Test Equipment Anonymous (TEA) group therapy thread

[m k]

Dallas chip is not ROM, it's RAM with battery, maybe also RTC.
It's completely internal when Vcc goes down, so you can't test its internal battery without opening its case.
If settings are not permanent you can guess that battery is empty.
If the chip includes an RTC and has low battery the time was usually first to stop functioning.

Normally PC has a setup where default values can be selected by a single button.
Old PCs had it differently and very old PCs had old style HD settings.
Back in the day empty batteries was a regular thing, so how to boot was also noted somewhere.
I had a habit to ink HD number on the back of the case.
If current time and power off was needed inputting time after every power on was irritating very fast.

Some PCs had also an external battery connector.
I remember that it was regularly changed to in use, but can't remember what the actual chip was.

Would like to strip these boards, but it just takes to long

Unbent legs and you have a change.

I tried unregulated hot air fun, it wasn't very nice.
Chips didn't fall out, I had to knock the board.
Finally many were off, but many were also lumped together.

Pros had a small wave pot.
There you had rollers inside a tin and moveable walls.
Rollers were pushing the wave up and over the walls.
Height is critical, so some sort of a jig is also needed.

Don't know how regular hot air thing works.
The body has quite a bit of mass.

[TERRA Operative]

OK, down the rathole again with a CSA8000b...

4 to 5 yrs ago, I bought a CSA8000B for $150.  The person was local, college student thought it was a scope, even delivered it. It powered on but had the Dallas eeprom (if that's the right term) issue so it didn't boot.  The instructions on eevblog are good and I was able to bring it up but you need the dallas eeproms to hold the boot instructions or its a hassle getting it to run.  So I bought the dallas modules for both the PC and PPC boards, carefully soldered them on, had to go back and touch them up, etc.  Not a lot of fun as one is up next to a card connector and yes, I had some melted plastic by the time it was done.  I had programmed the eeproms and the unit booted correctly. I have a 20Ghz electrical module and that came up.  But when I measured the calibrator, I remember the voltage was low by a factor of 10 maybe. So after playing around with settings I powered down, reseated the cards and of course, my brand new eeprom from asia hadn't held the config.  There isn't much in there, just a couple instructions on where to find the PPC boot code!  But do you think it could keep it just once!! Nope.

And this really po'ed me!  While typing this the guy who agreed to sell it to me for the asking price just said he had a higher offer, $50 more.  That's a little lame, don't you think?  Told him to keep it.  This is a company too, not just a person on the web.  I mean is that any way to do business? 

Jerry

What NVRAM's did it use? Some can be replaced with FRAM, other NVRAM's are still available new from Digikey/Mouser.
I have a couple new chips at home (date codes of late last year) that I bought as spares when I was replacing them in some TDS500/600 scopes. You can't buy the timekeeper ones new but some of the standard ones you can.

There's also a guy on ebay (kellyjo IIRC?) that makes reproductions that work great, and have accessible batteries for easy future replacement.
I have them in my TDS784D and TDS794D and they work great.

[m k]

What was the removable cover and changeable batteries version?

[TERRA Operative]

The NVRAM's? Here's a link to the ebay store.

https://www.ebay.com/str/kellyjo13

[wkb]

I hacked very similar battery backed RAM modules (albeit Mostek,I think 48T02 or so?,  as used by Sun in their Sparcstations) by gently filing (Dremel will do too) the top section off which contains the Li battery. Subsequently solder wires onto the original lead(frame) and wire it up to a fresh Li battery.

Looks so-so but worked like a charm. And cheap, if you do not count your time invested in the hack.

Wilko

[TERRA Operative]

Yeah, I have kept a bunch of the old Dallas chips to modify when I get around to it. Especially the timekeeper ones as they are unobtanium these days.

[wkb]

Should you ever need one, give me a shout. I have been packrat-ting them for quite a while now...

[Martin.M]

if any one have application from Tek 2755Ap (or 492 etc),

PSU: +9V: = 1,2V 

this please 

greetings
Martin

[cncjerry]

What was the removable cover and changeable batteries version?

No, you couldn't get NVRAM apart without a lot of work.  I also remember that some versions have the battery coupled to an external pin, and that wasn't the case with those in the CSA8000. 

