Test Equipment Anonymous (TEA) group therapy thread

[med6753]

just got back and unloaded my precccccious ....

http://www.thevintageknob.org/sony-TC-K88B.html
http://www.thevintageknob.org/sony-ST-J88B.html
http://www.thevintageknob.org/sony-TA-E88B.html


Below the top stack is another tuner and a TA-E86B
http://www.thevintageknob.org/sony-TA-E86B.html

The build quality is *superb*

I knew at one time Sony made quality stuff but not real high end equipment like that. Looks great! 

[25 CPS]

Those Time decade boxes are still made and not cheap either, but this doesn't stop that AVO murderer in Staffordshire from doing this shit to them. 



David

What a waste of a decade box and nixie tubes.  Frankly, what a waste all round.

[Specmaster]

Just like with vision, the brain makes a lot of it up, filling in the blanks as it were. So you may well "hear" the same record to be the same over the years, even as your hearing degrades, because your brain will compensate.

Usually only gross and/or acute changes will be noticeable (this of course will be eschewed by the audiophiles, as it involves science and engineering).

Very true, which is why I suggested that the only true way to blindfold test of gear, is to make sure that you are listening to fresh music that you have no idea of just how it should sound.

[mnementh]

I like the 2 Euros worth DVD player, because it's black, I prefer black.

Can you spray paint your Sony stuff in black for me ?

Question : since your ears need such expensive gear to be happy... and given that mother nature will make your hearing degrade inexorably over time, like it or not... this means that what you hear will actually change over time. The amplifiers and speakers will spit out the same sound that you love, but your brain will not hear the same thing....
So that means every year you need to try out new expensive gear to try and find gear that makes your brain think it's listening to the same sound as you do now. I am not sure I am being clear here, sorry...
All this research is very time and money consuming.

Or, will you just buy an equalizer and tweak its controls a bit more year after year, as your hearing degrades ?

Yes like Dragon I can stir ship up as well.... though it's a question that to me seems genuinely relevant, technically.

Have you, or audiophiles in general, thought of this problem ?

Yes; I have, quite a bit. Eventually you burn enough kilobux on boom-box cars and enough wasted weekends high as a kite 6 feet from the stacks at ever-louder rock concerts that when you get old, you're so fucking deaf a Toslink-plugged Home Theater soundbar plugged into your retired gaming PC on Prime Music sounds "good enuf" and you get on with your life. 

   *cups hand around ear...* "WHAAAAAAAAT?!?"

mnem
"A misspent youth is better by far,
than a wise & productive old age..."

[bd139]

Hi fi kit sounds better when you’ve just paid for it.

On TE, just checked the EFC range of all the OCXOs from China and they’re all good. Can’t moan at 5 for £12 delivered! Now I need a 1 PPS source…

[Specmaster]

Well the slightly younger HP 34401A that arrived last week seems to function OK (quick check on Sunday evening), quite a noticeable difference in display brightness too.





The older one I was having trouble with when testing the 745A AC calibrator, seems to have died completely on all AC functions & frequency measurement, it was OK when I acquired it, another DMM for the lengthy repair queue. 

 

David

Judging by the problems folk are having with their 34401A meters, I'm glad I have never been able to afford one, I'm very happy with my motley collection of DMM's.

[bd139]

The older one I was having trouble with when testing the 745A AC calibrator, seems to have died completely on all AC functions & frequency measurement, it was OK when I acquired it, another DMM for the lengthy repair queue. 

I would crack it open ASAP. There are some not very pleasant failure modes of the older revisions, particularly around the RMS converter tants which can lead to board damage. The carbonated area of course cocks the impedance controlled bits 

Judging by the problems folk are having with their 34401A meters, I'm glad I have never been able to afford one, I'm very happy with my motley collection of DMM's.

I've never had a problem with any of them myself.

Mine will now immediately explode.

Edit: I am mostly using the Fluke 75 at the moment as it's the smallest meter I have and everything is packed away. The 34401A only got lugged out earlier because it has min/max and I was cooking lunch when I was testing the OCXOs and needed some unattended measurements 

[Neomys Sapiens]

I got myself a TCP202, and waiting a bit paid this time - as the same seller was offering them on Ebay Kleinanzeigen, I got it on Ebay proper well below the lowest limit that he would have accepted.
Also got a military operation panel manufactured by Siemens, I'll probably let it sit on the shelf until I need some of its indicators or switches, which were the reason to get it.

