The 576 manual is the August 1984 revision and in excellent condition.

The "Type 172 Programmable Test Fixture" for the 576 is in likewise excellent shape.

I want to sell them as a pair, they'll be shipped from Calgary, AB, Canada and UPS Ground into the ConUS I guess might run $US50-75.00, depending.

The 172 comes with a programming card and I swear up and down I have a slew of original pins and an extra couple of programming cards sitting in one those places where I'll be -sure- to be able to locate them. They're included once I do.

A cleaned up, OCR-d copy of the manual from the TekWiki is here:




PayPal pretty much works but for unknown "reasons" that I ascribe to brain dead AI it has begun randomly withholding payments into and transfers out of the account, so I'll ask that any payment be sent as, "Money to those you trust" or whatever they call it these days.

Hit me off list please at sales – at – pearl-hifi – dot – com

Liam

Hi Chris,

I just checked before the A21 unit, without pulling out it, according to the Service Group B of Section 11: when I started directly from the "Service" chapter, the "LOCAL OSC. UNLOCKED" error led me to that Group. By following the "Main Local Oscillator Troubleshooting Tree" (11-151/11-152), I found perfectly within the tolerances the following signals:

• 90 MHz ± 10 Hz at A21J2
• 10 MHz?± 2 Hz at A21J6
• 100 kHz?± 2 Hz at A21J9
• ≥ 1 V pulses at A21J8

and so on in the flowchart, choosing YES until the last decision block, where is asked if any LED of the A34 board is blinking: before the replacement of the 2N3055 in that board, the answer was NO, but now I don't know if the slow blinking of the FRN LED can be interpreted as "blinking" and I have to change the direction... The REF LED is off at power on, but becomes on after warmup: at that moment, the sounder, that follows the FRN LED, ceases beeping.

Now, by restarting from Section 5 - as you advised - the first step I should begin from is § 5-7 "90 MHz Reference Board Adjustment (A21)": in fact I just checked the voltages of the Low Voltage Power Supply and I should prefer to avoid checking its current protection. NB In Section 11 Group B the frequency counter and the RF synthesizer had to be externally sync'd to the 10 MHz reference output of the 3585A, but in Section 5 this is true only for the synthesizer (see § 5-5). Therefore I will sync the frequency counter to my GPSDO 10 MHz reference.

Last (by now): you wrote that in you troubleshooting you bought a second unit as donor, to help you focus the possible fault in case of multiple failures. I have not this possibility, unless buying certain replacement boards: it is a little expensive approach and meanwhile I got almost all the ICs of the A34 board that I considered possibly involved, by following the schematic diagrams up to the TP2, where I cannot find the expected "pulses"... I didn't replace all of them, but now I'm dubious if a spare A34 board could be a good choice.

PS if this posting begins boring someone, please tell me: I will go on in private form.

Tnx de Alberto, IZ2EWV

Sorry, yes. 8924C

I have a question for any HP4140B users out there... Mine seems to power up with an offset of around -230fA when on the 1pA range. After about an hour's warmup this drops to around -120fA but no lower. And the 'Zero' button has no effect (presumably as it says it can only compensate for +/- 100fA?).

I have tried adjusting A1's offset as per the 'adjustments' section of the manual, but it doesn't change things. It seems to be a 'real' current - leakage possibly (the triaxial socket is clean, not looked at the A1 input board yet). Has anyone had a similar problem and if so did you manage to cure it?

After researching the matter of copying 4145A diskettes I've concluded that my
earlier statements regarding the diskette format were totally wrong.

I have now made copies, copies of copies, etc. of the original HP4145A
diskette that came with my 4145A - and it was simple and straight-forward.

I was simply WRONG about the diskette being hard sector. I was told that by
the previous owner - who is a technically astute person - and I just believed
him. I thought I had checked it myself, but that must have been an "illusion".

Today I used IMD to read my original HP diskette on my "copy stuff PC". I used
a floppy drive capable of single to quad density to create the "copy
diskettes". The parameters I used were 40 tracks, single side and double step.

My original diskette read in flawlessly and created an IMD image file. I then
used that file to create another diskette. I then read that diskette to create
a second IMD file - and used that file to produce another diskette (copy of a
copy).

I also used a 4145A IMD image I retrieved from the Internet and used it to
create a third diskette.

I tested out all of the diskettes on my HP 4145A - and ALL worked flawlessly.

In short, the diskette is NOT weirdly formatted! It is single density (FM -
250K), 9 sectors/track, 256 byte sectors for a total of 360 sectors on the
diskette.

Sorry that I didn't research this properly before I made invalid comments on
this list and wasted Dave McGuire's time (and energy) and others who were
following our discussion...

Best,
Lyle

BTW: I studied the 4145A schematics and the chip associated with the floppy
controller - which is a Fujitsu MB8866. It only is capable of handling a
single index and its single density FM format and frequency is the same as that
of an IBM 3740. It is also capable of MFM double density (not used in the HP
4145A).

