Test Equipment Anonymous (TEA) group therapy thread

[Vince]

Thanks for the info David. Let me know if you might be interested in the remains of mine to enrich your collection... I think I will keep it for a few days then it will dispose of it .... 

[Robert763]

Hi Vince,
Factory said it all. Bit of info on repair here:
https://www.samuelritchie.com/repair-hp10525a
For some reason the complete probes have been fetching a fair bit on ebay in rcent years.
I have few HP logic troubleshooting bits including a probe, pulser, currrent tracer, clip and comparator. don't really need any more.

Robert.

[Vince]

Thanks for the links, interesting. There is more electronics inside this thing than I would have believed given its vintage...

OK so looks like there is not much hope to rescue this little guy then... at least I tried, I gave him a chance...

[factory]

Thanks for the info David. Let me know if you might be interested in the remains of mine to enrich your collection... I think I will keep it for a few days then it will dispose of it .... 

Yes I would be very interested in saving this early version of the HP logic probe & adding it to my collection  , seems they redesigned the circuit to use less parts for the 1973 "T" version. The tips are almost certainly the same types, that can be used with the HP or Tek scope probes of similar age.

If it needs a new lamp, I won't ruin it with a crappy blue/white LED.

Thanks Robert for the link that shows what is inside, I would never have guessed it was different otherwise. The logic kits seem to be popular with repairers of older computer & arcade boards, can't understand why they are willing to pay crazy money for them though. 

David

[Vince]

Yes ! Little guy just found a new home !    Thanks David !

I will send it shortly.

Yes please no blue LED... when I saw that in this repair PDF I just couldn't believe my eyes, I was appalled... I was hoping someone who can appreciate vintage stuff would be a little different from the blue LED band wagon but looks like no, I was wrong, the dreaded blue LED trend has corrupted even the tiniest of niches 

[factory]

Rather than go for the overpriced manuals on ePay for the 10525A (two of which are $50 each, more than a listing for a probe complete with the manual at $35 ), I've done some research and have found out a patent was issued for this HP logic probe, it contains a description of the circuit and a circuit diagram (differs slightly from the 1969 variant in the repair im-pair pdf, which has an extra diode & resistor).



The only IC is a quad TTL Nand gate from TI, the later probe appears to have a custom IC, possibly related to adding the dim lamp mode for detecting open circuits, as well as reducing the parts count.

David

[McBryce]

Rather than go for the overpriced manuals on ePay for the 10525A (two of which are $50 each, more than a listing for a probe complete with the manual at $35 ), I've done some research and have found out a patent was issued for this HP logic probe, it contains a description of the circuit and a circuit diagram (differs slightly from the 1969 variant in the repair im-pair pdf, which has an extra diode & resistor).



The only IC is a quad TTL Nand gate from TI, the later probe appears to have a custom IC, possibly related to adding the dim lamp mode for detecting open circuits, as well as reducing the parts count.

David

I wonder why he placed the Bulb (43) all the way to the left instead of over TR41? It complicates the diagram for no real reason.

McBryce.

[tggzzz]

I wonder why he placed the Bulb (43) all the way to the left instead of over TR41? It complicates the diagram for no real reason.

The patent is explicit about having the "visual indicator" right next to the test point / electrode.

[Vince]

Yes that's what I thought too, sounded logical to me.
However what I fail to understand is why they tapped the +5V rail at the other end of the schematic, running a super long wire, even crossing another wire... instead of just tapping it literally right by the bulb ?! 

[tggzzz]

Yes that's what I thought too, sounded logical to me.
However what I fail to understand is why they tapped the +5V rail at the other end of the schematic, running a super long wire, even crossing another wire... instead of just tapping it literally right by the bulb ?! 

I guess it is merely visual emphasis that the indicator isn't "at" the output, it is "by" the input.

[McBryce]

I wonder why he placed the Bulb (43) all the way to the left instead of over TR41? It complicates the diagram for no real reason.

The patent is explicit about having the "visual indicator" right next to the test point / electrode.

Fully with you, but a schematic is a schematic. It's not meant to contain any physical / positional information. I could understand it, if it was some critical RF part that needed to be distanced from some other component, but this is an indicator bulb.