[Vince]

I can resume sorting the few remaining IC's I had dug out the other day.
DS1489  DIP14
75452 DIP 8
TS4116-20NL  DIP16.... looks like a memory / PAL / GAL kind of part number...

All from memory...

TS4116 = 16k x 1 bit SRAM

OK I am done Googling... here is the result !

Almost correct on this memory ! 16x 1bit indeed, but DRAM not SRAM. 20ns access time.
I have 8 of them so I could make a more useful byte wide memory out of them. However DRAM is a pain, so why would I inflict such a pain to myself instead of just using an SRAM...
However they don't take much space so might keep them anyway in case I encounter some old Gizmo one day that needs these...
I can always throw them away if I need the space and / or want to clean up my inventory.

D765 = not an FDC controller. It's an OTP microcontroller. Think it had something like 1K of OTPROM and a few bytes of RAM. It probably ended up as an FDC.

Wow I can't believe you know this chip ?! 
I thought it was exotic...
What I don't understand is that other than you and a couple Ebay sellers :

https://www.ebay.com/itm/173966485163

https://www.ebay.com/itm/363746983177


...that have one for sale and advertise it as an MCU with as you said 1KB of PROM and 64 bytes for RAM.... other than that then, the entire internet says it's a floppy disk controller ! The datasheet says so, and I found a NEC product catalogue from 1990 that lists all their MCU and CPU peripherals and... the (µP)D765 is in there.... as a disk controller not an MCU. 
So I am flabbergasted (first time I use that weird word, hope I got it right !  ), as to how you and these 2 Ebay sellers think it's an MCU ?!

How did you come to think it's one ? Even know its specs... I am stunned. As you said maybe it's an MCU that NEC pre-programmed to serve as a disk controller.... but still how would you know it's an MCU inside ?! 

Maybe if you were a company big enough (that you may have worked for in the past) NEC would sell you this micro, and give you its datasheet so you can use it but....  they did not advertise it in their own products catalog, somehow. Also why would they use the same part number for the MCU and the pre-programmed disk controller... confusing at the least...

I am .... very confused and.... very curious to know what's what.

However at the end of the day, I guess it's not a big problem because in either case, since it's OTP, I can't make use of this chip so I don't really NEED to know what it is nor have a datasheet for it. So I will just keep it for the sheer beauty of its package and that's all...

DS1489 = RX end RS232 driver. Or TX end. Can't remember. Usually paired with 1488 at the other end.   

Wow impressed again...  It's a QUAD RS-232 receiver.

MMI = probably custom PROMs looking at the manufacturer and package. Same as the bugger that blew up in my 465B.  Based on what looks like an NSN number on them they are probably programmed with some random shit already.

Yes again !

They are MMI 6301-1J, TTL PROM 256x4 bits.
I also have another one, same specs, made by HARRIS : a M3-7611A
Both have the same pinout according to their datasheet.
Found also a data sheet from Signetics for their own version of the same chip. At the end of their datasheet is a full page of cross references.
Looks like these DIP 16 TTL PROM were trendy baxck in the day, they were made by numerous manufacturers under various part number styles.
Hell, maybe the ones at ch_scr TEA Auction the other day will be the same as well ?!   
Hmmm... so the programmer I will make for his PROMs might work to read these other PROMs as well 

Rest no idea 

Well here it is then :

- Blue coloured plastic DIP16, marked 16-1-151. No info, so in the trash it goes. At some point Google fooled me  into thinking it could be a resistor array, but I buzzed it and no way.

- FDC 9216 DIP 8 = floppy disk "data separator"... guess it's consistent with the NEC chip discussed above... not much use for that. Dismissed.

- µA747 = it's a dual 741 ... and I have 18 of them. Add x18 "standalone" 741 (including 3 in a cool metal can), that means I have x54  741 op-amps  ! 

That's my #1 in my inventory then.... I hope it's good enough for general purpose.

Next most popular in my inventory is the LM324. Have x11 of them... times 4, 44 op-amps.

Next is the 358. 8 chips, 2 per packages, so 16 of them.

So I guess these will be my 3 most used op-amps when fucking around on a breadboard...

- 75452 = well turns out I already have 3 of them. DIP8, contains a single TTL logic gate with an open-collector output.