=========

On Fri, 4 Jun 2021 18:39:27 -0400
"Dave McGuire" <mcguire@...> wrote:

On 6/4/21 5:24 PM, Lyle Bickley wrote:

Uhh, waitaminute. Is it possibly the case that there are two
different versions of the 4145A? Or maybe that it can boot from EITHER
hard- or soft-sectored media?? The latter would be most unusual. This
is the first I've heard of this; I had assumed (sorry!) that you were
just misremembering about your 4145A's boot disk being hard-sectored.

When I got my 4145A (and a floppy diskette that would boot) I talked with
the previous owner (a senior Google Robotics guru) and he told me the
5.25" FDD was hard sectored and would not copy on anything he had. When I
got the 4145A home, I checked the diskette - and it was easily observed to
be hard sectored.

Wow, ok.

I then went online and checked this site and Googled other specific 4145
sites and found the following, seemingly definitive, information:

...

After reading the above - and observing the hard sector diskette, I didn't
even try to copy the 4145A diskette.

That's reasonable.

I subsequently used Dunfield's "imagedisk" to make a copy of my 4145B
diskette [which I attached in an email for folks on this list].

Excellent. :-)

We should probably suss this out.

Agreed!

So yes, thank you for NOT suggesting that perhaps I don't know how to
accurately identify a hard-sectored disk. ;)

I just went and looked at it a THIRD time, because I know just how
little sleep I've been getting lately. ;) Spinning the media around
inside its jacket, there is precisely ONE hole visible through the
sensor window as the media makes a complete turn. One. And yes, it's a
5.25" disk, and the box says "4145A" on the front. It has the original
beige drive with the flip-up front door; I don't recall the manufacturer
of the drive offhand.

I wonder if I have some sort of weird variant of the 4145A? (this one
is the only one I've ever owned or directly used)

I'll have to give it a shot - I picked up the zip file 4145A image - and
have a linux/DOS (dual boot) system with both low/quad density and high
density 5.25" diskettes. (This system is only used to make copies of
"weird" FDDs).

I have one of those set up as well, with an 8" drive connected too, in
an external chassis with a switchbox and one of John Wilson's FDADAP
boards to handle the TG43 signal and such.

Yup, mine has all that, too ;)

Excellent.

That system also has a 9-track tape drive, as well as 3480 and 3490 (IBM
mainframe) cartridge tape drives, and a DEC TZ85 for reading DEC TK50 and
TK70 tapes.

I still have a DEC TK50 attached to mine -

Uh, by what interface?

but gave my HP 9-track tape drive
(800/1600/6250) to the Computer Museum of America...

Sigh...black hole...

I also use my vintage MB's integrated floppy controller - which has handled
every soft sector format I've "thrown" at it. I have HD and low density
3.5" and 5.25" and Dual 8" FDDs. So we have similar setups (especially
before I donated my tape drive). :)

Very cool.

Not familiar with "GreaseWeazle" - but it sounds similar to the KyroFlux.

Yes, a similar idea, but a newer implementation using one of the later
crop of fast microcontrollers, and its host interface is USB. All open
source, of course.

[BTW: I'm on the PDP-1 Restoration Team at the Computer History Museum
(CHM) and have on several occasions helped the Museum copy/analyze
tapes/diskettes, etc.]

Yes, I know you're on that team. My hat's off to you! :-)

-Dave

--
73 NM6Y
Bickley Consulting West


"Black holes are where God is dividing by zero"

I think that this has been asked before, however I am not aware of a definitive answer.
My question is were or how can I obtain the 1D2 option for the 35670A?
This appears to be a software upgrade (via floppy disk) but I have seen references to ROM upgrades. I am confused.

My thanks for any assistance with this.

Mark

Maybe should be making a new topic for "Reading/Writing Unusual Disks"

For those interested in Kryoflux/Greaseweasel, also have a look at

I killed my Kryoflux (dont ask...) and found FluxEngine when looking for a replacement.

I have the parts on my bench waiting so I cannot vouch for it, but it's a very economical alternative to KryoFlux.

Very nice project indeed!
Thank you for sharing

Hello, anyone got lost on his junk box one frequency doubler for my 1Ghz signal generator Farnell PSG1000?
Best regards.
Francesco.

Also:

Try these steps

Hi Alberto,

I might not have pointed out well enough (but you might have read that between the lines): be very careful when re-seating A21 after having it pulled out. The two SMB connectors at the bottom edge of the PCB are very sensitive and can easily be destroyed when not centered well (that happened to the previous owner and to a certain extend, I can understand why). It helps to remove (desolder) one of the leaf springs (and does not affect the performance of A21 at all) that connect the PCA ground to the housing. Also, I recommend to clean the card edge connector with a lubricating contact cleaning agent. This facilitates insertion quite a bit and gives you more tactile feedback about if the connectors are sitting in the right place before pushing them in.
Please feel free to ask when you hit a roadblock, I will support you as good as I can.

