Test Equipment Anonymous (TEA) group therapy thread

[Ero-Shan]

Bugger it, soldering the back battery into place, thought I'd just check that the Cal data was safe before disconnecting the fitted battery, screen says "uncalibrated".

Then it hit me, the solder was touching the bloody chassis as I was making the positive connection to the ram, so now I too have to get the 3478A calibrated, I fucked it 

Oh well I'll continue with the battery and filter caps replacement, then look for a calibration centre near me 

Oomph. This only shows that my precautions with reading the cal data via GPIB off my 3458A was a sensible thing to do, even though it proved unnecessary in the end. I'm just too prone to fucking up myself. I'm sorry for you and bd139, really.

When I do start on my 3478As, I'll hopefully remember these lessons!

I'm asking myself if it had made sense to make the batteries easily replaceable. Not much danger with corrosion and lithium cells, is there? And no need to use the cheapest holders. But maybe the designers thought that by the time a battery change was required, a re-calibration would be also due anyway ...

And with the 3458A, it's not just one battery, but three RAMs! Did they really think this instrument would be used just for about ten years? Or that desoldering/soldering them every ten years would be normal maintenance? I have the greatest respect for HP engineers, but some design decisions are questionable. 

Ero-Shan, who's not the best engineer in the world

[Ero-Shan]

I think to be honest its a failing of all the more modern meters which have the software driven calibration  that require a battery to retain the data. That battery will at some point need replacing before it fails and accident while replacing could erase the cal data. I would thought it might be better to use something like an EEPROM that does not requires batteries, may be newer meters do?

That was my thought also. But 30 (or more) years ago, when these meters were designed, typical EEPROMs guaranteed only 10 years data retention, just like the batteries. And RAMs are so much easier to work with. I think that design decision was sound.

Ero-Shan, who's written several "failsafe EEPROM file systems".

[Specmaster]

Well it's like bd139 said, at least others can learn from our mistakes so that's good. As to the battery / recalibration timing, yes I think you may have a point, although calibration should be annually. Maybe they thought the battery replacement would coincide with calibration. The target buyers for these meters was always the professionals such as labs etc, never hobbiests or collectors like most of us, so expense was not an issue to those customers.

It is however a very nice meter and if you don't need to have a traceable calibration certificate, more than capable of holding the calibration for many years as per Davies video.

Bugger it, soldering the back battery into place, thought I'd just check that the Cal data was safe before disconnecting the fitted battery, screen says "uncalibrated".

Then it hit me, the solder was touching the bloody chassis as I was making the positive connection to the ram, so now I too have to get the 3478A calibrated, I fucked it 

Oh well I'll continue with the battery and filter caps replacement, then look for a calibration centre near me 

Oomph. This only shows that my precautions with reading the cal data via GPIB off my 3458A was a sensible thing to do, even though it proved unnecessary in the end. I'm just too prone to fucking up myself. I'm sorry for you and bd139, really.

When I do start on my 3478As, I'll hopefully remember these lessons!

I'm asking myself if it had made sense to make the batteries easily replaceable. Not much danger with corrosion and lithium cells, is there? And no need to use the cheapest holders. But maybe the designers thought that by the time a battery change was required, a re-calibration would be also due anyway ...

And with the 3458A, it's not just one battery, but three RAMs! Did they really think this instrument would be used just for about ten years? Or that desoldering/soldering them every ten years would be normal maintenance? I have the greatest respect for HP engineers, but some design decisions are questionable. 

Ero-Shan, who's not the best engineer in the world

From mobile device so predictive text might have struck again [emoji83]

[Ero-Shan]

Here we go again ...

After acquiring that boat anchor I resolved to fight GAS and ignore fleabay. This worked amazingly well for two months. It wasn't too hard, even. As a result, I spent my time and money to my other hobbies.      Since my rooms are full enough, I thought it would be easy to stick to it.

Then, last week, I sat in front of my computer, drinking my coffee and idly browsed the web. Nobody knows how I landed at the bay, but suddenly I was there! And then I saw it: a beautiful Philps PM2421 DMM. Reasonable price. How in all the world could I have resisted this? I'm just a weak human, after all! This DMM could not be allowed to go anywhere but my place. Isn't it understandable that I relapsed? I won the auction late Friday night at a still reasonable bid. Although I wire transferred the money within 5 minutes, that thing wasn't sent until Thursday and still hasn't arrived. 

I found a good scan of the manual, and looking at the schematics, it suddenly occurred to me why I might have that sweet spot for Philips.

Our first radio was a Philips Philetta, bought a year before I was born. I remember looking through the perforated cardboard back panel as a kid and being mesmerized by the magical glow of the valves and the mysteries of its operation.
Our first record player was a Philips.
Our first TV was a Philips b&w set. We were the last in the street to own one.
With the first money that I earned myself (a holiday job), I bought a Philips EE2000 "electronics lab".
Now, looking at the schematics all this came back to me. Philips' schematics are my reference. They are just beautiful. Highly skilled draftspersons created pieces of art that really help understanding the function.
Philips may not be revered as HP, Fluke or Tektronix are. But, IMHO, they were not that far behind.

