Test Equipment Anonymous (TEA) group therapy thread

[VK5RC]

@oculus - congrats on the graduation - good no overhanging debt - I was lucky enough to have finished my degree before the Aus gubbermint decided to make a new money printing press out of Universities. A recent journalist has shown emails in one Uni letting down the standards to keep the coffers full!
After my first degree/s, I got thoroughly screwed by a national training college - man am I still angry at a couple of characters there! Vengeance is a very destructive emotion but a few of those guys - I will have to try hard not to smile when I hear of their demise.
Rob

[VK5RC]

I shouldn't be too pissy, the extra 4 years the guys mucked me around, got me well known in my area so when I finished - things went really well.
Make lemonade!
Rob

[VK5RC]

Backing plate made and painted for the HP 608D - the original 'socket' is attached inside the unit if someone wants to fully restore to original - no front panel bashing was required.

[beanflying]

Shack market 'leftover' Lunch for no reason other than gratuitous Double Smoked Bacon and HP Sauce porn.

Cooked several forms of Plastic for the day, Steamed some milk, Extracted Bean Juice, Baked some Electronic bits, Fried Bacon and now time to Roast some Beans 

[tggzzz]

Yeah, over here it's the newest branch of legalized loan sharking; very low interest rates but compounded daily, and if you take the lower payment rate options (which most can't afford not to, as the rate starts in the hundreds and then doubles or triples each year) then the loan "recapitalizes unpaid interest" every year. This then also gets compounded daily; such that I've been paying for nearly a decade, and still owe more than I ever received.

Compounding daily is a sneaky trick. I was introduced to it by my father when I was looking for my first mortgage. Fortunately compounding was biannually.

Over here a trick is to have the government issue a loan, and then years later sell the loan onto a commercial outfit. How much the commercial outfit can change the Ts&Cs is unclear to me, but I'd trust them as far as I could throw them.

On the plus side, the loan is only repaid at a rate based on the proportion of your income above a reasonable level, and it is written off after a few decades. That also removes some of the disincentive to take courses in competitive basket weaving etc.

[bd139]

They’re pretty much boxed in by the FSA’s massive beating stick now. This is why most of the rip off bits of the front office finance sector in the UK has disappeared to other reputable careers such as estate agents, selling double glazing and running care homes.

To give you an idea how afraid they are, i regularly stooze on credit cards. MBNA Europe and me had a little disagreement on credit card interest and terms and conditions and they wrote off £3k the moment I threatened to complain and closed the account. Most profitable finance product I’ve ever owned (well apart from fintech stock).

There little to no risk now.

[Kosmic]

Tracking generator question:

I understand in general how they do what they do, however the page for the DSI TG6000 says that the indicated spectrum analyzers "without LO output option must be modified with a simple directional coupler." How does that work? I assume it has to be added inside the analyzer and then the LO signal brought out somehow.

The reason I ask is that my not-yet-arrived R3465 doesn't appear to have any LO output, yet it's not marked in the list of supported devices as lacking an LO output. Maybe just an oversight or am I not seeing where the LO output is?

If I can't easily add a TG, I suppose an alternative to modding the analyzer or buying a noise gen would be to sweep a sig gen with the spec an set to max hold. Should work fine for DUTs that don't change their characteristics over time. My first use for this would be to check out the flatness of some scope probes.

Looking at the manual and all the connectors on the back, it doesn't look like the R3465 has a LO output. To add one, you would have to put the directional coupler in the instrument. You must think of the directional coupler has a tap on the LO signal line. The problem is that by inserting the directional coupler you will attenuate the LO and that will change the characteristic of your SA. LO is used to mix the input signal down (like a down converter) and need a certain power to be efficient. The loss of efficiency might not matter though.

So if you don't mind having a instrument not necessarily meeting all his specs, might be a option for you. Also it's probably a good idea to recalibrate the instrument after the modification.

 

[mnementh]

   Backing plate made and painted for the HP 608D - the original 'socket' is attached inside the unit if someone wants to fully restore to original - no front panel bashing was required.

L00ks g00d.  Not original, but definitely better than the usual hack & silicone bodge I see all too often.    A word of advice, from somebody who's made hundreds of such filler panels: put a couple layers of Kapton tape on the back and trim the edges close with sharp scissors. This will keep the filler plate from discoloring the metal behind it if somebody decides they want to revert to original.

   Shack market 'leftover' Lunch for no reason other than gratuitous Double Smoked Bacon and HP Sauce porn.

