On December 14, 2019 at 5:17 AM Terry Gains <terry.waihi@...> wrote:

Hey Pat,

What good fortune to find you here. On behalf of many, thanks for your photo essay on the?and other fine HP instruments. Your work is no-doubt preserved as the screen saver or desktop image of choice by many HP fans. Maybe your?2410B might get the same treatment one fine day?

If I recall correctly, we once bought?HP 3460B digital voltmeters from the same source?

Re: "I'll need to fabricate some boards to integrate them, though, as they weren't a set and the 2401C is not equipped with the boards needed to let it talk to the 2410B".
Magic! You might be speaking of the A9 Units Coupling and the A3 Delay Gate boards. I'm not expecting to find those installed when I open the 2401C and will need to look at getting some PBCs made to order and share them with folk like yourself.?

I'd also like to have Option 29 Frequency Measurement to 1.2 MHz, so this is another PCB to be ordered and shared. If you have to go to extent of making option 29, then you might as well look at pushing the frequency.?

Please let me know if you were thinking of additional options.

I'll be re-producing the PCBs from images using the service manual as a reference, so there's no telling how long this might take.

Re: "Gotta love a full rack width, 20+ inch deep, 13-1/2" tall nearly 100 lb stack of gear that will measure DC and AC voltage, and resistance.? One of these years, in my spare time (so called because I have so little of it...)? Cool old boat anchors - it's nice to know others are keeping them alive, too.".?
Absolutely. HP certainly believed this when placing them prominently in a number of late 60's advertisements.?




Hello Dave,

Thank you for taking the time to reply.

It's amazing to hear that you keep both a 2401C and an working order?2402A. I've never heard of a 2402A for sale, so you have an?ultra rare part of HP history on your hands. Well done. I've seen two 2410Bs and one?2410A?on eBay in the last ten years and was lucky enough to win a?2410B.

Some of my Christmas leave will be devoted to at least getting the?2401C?operational and recalibrated. That and reproducing some PCBs to interface the 2401C and 2410B.

I apologise for a quality of the picture below (1. I'm no Patrick Manning, and 2. it was taken with an old phone just now) but if you've never seen a?2410B, my?2410B is between the 2401C?and the 3460B?at the bottom.



Let's stay in touch.?If you ever want some options for the?2401C,?I'm looking at reproducing some.

Kind regards,
Terry

On December 14, 2019 at 12:05 PM Jeremy Nichols <jn6wfo@...> wrote:

Gentlemen,

There is also a 3461A, which is the AC-Ohms converter for the 3460A. It’s the equivalent of the 2410, I believe. I’ve never seen a 3461 outside of a catalog.

Jeremy?

On Fri, Dec 13, 2019 at 10:39 PM Patrick Manning < pbmanning@...> wrote:

I have also a set in the repair queue.? My 2401C sounds to be a bit older than yours, Terry, as it's the Dymec-labeled version, s/n 622-01154.? The 2410B is 644-01052, and despite having a lower serial number than yours, mine has an HP-labeled front panel.

I'll need to fabricate some boards to integrate them, though, as they weren't a set and the 2401C is not equipped with the boards needed to let it talk to the 2410B.

Gotta love a full rack width, 20+ inch deep, 13-1/2" tall nearly 100lb stack of gear that will measure DC and AC voltage, and resistance.? One of these years, in my spare time (so called because I have so little of it...)? Cool old boat anchors - it's nice to know others are keeping them alive, too.

Some photos of the 2401C are at?

-Pat

On December 13, 2019 at 6:37 PM Terry Gains < terry.waihi@...> wrote:

Who here, runs these find beasts?

My HP 2401C Integrating Digital Voltmeter (SN 811-02807 opt 21,31,146) and HP 2410B AC - Ohms Converter Dymec (SN 644-01126) are about to be restored, interconnected and calibrated.

They don't appear to have been mentioned in this forum before, but I'm betting someone out there is also keeping these in working order.

Incidentally, they are both in pristine condition, remarkable for their age, and the?2410B has a asset sticker from a previous owner, the NASA? Goddard Space Flight Center, which will be left on the instrument.?

Kind regards,
Terry

?

?

--

Jeremy Nichols
6.

Extended temperature range PIC17C42A version in PLC44 ...

Thanks David

On 8Dec, 2019, at 8:56 PM, Roy Thistle <roy.thistle@...> wrote:

On Sun, Dec 8, 2019 at 06:21 PM, <julien.monette@...> wrote:

if you purchase any other vega450, you can have it for around 150$ on ebay.?You just have to swap the modules between those two psu and it should work fine.