Chris

"Dave McGuire" <mcguire@...> writes:

On 6/6/21 11:02 PM, Matt Huszagh wrote:

When I receive a new piece of vintage equipment I like to back up the
firmware in case the EPROM containing it one day becomes
damaged. Equipment often also contains calibration constants in a
separate EPROM.

What are these calibration constants? How does the device firmware use
them at a high level? Or, if that question is too broad, what are some
examples of how that data is used?

Calibration constants are numbers that are generated during a
calibration procedure, starting at the factory and possibly regenerated
during later recalibration. These numbers are constants that describe,
essentially, the difference in behavior of an instrument or assembly
from "ideal", and are used as correction factors. Different instruments
or assemblies will have different types of calibration constants
depending on their purpose.

For example, you've seen sensor heads for HP RF power meters that have
a list of correction factors on the side. These numbers describe the
measured behavior of that sensor at the listed frequencies. For the
mid-aged power meters like the 437B and 438A, you enter those numbers
into the meter, tell the meter what frequency you're measuring, and it
applies, those correction factors to the displayed data.

Later HP RF power sensor heads have those correction factors stored in
an NVRAM chip within the sensor head, and they're read out by the power
meter at power-up time. This saves the operator from having to enter
those numbers, but if it's lost, it's very difficult to regenerate.

Are these calibration constants particular to a specific unit? For
example, would 2 8340B's have the same calibration constant data?

No, these are per-instrument. (or per-assembly, or per-component)

Is there any reason why I might not want to, or it might not be
necessary, to backup this data? For firmware, I can often track down
copies of the firmware online (e.g., at ko4bb.com). I have not found
this to be true for the calibration constants. Is this because it is
unit-specific and therefore would not make sense to share?

Yes, they are unit-specific. Calibration constants from a different
instrument of the same model will usually be useless. If your data is
completely lost, constants from another identical model may get you
somewhat close, perhaps close enough to run the instrument, but there
will be inaccuracies. Some types of instruments have calibration
constants that are so critical to the internal operation of the
instrument that the instrument will fail power-up self-tests, and even
fail to function at all.

You should try hard to not lose any calibration constants from any
instrument. In some cases they can be regenerated, but in many such
cases the procedure is difficult and requires very specific equipment to
perform.

That was an incredibly clear and useful explanation. Thanks so much for
taking the time to respond! I will be backing up all calibration
constants for each instrument then.

Matt

Using a 3325B feeding a -20dB sine wave signal at 10 MHz with the reference level of the 8566B set to -20dB to put the trace just at the top of the screen with the scale set to 1dB increments, I find if I reduce the amplitude in -1dB increments on the 3325 then this is the readout I get

Measurements made with peak detector marker
Left value is 3325 amplitude readout on screen and right value is 8566 detected on screen
-20/-20.5
-21/-21.04
-22/-22.02
-23/-23.00
-24/-24.02
-25/-25.10
-26/-26.17
-27/-27.29
-28/-28.31
-29/-29.39
-30/-30.00 (Not visible on screen

The 1dB increments on the 8566 doesn't appear to be linear at the bottom of the screen compared to 2dB and 5dB which match that of the 3225 on all of the 10 increments of the display. If I use the reference level to adjust the position of the trace on the screen I find I get the same results where the trace starts falling off at the bottom the screen but matching towards the middle and top of the screen.

?Is there an adjustment to make the 1dB scale linear at the bottom the screen?

Hello,

I have a few questions about this analyzer that I’m not used to using.
I notice that the "Freq Span Div" button when one pulls on it only goes on the scale 500 full right and 10/20 if one goes full left.
Impossible to go on 1/3/5 graduations. I do not know if this is normal.(?)

Since I only have a 60 MHZ generator, I would like to have an example of the positioning of the 2 sets of main buttons (Freq level and span div) for an AM or FM or other signal of 40MHZ with a voltage of 0.3v in input ( it seems that it is -10dbm)? or other as you prefer.? My generator is à FY6900 60 MHZ
I need? an example? to understand how it works

Within a week I managed to get a signal, but I couldn’t get one this weekend.
I wonder if the entrance is not "out of order" by a to srong signal?
Thank's for your help.

cdt

开云体育

Do you know Greasewheazle?

Keir is an earthly god when talking about floppy emulation/imaging. He is the author of FlashFloppy and Greaseweazle. If you ask him to add a bizarre, rare and complex diskette format to GW, he'll do that just for the fun =)

Contact him, you won't be disappointed.

73 de PU2SEX Alexandre, GG66QM =)

Em 04/06/2021 16:02, Lyle Bickley escreveu:

--
---8<---Corte Aqui---8<---

Tnx Chris!

I expected your reply and it was very useful! I know that remote-troubleshooting is impossible, but your advises (e.g. by starting from Section V, Vol. 1) seem to be golden. By the way I should like to share - when strictly needed - some photo/video of my 3585A, with you and the other interested people (obviously I will post a link for downloading).

Alberto, IZ2EWV