Test Equipment Anonymous (TEA) group therapy thread

[vk6zgo]

When scanning, how frequenty should you take your eyes off the road for a couple of seconds? That's to re-focus on the digital display, read the numbers (ugh, but that's the modern way), re-focus on the road.

A lot can happen in a couple of seconds.

The idea of digital speedos is pretty much a "Back to the future" concept.
 
Some cars had them back in the 1980s, & they were a disaster!
The big problem was that, as the car changed speed, the numbers tried to change fast enough to keep up, resulting in a display which was difficult to read.
I guess they could to be made to change in wider steps, but it's a bit like polishing a turd!

An "analog" display doesn't even need to have any mechanical components---ham radios have rendered "S" meters which look exactly like a moving coil meter.
Even if they don't want to go to that much trouble, they could make bargraph displays similar in appearance to the mechanical "ribbon" speedos of the early 1960s.

[dl6lr]

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

Yes. He’s the sort of individual who would use comic sans on his mother’s funeral invitations. Distinctly lacking in class, taste, aesthetic appreciation, quality, form and ethics. Rancid scum. Grr.

All I say is WTF. 

At least there are real nixies! Imagine the same crap using some chinese OLED displays like this: https://www.aliexpress.com/item/1005003208960365.html

[capt bullshot]

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's wrong with that, it's a "Time" box anyway

[dl6lr]

An "analog" display doesn't even need to have any mechanical components---ham radios have rendered "S" meters which look exactly like a moving coil meter.
Even if they don't want to go to that much trouble, they could make bargraph displays similar in appearance to the mechanical "ribbon" speedos of the early 1960s.

I remember cars that had an analog "bar graph" display in the seventies: They used a regular speedo that has a drum instead of the needle and you watch the spiral on it through a slot.

[Cubdriver]

When scanning, how frequenty should you take your eyes off the road for a couple of seconds? That's to re-focus on the digital display, read the numbers (ugh, but that's the modern way), re-focus on the road.

A lot can happen in a couple of seconds.

The idea of digital speedos is pretty much a "Back to the future" concept.
 
Some cars had them back in the 1980s, & they were a disaster!
The big problem was that, as the car changed speed, the numbers tried to change fast enough to keep up, resulting in a display which was difficult to read.
I guess they could to be made to change in wider steps, but it's a bit like polishing a turd!

An "analog" display doesn't even need to have any mechanical components---ham radios have rendered "S" meters which look exactly like a moving coil meter.
Even if they don't want to go to that much trouble, they could make bargraph displays similar in appearance to the mechanical "ribbon" speedos of the early 1960s.

In my opinion, the big down side of the digital display for something like a speedometer indicator is the ease/speed of reading and comprehension.  An analog speedometer can be read at a glance - I know where the needle should be for various driving situations - for instance, it will normally be pointing somewhere between twelve and one o'clock when I'm traveling on the highway at speed.  A quick glance can tell me if it's where it should be, and also in which direction it's 'off' if it isn't.  A digital readout requires you to read it, then process the numbers, and decide how they relate to the desired speed.

On a freeway with a 65 MPH limit, a quick glance might show the pointer is a needle width above the small tic at 12:30 on the gauge face.  I know in an instant I'm close enough to 65 that a cop is unlikely to have any interest in me, so I'm good.  A digital readout indicating 67 MPH is going to require one to read the 67, process and compare it to 65, then judge if they're in a 'safe' speed zone.  Higher mental load than a glance at a needle that will almost instantly show how far and in what direction you're off from the posted limit.

-Pat

[Zoli]

When scanning, how frequenty should you take your eyes off the road for a couple of seconds? That's to re-focus on the digital display, read the numbers (ugh, but that's the modern way), re-focus on the road.

A lot can happen in a couple of seconds.

The idea of digital speedos is pretty much a "Back to the future" concept.
 
Some cars had them back in the 1980s, & they were a disaster!
The big problem was that, as the car changed speed, the numbers tried to change fast enough to keep up, resulting in a display which was difficult to read.
I guess they could to be made to change in wider steps, but it's a bit like polishing a turd!