- D3-6402-9 , DIP40, x7 of them.  No info other than 3 sellers Google found me, 15 Euros a piece (I am rich now), but none of them actually tell you what this chip is. They sell it, that's all. So since I can't know what they are at all.... dismissed.

https://www.ebay.com/itm/194905372556

https://www.radio741.com/62713-d3-6402c-9-harris-integrated-circuit.html


- TDA1085C, DIP 16, x12 of them. Not an audio amp for a change. No, this thing is apparently very specialized  says its datasheet. It's phase angle TRIAC controller, meant to provide speed control for "universal" type motors,, in washing machines. There you go ! I guess it makes sense that my dad stocked on these, since he was teaching white good servicing/repair, back then, and washing machines obviously amounted to a good chunk of the curriculum. I guess this chip was common place in washing machines at the time.


OH !!! Just had an idea !!!  Let's see...

[mnementh]

On The Bench Tonight: Belkin MagSafe Phone Charger



So... I picked this up at the Thrift a couple weeks ago cuz 5 bux, and I could see it is a 15W charger. I've been using it like this, figuring it was just a garden variety Qi-wireless charger, and the upright paddle was something for charging a smartwatch. 




I liked it mostly because it's so much smaller than my Qi charger lamp from IKEA, and that is pretty finicky aboot where you place the phone while this one is just happy as all get-out as long as you get it within 10-15mm of centered.





So when I brought it down to the bench to clean off the stickers and goopy, I was able to read the bottom of the thing; which says it is a 15W MAGSAFE charger for iPwn and AirPods. 

A little Guugl-Fu revealed just how it is supposed to work... and much to my surprise, there is a whole secondary market of self-adhesive metal rings in various colors that allow the main port up on that stalk to be used with any Qi-enabled phone, not just a iPwn. This cheapest kit cost 5 bux & change. 




Now how "Batman" is THAT...?!?    

The mag-ring seems to stick very aggressively to the case on my cheap android smartpwn; as you bring the phone to the charging pad, it pulls the phone so it is centered perfectly. Now that is damn clever; definitely one of the things Apple just plain did better.

mnem
can you hear me now...?    can you hear me now...?

[EEVblog]

I've been working hard for weeks here to generate on-topic stuff, and deliberately avoided all the talk of prepping, gun-nuttery and the collapse of civilization... I make one response to the topic folks are on about at the moment, deliberately talking only about one tiny, harmless aspect of it... and I get spanked.

Pro Forum Tip: Responding like this is just perpetuating the off-topicness.

This is the biggest and most active thread on the forum, we can't have it ruined by drifting off-topic in the same way many other small threads are left alone to let to go because we know those threads will just naturally die out anyway.

[gnif]

Hear, hear! 

mnem

I'll direct your attention to the line above regarding OT posts...

Forum rules trump thread rules

See forum rule #5

This is an electronics forum, so try to stay on-topic. We understand that threads drift off-topic, but try not to start deliberately and grossly off-topic stuff.

megahaul of nicest vintage gear. is it permissible to post pinball and audio stuff ? @gnif ?

Acceptable, but taking this off topic to non-electronic related things is not permissible. This is an electronics forum and this topic is under "Test Equipment", so please keep it related even it it's tenuous.

There is some flexibility but this thread had gone too far off topic.

[Zoli]

...
OK I am done Googling... here is the result !

Almost correct on this memory ! 16x 1bit indeed, but DRAM not SRAM. 200ns access time.
I have 8 of them so I could make a more useful byte wide memory out of them. However DRAM is a pain, so why would I inflict such a pain to myself instead of just using an SRAM...
However they don't take much space so might keep them anyway in case I encounter some old Gizmo one day that needs these...
I can always throw them away if I need the space and / or want to clean up my inventory.
...

FTFY; beside, they need 3 voltages:-5V,+5V,+12V . One of the applications was in ZX Spectrum(base+video RAM).

[mnementh]

I've been working hard for weeks here to generate on-topic stuff, and deliberately avoided all the talk of prepping, gun-nuttery and the collapse of civilization... I make one response to the topic folks are on about at the moment, deliberately talking only about one tiny, harmless aspect of it... and I get spanked.

Pro Forum Tip: Responding like this is just perpetuating the off-topicness.