McBryce.

[tggzzz]

I wonder why he placed the Bulb (43) all the way to the left instead of over TR41? It complicates the diagram for no real reason.

The patent is explicit about having the "visual indicator" right next to the test point / electrode.

Fully with you, but a schematic is a schematic. It's not meant to contain any physical / positional information. I could understand it, if it was some critical RF part that needed to be distanced from some other component, but this is an indicator bulb.

Oh, we agree, but it is fun to be the Devil's Advocate.

The purpose of any diagram is to communicate anything that is considered important.

Many schematics include more than just connectivity, e.g. the Tek 4x5 scopes where schematics also include PCB boundaries, and a PCB is spread across several schematics. Some schematics include physical info, e.g. notation indicating thermal coupling or being on a heatsink etc.

More importantly, they ought to show components grouped in familiar "design patterns" that indicate the subcircuit's intention. That allows anything departing from that to be instantly visible, and hopefully to highlight something novel and relevant.

[tautech]

I wonder why he placed the Bulb (43) all the way to the left instead of over TR41? It complicates the diagram for no real reason.

The patent is explicit about having the "visual indicator" right next to the test point / electrode.

Fully with you, but a schematic is a schematic. It's not meant to contain any physical / positional information. I could understand it, if it was some critical RF part that needed to be distanced from some other component, but this is an indicator bulb.

Oh, we agree, but it is fun to be the Devil's Advocate.

The purpose of any diagram is to communicate anything that is considered important.

Many schematics include more than just connectivity, e.g. the Tek 4x5 scopes where schematics also include PCB boundaries, and a PCB is spread across several schematics. Some schematics include physical info, e.g. notation indicating thermal coupling or being on a heatsink etc.

More importantly, they ought to show components grouped in familiar "design patterns" that indicate the subcircuit's intention. That allows anything departing from that to be instantly visible, and hopefully to highlight something novel and relevant.

Which in this case, the lodging/registering of a patent, only the bare essentials to protect IP are ever included.

[tggzzz]

I wonder why he placed the Bulb (43) all the way to the left instead of over TR41? It complicates the diagram for no real reason.

The patent is explicit about having the "visual indicator" right next to the test point / electrode.

Fully with you, but a schematic is a schematic. It's not meant to contain any physical / positional information. I could understand it, if it was some critical RF part that needed to be distanced from some other component, but this is an indicator bulb.

Oh, we agree, but it is fun to be the Devil's Advocate.

The purpose of any diagram is to communicate anything that is considered important.

Many schematics include more than just connectivity, e.g. the Tek 4x5 scopes where schematics also include PCB boundaries, and a PCB is spread across several schematics. Some schematics include physical info, e.g. notation indicating thermal coupling or being on a heatsink etc.

More importantly, they ought to show components grouped in familiar "design patterns" that indicate the subcircuit's intention. That allows anything departing from that to be instantly visible, and hopefully to highlight something novel and relevant.

Which in this case, the lodging/registering of a patent, only the bare essentials to protect IP are ever included.

The patent summary and claims both indicate having the indicator next to the electrode are part of the IP being protected. It is highly beneficial if the text and diagrams support and enhance each other.

[McBryce]

I wonder why he placed the Bulb (43) all the way to the left instead of over TR41? It complicates the diagram for no real reason.

The patent is explicit about having the "visual indicator" right next to the test point / electrode.

Fully with you, but a schematic is a schematic. It's not meant to contain any physical / positional information. I could understand it, if it was some critical RF part that needed to be distanced from some other component, but this is an indicator bulb.

Oh, we agree, but it is fun to be the Devil's Advocate.

The purpose of any diagram is to communicate anything that is considered important.

Many schematics include more than just connectivity, e.g. the Tek 4x5 scopes where schematics also include PCB boundaries, and a PCB is spread across several schematics. Some schematics include physical info, e.g. notation indicating thermal coupling or being on a heatsink etc.

More importantly, they ought to show components grouped in familiar "design patterns" that indicate the subcircuit's intention. That allows anything departing from that to be instantly visible, and hopefully to highlight something novel and relevant.

Which in this case, the lodging/registering of a patent, only the bare essentials to protect IP are ever included.

