://www.ebay.co.uk/itm/122697662787

 

Well I can report that it certainly isn't 0.05" as I have that size already in a large set I purchased in an effort to find one that fitted (a draper metric/imperial 30 piece set). I have removed all the other knobs with problems using the 0.05" key but this one grub screw just will not budge.

It's 050", I just checked and measured the key with calipers. Dead 1740A here too for the 'one day' repair.

For stubborn stuff (generally larger) I've used shock down the line of the screw to crack the bond of the threads. IIRC someone suggested using heat from an iron but go easy on things or you'll bugger it. 

[tggzzz]

So do you think that I fit into the TEA category or not, I certainly need help 

No, you're not there yet: while the hp1740a is a good start, you are missing Tek scopes, analogue storage scopes, signal generators, spectrum analysers, network analysers, PSUs, voltage and resistance references.

PM me if you want me to help rectify those discrepancies 

What do you mean analogue storage scopes, what's the Hameg HM 408-1A then? Admittedly, it doesn't have a lot of storage but it does have some. 

If it has "some storage" and has a samples/sec spec, then it isn't an analogue storage scope! Even the specsheet calls it a "digital storage oscilloscope".

Analogue storage scopes store the trace in the tube. Example of a 1975 scope  showing a trace that went through one revolution per second:
https://farm1.static.flickr.com/694/32188654120_59cc4d01f9_b.jpg

Tek scopes I've steered clear of them as for the most part they seem to use a lot of custom chips, especially those god awful, expensive and hard to find hybrid chips that I keep hearing people moan about. They have to be fed with forced air cooling all the time and is even more difficult to do when you have the chassis out on the bench.

Too pessimistic. Don't forget the old adage "Tek for scopes, HP for everything else"

Spectrum analysers, network analysers, precision PSU's, voltage and resistances references I cannot see me ever getting those as they don't fulfill any useful purpose for me. I tend to look at items that I can see could be very useful for me once fixed etc rather than fixing them for the sake of fixing them.

I question whether you are a TEA 

[bd139]

My new counter arrived and works.

However it's yellow with nicotine and stinks. YUCK. Dismantling it right away for cleaning.

[Berni]

Spectrum analysers, network analysers, precision PSU's, voltage and resistances references I cannot see me ever getting those as they don't fulfill any useful purpose for me. I tend to look at items that I can see could be very useful for me once fixed etc rather than fixing them for the sake of fixing them.

Signal generators, yes, especially ones that cover the normal domestic wavebands of MW/LW and FM to assist in the restoration of radios. All of the ones I have seen so far are way out of my reach on a pension. The Sharetree Type 450 does that very nicely if ever I can get it to work, struggling to obtain a manual for it so I can start the restoration process 

Well it all depends on what you work on. Very few pieces of test gear are as universally useful as DMMs and scopes.

Some RF work can really benefit from spectrum/network analyzers. And even for non RF work such things can be useful if you for example want to test ripple rejection of your regulators or testing if a product your designing is radiating EMI or other interference. If you restore a lot of old multimeters then having wide and stable voltage and current sources can be very useful for calibrating and testing them.

But then there is also the sort of equipment that doesn't actually let you do something you couldn't do without it, but instead lets you do the thing faster or is simply convenient. This is perhaps the most evident with PSUs. Sure a few good ol twidly pot single output analog PSUs do pretty much everything that a fancy multichannel digital one might do(minus remote control). But if you often need multiple power rails its so much quicker to get +/- 5V using the push of like 5 buttons on a single piece of equipment than gang together and adjusting two analog single rail ones. You can simultaneously power on/off all the rails at the same time or even sequence them at a push of a button. Some might let you type in the current limit to 1mA resolution and also display it that fine (Nice for driving constant current devices). So the fancy PSUs is perhaps just more convenient to use and tha's the only point.

But yes fancy test equipment gets expensive REALLY fast.

[Specmaster]

My new counter arrived and works.

However it's yellow with nicotine and stinks. YUCK. Dismantling it right away for cleaning.

Its a nice unit, I had the 100Mhz version but sold it because it needed more input voltage than my old signal generator was capable of providing so I replaced it with the Velleman DVM13MFC multi function counter which goes upto 1.3Ghz and works perfectly with my generator.

I had the smoke issue with my Hitachi scope which came with a carry bag and the only way I could get rid of the stench was to hang it outside on the washing line for a few days, sure it got rained on but that helped to rinse the smell away and then I had divest it of spiders, give it good old spray with "Oust" before bringing it back indoors again. It worked a treat, as for the scope itself, I gave the casing a good scrub in the kitchen sink.

[bd139]

I'm rather happy with it now it doesn't stink. The irony is I just bought this because it's more sensitive than my other counter (built into DG1022Z). I just scrubbed the casing with bathroom cream cleaner. Works wonders that stuff. The front panel (well actually the entire counter is the front panel) was carefully cleaned with Dettol. No more smell!

I had a leather pouch on a Tek 465 that was green because of the previous owner being a smoker. I decided to give up on that

[VK5RC]

I am a great fan of "Magic" or melamine sponges, I will often progress through soapy water, window cleaner, IPA, for some plastics I use Meguiars PlastiX.
Always start on a non-exposed area first.
Rob

[xrunner]

Well I can report that it certainly isn't 0.05" as I have that size already in a large set I purchased in an effort to find one that fitted (a draper metric/imperial 30 piece set). I have removed all the other knobs with problems using the 0.05" key but this one grub screw just will not budge.