This is the biggest and most active thread on the forum, we can't have it ruined by drifting off-topic in the same way many other small threads are left alone to let to go because we know those threads will just naturally die out anyway.

With all due respect, this is the biggest thread on the forum because up til now it has been generally tolerant and inclusive of all the varied interests of the regular contributors. We who frequent this space have done very well, work hard even, to self-regulate.

But we have also taken for granted the general "water-cooler talk" relaxed nature of this space.

If that general permissiveness is taken way to make the space tidier, it will also be much less interesting. There will simply be much less activity, and much less content of any sort. I've seen it happen in more places than I can count.

But this is of course your bailiwick... and we will do our best to comply.

Thanks again for providing this space,

mnem
*slips sadly back inside his cave*

[med6753]

Upcoming capacitor replacement on the B&K 2120. All the electrolytics in the PSU will be replaced as well as in the HV Oscillator and other assorted in the rest of the instrument. Replacement capacitors will be here tomorrow (Wednesday).

Schematic of PSU.

[scl]

I can resume sorting the few remaining IC's I had dug out the other day.
DS1489  DIP14
75452 DIP 8
TS4116-20NL  DIP16.... looks like a memory / PAL / GAL kind of part number...

All from memory...

TS4116 = 16k x 1 bit SRAM

OK I am done Googling... here is the result !

Almost correct on this memory ! 16x 1bit indeed, but DRAM not SRAM. 20ns access time.
I have 8 of them so I could make a more useful byte wide memory out of them. However DRAM is a pain, so why would I inflict such a pain to myself instead of just using an SRAM...
However they don't take much space so might keep them anyway in case I encounter some old Gizmo one day that needs these...
I can always throw them away if I need the space and / or want to clean up my inventory.

D765 = not an FDC controller. It's an OTP microcontroller. Think it had something like 1K of OTPROM and a few bytes of RAM. It probably ended up as an FDC.

Wow I can't believe you know this chip ?! 
I thought it was exotic...
What I don't understand is that other than you and a couple Ebay sellers :

[url]https://www.ebay.com/itm/173966485163[/url]

[url]https://www.ebay.com/itm/363746983177[/url]


...that have one for sale and advertise it as an MCU with as you said 1KB of PROM and 64 bytes for RAM.... other than that then, the entire internet says it's a floppy disk controller ! The datasheet says so, and I found a NEC product catalogue from 1990 that lists all their MCU and CPU peripherals and... the (µP)D765 is in there.... as a disk controller not an MCU. 
So I am flabbergasted (first time I use that weird word, hope I got it right !  ), as to how you and these 2 Ebay sellers think it's an MCU ?!

How did you come to think it's one ? Even know its specs... I am stunned. As you said maybe it's an MCU that NEC pre-programmed to serve as a disk controller.... but still how would you know it's an MCU inside ?! 

Maybe if you were a company big enough (that you may have worked for in the past) NEC would sell you this micro, and give you its datasheet so you can use it but....  they did not advertise it in their own products catalog, somehow. Also why would they use the same part number for the MCU and the pre-programmed disk controller... confusing at the least...

I am .... very confused and.... very curious to know what's what.

However at the end of the day, I guess it's not a big problem because in either case, since it's OTP, I can't make use of this chip so I don't really NEED to know what it is nor have a datasheet for it. So I will just keep it for the sheer beauty of its package and that's all...

DS1489 = RX end RS232 driver. Or TX end. Can't remember. Usually paired with 1488 at the other end.   

Wow impressed again...  It's a QUAD RS-232 receiver.

MMI = probably custom PROMs looking at the manufacturer and package. Same as the bugger that blew up in my 465B.  Based on what looks like an NSN number on them they are probably programmed with some random shit already.

Yes again !

They are MMI 6301-1J, TTL PROM 256x4 bits.
I also have another one, same specs, made by HARRIS : a M3-7611A
Both have the same pinout according to their datasheet.
Found also a data sheet from Signetics for their own version of the same chip. At the end of their datasheet is a full page of cross references.
Looks like these DIP 16 TTL PROM were trendy baxck in the day, they were made by numerous manufacturers under various part number styles.
Hell, maybe the ones at ch_scr TEA Auction the other day will be the same as well ?!   
Hmmm... so the programmer I will make for his PROMs might work to read these other PROMs as well 

Rest no idea 

Well here it is then :

- Blue coloured plastic DIP16, marked 16-1-151. No info, so in the trash it goes. At some point Google fooled me  into thinking it could be a resistor array, but I buzzed it and no way.