An "analog" display doesn't even need to have any mechanical components---ham radios have rendered "S" meters which look exactly like a moving coil meter.
Even if they don't want to go to that much trouble, they could make bargraph displays similar in appearance to the mechanical "ribbon" speedos of the early 1960s.

In my opinion, the big down side of the digital display for something like a speedometer indicator is the ease/speed of reading and comprehension.  An analog speedometer can be read at a glance - I know where the needle should be for various driving situations - for instance, it will normally be pointing somewhere between twelve and one o'clock when I'm traveling on the highway at speed.  A quick glance can tell me if it's where it should be, and also in which direction it's 'off' if it isn't.  A digital readout requires you to read it, then process the numbers, and decide how they relate to the desired speed.

On a freeway with a 65 MPH limit, a quick glance might show the pointer is a needle width above the small tic at 12:30 on the gauge face.  I know in an instant I'm close enough to 65 that a cop is unlikely to have any interest in me, so I'm good.  A digital readout indicating 67 MPH is going to require one to read the 67, process and compare it to 65, then judge if they're in a 'safe' speed zone.  Higher mental load than a glance at a needle that will almost instantly show how far and in what direction you're off from the posted limit.

-Pat

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.

Just a small reminder from yesterday, until somebody will find the proper test equipment to measure the driving attention distribution/distraction - strictly scientifically(and double blind  ).

[Cubdriver]

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

Yes. He’s the sort of individual who would use comic sans on his mother’s funeral invitations. Distinctly lacking in class, taste, aesthetic appreciation, quality, form and ethics. Rancid scum. Grr.

All I say is WTF. 

At least there are real nixies! Imagine the same crap using some chinese OLED displays like this: https://www.aliexpress.com/item/1005003208960365.html

As long as they're using NOS surplus Russian nixies, and not Burroughs or National tubes that have been obtained by scrapping out vintage gear, I'm a little less annoyed by them, but only slightly - still don't like repurposing destroying any test gear to make a clock.  If you want a clock, make a damned clock, and build an enclosure for it - don't strip something else.

-Pat

[Saskia]

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.

nope, you would be missing the baseline to compare it to. A comparison always includes a baseline, and a baseline test will not be objective either. If you want an objective test you will take a spectrum analyzer and analyze the frequency / dynamic response using white noise at your listening position.
Which we did for my big stereo set and will do with my secondary. Those sets will then get tuned using active crossovers with appropriate programming derived from the SA output. Which in turn will get it close to my expectations.

I am not buying the "completely OTT" stuff. I am into very solidly engineered equipment with superb build quality which offers good value for the money, reminds me of some good times in my life, and is at a level which is "good enough". Good enough most likely being OTT for many here, but have a look at your DMMs.
Many of you are into 7.5 digit DMMs, make fun of me because I do not own a 34401A (and never will due to that Keysight rubbish) and frown at me for saying that a Fluke 179 will do nicely for my kind of measurements. I did aquire a couple of Keithley DMMs lately, and the Metrahit is also *very* acceptable, however for my measurements I honestly do not need them.

As for FPGA, Xilinx folks have shot themselves into the off, so my FPGA projects are cancelled and we will go with Nvidia and GPUs. That being said I currently have no need for high end electronics development equipment. I do have a need for equipment that helps me repair my pinball machines, my computer equipment, my audio equipment. But: a Hameg analog scope, a Tektronics Handheld THS 720A, a 4 channel Tek scope and a Rohde&Schwarz RTC1002 should be more than sufficient to accomplish those tasks. Furthermore I do have my Anritsu SA which I need to set up to do some of the audio gear measurements that I mentioned.
My friend who is doing speaker development has one of these nifty hand held SAs ... But I am not willing to throw that kind of money into something that he owns and can use at my place, and I rather pay him for this service than spend kilobucks on that equipment. Doing so will reimburse him for the time he would otherwise spend with customers and also allow him to provide this service. He needs to earn a living, too.

