Test Equipment Anonymous (TEA) group therapy thread

[44kgk1lkf6u]

I might order some of those chips you mentioned to see what I can do.
However I suspect that the actual rise time of this chip might be heavily influenced by the board layout and practical implementation overall.
So I would have no idea what rise time I am actually getting out of a complete, finished product, no ? Or am I being too pessimistic ?!....

Are there "reference" / proven designs and board layouts out there for this chip ?

[...] I put the chip and an LVDS oscillator on a 2 layer PCB without the fancy controlled impedance stuff.  It only needs a -3.3 V power supply. Measuring on a 7.1 GHz spectrum analyzer showed that its knee frequency is likely faster than what the spectrum analyzer can measure.  It did not feel right to measure an oscilloscope, and then buy a sampling oscilloscope just to measure what measures it.  I did not optimize the board because the first version was already good enough.

 I can upload the design if you want it.

Well yes why not ! Please do 

I was reluctant to show my design because it is messy.  Components are so close.  The silkscreen overlaps with other pads.  I simply didn't generate the silkscreen in the Gerber.  To keep the trace as short as possible, the pin in the edge launch SMA connector has to be cut short.  If the design were neat I would have uploaded it when I made it.

[m k]

Unwillingness is not a virtue.

There are also designs and then non designs.

E,
can't do an image tag.

[Vince]

Are there "reference" / proven designs and board layouts out there for this chip ?

[...] I put the chip and an LVDS oscillator on a 2 layer PCB without the fancy controlled impedance stuff.  It only needs a -3.3 V power supply. Measuring on a 7.1 GHz spectrum analyzer showed that its knee frequency is likely faster than what the spectrum analyzer can measure.  It did not feel right to measure an oscilloscope, and then buy a sampling oscilloscope just to measure what measures it.  I did not optimize the board because the first version was already good enough.

 I can upload the design if you want it.

Well yes why not ! Please do 
[/quote]

I was reluctant to show my design because it is messy.  Components are so close.  The silkscreen overlaps with other pads.  I simply didn't generate the silkscreen in the Gerber.  To keep the trace as short as possible, the pin in the edge launch SMA connector has to be cut short.  If the design were neat I would have uploaded it when I made it.
[/quote]

Thanks a lot, looks great to me  Much better than I would do, your PCB saves me a lot of time. I can't visualize the schematic though... Kicad complains that I need a version more recent than November 2023. I renewed my computer just 3 months ago and installed the latest stable release of XUbuntu, that's 23.10...  one month too old, too bad. Came with Kicad v7. I guess there s a newer version then... Kicad gets updated quite often in the recent years I find ! I guess that's a good thing if that means it gets better...
I can only see the top side of the PCB, I assume there mus be some components on the underside to implement an oscillator of some kind...
Will see if I can install the latest Kicad version on my computer.

Thanks for sharing anyway 

[Vince]

[...]
I need an HP cable now...

Is it for this TE ? https://www.eevblog.com/forum/testgear/test-equipment-anonymous-(tea)-group-therapy-thread/msg5752273/#msg5752273

Yep that's my puppy indeed ! 

Can you provide a picture or a link showing the male plug ?

The plug is actually the female part (only holes in it), the socket is the male part, with 3 prongs.

I found this picture on Google :




Hold on though... a fellow TEA member from Germany contacted me a few days ago, he might have one... but I guess the most efficient would be to get one from Factory maybe ? If he has a CRT neck cover for me (do you David ?) then maybe if he has a spare cable he is willing to sell to me, this way I would have only one shipment to arrange.
Worse case scenario, short term, I hardwire a Euro power cord to the thing (there is no shortage of holes at the rear of that scope ! ) ! Then if find out that the scope is repairable, I would seek a vintage original cable for it, or just make the effort to fit an IEC socket.

Stay tuned...

[Vince]

Oy !

I just couldn't resist.... an A.1211 Rochar counter, for only 20 Euros and on offer at that !
Offered the guy 10 Euros... add 17 Euros for shipping, for 27 Euros this thing just arrived to me today, now on the bench.