OK I've done this on a Tektronix plug-in dial that I needed to remove but the hex screw would not budge. If you are brave ... get a set of numbered drill bits. Drill out the center carefully until the center part of the screw is gone down to where it holds the knob. The knob will then come right off. After that, grub out the rest of the screw revealing the threads left intact on the dial. If you are careful they will be OK because all you need to do is take out the center part of the screw, because that's where, at the bottom, the screw is holding against the shaft.

As I said I've successfully done this but if you aren't brave you won't wish to attempt it. 

[Specmaster]

OK I've done this on a Tektronix plug-in dial that I needed to remove but the hex screw would not budge. If you are brave ... get a set of numbered drill bits. Drill out the center carefully until the center part of the screw is gone down to where it holds the knob. The knob will then come right off. After that, grub out the rest of the screw revealing the threads left intact on the dial. If you are careful they will be OK because all you need to do is take out the center part of the screw, because that's where, at the bottom, the screw is holding against the shaft.

As I said I've successfully done this but if you aren't brave you won't wish to attempt it. 

Hmm, I'm warming to that idea myself, If it goes wrong, I still have the other grub screw to hold the knob back on, although come to think of I don't because the knob broke so I'll need a new knob as well, and its the worst one of course being its the outer knob.

[AF6LJ]

An easier way to remove a grub screw that is stuck is to buy a left hand drill just over the size of the hex wrench used to remove it and drill it.
As the bit enters the screw it will grab and may extract the grub screw.
This is a much preferred way....
If need be go up a drill size until the wall of the grub screw is thin enough it relax and back out on the end of the drill.

[Specmaster]

An easier way to remove a grub screw that is stuck is to buy a left hand drill just over the size of the hex wrench used to remove it and drill it.
As the bit enters the screw it will grab and may extract the grub screw.
This is a much preferred way....
If need be go up a drill size until the wall of the grub screw is thin enough it relax and back out on the end of the drill.

I also thought about this method but couldn't locate any left hand drill bits, are they available then?

[xrunner]

An easier way to remove a grub screw that is stuck is to buy a left hand drill just over the size of the hex wrench used to remove it and drill it.

That's probably true Sue, but you know I love drama in the lab ... 

[AF6LJ]

An easier way to remove a grub screw that is stuck is to buy a left hand drill just over the size of the hex wrench used to remove it and drill it.

That's probably true Sue, but you know I love drama in the lab ... 

If you like drama...
remove it by applying LN2 and tapping on it with a awol and hammer.

Although you are missing out on all the fun.
Hand someone a left hand drill bit and watch them as they try to drill a hole with it...
And then when they swear up and down the drill is defective, go over and reverse the drill and watch them realize how they were pranked...

[Specmaster]

If it has "some storage" and has a samples/sec spec, then it isn't an analogue storage scope! Even the specsheet calls it a "digital storage oscilloscope".

Analogue storage scopes store the trace in the tube. Example of a 1975 scope  showing a trace that went through one revolution per second:
https://farm1.static.flickr.com/694/32188654120_59cc4d01f9_b.jpg

Surely it's a combi scope then, digital storage via memory chips and analogue in all other aspects with a CRT display as opposed to LCD panel?

[bd139]

What about analogue sampling scopes with storage tubes

[AF6LJ]

What about analogue sampling scopes with storage tubes

I have one; it is a bit of an art to get good clean traces.
It is a lot more useful in variable persistence mode. 

[bitseeker]

I also thought about this method but couldn't locate any left hand drill bits, are they available then?

If you can't find left hand bits, look for a screw extraction kit. Same idea.

[bitseeker]

Future reference: if you have something nice and HP, don't sell it to buy some Chinese crap

Fixed that for ya:

          if you have something nice, don't sell it

[tautech]

I also thought about this method but couldn't locate any left hand drill bits, are they available then?

If you can't find left hand bits, look for a screw extraction kit. Same idea.

Rarely do these work out well for very small fasteners. 
Commonly they bust off and then the very best of luck trying to drill the broken stub out.
They're as hard as shark sh*te and impossible to drill with normal gear.

Absolute last resort IMHO.

[AF6LJ]

I also thought about this method but couldn't locate any left hand drill bits, are they available then?

If you can't find left hand bits, look for a screw extraction kit. Same idea.

Rarely do these work out well for very small fasteners. 
Commonly they bust off and then the very best of luck trying to drill the broken stub out.
They're as hard as shark sh*te and impossible to drill with normal gear.

Absolute last resort IMHO.

Screw extractors are a waste of time on anything smaller than #8 and harder than grade-5.

[Specmaster]

I also thought about this method but couldn't locate any left hand drill bits, are they available then?

If you can't find left hand bits, look for a screw extraction kit. Same idea.

Rarely do these work out well for very small fasteners. 
Commonly they bust off and then the very best of luck trying to drill the broken stub out.
They're as hard as shark sh*te and impossible to drill with normal gear.

Absolute last resort IMHO.

Screw extractors are a waste of time on anything smaller than #8 and harder than grade-5.

So then, effectively, unless I can source another knob so that I can cut through the brass boss in order to gain access to repair it, it is likely to be consigned as a parts donor for another one