¿ªÔÆÌåÓý

  1. HP-Agilent-Keysight-Equipment
  2. Topics

Question about cables and probes for hp 16715a.

 

Hi all. I have two 16715a cards, with cables, but without pods with wires to connect to hooks. I would like to make them myself, but I need more information about them. Specifically, I need to understand the pinout of the pod connector, and how they differ from each other.
A) What does "L clock / K clock / M clock / J clock" mean and the pod numbering, is there any difference in them, or are they just stickers for the symbol?
B) And, I wonder what kind of 40 pin pods existed for logic analyzers? Were they purely passive, or was the +5V line in the cables used to power the probes?
B) Also, do the wires themselves, going from the 40 pin connector to the hooks?, have the same resistance as the 16715-61601 cables? (thanks Keith) https://www.techtravels.org/2022/11/agilent-logic-analyzer-cable-teardown-photos/
if someone measures the cable resistance with a multimeter, it will help me a lot.
? - Photo 40 pin pod that I'm talking: https://drive.google.com/file/d/1BQOlGv18P4PRovAiXgYvDBW13E3l8o9p/view?usp=drivesdk
?
?
If you have any information on this topic, please share it.
 

¿ªÔÆÌåÓý

On 2024-08-29 06:05, Don't Know via groups.io wrote:
Hi all. I have two 16715a cards, with cables, but without pods with wires to connect to hooks. I would like to make them myself, but I need more information about them. Specifically, I need to understand the pinout of the pod connector, and how they differ from each other.
A) What does "L clock / K clock / M clock / J clock" mean and the pod numbering, is there any difference in them, or are they just stickers for the symbol?
B) And, I wonder what kind of 40 pin pods existed for logic analyzers? Were they purely passive, or was the +5V line in the cables used to power the probes?
B) Also, do the wires themselves, going from the 40 pin connector to the hooks?, have the same resistance as the 16715-61601 cables? (thanks Keith)
if someone measures the cable resistance with a multimeter, it will help me a lot.
? - Photo 40 pin pod that I'm talking:
?
?
If you have any information on this topic, please share it.
_._,_._,_

A lot of the information you are looking for may be found in the manual "Logic Analyzer Probing Solutions" available from Keysight On the flying lead probe you have pictured, the individual wires from the connector to the plastic piece with the probe number on it is a coax and may be lossy coax however even it it is, it is only about 22cm long and would contribute little to the 90.1K I measured compared to the the resistance of the isolation network housed in that same little piece of plastic.? I suspect the last 3cm from the isolation network to the tip is just a straight wire.? In the manual there is a section concerning custom probing that includes cautions about lead length and grounding.??

When I first got an HP analyzer? I made up rough isolation networks based on the information from the above mentioned manual and used about 15cm long jumpers to connect to the signals I wanted to monitor, they worked but may have been problematic if I had tried to monitor any really fast signals. ?

Each of the 40 pin connectors has one signal line designated as a clock the letters assigned relate to the pod number for instance the pod 1 in your picture is clock "J", pod 2 has clock "K" and so on, this is how the software on you logic analysis system will refer to the clocks.? In a pinch the clock lines can usually be used as another probe line too.

Paul.?


 

I believe the cable from 40-pin connector to tip moulding is actually twisted pair rather than coax. It certainly was in the burnt one I took apart. The tip moulding contained a ceramic hybrid circuit as documented in the probing manual, with SMD capacitors and a thick film resistor on the substrate. However, I didn't measure the cable resistance.
 

I seem to remember that the cable is nichrome, and about 200 ohms.

IIRC about a 10K input impedance at the analyzer, and a 100K at the probe tip.? From what I remember, there's about a 7pf capacitor to compensate the divider, and HP did sell parallel RC networks for building into a project and using direct connection to the analyzer.

You have 2 commonly available connections, the 20 pin pod (which I build into PC boards), and the squid (which I use only for debugging of other parts of the circuit).? The less common method would be a direct connection to the 40 pin connector with you supplying the RC networks.

Harvey

On 8/29/2024 9:56 AM, Adrian Godwin wrote:
I believe the cable from 40-pin connector to tip moulding is actually twisted pair rather than coax. It certainly was in the burnt one I took apart. The tip moulding contained a ceramic hybrid circuit as documented in the probing manual, with SMD capacitors and a thick film resistor on the substrate. However, I didn't measure the cable resistance.
 