Bought it for parts : I have no interest in these A12xx series, prefer my slightly more recent A13xx series TE, but they share many parts.
For the 5 spare Niksee tubes  it provides, alone, it's worth the money I paid. Plus I get knobs and toggle switches and many other misc parts.
A good deal. Even has an extended cabinet to host a battery at the bottom. Battery is not present. Power switch has 2 extra positions : "Battery" and "Recharge".
At the back there is a switch toggle between the internal battery, or an external 12Vdc source, via a couple 4mm binding posts.

However I am hopeless : even though I bought it for parts, I just couldn't help but give it a quick clean and give it power...
I should not have done that ! It DOES work as is, and is accurate on all ranges at that !   
Even has an OCXO inside ! .. and the thermostat light on the front panel, is working, it is coming on and off every few seconds, makes it look like this puppy has a pumping heart, it's alive... how can I take a living thing apart, that would make me a MONSTER wouldn't it !   

I feel so guilty, it's horrible !!   

Nooooo ! 


Oh boy, now I feel guilty and have remorse... how can I deal with that...

[tggzzz]

Oh boy, now I feel guilty and have remorse... how can I deal with that...

The best way to take you mind off that is, of course, to buy something else. 

Or you could sell it for a profit.

[factory]

P.S. The design file is from this post; https://www.eevblog.com/forum/testgear/replacement-knobs-feet-and-fittings-for-test-equipment/msg2472369/#msg2472369

David

Online viewer I tried had no measurements, but the picture was pretty symmetrical.

Maybe somebody has a real CAD and can check the situation.

Same problem I have, the built in 3D viewer in Microturd Windows does have a grid option, but no measurements,  is the point of that.

If the overall dimensions and angles are correct, I can fix it up.
Let me know if there are any other modifications you want made too.

Unfortunately I don't have any gear with that foot, but if you want a more accurate replica, get your vernier calipers out and I can make one while you measure for me.

Guess you've either not seen any, or decided not to acquire any, I'm loosing count of how many are here, maybe I need another. 



There is another 3DP version in the thread, from beanflying, no idea if that one will print correct dimensions with JMCPCB, I notice he hasn't posted since June last year, anyone know if is he OK?
https://www.eevblog.com/forum/testgear/replacement-knobs-feet-and-fittings-for-test-equipment/msg2255136/#msg2255136

I took one of the batch I bought to work yesterday and modified it while waiting for the CNC machine to run it's program (about 2 minutes at time), it's a bit shorter now. Fitting has revealed another problem, the thickness of the section where the spacers fit, it's too bloody short. The V shape is off centre too, as well as one of the holes, I think I'm going to write these off, cost was $41 for 10 made from nylon.  Maybe the local Clowncil subsidised waste incinerator will enjoy them.

Apparently I have just one original that hasn't turned into many bits & mostly vanished, it's a bit banana shaped, length approx 4.5 inches, still need to check hole spacing.







David

[factory]

Here is what I've been working on for the last 10 days, an Advance TC6 counter timer, good for 10MHz in the mid 1960s.

As found, one dead display, not much activity from the inputs.



Faults repaired have been; many spewed & open circuit capacitors, the 350V Plessey capacitor decided it didn't want to see the new year & expired short circuit on new years eve, thankfully Advance fitted a sacrificial carbon resistor in series with the supply, saving the Se rectifier from dying too. 



The stop input board(used in low frequency mode) needed two replacement transistors, one had rusted leads, the other was intact but dead.



Quite a few Ge diodes on various boards had suffered fractured leads from rust, or had a high volt drop leading to various counting failures, either stopping at a number or missing numbers.



One number readout bulbs had a major neon deficiency, now replaced.
The final problem is a common problem with Advance counters, the switch that is built into the external ref input socket (ext Std) was open circuit, causing none of the functions to work except count.



It's about 80% working at the moment, just two missing digits, 4 dead decimal point lamps and an intermittent miscount of one of the decade ring counter/display boards to fix.



A few of the dead/replaced parts, I decided on a full recapicide because of the amount of knackered caps. 





Testing last night, the signal generator still needs a little attention, should have replaced all the display decoder ICs while I was in there previously. 





David

[Vince]

Wow sounds like a lot of work is required for this counter... I am sure he is glad you brought him home to heal him ! 

[Vince]

Oh boy, now I feel guilty and have remorse... how can I deal with that...