The patent summary and claims both indicate having the indicator next to the electrode are part of the IP being protected. It is highly beneficial if the text and diagrams support and enhance each other.

Then they really should have included a mechanical drawing to document the mechanical features that are to be protected by the patent.

McBryce.

[nfmax]

Remember the purpose of a patent description is to describe everything, but explain nothing.

[tggzzz]

Remember the purpose of a patent description is to describe everything, but explain nothing.

Tee hee

Most patents fall into the "never mind the quality, count the number" category. IBM says to HP "you can use 1523 of our patents royalty free in exchange for 1492 of your patents".

[Messtechniker]

There are patents and patents.
I.e. patents which describe a true invention, and silly blocking or money making patents.
Translated quite a few belonging to the first category.
I love this patent speak by the way. Once I got the hang of it.

[tggzzz]

There are patents and patents.
I.e. patents which describe a true invention, and silly blocking or money making patents.
Translated quite a few belonging to the first category.
I love this patent speak by the way. Once I got the hang of it.

The third category is larger: genuine inventions that don't make money.

There's an important fourth category: genuine inventions used to increase a company's sale price. If there is an unexpected edict to write patents, then it might well mean somebody intends to sell the company or float it on a stock exchange. A company is worth more if it has unique products where the IP  is protected.

[McBryce]

There are patents and patents.
I.e. patents which describe a true invention, and silly blocking or money making patents.
Translated quite a few belonging to the first category.
I love this patent speak by the way. Once I got the hang of it.

The third category is larger: genuine inventions that don't make money.

There's an important fourth category: genuine inventions used to increase a company's sale price. If there is an unexpected edict to write patents, then it might well mean somebody intends to sell the company or float it on a stock exchange. A company is worth more if it has unique products where the IP  is protected.

Yes, but all four types still need to adhere to certain rules to ensure that they can't be circumnavigated. They are also useful to attract investors or VC's, even if they are just of the "blocking" type.

McBryce.   

[Robert763]

There is a 5th category: disinformaton. Some patents provide false infomation to obfsucate the real invention or send compeditors down blind alleys.
This is of course contray to the original purpose of patents.

Robert
(inventor on several patents but all owned by previous employer)

[srb1954]

There is a 5th category: disinformaton. Some patents provide false infomation to obfsucate the real invention or send compeditors down blind alleys.
This is of course contray to the original purpose of patents.

Robert
(inventor on several patents but all owned by previous employer)

Or is it just incompetence on the part of the patent attorney?

One firm I worked for decided to patent one of my designs and they handed over my circuit description and diagrams to the patent attorney for reworking into a suitable format for a patent application.

After the patent attornies had finished their "reworking" even I, as the original designer, couldn't figure out what the circuit was supposed to do from the description in the patent. They also redrew the logic schematic removing all logic negation bubbles, perhaps deciding that they were an unnecessary embellishment.

[factory]

Didn't get too much done at the weekend, but I finally got round to the re-capicide of the Tek THS710STD scope, the small surface mount caps are known to leak in the older THM series scopemeters, the ones I removed from the THS had no leakage & have been replaced with solid polymer types.
The four through-hole caps on the other hand are showing signs of peeing  , I think I got these removed just in time before they could make a right mess of the PCB. 







Another thing I've noticed with this THS scope, the shielding cans covering the front end hybrids seem to have a tin whisker problem. 





David

[factory]

Mystery TE time, just pulled this board after noticing an expired tant  , my web search has drawn a blank on the BBC Metrawatt V-Modul block and the Datel AM 490-2C IC.
Some electrolytic capacitors on another board are past it too.

Edit: why does search work better after I post?  The Datel is apparently a chopper stabilized op-amp.

David

[AVGresponding]

Mystery TE time, just pulled this board after noticing an expired tant  , my web search has drawn a blank on the BBC Metrawatt V-Modul block and the Datel AM 490-2C IC.
Some electrolytic capacitors on another board are past it too.

Edit: why does search work better after I post?  The Datel is apparently a chopper stabilized op-amp.

David

Whether it helps or not idk, but in this case BBC will not be British Broadcasting Corporation, and instead will be Brown, Boveri & Cie, now ASEA Brown Boveri (ABB)...