- FDC 9216 DIP 8 = floppy disk "data separator"... guess it's consistent with the NEC chip discussed above... not much use for that. Dismissed.

- µA747 = it's a dual 741 ... and I have 18 of them. Add x18 "standalone" 741 (including 3 in a cool metal can), that means I have x54  741 op-amps  ! 

That's my #1 in my inventory then.... I hope it's good enough for general purpose.

Next most popular in my inventory is the LM324. Have x11 of them... times 4, 44 op-amps.

Next is the 358. 8 chips, 2 per packages, so 16 of them.

So I guess these will be my 3 most used op-amps when fucking around on a breadboard...

- 75452 = well turns out I already have 3 of them. DIP8, contains a single TTL logic gate with an open-collector output.

- D3-6402-9 , DIP40, x7 of them.  No info other than 3 sellers Google found me, 15 Euros a piece (I am rich now), but none of them actually tell you what this chip is. They sell it, that's all. So since I can't know what they are at all.... dismissed.

[url]https://www.ebay.com/itm/194905372556[/url]

[url]https://www.radio741.com/62713-d3-6402c-9-harris-integrated-circuit.html[/url]


- TDA1085C, DIP 16, x12 of them. Not an audio amp for a change. No, this thing is apparently very specialized  says its datasheet. It's phase angle TRIAC controller, meant to provide speed control for "universal" type motors,, in washing machines. There you go ! I guess it makes sense that my dad stocked on these, since he was teaching white good servicing/repair, back then, and washing machines obviously amounted to a good chunk of the curriculum. I guess this chip was common place in washing machines at the time.


OH !!! Just had an idea !!!  Let's see...

Vince,
Your D3-6402's should be a UART, they were pretty common once upon a time.
The blue DIP-16 is (or was) indeed a resistor network, look for 150 ohms from pin 16 to every other pin.

[Vince]

...
OK I am done Googling... here is the result !

Almost correct on this memory ! 16x 1bit indeed, but DRAM not SRAM. 200ns access time.
I have 8 of them so I could make a more useful byte wide memory out of them. However DRAM is a pain, so why would I inflict such a pain to myself instead of just using an SRAM...
However they don't take much space so might keep them anyway in case I encounter some old Gizmo one day that needs these...
I can always throw them away if I need the space and / or want to clean up my inventory.
...

FTFY; beside, they need 3 voltages:-5V,+5V,+12V . One of the applications was in ZX Spectrum(base+video RAM).

Oops sorry, yes you are right... should have read the datasheet  less hastily... they do indeed ad a zero to that number   

Funky voltages indeed... as I said I am never gonna be using them for my own designs, silly. Only keeping them in case it helps fixing an existing old instrument....

OK so I am just finished testing my idea....

Decided to try to read these 3 PROMs by hand.

30 years ago as I entered high-school, old man gave me this brief case fro his work, used to teach the basic of digital logic. It's made for TTL chips.
In 30 years I can't remember ever using it... feeling ashamed. So I thought hey great, I have now an opportunity to use it !
I could use it to read my TTL PROMs !!! 

I mean they have only 8 address lines and 4 bits of data. The brief case has 8 switches so I can use those to drive the address bus, and it also has two of these cool super cute dot matrix LED HEX displays of the old time    So I could use one of these displays to show the contents of the data bus.

So first, before I do anything with these PROMs... seeing the brief case is so old and has not seen any use inu 30 years.... first I checked the power supply to make sure I was not gonna blow my PROMs.
No, everything is fine believe it or not. 5V still there and accurate, and zero ripple, solid as a rock. It uses a TO3 LM309K 5V regulator.

Checked the power rails / distributions of ground and 5V all over the kit... it goes everywhere, power is good everywhere.

I checked all 8 switches. The first 4, starting from the left, put out 4.4V. The last 4 give only 3.8V. Still, plenty enough to drive reliably a TTL input, so I didn't investigate that any further.

Then wired these switches to the two dot matrix displays and ran through all the codes manually. They work just fine.

OK so I then grabbed one of the two MMI 254x4 PROMs, and read its contents manually, and wrote all 256 memory locations on a piece of paper.