The best way to take you mind off that is, of course, to buy something else. 

Or you could sell it for a profit.

Yeah I think I will go with the former rather than the latter... for it cost me 27 Euros all in, and resale price would be 50 or 60 Euros at best, assuming I can even find a buyer. That would leave me with 23 to 33 Euros profit. That puppy is worth a lot more to me than that, in parts. So... in my possession it will remain...

[factory]

Hold on though... a fellow TEA member from Germany contacted me a few days ago, he might have one... but I guess the most efficient would be to get one from Factory maybe ? If he has a CRT neck cover for me (do you David ?) then maybe if he has a spare cable he is willing to sell to me, this way I would have only one shipment to arrange.
Worse case scenario, short term, I hardwire a Euro power cord to the thing (there is no shortage of holes at the rear of that scope ! ) ! Then if find out that the scope is repairable, I would seek a vintage original cable for it, or just make the effort to fit an IEC socket.

Stay tuned...

The sending roundtuit hasn't been located yet, let me know if you manage to find a power cord in Germany, postage will probably be cheaper from there, the CRT socket cover will be sent free of charge eventually.

Wow sounds like a lot of work is required for this counter... I am sure he is glad you brought him home to heal him ! 

There is another to rescue this weekend, hopefully no more bloody snow & ice, got to go west to collect it, don't trust the couriers not to ruin it.

David

[TERRA Operative]

P.S. The design file is from this post; https://www.eevblog.com/forum/testgear/replacement-knobs-feet-and-fittings-for-test-equipment/msg2472369/#msg2472369

David

Online viewer I tried had no measurements, but the picture was pretty symmetrical.

Maybe somebody has a real CAD and can check the situation.

Same problem I have, the built in 3D viewer in Microturd Windows does have a grid option, but no measurements,  is the point of that.

If the overall dimensions and angles are correct, I can fix it up.
Let me know if there are any other modifications you want made too.

Unfortunately I don't have any gear with that foot, but if you want a more accurate replica, get your vernier calipers out and I can make one while you measure for me.

Guess you've either not seen any, or decided not to acquire any, I'm loosing count of how many are here, maybe I need another. 



There is another 3DP version in the thread, from beanflying, no idea if that one will print correct dimensions with JMCPCB, I notice he hasn't posted since June last year, anyone know if is he OK?
[url=https://www.eevblog.com/forum/testgear/replacement-knobs-feet-and-fittings-for-test-equipment/msg2255136/#msg2255136]https://www.eevblog.com/forum/testgear/replacement-knobs-feet-and-fittings-for-test-equipment/msg2255136/#msg2255136]https://www.eevblog.com/forum/testgear/test-equipment-anonymous-(tea)-group-therapy-thread/?action=dlattach;attach=2479257[/urlimg]

There is another 3DP version in the thread, from beanflying, no idea if that one will print correct dimensions with JMCPCB, I notice he hasn't posted since June last year, anyone know if is he OK?
[url=https://www.eevblog.com/forum/testgear/replacement-knobs-feet-and-fittings-for-test-equipment/msg2255136/#msg2255136]https://www.eevblog.com/forum/testgear/replacement-knobs-feet-and-fittings-for-test-equipment/msg2255136/#msg2255136

I took one of the batch I bought to work yesterday and modified it while waiting for the CNC machine to run it's program (about 2 minutes at time), it's a bit shorter now. Fitting has revealed another problem, the thickness of the section where the spacers fit, it's too bloody short. The V shape is off centre too, as well as one of the holes, I think I'm going to write these off, cost was $41 for 10 made from nylon.  Maybe the local Clowncil subsidised waste incinerator will enjoy them.

Apparently I have just one original that hasn't turned into many bits & mostly vanished, it's a bit banana shaped, length approx 4.5 inches, still need to check hole spacing.

https://www.eevblog.com/forum/testgear/test-equipment-anonymous-(tea)-group-therapy-thread/?action=dlattach;attach=2479245

https://www.eevblog.com/forum/testgear/test-equipment-anonymous-(tea)-group-therapy-thread/?action=dlattach;attach=2479249

https://www.eevblog.com/forum/testgear/test-equipment-anonymous-(tea)-group-therapy-thread/?action=dlattach;attach=2479253

David

Oooh, lots of angles and curves. I'll need it in my hand, unless you can measure every dimension, angle and radius with calipers...

