On 08/27/2018 07:32 PM, John wrote:

As I said eBay sellers seem to want the earth for them. As an example
one seller wants $34.00 AUD for a single 18 pin card and the shipping to
Australia will be another $35.00. I can get boards made up in China of
good quality for about $30.00 for 10 boards of that size and shipped to
me for free. Yes I still need to add the connector and the board contact
fingers will not be gold plated but hell it is a service tool not an
operational component. You see the problem;-)

Yes. It was not my impression that the guy up in the NE US was that
expensive, but I don't remember offhand. I think $34 is pretty
reasonable for an extender board, but double that with shipping is
rather steep, I must agree.

-Dave

--
Dave McGuire, AK4HZ
New Kensington, PA

Dave,

As I said eBay sellers seem to want the earth for them. As an example one seller wants $34.00 AUD for a single 18 pin card and the shipping to Australia will be another $35.00. I can get boards made up in China of good quality for about $30.00 for 10 boards of that size and shipped to me for free. Yes I still need to add the connector and the board contact fingers will not be gold plated but hell it is a service tool not an operational component. You see the problem;-)

John
VK2DLP

Further to my previous e-mail the HP part number for the extender card in question is 08662-60275 as per the 8662A Operating and Service manual part 1.

John
VK2DLP

On 08/27/2018 07:22 PM, John wrote:

I am wondering whether anyone has generated PCB files to build extender
cards for service work on an 8662A signal generator? Initially I will
need 2 18 pin (dual sided 36 total contacts) cards but will eventually
need others. On eBay people want ridiculous amounts for these cards and
given that I think the backplane connector is an Amphenol E8 family
connector it shouldn't be too hard to make them up. I thought I'd ask
the group before venturing off to lay out a PCB.

Do you know of that nice fellow up in New England somewhere (I think)
who makes extenders and sells them on eBay? I've forgotten his eBay ID,
but he makes lots of different types for many different instruments.

-Dave


--
Dave McGuire, AK4HZ
New Kensington, PA

I am wondering whether anyone has generated PCB files to build extender cards for service work on an 8662A signal generator? Initially I will need 2 18 pin (dual sided 36 total contacts) cards but will eventually need others. On eBay people want ridiculous amounts for these cards and given that I think the backplane connector is an Amphenol E8 family connector it shouldn't be too hard to make them up. I thought I'd ask the group before venturing off to lay out a PCB.

John
VK2DLP

Thank you, it's good to have a manual to go with the hardware now
John

He does write good stuff.

?

Aspie? Oh h*ll yes.? But that's how we know enough to ask the right questions at work.?

?

?

Cortland

Hello,

I'm selling two oscilloscopes HP Agilent and some spare parts :

- a HP54645D MSO 2x100MHz + 16 logical inputs and its probe + GPIB module

- a HP54616B DSO 2x500MHz + GPIB module

- two Mainboard for HP54645A

I can ship worldwide if necessary with insurance. Make offers by private message please.

Best regards,

Fabien, F4CTZ.

Long time I have not posted here :-)
I have uploaded the op/svc manual for the historical HP 524C/D counter on KO4BB.
I never found it on the web, so it may be useful to others.

73 - Marco IK1ODO / AI4YF

Looking some more at the schematic, and estimating the currents in the output stage, I think it would be good to check for another possible feedback loop issue. The electrolytic caps C5 in particular, and C8, should be checked, if not already done.

Looking into the emitter of Q6, it and the entire output stage can be considered a non-inverting amplifier with the output being the +24V supply. There's a short positive feedback loop from there via Q5 acting as a common-base amplifier, with C8 bypassing the AC and limiting the gain. There is also a negative feedback loop via C5 and Q3, counteracting the action at Q5.

If C5 and/or C8 have deteriorated over the years, it could be detrimental to the overall stability. This is also a more logical and comfortable possibility to explain why something used to work, then didn't - electrolytic caps are usual suspects for such things. The inclusion of these caps in the design is likely why they didn't have HF bypassing caps (as you noted) on the +24V PS - they apparently weren't needed.

