HP 70K/HP 70000 Modular Measurement System Thread

[dxl]

I'll add the wider 70903A IF module and go from there.  So now I am going to sell my 8568b with 85685a, my R&S FSB and I'm kicking around selling my 8566B but note, and reason for my post, that to get the MMS to 22Gig, you have to spend a fair amount of money.  What modules do I need to take it to 22Gig?

Not sure whether i get the question. If you have a 70908A with it, you have already a frequency range up to 22GHz? The only other option is the 70909A/70910A which go up to 26.5GHz, but they have no fundamental mixing.

[cncjerry]

yes, I just went back and looked and that does go to 22gig.  I guess I was looking at the tracking generator and that is limited to 2.9gig.

Other question, with the TG I can do scalar but is there a VNA option for the MMS?

[cncjerry]

I posted this in the groups.io site about the sidebands I see in all signals, not just the cal posted here and was wondering if others see the same thing?

Thanks

[cncjerry]

if you have an MMS analyzer, if you wouldn't mind posting a picture or just the results as below:

a view of the 300Mhz cal signal with:

span:   1Khz
RBW: 10.0hz
VBW: 10.0hz
atten:  10dB
scale: 10dB per div
RL:     -10dB

My analyzer requires me to hit the reference line down once or twice to get to -10db.

and if you don't want to post, find the 300Mhz peak and then check the dBc to the right or left at 120, 18, 240 or 300hz offset, whichever is highest.  I'm seeing about -83dBc or so with my noise floor much lower, down around -90 or so.  If I can get rid of the line noise...

Thanks

Jerry

[Oldtestgear]

 I have an early 70900a that is not working -- seems to loop around self test -- which I hope is down to an EPROM failure.  Now the problem. Mine uses six 27512 EPROMs, not eight as used in later variants.

Does anyone have a copy of the firmware I need for this one?  Codes are:
70900-80031
70900-80032
70900-80033
70900-80034
70900-80035
70900-80036

Any help appreciated as it would be nice to see if the firmware is the problem before trying any other options.

I aslo bought a 70004a display from the same source which did have a dead EPROM but I copied the file from another display to get it working again.


Thanks in advance

Phil

[gabor.dani]

Does anyone have a working spare SYTFMD (5086-7741) YIG mixer up for sale for my HP 70908A RF section?

[Doug Smith]

First post since joining, as am also looking for some advice after repairing a HP 70908 with LO and Multiplier unleveled errors.  I'll get to that momentarily.  I hope the following is of some assistance to you.   If not, I hope I didn't insult your intelligence by going though it below.

How did you conclude it was the YIG?   It's probably the most unobtanium part of the 70908, and the setup is long and involved after replacement (software and dozens of HP instruments).   I'd rule out everything else possible before concluding the YIG was defective.   To troubleshoot the 70908, I had to arrange the 70310, 70902, 70900, and 70908 modules in a 70001 with the cover removed, as in the attached picture.   I folded out the 70908 power supply board in the remaining space, to get at the adjustments.   I had to verify the DC supply voltages and ripple, the LEDs on or off, the LO output at the rear, and voltages at A1 LOLA G1 G2 G3 and A2 Multiplier G1 G2 G3, and the LO out with another spectrum analyzer, to rule out a possible LO problem from the 70900.  Note the warnings about extreme static sensitivity of these modules.   The problem turned out to be the adjustment pots R11, R12, R13, R46, R47, R48 were open circuit or way off.   I set R34 replacement to exactly the same resistance setting as the old one, and avoided touching R19, R21, and R23 as the setup is difficult.

The problem with adjusting/calibrating the 70K units is not only the software running on HP BASIC on HP-UX controller 382, but also the large number of HP test instruments demanded by the software, and also the test constants buried in the software.    If you don't have the instruments, the software won't run (ask me how I know) and you have to rewrite it for the instruments you have.   In the repair above, I touched only the service manual adjustments that were straight-forward, and hoped the rest were close enough.   I got lucky this time.

