EEVblog #1013 - Mailbag

Monster 45min Mailbag!
Get the 555 Timer T-shirt

SPOILERS:
Analog meters + VTVM's + Dave's first multimeter.
Brady label maker teardown
SushiBits M193v2 Arduino PCB
2DW233 Voltage Reference Zener
Fitbit Teardown
University of Bristol UB20M Zero Power Standby chip

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[jameshunt]

Dave, USB's wear out quickly and 3.5mm jack plugs do not, jacks also rotate

[hi-friaudioman]

Viewers in florida are indeed called floridians Dave! You got it.

[PapasDino]

The TTC CT-1001 VOM was my first meter back in 1969...mom bought it for me at a real life electronics/surplus store in San Francisco where the surplus stores lined up along Market Street. Still have it to remind me of the good old days!

[russellhltn]

41:05 - looks like my very first meter. Good unit. It served me well.

[anotherdayisforever]

Mailbag really is my favorite segment.

[peterg.]

Violated the first rule of eevblog, don't turn it on, tear it apart!

Paging Mr Carlson to replace those wax caps!!!

[tomjones]

'Floridians' is correct! And, it looks better with the lighting, more professional...keep it up!

[williamsquires]

Let's have a 2-minute restore here. Replace the old selenium rectifier with some 1N4007's, replace the wax-paper caps and the (no doubt leaky) electrolytic cap, and I'll bet that old VTVM will work like new! Nothing like some nice vacuum bulbs - none of this IC rubbish! :)

[gip-gipsr.]

See Mr Carlson's Lab's video on VTVMs if you wanna keep it. If not I may/may not be willing to pay shipping to the US.

[tonypeaches]

David- the San Jose Light tower was at the intersection of Market and Santa Clara streets but came down in a storm at 11:55 am December 3 in 1915. There is a 1/2 scale replica at the San Jose History Park today and an effort to rebuild a modern replica of the original at the same location is underway.

[grantrennie]

On the aluminium can cashing there used to be in Australia and the UK, I had a place in Boston Massachusetts for a while and when I was over there I found that all cans and bottles had a deposit on them and it was almost impossible to cash them in anywhere, nobody wanted them but the state/county/council would happily take them for free in the recycling bins that were everywhere.. They are trying to bring in compulsory deposits in the UK and I can see it going the same way, nowhere to get back the deposits, just an extra tax with the state collecting the cans/bottles to sell on for recycling

[richfiles]

I own a Friden EC132, which added a square root key. It came out a few months after the 130. Also own an SCM Cogito 240SR, which is a cool old machine. There's some history between the two machines. Stanley Frankel designed the 240SR, and was a mathematician who worked on the Manhattan project. He had been censured over his views on the direction nuclear development should follow. That basically barred him from government work, so he went to Marchant with an idea for an electronic calculator. Marchant (who had either just merged, or was in the process of merging with Smith-Corona... I don't recall) was interested in the idea, but not the risk. They decided it would be better to offer to license the technology to their competitor, Friden. If the product failed to sell, Friden would take the loss, and if it was a success, they could collect royalties...

Friden, rather than taking the bait, said they were not interested. Instead, they rushed their own design to market, beating the Cogito by months. Friden's design was huge, clunky, and wasn't all that efficient, design wise. It did introduce RPN, if only for the fact that it made the hardware design simpler. Ultimately, it did work though.

The Cogito 240SR had an unusual input method, and an unusual output that could effectively count to infinity, at the expense of discarding least significant digits, and outputting a marker on the display that allowed you to keep track of the number of display overflows, so long as you manually counted the transitions. The Cogito was markedly smaller, and weighed a slightly less. It had a much more compact, narrower design, Had a wider variety of input options (like a grand total mode, and the ability to manually swap the contents of registers).

I love collecting old calculators, and those old models from the 1960s are some of my favorite ones!

[SianaGearz]

Ooooh i'm loving that ST PSD8XXFX in that labelling machine! Seems so immensely useful!

[douro]

The VTVM is from the 1940s. The battery will be for resistance measurement. Precision Apparatus Company made some very nice equipment.

[carlosedwardos]

DAVE ---> L.I. = Long Island

also, replace all of the caps and it will work fine! - the tubes are likely OK!

[cdw]

The multimeter connector appears to be an Amphenol 75-mc1 series connector,

[Herby-]

On the VTVM the battery is used for the ohms scale. The connector was commonly a microphone (unbalanced) connector. If I were "updating" the device I'd make it a BNC connector. Typically the input impedance was 1 meg ohm, and the "probe" added another 9 megs to make it a total of 10 megs.

[ianide]

Yes, Floridian is a "thing"

[robertlach]

I am not an expert but 1080 looks like 480p... strange.

[joemmac]

L.I. is Long Island. That's the large island at the bottom of NY State that part of NYC is on (Brooklyn and Queens) as well as two other counties (Nassau and Suffolk).