So, even though you tried extra bypassing on the PS, it may not have been enough to suppress these loops. C5 and C8 are much more effective than brute force supply bypassing, since they work into much higher impedance.

Again, if you've already thoroughly checked these caps and added HF bypassing there too, then this hypothesis is out the window. If not, I'd recommend doing so, or maybe just adding new big caps across them to see what happens.

Ed

开云体育

开云体育

Hello,
to be honest - I use them quite a bit and never had as much as an eeker's worth of trouble.

You only need to be tough as fuck on the sellers...

Tam
---
With best regards
Tam HANNA (emailing on a BlackBerry PRIV)

Enjoy electronics? Join 11k other followers by visiting the Crazy Electronics Lab at

I've never used them, but some people seem to find it useful. Their website is harder to use than Ebay and they don't accept Paypal.


Michael A. Terrell

开云体育

Hello,
on the risk of sounding unpatriotic - why not try AliExpress?

Tam
---
With best regards
Tam HANNA (emailing on a BlackBerry PRIV)

Enjoy electronics? Join 11k other followers by visiting the Crazy Electronics Lab at

开云体育

Dear All,

Dave,

This is inspirational! I particularly liked the part about our kind of engineers being somewhere on the autistic spectrum. When I was still working, colleagues and I would have huge discussions around this subject, and even the young’uns (who are more easily offended by perceived “labels”) agreed that we are simply “wired differently” to -ahem! - “normal” folks! I for one, know perfectly well that I am ?- unusual - to say the least! ?Thank you for showing us all how to be precise, non-inflammatory, polite and downright pleasant - we all know this is the way to get the results we want!

cheers,
Mel

On Sun, 26 Aug 2018 19:22:25 -0700, you wrote:

Ok just ordered these:
1X-40PCS-Dupont-Wire-Jumper-Cable-10cm-2-54MM-Female-to-Female-1P-1P-For-Arduino

$2.75 and free In-US shipping

I think these don't have to be cut to remove the header. Don't they have kind of a small hook on one side that keeps the connector from sliding out? If so its just a matter of pressing on this hook and the connector should come out easily.

There's a small tab that you need to lever out a bit, then the
connector just pulls out.

Looking carefully at one will show you how.

Harvey

On Sun, 26 Aug 2018 19:08:35 -0700, you wrote:

My wife is constantly ordering books from them, so we get over the
minimum rather easily. Some vendors offer free shipping, you just
need to see what the category is. One or two TFT displays of the
right type, or 40 or 50 connectors, and you're in.

I do tend to stock up.

I could just as easily put a few in an envelope and send them to you
if you need it.

Harvey

On Sun, Aug 26, 2018 at 04:54 PM, Harvey White wrote:

This is a vendor I have ordered from before with decent results. Note
that you're mostly interested in the M-F and perhaps the F-F ones.

F-F would be perfect, the grabbers also have the same pin receptacle as the probe.

Amazon has free shipping if you order more than a certain amount.

Yes but one would have to order over $25 for it to qualify for free shipping, and that's a whole lot of jumpers. Thanks for the link, we are now definitively on the same page, that was very helpful -thank you Harvey. Still going to try and find these same jumpers on ebay, over there even very small orders have usually free shipping, or a buck or two at most, specially the chinese generic stuff. Anyway, just my experience over time, and not to defend the e-pay place, but that is why I rarely even consider ordering anything on Amazon anymore.

All that I've ever seen had to be lifted, not pushed in. That damages the tab on the pin. Here is a closeup image of the single pin housing:



I think you are confusing these with Molex or AMP housings.

Michael A. Terrell

--

On 08/26/2018 11:09 PM, Alex wrote:

Also problem seems in these cases that a
capacitor above a certain size actually behaves as a short for a very
short time until it charges, so I was getting some false readings from
good caps as well.

Not capacitors above a certain size, but *all* capacitors.

In fact, all capacitANCES, whether you're looking at an actual
capacitor or not.

-Dave

--
Dave McGuire, AK4HZ
New Kensington, PA