Hi Julien, Hi Ken"
Ya, it might be okay to drop 150.00, for a Vega, on the chance of getting a working Infinium... if the psu is the real problem. Most of the Vega 450 modules have a voltage/current range, and are user adjustable... see the link to the Vega 450 configuration table, in one of my previous posts. You might be able to find just a module.
Yes, the Vega is a tightly speced psu… they use a thick and tough conformal coating for isolation... that makes it hard to work on the board... unless you know what the coating is.? I think the boards are manufactured in China. Don't think TDK does much board level stuff. Probably they sell the defective boards to scrappers, that sell them back to China, where they probably burn the parts off.
Best regards and wishes.
Roy

I can't help marveling at the workmanship that went into that equipment.

On 12/14/19 12:39 AM, Patrick Manning wrote:

I have also a set in the repair queue.? My 2401C sounds to be a bit
older than yours, Terry, as it's the Dymec-labeled version, s/n
622-01154.? The 2410B is 644-01052, and despite having a lower serial
number than yours, mine has an HP-labeled front panel.

I'll need to fabricate some boards to integrate them, though, as they
weren't a set and the 2401C is not equipped with the boards needed to
let it talk to the 2410B.

Gotta love a full rack width, 20+ inch deep, 13-1/2" tall nearly 100lb
stack of gear that will measure DC and AC voltage, and resistance.? One
of these years, in my spare time (so called because I have so little of
it...)? Cool old boat anchors - it's nice to know others are keeping
them alive, too.

Some photos of the 2401C are at


-Pat

On December 13, 2019 at 6:37 PM Terry Gains <terry.waihi@...>
wrote:

Who here, runs these find beasts?

My HP 2401C Integrating Digital Voltmeter (SN 811-02807 opt 21,31,146)
and HP 2410B AC - Ohms Converter Dymec (SN 644-01126) are about to be
restored, interconnected and calibrated.

They don't appear to have been mentioned this forum before, but I'm
betting someone out there is also keeping these in working order.

Incidentally, they are both in pristine condition, remarkable for
their age, and the?2410B has a asset sticker from a previous owner,
the NASA Goddard Space Flight Center, which will be left on the
instrument.

Kind regards,
Terry

I took a look at the blockdiagram of my 83592, which differs only with an

The sweeper unit is a cascade of
a) YTO o/p 2.4-7.0GHz
b) amplifier
c) isolator
d) YTM (multiplier)
e) YTF
The most probable cause imho is tracking of the 3 YIG devices, at least

The tracking is done by opamp controlled current sources and can be caused

Unfortunately I gave a few years ago my 83590 manuals away
Best regards Rien

I have also a set in the repair queue.? My 2401C sounds to be a bit older than yours, Terry, as it's the Dymec-labeled version, s/n 622-01154.? The 2410B is 644-01052, and despite having a lower serial number than yours, mine has an HP-labeled front panel.
I'll need to fabricate some boards to integrate them, though, as they weren't a set and the 2401C is not equipped with the boards needed to let it talk to the 2410B.
Gotta love a full rack width, 20+ inch deep, 13-1/2" tall nearly 100lb stack of gear that will measure DC and AC voltage, and resistance.? One of these years, in my spare time (so called because I have so little of it...)? Cool old boat anchors - it's nice to know others are keeping them alive, too.
Some photos of the 2401C are at
-Pat

On December 13, 2019 at 6:37 PM Terry Gains <terry.waihi@...> wrote:

Who here, runs these find beasts?

My HP 2401C Integrating Digital Voltmeter (SN 811-02807 opt 21,31,146) and HP 2410B AC - Ohms Converter Dymec (SN 644-01126) are about to be restored, interconnected and calibrated.

They don't appear to have been mentioned in this forum before, but I'm betting someone out there is also keeping these in working order.

Incidentally, they are both in pristine condition, remarkable for their age, and the?2410B has a asset sticker from a previous owner, the NASA Goddard Space Flight Center, which will be left on the instrument.

Kind regards,
Terry

I took a look at the blockdiagram of my 83592, which differs only with an extra low band mixer,
The sweeper unit is a cascade of
a) YTO o/p 2.4-7.0GHz
b) amplifier
c) isolator
d) YTM (multiplier)
e) YTF
The most probable cause imho is tracking of the 3 YIG devices, at least that's my experience with the older 86290B which showed the same symptoms.
The tracking is done by opamp controlled current sources and can be caused by resistor ageing
Unfortunately I gave a few years ago my 83590 manuals away
Best regards Rien