The only place lossy cable is present is in the 4.5-foot coax ribbon cable going from the chassis to the pods. ?Earlier versions of this cable are woven, but they are still lossy. ?Its purpose is to reduce reflections to preserve signal integrity. ?(Note that this applies for the 40-pin probing system for the 16715A cards and family. ?The 90-pin probing system used on more recent cards is NOT lossy with Z approx. 93 ohms.)
?
The +5V run in the ribbon cable is used to power accessories, such as the E2433-66502 training card (aka "Credit Card Board"). ?The probe pods themselves are passive do not need power.
?
n addition to providing an isolation network, the flying lead pods also have a spark gap in them for static protection.
?
I'd really recommend just buying the cables and pods you need. ?By the time you're done with specialized parts and your time, I don't think it would be a win or have equivalent performance. ?If you're patient, ribbon cables can be had for US$25 and flying lead sets for around US$20 (need two per cable).? Good deals can be found when buying them in sets instead of individually.
?
-mark
 

I appreciate that you want to make your own pod ends, and would encourage you. They can be difficult to find in sufficient quantity or at a reasonable price. I can see single sets of these - without clips - for typically $50 and you need 4 per card. If you find a good way to it please document it as they will only get harder to find.
?
I'm not familiar with the 16715A card (mine are older 16555 and similar) but as far as I understand from your message they also use the 40 pin format and not the later 90 pin format.?
?
If you're in the US, this ebay lot seems quite a good buy : - elsewhere it's rather expensive. For the UK you have to add $77 and possibly VAT and duty costs too. This was after I'd discussed lower postage costs (USPS) with the seller - it was initially listed with $190 postage (expedited fedex).
?
?
 

I said:
?
...The 90-pin probing system used on more recent cards is NOT lossy with Z approx. 93 ohms.
?
To be clear, what I mean is the tiny ribbon coax used in the 90-pin system has a characteristic impedance of 93 ohms.? I did not mean to imply that's the impedance at the probe tip.? The input impedance at the probe tip is much higher and is given as a model depending on the pod being used.
?
-mark
 

Mark, or anyone -
Do you know if there's any significant difference between the various long cables ?
?
I have some woven cables with 40 pin 0.1" connectors both ends. I think these were used on the 1650 portable analyser and they also fit a DSO7000 digital input.
?
I also have a set of similar woven cables with 40 pin one end and a higher density (I think 0.05" x 0.1") the other end which fits 16555 - 16557 cards, and possibly also 16715.?
?
Then I have several sets that are possibly similar but have a grey plastic skin over the cables. The texture suggests the same woven cable is underneath but I don't know if it also has a screen.
Finally, I have a further set with the sdame connectors but what looks like micro-coax, light gray for most of the width and dark gray at the edges. This set came with a 16557 card.
?
Are they all equivalent ? Or are the coax ones better ? The 16557 is only marginally faster than the 16555 but does have a completely different input stage. The coax cables are 'nicer' than the sleeved ones, narrower and more flexible, but the earlier uncovered cables are also fairly lightweight.
?
 

Hi Adrian,
There is a good cable compatibility table in the "Logic Analyzer Probing Solutions" that Paul posted earlier in this thread.
?
There are four cable types that I've seen that have the 40-pin connector on the probe side:
?
- Lightweight, tan color, "woven" cable where you can see the actual conductors in the weave.
?
- Coax ribbon where the the individual coaxes are bonded together and it looks like a regular ribbon. ?The inner coax runs are light gray, and there are two dark gray regular conductors on each outside edge which carry power for accessories.
?
- Coax ribbon where the individual light gray coaxes are lashed together. ?This also has two dark gray conductors on the outside edges.
?
- Flat cable where the inside is not visible. ?It has a "gray skin", as you put it. ?I've never had one or seen it disassembled, but it appears stiff and may incorporate a copper shield.
?
As far as I know, all the above cable types are lossy and electrically identical, but differ in shielding. ?I can speak definitively for the first two types because I have them and tested them.
?
What varies, however, is the chassis connector. ?This is where the compatibility table is useful.? It's possible there are some connectors that are mechanically compatible, but differ in shielding (e.g., metallic or coated shells).
?
There is some additional detail in this thread which may be helpful:
?
? https://www.eevblog.com/forum/testgear/hp-1670g-logic-analyzer-probe-cables-repair-compatibility/msg2238264/#msg2238264
?
-mark
 

¿ªÔÆÌåÓý

I have a spare complete lead set (16715-68702) here in the UK ¨C open to offers.? Includes ribbon cables flyleads, grabbers etc..

?

David

?

From: [email protected] <[email protected]> On Behalf Of Adrian Godwin
Sent: 29 August 2024 16:51
To: [email protected]
Subject: Re: [HP-Agilent-Keysight-equipment] Question about cables and probes for hp 16715a.

?

I appreciate that you want to make your own pod ends, and would encourage you. They can be difficult to find in sufficient quantity or at a reasonable price. I can see single sets of these - without clips - for typically $50 and you need 4 per card. If you find a good way to it please document it as they will only get harder to find.

?

I'm not familiar with the 16715A card (mine are older 16555 and similar) but as far as I understand from your message they also use the 40 pin format and not the later 90 pin format.?

?

If you're in the US, this ebay lot seems quite a good buy : - elsewhere it's rather expensive. For the UK you have to add $77 and possibly VAT and duty costs too. This was after I'd discussed lower postage costs (USPS) with the seller - it was initially listed with $190 postage (expedited fedex).

?

?

1 - 10 of 10