A few minutes ago I saw the DHL van in the street next to mine. Where has it gone? It ought to be in front of my house by now! 

[tautech]

Even here in NZ on the other side of the world the 60's (when I was a tot) were mostly 'owned' by Philips gear too.

[Specmaster]

The only problem with Philips gear is the quality of their plastics. I have a pm2521  that sadly now has stopped working, I think the eprom has become corrupted as every range ends up displaying 2[emoji852]️

If I could find another at reasonable cost I'd have a go at making at least one from 2, I loved that meter, my first 4.5 digit one.

Here we go again ...

After acquiring that boat anchor I resolved to fight GAS and ignore fleabay. This worked amazingly well for two months. It wasn't too hard, even. As a result, I spent my time and money to my other hobbies.      Since my rooms are full enough, I thought it would be easy to stick to it.

Then, last week, I sat in front of my computer, drinking my coffee and idly browsed the web. Nobody knows how I landed at the bay, but suddenly I was there! And then I saw it: a beautiful Philps PM2421 DMM. Reasonable price. How in all the world could I have resisted this? I'm just a weak human, after all! This DMM could not be allowed to go anywhere but my place. Isn't it understandable that I relapsed? I won the auction late Friday night at a still reasonable bid. Although I wire transferred the money within 5 minutes, that thing wasn't sent until Thursday and still hasn't arrived. 

I found a good scan of the manual, and looking at the schematics, it suddenly occurred to me why I might have that sweet spot for Philips.

Our first radio was a Philips Philetta, bought a year before I was born. I remember looking through the perforated cardboard back panel as a kid and being mesmerized by the magical glow of the valves and the mysteries of its operation.
Our first record player was a Philips.
Our first TV was a Philips b&w set. We were the last in the street to own one.
With the first money that I earned myself (a holiday job), I bought a Philips EE2000 "electronics lab".
Now, looking at the schematics all this came back to me. Philips' schematics are my reference. They are just beautiful. Highly skilled draftspersons created pieces of art that really help understanding the function.
Philips may not be revered as HP, Fluke or Tektronix are. But, IMHO, they were not that far behind.

A few minutes ago I saw the DHL van in the street next to mine. Where has it gone? It ought to be in front of my house by now! 

From mobile device so predictive text might have struck again [emoji83]

[Specmaster]

Apparently my AM/FM signal generator is out for delivery to me today, oh goody more new toys to play with. Just hope I have a better day today then I did yesterday

[bd139]

Good luck 

I’m doing a kids party today for 5 year olds so no TEA for me 

[Specmaster]

Well enjoy it anyway and I expect that they'll be plenty of "coke" on offer  and you can follow the rest of poor TEA addicts on your phone no doubt.

[GerryBags]

Good luck 

I’m doing a kids party today for 5 year olds so no TEA for me 

See, if you had some of that oscilloscope music to hand and could get all the digits on your DMMs fluctuating in time to it, you could throw the ankle-biters a proper TEA-party! Most of the big kids on this forum would love it, so the little kids probably would too 

[bd139]

If only. Contemporary music, plastic crowns and tantrums here we come.

[Ero-Shan]

Part II

With the floodgates already opened, had me in its ugly claws again. And as I always wanted to have a pulse generator (for whatever reason still unknown), a Systron-Donner Datapulse 101 seemed like a good first start. I was at a birthday party when the auction ended, so I placed a decent bid on it. against my expectations, I did win the auction (Sunday evening), and received the device on Tuesday.



Not exactly a beauty, but OK.

Heeding all your warnings and having learned something myself, I opened it only to find that one of the filter caps rattled. A bad solder joint.



I checked the bigger caps with my LCR meter and they all looked good.

So I powered it up. I do this now with a variac and monitoring the current while. No surprises. If only it worked, though. There's a signal coming out of it, and the amplitude can be altered by the output control, but that's about it. It doesn't really look like what I'd call a pulse, and the repetition rate and pulse width settings don't affect it.

Not having a manual for the 101 (maybe the available 100 manual/schematics is reasonably close), I wasn't in the mood to investigate further.
For the moment, I count this as a blank. 

[bd139]

I'm always surprised at the number of dodgy joints you get on test gear.

On the LCD vs illumination thing earlier, I have installed the lights on my bench now, a shitty LED strip + inline switch + wall wart. Under £15 the lot.

It reflects enough light off the walls and around that it lights up all the LCDs on the shelf above (!)

Need to stick some aluminium L section in front of it to stop it shining directly in the eyes.

[Specmaster]

I'm always surprised at the number of dodgy joints you get on test gear.

On the LCD vs illumination thing earlier, I have installed the lights on my bench now, a shitty LED strip + inline switch + wall wart. Under £15 the lot.

It reflects enough light off the walls and around that it lights up all the LCDs on the shelf above (!)

Need to stick some aluminium L section in front of it to stop it shining directly in the eyes.

Looking very nice, I have some LEDS on the wall behind me at face level and they also illuminate my LCDs OK but would be nice to have lights in the displays as well.