Must have taken me like 30 minutes, a chore.... which means I will definitely build this PROM programmer... even tiny memories like this are a chore by hand....
Also, since it looks like these TTL PROMs where rather standardized across all manufacturers, it makes a programmer an even more useful idea...
Looks like there were 8 different configurations. DIP 16 up to DIP24, 4 or 8 bit wide. 10 different configurations.
So I could use a ZIF socket and make little adapter boards to cater for all 10 configurations.
Yeah.... I like this little programmer project a lot 

Anyway. So as you can see from my notes on paper... the first MMI PROM I read was 99% empty ! Only the first column has data in it, and it always '8' bar the very first cell that reads '9' instead, great...

I tried the second MMI PROM.... same thing.

Tried the third and last PROM, this one made by HARRIS instead, but same configuration... tried a few random memory locations... looks all zeros again .... 

Datasheet that by default memory locations are a '1' and only can become '0' if you program them / blow the fuse.
So one would guess that if the memory cells went bad and would lose their contents... they would come back to a '1' state, not switch to '0'.
That would mean they have actually been programmed with 99% of zeros ?! Doesn't make sense... especially not all 3 of them, too suspicious....

So I don't know... I measured voltages directly at the pins of hte chips, they do get proper voltage, no worries, the switches drive them as expected.

 

[Vince]

Vince,
Your D3-6402's should be a UART, they were pretty common once upon a time.

Oh thanks ! 

I can see it now... datasheet duly downloaded. 

I don't know how I managed to miss it the first time I googled it
Google can't find my exact part number : 6402-9 , it only finds 6402R-9 though.
However when you open the datasheet, at the top the title drop the 'R', so yeah I am all good... but then further down the page in a little table where they give the full / actual part number, the introduce the 'R'... pfff... confusing. What does this 'R' do, how important is it....
I will never know. I guess for now this datasheet is good enough to let me use this chip if I fancy so one day.
Glad to know it was widespread back in the day, means I may stand a chance of actually encountering one in some piece of gear, and might be happy to have some in stock...

The blue DIP-16 is (or was) indeed a resistor network, look for 150 ohms from pin 16 to every other pin.

Yeah but as I said I buzzed the chip with the ohmmeter and no matter what pins I buzz, all I get is open circuit, or tens of Megs at best....

According to the datasheet I found, a modern one for surface mount stuff but still using the same part number system apparently :

" 16 " means 16 pins. This ads up.
" 1 " refers to the configuration / topology of the array. In this case it means the resistors all have a common terminal, which is connected to pin #1 of the package
" 151 " as you said means 150 ohms.

So yeah should have lots of 150 ohms resistors with a common pin at #1. Doesn't happen at all....
Maybe all the resistors inside are all blown, it's the only way I could explain reading open circuit everywhere 


EDIT :  OK, gave that thing one last chance... I thought OK what if the topology inside was not as advertised... so I tested for a different configuration : instead of common on pin #1, I tested for no common point at all, independent resistors arranged as a "ladder", so to speak. Well that works much better !! I now can "see" all the resistors no worries, all at 150 ohms indeed, YEAH !!!!! 

That means I need to add a new tab to my inventory spreadsheet : " Resistors ". Boy if I start keeping track of all my resistors I will never see the end of it ! 
But I guess one can make an exception for special types of resistors like this one...

04H15 here, going to bed....   

[25 CPS]

I did the majority of the handheld equipment battery replacement program this evening after a couple of things set me back a few days.  I'd already gotten most of the preparatory work buying fresh batteries and laying out the recordkeeping spreadsheet out of the way earlier so tonight was spend a chunk of the evening in the workshop going through item by item.  Everything was good until I got to the U1282A multimeter.  Once I finally got it out of the bumper and opened up the battery compartment, this is what I found:





Not what I was hoping to see in any more equipment.  The meter itself was running though and none of the cells in it had leaked so this is pre-existing damage that the previous owner did not clean up.  They went into the bag of batteries that's going to be disposed of and were replaced with new.



Unlike the two U1177A adapters that got killed, the U1282A survived this and has received a much better cleanup job than the one the previous owner did, if they even did any beyond replacing the leaked batteries with new.  The same thing happened a couple of years ago with my U1242A.  Open it up for its first battery change and there was a nasty surprise waiting to be discovered but it wasn't as severe as this.