What bugs me the most is the seller backed out and sold it to another person for $50 more.  Then said I was the bad guy.  So I wrote a letter to his CEO asking if he condones that behaviour.  We'll see what he says.  In over a hundred transactions on craigslist, this never happened before.  I hope the new buyer needs the disk images at some point, they all do eventually, because i am one of the few that still has them.

I have to fix the display power supply on my TDS784.  Then I'll take a crack at the CSA8000 that I have.

Jerry

[TERRA Operative]

I have some spare CRT boards for the TDS700 scopes if you need one.

[m k]

The NVRAM's?

Not that, the old one.

It can't be a dream, it was just like the Dallas on, maybe a bit thicker with two changeable coin cells, I can even "see" its flayer.
It came by when Dallas was leaving behind, from PCs that is, must early '90s the latest.
Maybe it was too short lived thing to be remembered and I saw its peak.
Anyway, most likely not among us anymore, and google was of course the usual self.

[TERRA Operative]

Analog/Maxim have their PowerCap module that is an NVRAM in which the battery clips on top, but it's a coin cell in a plastic/PCB holder.

https://www.google.com/search?q=PowerCap+Module&tbm=isch

[m k]

Yes, generally quite nasty construction if exporting valuable data is not trivial.
Though the next step after that for PCs, a rechargeable and leaking battery, was not much better.

I'm also having more recollections, possibly fake.
One is that one Dallas clone wasn't a clone enough, possibly missing a century data.
There probably wasn't very many of them, so maybe this is the one with changeable batteries, or maybe it was so clone that Dallas took it down.
One other is that some possibly RTC chips had a special DIL socket with claws preventing them popping out.
Some also had panduits around them, but that's just ad hoc evolution.

Maybe I must start digging through old magazine ads, maybe not.

[Ice-Tea]

I found someone that is reasonably equiped to do some hobby+ grade adjustments and calibrations for me from time to time. Certainly not for all devices but I hope to be able to work with him for devices that have lost cal memory. Example:

https://www.ebay.de/itm/145695383205?itmmeta=01HT8G38K40K7WEK06B9FP4Q64&hash=item21ec1f1ea5:g:gpkAAOSw4cZmB~NT

I'm not trying to flip the unit to you guys but I was just wondering what your impression is? Does this offer added value? Would it increase your likeliness to purchase? Would you be willing to pay a few bucks more? Further tips and tricks?

Thoughts greatly appreciated...

[AVGresponding]

I found someone that is reasonably equiped to do some hobby+ grade adjustments and calibrations for me from time to time. Certainly not for all devices but I hope to be able to work with him for devices that have lost cal memory. Example:

https://www.ebay.de/itm/145695383205?itmmeta=01HT8G38K40K7WEK06B9FP4Q64&hash=item21ec1f1ea5:g:gpkAAOSw4cZmB~NT

I'm not trying to flip the unit to you guys but I was just wondering what your impression is? Does this offer added value? Would it increase your likeliness to purchase? Would you be willing to pay a few bucks more? Further tips and tricks?

Thoughts greatly appreciated...

People on ebay want bargains; I doubt you'd get the money back you spent, at least on "calibration". Calibration only really adds value when it's traceable and over a period of time in order to demonstrate drift, or lack thereof, for example.

It might be worth it for as you say things that have lost cal memory, maybe...

[tggzzz]

I found someone that is reasonably equiped to do some hobby+ grade adjustments and calibrations for me from time to time. Certainly not for all devices but I hope to be able to work with him for devices that have lost cal memory. Example:

https://www.ebay.de/itm/145695383205?itmmeta=01HT8G38K40K7WEK06B9FP4Q64&hash=item21ec1f1ea5:g:gpkAAOSw4cZmB~NT

I'm not trying to flip the unit to you guys but I was just wondering what your impression is? Does this offer added value? Would it increase your likeliness to purchase? Would you be willing to pay a few bucks more? Further tips and tricks?

Thoughts greatly appreciated...

People on ebay want bargains; I doubt you'd get the money back you spent, at least on "calibration". Calibration only really adds value when it's traceable and over a period of time in order to demonstrate drift, or lack thereof, for example.

It might be worth it for as you say things that have lost cal memory, maybe...

That's pretty much my feeling too.

When I flog stuff on fleabay, I show the readings alongside the readings of other good quality but out-of-calibration equipment.

