Test Equipment Anonymous (TEA) group therapy thread

[AVGresponding]

They both use low voltage displays, I don't particularly want to mention the type on here.

David

My bad, brain fart. They are the incandescent lamp with light pipe type, whose name escapes me currently

[Robert763]

Have a look at the 1N829A in the die pictures thread, it contains two diodes in series, one of which is used as the reference Zener junction & the other a diode junction connected opposite for temperature compensation, both junctions balance the temperature coefficient, the better grades are selected for lower TC.

https://www.eevblog.com/forum/metrology/more-voltage-references-die-pictures/msg4262863/#msg4262863

A datasheet for temperature compensated reference Zeners that are still available;

https://www.mouser.co.uk/datasheet/2/268/1N821_1N829A_1-3499699.pdf

Any diode could become a Zener (with current/power limiting), but most have too high a breakdown voltage to be of much use for that.

This begs the question, what type of regular (non Zener) diode has a volt drop of 6.2V, for the Peak to determine it to be a diode & not a faulty part?

David

Some very high voltage diodes have high forward voltage drop. They are  a stack of PN junctions in series so Vf is correspondingly high.

[Harry_22]

ummmmm.  just a thought.

while you were in there did you check the date code on the dallas nvram?  (am thinking that it may not outlive you per the plan) replaced the one in my hp54601 with separate sram, controller chip, and battery. (encapsulated batteries really piss me off)

but iirc yours uses an 8kx8 (and maybe STMicro vice dallas?), and mine was a 2kx8. 

https://www.eevblog.com/forum/repair/hp-54601a-nvram-substitute/

   That... is a question for when I replace caps in the thing. I did notice a label on the back stating it contains a BR1225 coin cell; pretty sure that means NVRAM battery will be replaceable. May need some soldering, of course.

Hmmm... that warranty label appears OEM issue; maybe the Agilent-branded handle IS original. 

These points are also something I can get into after the move; in the meantime, just going to love it and use it as needed.

mnem
 

   Looks like you were right; good memory. 

While I was in there molesting the PSU, I looked all over and under the mainboard and nope, nothing like a coin cell anywhere. Pretty sure a peek at the datasheet on this NVRAM would tell me there's no way to connect a external battery (aside from that CNC the IC down to the battery mod I saw in the 2465 thread), but of course I had to see for myself. 

Now of course it's in the queue for recapping; no idea if I'll have time for that before the move or not. 

mnem
*sigh*

crap.  unfortuately the specsheet says "caphat".  if it were a "snaphat" it would be a piece of cake.

my attempt to drill, file, or whittle down to the battery connections on a few of these bastards were unmitigated disasters.

maybe if you had an xray rig and a real milling machine it would be possible.  saw that a guy claimed he was able to "melt"  his way down to the battery leads.  good fecking luck with that.

https://www.st.com/content/ccc/resource/technical/document/application_note/9e/6f/ee/57/a8/56/44/d0/CD00004060.pdf/files/CD00004060.pdf/jcr:content/translations/en.CD00004060.pdf

that is what drove me to the ugly/hamfisted but workable sram, controller chip, coin cell in a holder bodge.  it worked in my 54502a, 54504a, and 54601a. 

but it is as elegant as a turd.


edit  if you come up with novel fix for this predicament please post details.

Less than four years later I decided to replace the same battery. Not that it bothers me too much. But in order to enter GPIB number, which was erased every time the device was turned off, I had to kneel down and look near the floor where the required button was.
The treatment went quite quickly. There is exist information about replacing the battery in CAPHAT case.
I made several pictures to make everything clear.

Of cause was possible to buy a new one SRAM, but in our village it costs almost 50Euro and I didn’t want to get hooked again.

[Ice-Tea]

Pretty neat!

I've seen cases where the leakage or consumption of these devices has increased considerably. So , keep an eye on that CR2032 ;-)

[Harry_22]

Pretty neat!

I've seen cases where the leakage or consumption of these devices has increased considerably. So , keep an eye on that CR2032 ;-)

Thanks, it seems like this is already happening. A week ago I ordered 50 pieces of CR2032. They leave me with terrible speed.

[unseenninja]

P.S. did your DCA75 lose the sound with the current firmware (V23)?

Maybe, but I probably wouldn't notice as I can't hear anything above 4kHz.

[m k]

Nowadays CR2032 is so regular appliance battery that soon we can expect fresh samples from local market.

[Ice-Tea]

I'm well aware it's not T&M but I'm going through a 20 page schematic checklist and the reference design ignores roughly 85% of it 

Fucks sake.

[timeandfrequency]

Something about TE :
Description of the repair of a digital handheld capacitance meter DM-6013

[Robert763]

Has anyone else noticed that ebay ahve buggered about with search options again?
On ebay UK on a basic search in a subcategory (TE) you can no longer filter by location. I'm now seeing lots of overpriced tat from too far away. That's in addition to the overpriced tat since ebay dropped fees for private sellers.
You can filter by location in advanced search but you don't seem to be able to limit to a subcategory so would see all of business and industrial.
  

[m k]

It's still there.
Filter location and check URL, here LH_PrefLoc=5 is EU for .com site.