Cooked several forms of Plastic for the day, Steamed some milk, Extracted Bean Juice, Baked some Electronic bits, Fried Bacon and now time to Roast some Beans 

Mmmmm... frizzled ham & manhole covers on a biscuit! Looks like Heaven.  And a little bit Hell, since I'm back on the Keto after my day off yesterday. 

This morning I resisted; had the last leftover biscuit in the toaster, with leftover smoked sausages, eggs & frizzled cheese on the plate to go with them. Gave the biscuit to my son & ate the rest with a cup of fresh coffee and HWC.  I can still smell those delightful carbs emanating from the toaster...

mnem
One meal down... the rest of my life to go.  *wibble*

[bitseeker]

Looking at the manual and all the connectors on the back, it doesn't look like the R3465 has a LO output. To add one, you would have to put the directional coupler in the instrument. You must think of the directional coupler has a tap on the LO signal line. The problem is that by inserting the directional coupler you will attenuate the LO and that will change the characteristic of your SA. LO is used to mix the input signal down (like a down converter) and need a certain power to be efficient. The loss of efficiency might not matter though.

So if you don't mind having a instrument not necessarily meeting all his specs, might be a option for you. Also it's probably a good idea to recalibrate the instrument after the modification.

Thanks for confirming my sanity. It's an odd architecture since they do bring out the first and second IF. Had they brought out the LO with them, you'd have all the source signals for a straightforward tracking gen. Must've been intentional.

I'll try using max hold with a sweeping sig gen before modding. Who knows, an SA with TG might be just around the corner (or a VNA).

[mnementh]

Looking at the manual and all the connectors on the back, it doesn't look like the R3465 has a LO output. To add one, you would have to put the directional coupler in the instrument. You must think of the directional coupler has a tap on the LO signal line. The problem is that by inserting the directional coupler you will attenuate the LO and that will change the characteristic of your SA. LO is used to mix the input signal down (like a down converter) and need a certain power to be efficient. The loss of efficiency might not matter though.

So if you don't mind having a instrument not necessarily meeting all his specs, might be a option for you. Also it's probably a good idea to recalibrate the instrument after the modification.

Thanks for confirming my sanity. It's an odd architecture since they do bring out the first and second IF. Had they brought out the LO with them, you'd have all the source signals for a straightforward tracking gen. Must've been intentional.

I'll try using max hold with a sweeping sig gen before modding. Who knows, an SA with TG might be just around the corner (or a VNA).

I wouldn't go THAT far...    ESPECIALLY after that statement.   

mnem
*Couch-tuber time widda kiddles*

[Kosmic]

Thanks for confirming my sanity. It's an odd architecture since they do bring out the first and second IF. Had they brought out the LO with them, you'd have all the source signals for a straightforward tracking gen. Must've been intentional.

I'll try using max hold with a sweeping sig gen before modding. Who knows, an SA with TG might be just around the corner (or a VNA).

Also the mod will be harder if the instrument is all PCB and SMD components. You would have to modify the pcb somehow to put 2 connectors (sma) in order to insert your directional coupler. I guess older SA are easier to mod.

[bd139]

Boat anchor alert: https://www.ebay.co.uk/itm/333189471616



Reference info: http://hpmemoryproject.org/timeline/art_fong/hp606_01.htm

[mnementh]

Wow... even as "Collection Only", it seems a worthwhile endeavour. Even if you have to spend a whole day driving; what it is, man. What it is. 

mnem
 

[bd139]

400 mile round trip for me which is definitely in can’t be arsed territory

[Kosmic]

Cheap probe question...

Hey guys... based on advice from some forum members, several years ago I bought some 100MHz TP6100 probes from ebayer scopewa as daily driver probes for my 2465. I've had good luck with them; they seem to compensate pretty well in 10x, though the 1X capacitance is a bit high, IMO. Def much better quality than the price indicates.

I know those and the P2200s supposedly sold out some while back, but there's a whole new boatload of cheap-cheap ones being sold under the same names now, and I don't know anything about those.

Checking again because bitseeker mentioned probes, looks like scopewa has got some more of the older ones in stock now. At least by the pics, these look like the same as the ones I bought years ago: https://www.ebay.com/itm/182595327054

Looks like he's also got some 200MHz P2200s in again... but the rise time seems a little high, IIRC. https://www.ebay.com/itm/182547468622

Anybody here got any intel on these?

mnem
 

About cheap probes, I just did some really non scientific tests, and the cheap Kuman p6100 probes are holding on up to 300Mhz easy. At 350Mhz they are just bellow the -3db mark.

They perform clearly better that the Tek P6054A and P6106 I have here. The Tek probes start dropping fast just after their rated bandwidth.

Also got a pair of Jinhao p6100, even if they look identical to the Kuman p6100, they don't perform as good.