[Saskia]

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

Yes. He’s the sort of individual who would use comic sans on his mother’s funeral invitations. Distinctly lacking in class, taste, aesthetic appreciation, quality, form and ethics. Rancid scum. Grr.

All I say is WTF. 

At least there are real nixies! Imagine the same crap using some chinese OLED displays like this: https://www.aliexpress.com/item/1005003208960365.html

As long as they're using NOS surplus Russian nixies, and not Burroughs or National tubes that have been obtained by scrapping out vintage gear, I'm a little less annoyed by them, but only slightly - still don't like repurposing destroying any test gear to make a clock.  If you want a clock, make a damned clock, and build an enclosure for it - don't strip something else.

-Pat

Clock.

[tautech]

Could chat about firearms all day but it’s best done via PM so to not draw the attention of Mods. 

But of course we could instead chat about screwdrivers, hammers, baseball bats or cars….all lethal weapons also.

[Saskia]

@vk6zgo

Even though I would love to discuss this stuff this forum is the wrong place to do so. Please see gnif's post.

Guys, please stay on topic here. If you want to discuss something else please create a thread for it.

Edit: More off topic posts will be removed, keep doing it and you will be restricted from participation here.

[capt bullshot]

Clocks (and some TE):

http://wunderkis.de/dcf-rcvr/gallery/index.html

[vk6zgo]

I’ll have you know it’s Lord Cthulhu who’s going to smite me.

Have you considered the advantages of converting to one of the other tentacled deities, namely Our Lord the Flying Spaghetti Monster? Instead of effete methods of cheating death, such as playing chess, that are available to other religions all the worshipers of the FSM need is a jar of tomato sauce and a fork. Should you fail in your endeavours to cheat death at least you go down with a satisfying meal inside you.

I'm with Odin. At least there is Meade in Valhalla.

I'd back the Wagyl against both of them---any creature which can produce gorges & river valleys deserves respect!

[m k]

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...

uPD765
Back in the day PC market exploded and every machine needed a floppy controller.
I found one UM8397 and a tube of keyboard controllers, one was D8742 from Intel.

Maybe we are seeing different market behaviour here, Japan and USA.
I've been told that Japan has two modes, internal and external, when USA has none.
So when economy in Japan operates in external mode they become sort of one entity againgt external powers and before that they have competed internally who will lead and in this case uPD765 was the winner.
For PCs Japan had an MSX route but it didn't last very long, externally, no idea how it did internally, so minimal lost effort for external competition.

Keyboard controller case is different, the chip is never defined as its main use, it retains its original form because that is how it is marketed.

RS-232
It was a bit wide thing back then.
1488/1489 pair was the sort of original work horse but when cables became longer they couldn't cope.
Xon/Xoff flow control was also pushing its way so dual driver was enough and so 9636/37/38/39 and the likes appeared, occasionally that didn't do much since shielded cable's shield was connected at both ends.
Many machines were also frame grounded.

PROMs
4 data and 8 address lines, that's 12 pins plus power.
00 = 9 is 8 input NOR for D0.
x0 = 8 is 4 input NOR for D3, so another chip.
PROM is at least space effective.

BTW,
the old clothes washer had an open bottom and probably just worn out carbon brushes.

[bd139]

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...

Just to clarify here, confusion on the D765 is on me. It is an MCU though. Mask ROM programmed. They did a whole line of peripherals in that series back in the dark ages. It’s basically a CPU, serial and parallel IO in one IC with FDC code blown into it. They did sell the MCU with an EPROM on it but I can’t remember what it was. V-something.

[m k]

V20 was faster 8088.

[duckduck]

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.

<SNIP>

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. 

<SNIP>

David

I fixed my 34401A that had the exact same problem. See my post:

https://www.eevblog.com/forum/testgear/test-equipment-anonymous-(tea)-group-therapy-thread/msg4267654/#msg4267654

Message me when you go to fix it and, if it helps you, I'll mail you the parts I used to fix it. I ordered spares since they were tiny and cheap.