Here LH_ItemCondition=4 for .com site is used, for UK site the number here is 3000.
LH_PrefLoc=1 for UK and FR, but not .com, sites gave my local sellers.

[AVGresponding]

Has anyone else noticed that ebay ahve buggered about with search options again?
On ebay UK on a basic search in a subcategory (TE) you can no longer filter by location. I'm now seeing lots of overpriced tat from too far away. That's in addition to the overpriced tat since ebay dropped fees for private sellers.
You can filter by location in advanced search but you don't seem to be able to limit to a subcategory so would see all of business and industrial.
 

They are always "experimenting" with the UI. It does my fecking napper in

[Robert763]

Thanks M K
The option isn't there on ebay but the url switch &LH_PrefLoc=1 works.  URLs saved.

Robert.

[tggzzz]

Has anyone else noticed that ebay ahve buggered about with search options again?
On ebay UK on a basic search in a subcategory (TE) you can no longer filter by location. I'm now seeing lots of overpriced tat from too far away. That's in addition to the overpriced tat since ebay dropped fees for private sellers.
You can filter by location in advanced search but you don't seem to be able to limit to a subcategory so would see all of business and industrial.
 

If I search for "Fuller calculator" in "scientific collectibles", then the "item location" appears in the usual place in the results pane.

The second option is "within 25mi", and 25mi is a link to a popup that allows 10mi, 25mi, 50mi...1000mi.

[m k]

LH_PrefLoc selections here:
.com
98 Default
 3 US Only
 4 North America
 5 Europe
 6 Asia

n.a for .uk, .fr, .de, .ca and .au sites.

So it seems to be available only for correct zone site.
.au has much more filters, but no location.

And .com setting here is clearly indicating that UK is not in Europe.
Second hit is from UK and only present with Default setting.

Other .com numbers here
 1 local
 2 ?
 7 - invalid
 8 - invalid
 9 - invalid
10 - invalid
99 ?

E,
difference between local settings here and earlier is that earlier .com had no locals available.

[Robert763]

Has anyone else noticed that ebay ahve buggered about with search options again?
On ebay UK on a basic search in a subcategory (TE) you can no longer filter by location. I'm now seeing lots of overpriced tat from too far away. That's in addition to the overpriced tat since ebay dropped fees for private sellers.
You can filter by location in advanced search but you don't seem to be able to limit to a subcategory so would see all of business and industrial.
 

If I search for "Fuller calculator" in "scientific collectibles", then the "item location" appears in the usual place in the results pane.

The second option is "within 25mi", and 25mi is a link to a popup that allows 10mi, 25mi, 50mi...1000mi.

Yes it is there for a specific search but not an open search on a sub category.

Robert.

[factory]

I've not got that ePay search problem yet, mine still has the options visible in sub-categories, but I rarely use ePay to do the searches as their servers are so slow, instead have saved bookmarks with a third party website (picclick), this also gets around the unwanted geoblocking shite from ePay. 

There was a different problem for me last week, the stupid captcha "select matching images/squares" crap kept appearing and it stopped working properly, it either kept asking to do it again for several minutes, or not working at all, thankfully the craptcha stuff seems to have disappeared this week.
And yesterday it decided I wasn't able to bid on something in the US, despite having a forwarding address, until I changed it (temp) to my default address. Bloody work experience kids must have been messing with the code again.  Having said that didn't they make a load of people redundant earlier this year? I'm not surprized the code is so bad as a result.

David

[m k]

I think I've had that default address thing quite a long ago, but captcha, I think I've never seen any around epay.
Must be UK something.

PicClick is good, and fast.
Maybe we one day get even real exclusion settings.

[wkb]

I think I've had that default address thing quite a long ago, but captcha, I think I've never seen any around epay.
Must be UK something.

PicClick is good, and fast.
Maybe we one day get even real exclusion settings.

Maybe evilBay still have trouble figuring out Brexit?   

[factory]

ePay geoblocking & my use of PicClick predate Brexshit.

David

[factory]

Apparently this Tek TDS series PCB was made in two locations simultaneously. 



David

[TERRA Operative]

It was made in two places at once as it's part of the TARDIS

Tektronix And Relative Dimension In Space.

[timeandfrequency]

Apparently this Tek TDS series PCB was made in two locations simultaneously. 

The PCB was manufactured in the States.
In Taiwan, they only added the white silkscreen print.

[Robert763]

Original manufacture at time of board design was in USA hence laid in copper. Later manufacture was Taiwan and they just modified the silkscreen. Modification of the copper could accidentally introduce electrical faults.
Alternatively PCB made in UAS and final assenbly in Taiwan but then Id expect Taiwan mark to be a label rathe than silkscreen.

Robert.

[factory]

That probably the reason, the board being made in Taiwan (ROC), though they should really have covered it over with a correction sticker. Oddly the sticker on the back of the scope states made in China (PRC).

Apparently this Tek TDS series PCB was made in two locations simultaneously. 

The PCB was manufactured in the States.
In Taiwan, they only added the white silkscreen print.

Sending a board to ROC, just to have the silkscreen added seems crazy.

P.S. I won the ePay item in the USA (a HP 220A), my second bid also required default address (temp) changing to the US, despite already having a bid on it.  Strangely it doesn't require this to pay. 

David