[Robert763]

My THS720A arrived today. Apart from decaying foam in the case and a bad battery (stated in the listing) it looked good and showed two trace on the compensation output and passed self test.
However further testing was bad news 
Channel 1 does not work on some voltage ranges. It's OK on 1V, 2V, 5V, 100V and 500V ranges but shows a flat line below 1V and on 10V, 20V and 50V. Channel 2 is OK.  Looks like an issue with the input hybrid. These are unobtainium but I think I can fix it. Seller was OK about it and offered a full refund if I returned it of a 10% partal refund. I went for the partial refund.
I'm confident enough of the fault in the hybrid that I've ordered some parts from Mouser. The refund just about covers the parts but I like a challenge.
Repairing a thick film hybrid will be a first for me...
Update when I get the parts. They is a two day delay due to bad weather in the USA.

Robert.

[TERRA Operative]

Schematics are here if you don't already have them:

https://w140.com/tekwiki/wiki/THS720

I have a few of these scopes, but they are all working besides the usual shitty LCD panels so I can't give you parts...
But if you need measurements etc, I can help out.

Also, make sure to do the 720P mod too once you have it working.
https://w140.com/tekwiki/images/a/a5/Tektronix_THS720A_to_720P_Hack.jpg

[Robert763]

Hi Terra,
Already got the circuits and P mod already done 
I'm pretty certain the fault is the relay(s) on the hybrid. Unfortunatly they have a minimum order quantity of 3600 
I think I have a suitable alternative. More details when I have tried them.

Robert.
 

[squadchannel]

it checked?

https://www.ebay.com/itm/163718604787

and i think Panasonic TQ2 would be work.
https://www.digikey.com/en/products/detail/panasonic-electric-works/TQ2SL-L2-4-5V/649470?s=N4IgTCBcDaICoEUwGUAyBaVZ0BZ0FYA1EAXQF8g

[factory]

Hi Terra,
Already got the circuits and P mod already done 
I'm pretty certain the fault is the relay(s) on the hybrid. Unfortunatly they have a minimum order quantity of 3600 
I think I have a suitable alternative. More details when I have tried them.

Robert.

The THS710std I have has a similar problem with one of the input attenuator hybrids, I'm suspecting the relays are the cause, it's still in bits as I discovered the same minimum order quantity problem, maybe I should just cut the top off & see if cleaning would help, at least that would confirm the problem. Would be interested to know if the alternate relay works, I don't want to buy unknown age parts off feeBay.
The e-caps got replaced due to age of the 710std, several had signs of leakage starting, YMMV.
Almost forgot it was growing tin whiskers too.

https://www.eevblog.com/forum/testgear/test-equipment-anonymous-(tea)-group-therapy-thread/msg5499184/#msg5499184

Does changing to the P version lose any of the normal scope functions, as I have a working 720A too?

David

[factory]

P.S. The design file is from this post; https://www.eevblog.com/forum/testgear/replacement-knobs-feet-and-fittings-for-test-equipment/msg2472369/#msg2472369

David

Online viewer I tried had no measurements, but the picture was pretty symmetrical.

Maybe somebody has a real CAD and can check the situation.

Same problem I have, the built in 3D viewer in Microturd Windows does have a grid option, but no measurements,  is the point of that.

If the overall dimensions and angles are correct, I can fix it up.
Let me know if there are any other modifications you want made too.

Unfortunately I don't have any gear with that foot, but if you want a more accurate replica, get your vernier calipers out and I can make one while you measure for me.

Guess you've either not seen any, or decided not to acquire any, I'm loosing count of how many are here, maybe I need another. 



There is another 3DP version in the thread, from beanflying, no idea if that one will print correct dimensions with JMCPCB, I notice he hasn't posted since June last year, anyone know if is he OK?

https://www.eevblog.com/forum/testgear/replacement-knobs-feet-and-fittings-for-test-equipment/msg2255136/#msg2255136

I took one of the batch I bought to work yesterday and modified it while waiting for the CNC machine to run it's program (about 2 minutes at time), it's a bit shorter now. Fitting has revealed another problem, the thickness of the section where the spacers fit, it's too bloody short. The V shape is off centre too, as well as one of the holes, I think I'm going to write these off, cost was $41 for 10 made from nylon.  Maybe the local Clowncil subsidised waste incinerator will enjoy them.