From mobile device so predictive text might have struck again [emoji83]

[frozenfrogz]

Not having a manual for the 101 (maybe the available 100 manual/schematics is reasonably close), I wasn't in the mood to investigate further.
For the moment, I count this as a blank. 

All hail the mighty overlords of web services!
This might be what you are looking for: https://kb8ojh.net/images/datapulse-101.pdf

Kind regards, Frederik

Edit: On a side note, what a BEAUTY! this manual cover is!

[Berni]

I'm always surprised at the number of dodgy joints you get on test gear.

On the LCD vs illumination thing earlier, I have installed the lights on my bench now, a shitty LED strip + inline switch + wall wart. Under £15 the lot.

It reflects enough light off the walls and around that it lights up all the LCDs on the shelf above (!)

Need to stick some aluminium L section in front of it to stop it shining directly in the eyes.

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Nice tidy bench. Im just working on getting LED strips above my bench in the same way. I added a longer shelf above my existing ones so that it overhangs my bench more. Not terribly woried about LCD screens since all the gear has some sort of self illuminating screen like color LCD, VFD, LED, CRT etc

The snag so far is that the first cheap LED strip i got from china had a awful color temperature. I didn't have high hopes in the first place since it was so dirt cheep, the other one i bought as a backup hasen't got here yet. I think the mistake was that i ordered a "Pure white" color. They didn't say how many kelvin it was but i assumed it was the typical daylight white that i like in workplaces. Turns out the color temperature is significantly higher than 6500K as it looks quite blueish compared to my 6500K fluorescent lights, really unpleasant to work under i think. The other one i bought as a backup claims to be "6000-7000K" so that should be what i want, we will see when it gets here.

[bd139]

These are “warm white” ones from here: https://www.bitsbox.co.uk/index.php?main_page=product_info&cPath=172_367&products_id=3360

Agree entirely about the colour temperature. There too much blue in the non warm ones. Does your eyes in.

Slightly worried about the noise off the cheap switcher. Will fire up my radio and have a listen later.

[Specmaster]

These are “warm white” ones from here: https://www.bitsbox.co.uk/index.php?main_page=product_info&cPath=172_367&products_id=3360

Agree entirely about the colour temperature. There too much blue in the non warm ones. Does your eyes in.

Slightly worried about the noise off the cheap switcher. Will fire up my radio and have a listen later.

Exactly, the RGB ones might be an idea as you select a colour or mix your own using the remote control. My LEDS are proper under cabinet fittings my done got his work for me which I think are warm white but not sure as the packaging did not specify.

From mobile device so predictive text might have struck again [emoji83]

[Ero-Shan]

All hail the mighty overlords of web services!
This might be what you are looking for: https://kb8ojh.net/images/datapulse-101.pdf

Kind regards, Frederik

Edit: On a side note, what a BEAUTY! this manual cover is!

Thanks a million (hail, hail)! How did you find this one?

And yes, you're right, the manual cover is nice. Though the cover of the Datapulse-100 manual looks even better, IMHO.

No more excuses. Now I really need to try fix it.

[frozenfrogz]

How did you find this one?

And yes, you're right, the manual cover is nice. Though the cover of the Datapulse-100 manual looks even better, IMHO.

Just regular Google foo with rather fuzzy search terms (how I usually start). Since Google delivers personalized and localized search results, I tend to use both, Startpage and Google. I think I searched for "sd datapulse 101 schematic" and "sd datapulse 101 service manual" or "datapulse 101 service manual" on google first.

Need to check out the 100 manual for viewing pleasure

[Cerebus]

Good luck 

I’m doing a kids party today for 5 year olds so no TEA for me 

Ah! Van Der Graff generator time then, or perhaps the Wimshurst. 

[bd139]

These are “warm white” ones from here: https://www.bitsbox.co.uk/index.php?main_page=product_info&cPath=172_367&products_id=3360

Agree entirely about the colour temperature. There too much blue in the non warm ones. Does your eyes in.

Slightly worried about the noise off the cheap switcher. Will fire up my radio and have a listen later.

Exactly, the RGB ones might be an idea as you select a colour or mix your own using the remote control. My LEDS are proper under cabinet fittings my done got his work for me which I think are warm white but not sure as the packaging did not specify.

From mobile device so predictive text might have struck again [emoji83]

My desk lamp has an interesting design. It has yellow LEDs mixed with the white ones and you can change the duty cycle them. Results in infinite warmth adjustment.

[Cerebus]

One place I find LED lighting a PITA is when trying to decipher the modern "mud on light blue" colour code printing on through hole resistors. You only stand a chance with those if you use tungsten or daylight.

[Cerebus]

Heads up: probable fraudulent ebay TEA listings.

There are a couple of scopes listed (for auction) by sniff277 that use a link in the details to make 'buy it now' offers and say that bids will be ignored. From the poor use of English, versus the very English name of the account holder, I suspect this to be a hacked account.

[bd139]

Good spot. I was looking at his 83732A and it looked hooky.