Test Equipment Anonymous (TEA) group therapy thread

[Specmaster]

Dang it the SMU i was talking about got away from me: https://www.ebay.com/itm/152777499454?ul_noapp=true

Wasnt me, I don't have a use for a SMU anyway other than door stop.

[Cerebus]

Dang it the SMU i was talking about got away from me: https://www.ebay.com/itm/152777499454?ul_noapp=true

Bad luck. I've seen some of those go for rock bottom prices in the past, so it's  a good one to keep your eyes open for. One of the Japanese HP/Yokogawa designs.

[bd139]

Someone is selling 6632B’s for £100 a pop in the for sale thread. Trying not to buy one. Must resist!

[Specmaster]

What do you mean resist??? resistance is futile, you want it go get it.

[capt bullshot]

Someone is selling 6632B’s for £100 a pop in the for sale thread. Trying not to buy one. Must resist!

Don't buy one. They're noisy and IMO they should better have 25V / 4A than 20V / 5A, and you want to add front panel binding posts.
(already own 2, won't buy any more though they are at a bargain price)

[bd139]

Thanks for the tip. I assume as in fan noise? Expecting that in this case.

I was planning to use a spare 19" 1U blanking plate I had lying around from a network job and building a terminal array for it.

Toy arrived. Yay. I'm really liking this meter. Makes the UT61E's look like a joke. Also came with the USB-IR cable which I was not expecting so Im super happy 

[capt bullshot]

Thanks for the tip. I assume as in fan noise?

Yes, it is. It's beaten only by the Kepco BOP (half rack 100W variant), but it's quite possible to replace the fan.

[bd139]

Is it a mains powered fan or DC? I had a 5328A that was loud as hell with a mains powered fan. Decided to shift it after a bit because it wasn’t worth modding (it was sick anyway).

[bd139]

Got my U1241C to talk to the mac already. Turns out it has bog standard SCPI over serial even though it's not documented anywhere. Good job Keysight!


import serial
import time

p = serial.Serial('/dev/tty.usbserial')
while True:
   p.write(b"FETC?\r\n")
   print(float(p.readline().decode('utf-8')))
   time.sleep(1)


Serial driver is a case of installing the Prolific PL2303 driver. This has to be done twice because the kext isn't signed.

[Specmaster]

Looks a nice meter does that, like the illuminated buttons 

[bd139]

Indeed. Rather happy with it. I'll get shot probably but I'm actually glad I didn't buy Fluke.

Interestingly, and I don't know if this is just a conversion artifact or not, but it seems to have an extra digit when using the USB-IR interface:

[Specmaster]

Time to batten down the hatches and put the tin hat on 

[Mr. Scram]

Looks a nice meter does that, like the illuminated buttons 

I wanted to say the same!

[HalFET]

Indeed. Rather happy with it. I'll get shot probably but I'm actually glad I didn't buy Fluke.

Interestingly, and I don't know if this is just a conversion artifact or not, but it seems to have an extra digit when using the USB-IR interface:

Not unheard of (e.g. Keithley 2001 can be configured to 8.5 digit), question is if the hardware has the punch to back it up.

[Specmaster]

Looks a nice meter does that, like the illuminated buttons 

I wanted to say the same!

You just did 

[Mr. Scram]

Not unheard of (e.g. Keithley 2001 can be configured to 8.5 digit), question is if the hardware has the punch to back it up.

Yes. If I stick a lead in either ear I can tell you the voltage up to 12 digits. Accuracy isn't guaranteed, though.

[Specmaster]

Not unheard of (e.g. Keithley 2001 can be configured to 8.5 digit), question is if the hardware has the punch to back it up.

Yes. If I stick a lead in either ear I can tell you the voltage up to 12 digits. Accuracy isn't guaranteed, though.

Particularly at the higher voltages.

[ChrisLX200]

Oh I dunno, be a linear relationship to the audio output?

[Specmaster]

Oh I dunno, be a linear relationship to the audio output?

Complete with expletives 

[capt bullshot]

Is it a mains powered fan or DC? I had a 5328A that was loud as hell with a mains powered fan. Decided to shift it after a bit because it wasn’t worth modding (it was sick anyway).

It's DC powered, speed controlled by the main CPU depending on the load. However, it's a simple two wire model, no fancy PWM speed control afair. It's all in the service manual, the service manual has complete schematics of the analog / power electronics part. It's a two quadrant supply, handy if you need an electronic load, but not as versatile as a modern electronic load like the one Dave uses to test batteries - still looking around for such one.

Edit: Oh, it has another source of noise: The mains transformer. Due to its low profile, the transformer is a bit of a strange thing, sometimes causing the enclosures' sheet metal to hum at line frequency.

[bd139]

Thanks for info. I’m putting that purchase on hold until I’ve done some more research I think!

I’m trying to hold back on the TEA for a little bit and complete the first part of the project I’m working on. Not doing very well so far. I have however designed the power supply for it on paper. I’ve never put my brain to designing very low noise switching converters. Turns out to be a total dick to do when keeping it in a BOM price point.

[URI]

Is it a mains powered fan or DC? I had a 5328A that was loud as hell with a mains powered fan. Decided to shift it after a bit because it wasn’t worth modding (it was sick anyway).

As capt bullshot wrote: It's a DC-Fan, Papst 12V, 2.5W, Type 612; A 60mmx60mmx25mm ball bearing type with about 3000 to 4000 RPMs I guess. I've replaced one of those in my HP 6643A with a Sunon Maglev DC 12V 1.5W fan (MB60251V1-00U-A99). CFM was a wild guess but it seems I guessed quiet good. Nevertheless I also ordered another Model with higher CFM to test with it as the exhausted air gets quit warm (as with the papst).

The annoying sound of the papst is due to the ball bearings. The Sunon is much quieter -only the sound of the air flowing is there and that can't be avoided in this application. 

And yes, the transformer is humming relatively loud -you have to like the 50Hz sound -or keep the papst. 

But all things considered I like this beast and wouldn't give it away. Fitting front binding posts is in the queue*. 

--
* - meanwhile the paint job is done and the plate fits the colour of the 6632B quiet well.

[Specmaster]

Is it a mains powered fan or DC? I had a 5328A that was loud as hell with a mains powered fan. Decided to shift it after a bit because it wasn’t worth modding (it was sick anyway).

As capt bullshot wrote: It's a DC-Fan, Papst 12V, 2.5W, Type 612; A 60mmx60mmx25mm ball bearing type with about 3000 to 4000 RPMs I guess. I've replaced one of those in my HP 6643A with a Sunon Maglev DC 12V 1.5W fan (MB60251V1-00U-A99). CFM was a wild guess but it seems I guessed quiet good. Nevertheless I also ordered another Model with higher CFM to test with it as the exhausted air gets quit warm (as with the papst).

The annoying sound of the papst is due to the ball bearings. The Sunon is much quieter -only the sound of the air flowing is there and that can't be avoided in this application. 

And yes, the transformer is humming relatively loud -you have to like the 50Hz sound -or keep the papst. 

But all things considered I like this beast and wouldn't give it away. Fitting front binding posts is in the queue*. 

--
* - meanwhile the paint job is done and the plate fits the colour of the 6632B quiet well.

Nice job.

Sent from my SM-J510FN using Tapatalk

[bd139]

That looks pretty awesome. So you’ve pulled the sense lines and switch up front as well. Good plan. If I got one I’d be considerably lazier

[Zucca]

cool, please provide info how you did it.