EDIT:

Added picture of schematic (highlights are mine)

C312 is a "Capacitor-Fxd 22 uF ±20% 20 V"
CR304 is a "Diode-Zener 3.3V 5% TO-236"

[med6753]

My opinion, take it or leave it. I agree with Admin. Lately it seems this thread has been OT with some TE sprinkled in here and there. And I've been just as guilty at times for wandering into unrelated subjects. But if you noticed, or maybe you haven't, my overall participation in this thread has diminished lately but when I do post it's on topic. And also lately I may go a day or two and not even log in. Then I try to slug through what seems like 75% off topic vs 25% TE. It's getting old. We have Discord for that stuff.

The notion that this thread will die if we more closely police ourselves per admin's request is ridiculous. I'll always be here. And so will many others who like me are TE addicted. It's not necessary that this thread have 4 pages per day of unrelated topics in order to survive. In fact, we may attract more participants to this thread if we stick to it's main principle....Test Equipment.     

[bd139]

V20 was faster 8088.

Yeah wasn't a V20.

[gnif]

Post regarding firearms removed.

[Specmaster]

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 

Yes, the min/max is useful, that's why my 25s, quickly became 27s. 

[bd139]

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.

<SNIP>

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. 

<SNIP>

David

I fixed my 34401A that had the exact same problem. See my post:

https://www.eevblog.com/forum/testgear/test-equipment-anonymous-(tea)-group-therapy-thread/msg4267654/#msg4267654

Message me when you go to fix it and, if it helps you, I'll mail you the parts I used to fix it. I ordered spares since they were tiny and cheap.

EDIT:

Added picture of schematic (highlights are mine)

C312 is a "Capacitor-Fxd 22 uF ±20% 20 V"
CR304 is a "Diode-Zener 3.3V 5% TO-236"

I'm wondering if I should do a preemptive replacement on mine. I actually have the tants already.

It was even a featured failure on EDN 

https://www.edn.com/repair-hp-34401a-capacitor-failure/

And xdevs:

https://xdevs.com/fix/hp34401a/

Edit: now I'm looking at hot air stations. Seeeee what we do to each other 

[Specmaster]

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*

I couldn't agree more, only this week I was exploring another forum and like so many others that either I'm a member of but hardly ever go on them, or others that I explore looking for activity and answers, I'm appalled to discover that many seem to have last posts on them dated 2021 That is tumbleweed city territory.

Whenever this thread begins to go off-topic, it always coincides with the lack of bargains to be had on eBay or ham fests. It is also extremely self-regulating really, there may be the occasional hiccup when tempers get a bit frayed and then other members pile in and make the offenders fall back in line and as always, it's all done in the best possible taste.

[Zenith]

As long as they're using NOS surplus Russian nixies, and not Burroughs or National tubes that have been obtained by scrapping out vintage gear, I'm a little less annoyed by them, but only slightly - still don't like repurposing destroying any test gear to make a clock.  If you want a clock, make a damned clock, and build an enclosure for it - don't strip something else.

-Pat

Nixie clocks are one of my pet peeves. And as for wrecking a nice piece of vintage equipment to make one. GRRRRRHHHH!!!!

[Zenith]

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*

I couldn't agree more, only this week I was exploring another forum and like so many others that either I'm a member of but hardly ever go on them, or others that I explore looking for activity and answers, I'm appalled to discover that many seem to have last posts on them dated 2021 That is tumbleweed city territory.

Whenever this thread begins to go off-topic, it always coincides with the lack of bargains to be had on eBay or ham fests. It is also extremely self-regulating really, there may be the occasional hiccup when tempers get a bit frayed and then other members pile in and make the offenders fall back in line and as always, it's all done in the best possible taste.

There's a line to be drawn somewhere, and the mods have to step in and draw it as they see fit. TBH I don't think their stance was unreasonable - lamentable French shooting etiquette and the legal position of bonfires in France, amongst other topics, were perhaps going too far. They have a light touch and don't step in often.

I gave up on one forum because the mods were over active. Anything that could be considered off-topic and they closed the thread. They seemed to enjoy closing threads. There was a list of forbidden topics, such as ebay. Then they started correcting spelling and grammar - and getting it wrong. I thought it was damned rude. That was it for me.