All but two of the meters are done now along with the accessories except for current clamps.  I didn't account for those in the quick initial survey when I went shopping the other day and I ran out of 9V batteries so I took care of that this evening.  The two remaining meters and the current clamps will get done tomorrow along with the remote controls and couple of flashlights in the house and the cars, then the bags of waste batteries and compact fluorescent lightbulbs are going to go to the waste transfer station later this week.  I was able to work backwards from some of the information I had on hand and figure out when a couple of pieces of equipment got new batteries last so there are a couple of things waiting for October and January, but everything else with an unknown install date has been done or will be done tomorrow.  Then it's scheduled replacements on the one year dates from here on out.

[mnementh]

Jeebus... is there anybody left selling on fleaBay who isn't a complete muppet...?

I just had to poke this seller with the PM stick because 10 days after I paid, it is supposed to be delivered no later than tomorrow, yet still only shows "Label Created" and not in FEDEX possession.

Do they really think nobody is gonna click on the TRACK PACKAGE button...?

mnem
fleaBay: all they actually have now is fleas.

Didn't even ship it until this afternoon; long after I poked him with the PM stick. 

Def not getting 5 stars on the SHIPPING feedback.

mnem
*toddles off to ded* 

[Neomys Sapiens]

Upcoming capacitor replacement on the B&K 2120. All the electrolytics in the PSU will be replaced as well as in the HV Oscillator and other assorted in the rest of the instrument. Replacement capacitors will be here tomorrow (Wednesday).

Schematic of PSU.

For the sake of common understanding, you should stick with 'BK' for this company, as 'B&K' usually denotes Bruel & Kjaer in the world of Test & Measurement.

[TERRA Operative]

Ok, so it seems the 74AC14 has an output current of 50mA per buffer. So at 4.5V supply, we get a minimum voltage of 4.4V out, which comes to 2ohms source impedance.

To impedance match this to 50ohms, If I parallel 3 buffers (max Vcc/ground current for this chip is 150mA) followed each by a 150ohm resistor, I should get 51ohms impedance, right?

See https://www.eevblog.com/forum/testgear/show-us-your-square-wave/msg1902941/#msg1902941

You will need to pay careful attention to PSU decoupling, including lead length inside the package (hint: pins 14+7 is just about the worst choice that could have been made)

One way around that nasty is to parallel several of the tiny surface mount single gate packages. They have much, much better inductive performance thanks to having almost no lead worth mentioning at all. In fact they're so good that you start fussing over the inductance of the resistors rather than the inductance of the IC packaging.

Ah so TERRA O was in the early stages of building a pluser....that explains much and mimics where I was going a year back with a PCB all laid out, traces length matched and all the bits and bobs lined up to populate the PCB but darned if I could get a decent toner transfer with my laser printer when it had been no problem with the old one ! 

In the end I succumbed and splashed out on one from Leo that was properly characterized with a 30ps RT ! 
I'd recommend TERRA O goes this way too:
http://www.leobodnar.com/shop/index.php?main_page=index&cPath=124

I got one of those, and his GPSDO too.

My current project is just to square up the output from a spare OCXO to use for squirting the 10MHz square wave into TTL circuitry. Nothing fancy, just looking for a clean square wave.

[Neomys Sapiens]

EDIT :  OK, gave that thing one last chance... I thought OK what if the topology inside was not as advertised... so I tested for a different configuration : instead of common on pin #1, I tested for no common point at all, independent resistors arranged as a "ladder", so to speak. Well that works much better !! I now can "see" all the resistors no worries, all at 150 ohms indeed, YEAH !!!!! 

That means I need to add a new tab to my inventory spreadsheet : " Resistors ". Boy if I start keeping track of all my resistors I will never see the end of it ! 
But I guess one can make an exception for special types of resistors like this one...

04H15 here, going to bed....   

So this means that we must send you some resistor arrays, lest it be all alone in it's category?

[EEVblog]

For the sake of common understanding, you should stick with 'BK' for this company, as 'B&K' usually denotes Bruel & Kjaer in the world of Test & Measurement.

Yes, B&K means Bruel & Kjaer. Top notch stuff in the sound and vibration measurement industry.

[med6753]

For the sake of common understanding, you should stick with 'BK' for this company, as 'B&K' usually denotes Bruel & Kjaer in the world of Test & Measurement.

OK, in the future and to avoid confusion I will use their full name which is B&K Precision.