[Kosmic]

I found someone that is reasonably equiped to do some hobby+ grade adjustments and calibrations for me from time to time. Certainly not for all devices but I hope to be able to work with him for devices that have lost cal memory. Example:

https://www.ebay.de/itm/145695383205?itmmeta=01HT8G38K40K7WEK06B9FP4Q64&hash=item21ec1f1ea5:g:gpkAAOSw4cZmB~NT

I'm not trying to flip the unit to you guys but I was just wondering what your impression is? Does this offer added value? Would it increase your likeliness to purchase? Would you be willing to pay a few bucks more? Further tips and tricks?

Thoughts greatly appreciated...

Considering the calibration state and accuracy (vs Keithley 2700) of the Datron 4805, To me it's pretty much the same as saying it was 100% tested. I expect something like that if you sell something used. I wouldn't pay necessarily more but I might be more incline to buy since it look well tested.

BTW you should check the ACI 20mA range on your Keithley 2700. Something is off 

[Peter_O]

People on ebay want bargains; I doubt you'd get the money back you spent, at least on "calibration".
It might be worth it for as you say things that have lost cal memory, maybe...

Maybe most buyers might just want to play with the instruments. They want to take the fun action to gain additional value themselves and not pay for it. Maybe it's better to advertise the instrument models with additional value projects well documented in the community (like changing batteries or caps, calibration, EPROM burning, ...) without specific info, which actions have been taken. Better to tease the people e.g. with error messages or display pictures to indicate potential for this kind of projects. As a seller it might be imposslible to gain any margin on this kind of action, yes.

[factory]

People do sometimes buy the pricey items of TE on ebay, even those that are listed as untested or have damage/missing parts or are clearly faulty, from well known business sellers. They do take longer to sell though.

David

[m k]

At some point merchandise inventory is mostly paid, or should be.
Means that you can pay in cash.
Other direction is time.

Is this extra service a form of R&D, I'd say it is.
It may take some time, or some more.

What I've learned from daily stuff is that certain customer base is buying certain amount and widening inside a range is not really helping.
Maybe daily stuff is too different.

[Robert763]

I've noticed recently that a number of the descriptions for ebay items appeared to be written by AI.
Lots of waffle and "weasel words". I found out last night that ebay, in the UK at least, is offering AI generated descriptions   

Mind you they also have categories for items that are specificlly excluded by their prohibited items policy e.g. pulse oximeters.

[tggzzz]

I've noticed recently that a number of the descriptions for ebay items appeared to be written by AI.
Lots of waffle and "weasel words". I found out last night that ebay, in the UK at least, is offering AI generated descriptions   

The quality is completely unsurprising. If statistical parrots ever produce more than word salad, it is only random chance.

Time to have some fun by inserting the word salad in listings, marking it as such, and asking if people still think their jobs are at risk.

[Ice-Tea]

When I flog stuff on fleabay, I show the readings alongside the readings of other good quality but out-of-calibration equipment.

That's what I normally do. Most of the time not really an option to do that for all ranges etc. though...

Considering the calibration state and accuracy (vs Keithley 2700) of the Datron 4805, To me it's pretty much the same as saying it was 100% tested.

That's pretty much the target. I don't mean to confuse this with a proffesional calibration (even though the pedigree of 'my guy' suggest his gear would be prett close to calirbation standards...

I expect something like that if you sell something used.

For the most part, you'd be right but I sometimes I neither have the gear or the time to look into everythin.

I wouldn't pay necessarily more but I might be more incline to buy since it look well tested.

Looking at a potential ebay customer pool, being more inclined to buy equates ending up with a higher selling price ;-)

BTW you should check the ACI 20mA range on your Keithley 2700. Something is off 

Huh, thanks for that. Completely missed it. Need to check this with him, smells like a Datron issue to me but I'll double check on my end by pitting the 2700 against a 34401 ;-) This would also have been one of the things I wouldn't have checked so if it's not setup error this is proving it's value I suppose...

[KubaSO]

The last few months I've been working on resurrecting a HP 5245L counter, that was pillaged & left for dead, it's one of the few left that was built in the Bedford HP factory, which was only in use for a couple of years, before production moved to Scotland.

[...]

David

Wow, what an amazing rescue. Thank you for saving this girl from the recyclers. It was a labor of love, well appreciated.

[m k]

just got an order confirmation for ADJ LINEAR REG, LR8N3-G.
Maybe I'm actually getting them this time, original order was mid October.

Regulator is not futile.