Apparently I have just one original that hasn't turned into many bits & mostly vanished, it's a bit banana shaped, length approx 4.5 inches, still need to check hole spacing.



David

Oooh, lots of angles and curves. I'll need it in my hand, unless you can measure every dimension, angle and radius with calipers...

Did you had a look at beanflying's version? it does look better in the 3D viewer (the MS one with no measurements), even if the actual part appears to have the surface of the moon. 
The original has material missing where it's not seen, would this help reduce the cost of the print? or would this make it harder for them to print?



David

[Robert763]

it checked?

https://www.ebay.com/itm/163718604787

and i think Panasonic TQ2 would be work.
https://www.digikey.com/en/products/detail/panasonic-electric-works/TQ2SL-L2-4-5V/649470?s=N4IgTCBcDaICoEUwGUAyBaVZ0BZ0FYA1EAXQF8g

Looks like theTQ would work but needs to be the flat to pcb type so TQ2SA-L2-4.5V

[Robert763]

Hi Terra,
Already got the circuits and P mod already done 
I'm pretty certain the fault is the relay(s) on the hybrid. Unfortunatly they have a minimum order quantity of 3600 
I think I have a suitable alternative. More details when I have tried them.

Robert.

The THS710std I have has a similar problem with one of the input attenuator hybrids, I'm suspecting the relays are the cause, it's still in bits as I discovered the same minimum order quantity problem, maybe I should just cut the top off & see if cleaning would help, at least that would confirm the problem. Would be interested to know if the alternate relay works, I don't want to buy unknown age parts off feeBay.
The e-caps got replaced due to age of the 710std, several had signs of leakage starting, YMMV.
Almost forgot it was growing tin whiskers too.

https://www.eevblog.com/forum/testgear/test-equipment-anonymous-(tea)-group-therapy-thread/msg5499184/#msg5499184

Does changing to the P version lose any of the normal scope functions, as I have a working 720A too?

David

No the P mod does not reduce any of the standard capability. It adds power and harmonics. Haarmonics are a bit limited due to the 8 bit resolution but a lot better than nothing and cheaper than a Fluke 437 . It works with 400Hz fundamental which most power analisers won't.

[m k]

P.S. The design file is from this post; https://www.eevblog.com/forum/testgear/replacement-knobs-feet-and-fittings-for-test-equipment/msg2472369/#msg2472369

David

Online viewer I tried had no measurements, but the picture was pretty symmetrical.

Maybe somebody has a real CAD and can check the situation.

Same problem I have, the built in 3D viewer in Microturd Windows does have a grid option, but no measurements,  is the point of that.

My 5382A foot screws are ~24mm from side and ~69mm apart.

Its Operations Manual has a picture from rear, took pretty straight from back, but foot screws doesn't match if IEC connector rivets are 40mm apart.
It seems that pictured screws are a bit narrower, from machine the ratio is 1.725, but from manual picture I can't get it that high.

The manual is prefixed 1804A, feet there are 5040-7032 and 05301-40001.
5305B manual prefixed 1616A has rear foot as 5040-7032 and other plain foot as 05301-40001, 5307A manual prefixed 1308A is the same.

So it's a pretty safe to say that all feet should be the same.
Maybe screw holes of machine have a wide tolerance and 3D-models are from a machine bottom without the actual example.

E,
wrong type, even after recheck.
(2<->8 )

[Nanitamuscen]

The past year has given, in memory of himself, an Englishman in a box condition.
I found the technical manual for it, but I did not find the operating manual. Does anyone have a scan?

[AVGresponding]

The past year has given, in memory of himself, an Englishman in a box condition.
I found the technical manual for it, but I did not find the operating manual. Does anyone have a scan?

Looks to be available on BAMA: https://bama.edebris.com/download/solartron/7055/SchlumbergerSolartron%207055%207065.pdf

[Nanitamuscen]

Unfortunately, this is not the document I need.

[m k]

If you can consult 7081 manual, it is available.

Despite the listed name 7055/7065 stuff seems to be technical/service.