[factory]

Boat anchor alert: https://www.ebay.co.uk/itm/333189471616



Reference info: http://hpmemoryproject.org/timeline/art_fong/hp606_01.htm

If I had the space and didn't already have a rack mount 606B, I would have bought the first time it was listed. Chester is near enough to me, even if the trip is 40 mins to go only 20 miles each way.

Hope someone saves it.

David

[Specmaster]

Its a good bit of kit but stops at 65Mhz and so is of no interest to me plus it is AM modulation  and is also a 400 mile round trip.

[Mr. Scram]

Happy sort of binary number page!

[ArthurDent]

    Kosmic (post #31124) -“Some weeks ago, I got another piece for my instrument collection from ESI. This time it's a SV-194B Voltage Calibrator.” ….”After some tests I realized the resistors had drifted though. Will need to find a solution for that.”

 

  Are you sure the resistors have drifted? Here are the readings I get on my SV194 B without removing the resistors from the circuit. Some values are common, some aren’t but these resistors just don’t drift. The nine identical ones on the fuse side are all 40K and I have the ones across the bottom from right to left as 20K, 16K, 2K and 1.5922K The two up the other side are 1.038 ohms and 7.414 ohms. The four staggered ones from bottom to top are 200.13 ohms, 160.15 ohms, 20.172 ohms, and 20.172 ohms.

I mostly tested the ratio feeding 1kv. 10v was way off but it was getting better at 0.1V and 0.05V.

I believe it's a problem caused by improper use rather than a problem with the ESI SV194 B. I took some more accurate measurements and drew a schematic of the unit. As I said, these resistors just don't drift. This divider was designed before modern meters and the calibration of the input against a standard cell and the output voltage were both measured potentiometrically, i.e., no current being drawn. The reason you get lower errors on the lower taps is the parallel resistance of the meter used and the internal resistance it is in parallel with have a lesser effect if you have your 10Mohm meter in parallel with 20 ohm resister rather than across a 4000 ohm resistor.

[med6753]

Me: Hi Mom, did you get my flowers?

Mom: No, I didn't.

Me: They were supposed to be delivered Thursday.

Mom: Sorry, no flowers.

After I get off the phone with her I'm loaded for bear to call the flower place and bitch them out and get a refund. So I pull up my order. Look at it. Uh-oh. I screwed up. I put down May 16th delivery rather than May 9th delivery. DO'H 

I think I'll crawl back into my hole. 

[tautech]

Me: Hi Mom, did you get my flowers?

Mom: No, I didn't.

Me: They were supposed to be delivered Thursday.

Mom: Sorry, no flowers.

After I get off the phone with her I'm loaded for bear to call the flower place and bitch them out and get a refund. So I pull up my order. Look at it. Uh-oh. I screwed up. I put down May 16th delivery rather than May 9th delivery. DO'H 

I think I'll crawl back into my hole. 

In your defense, didn't you have a not so easily overlooked distraction visiting ? 

[VK5RC]

   Backing plate made and painted for the HP 608D - the original 'socket' is attached inside the unit if someone wants to fully restore to original - no front panel bashing was required.

L00ks g00d.  Not original, but definitely better than the usual hack & silicone bodge I see all too often.    A word of advice, from somebody who's made hundreds of such filler panels: put a couple layers of Kapton tape on the back and trim the edges close with sharp scissors. This will keep the filler plate from discoloring the metal behind it if somebody decides they want to revert to original.


mnem
One meal down... the rest of my life to go.  *wibble*

Thanks for the tip - will do.
Rob

PS have a HP 3325B on the way home!

[0culus]

Nice! I love my 3325B. It's a great function generator. Has a motorola 68k processor too, for the extra cool factor. 

[tggzzz]

400 mile round trip for me which is definitely in can’t be arsed territory

Yesterday I bought my hp8562b at 11:30. I then trogged off for a 250 mile round trip to pick it up before 5pm.

Fortunately,it works. But there are a couple of low level spurs which might be at a switching PSU frequency; must investigate.

Also need to find out why my Tek 492s fan has stopped

[med6753]

Me: Hi Mom, did you get my flowers?

Mom: No, I didn't.

Me: They were supposed to be delivered Thursday.

Mom: Sorry, no flowers.

After I get off the phone with her I'm loaded for bear to call the flower place and bitch them out and get a refund. So I pull up my order. Look at it. Uh-oh. I screwed up. I put down May 16th delivery rather than May 9th delivery. DO'H 

I think I'll crawl back into my hole. 

In your defense, didn't you have a not so easily overlooked distraction visiting ? 

Nope, no distractions so no defense other then a plain old screw-up.