About my question, for the audience's wisdom.    After getting it working, I found that the voltages at A1 SW1 and SW2 were not +11 and -11, rather +11 and -2.6.   I traced it back to two JFETs on A13, in a peculiar circuit.   Here's what I think happens.   Check me.  Each is driven by an op-amp IC with output at either +11 or -11.   When IC output is +11, the JFET gate is forward biased (Pull-up?), and when IC output is -11 the JFET gate is reverse biased to cutoff and the 380 ohm resistor feeds to the output.   So analysis shows the only way the output can be -2.7 volts if the JFET is defective and pulling a lot of current from the +12 volt source.   I'm also thinking the 2N4391 may not be the right choice because Vgs(off) is -4 to -10 volts, a large percentage of the +/- 12 volts available.   Would a 2N4392 be better for this circuit?   Or drive SW1 and SW2 directly from the IC's?   They seen to have enough short circuit current to drive the ~600 ohm resistance presented by SW1 or SW2.   Or does it even matter if it works?    What do you think?

All for now.   Doug

[K9DTV]

I posted this in the groups.io site about the sidebands I see in all signals, not just the cal posted here and was wondering if others see the same thing?

Thanks

Hope this is what you wanted.
Added another picture with AVG on as you had it on in yours.

[K9DTV]

I have an early 70900a that is not working -- seems to loop around self test -- which I hope is down to an EPROM failure.  Now the problem. Mine uses six 27512 EPROMs, not eight as used in later variants.

Does anyone have a copy of the firmware I need for this one?  Codes are:
70900-80031
70900-80032
70900-80033
70900-80034
70900-80035
70900-80036


Any help appreciated as it would be nice to see if the firmware is the problem before trying any other options.

I also bought a 70004a display from the same source which did have a dead EPROM but I copied the file from another display to get it working again.




Thanks in advance

Phil

There is a site that has images of the 70900a roms, and I know I have a spare 70900a rom board with the last update for the 128k dip rom board
You may want to PM me so we can figure something out to get you fixed up.

This board came with with 70900A Serial Numbers 2817A01886 to 2833A02083 Part number 70900-60114.
Software is version 880314 Revision B.00.00 code name Cheetah
32K usable ram

Supports the following hardware:

70205A, 70206A, 70300A, 70310A, 70600A, 70601A, 70620A, 70700A, 70810A, 70900A,
70902A, 70903A, 70904A, 70907A, 70905B, 70906A, 70906B, 90707A, 70908A

This revision introduced the new menu style, with firmkeys on the left.

This also allowed use of the 70620A preamp.

As long as the Controller board is 70900-60111 this will work (note I have this board as well)

Going over all this, you would need the Controller board 70900-60111 and the rom/ram board 70900-60114, it can be updated to 70900-60126 rom/ram code name Cheetah 2
Date code 880901 rev b.01.00 this add module 70301A tracking gen.


Hope this info helps.

Added picture of the board I have, and more info about the board.
had some wrong info, fixed that.
added a few more pictures

Board is no longer available as a member has asked for it
Maybe they will posted their older board for someone in need.

[K9DTV]

I am still looking for help setting up an HP 9000/300 series computer to work with my MMS system.
I have like four systems, from a 68010 at 12MHz to the 68030 system with gobbs of ram.

This includes setting up the software for the system and installing all the test and cal software for the MMS system.

Its been years and not had any luck, anyone willing to help?

[K9DTV]

yes, I just went back and looked and that does go to 22gig.  I guess I was looking at the tracking generator and that is limited to 2.9gig.

Other question, with the TG I can do scalar but is there a VNA option for the MMS?

The 70820A Microwave Transition Analyzer does VNA

[K9DTV]

Picked up a new toy for my 70K system last night and figure I would show it off.

It is a 70951B and picked up off eBay for cheap (cough, cough).

Unit was unopened and reported as bad, pictures of the it confirmed this, but was an easy fix.

Anyone that has one of these I would love to talk to you about it.

Anyways on with the equipment porn!

[materialsguy]

Firmware Files Uploaded:

I have uploaded 70100A Power Meter firmware files 1.21, 1.24, 1,27 to the groups.io files section https://groups.io/g/hp70000/files
and to KO4BB.

--materialsguy

[materialsguy]

Firmware Files Uploaded:

I have uploaded 70004A Display Mainframe firmware v7.04 to the groups.io files section https://groups.io/g/hp70000/files
and to KO4BB.

-materialsguy

[cncjerry]

It turned out that my frame had a power supply problem.  I bought another after finding out you cant shoot the power supply bugs without a load.  I could have just swapped the caps but one was hard to find size-wise, I think it was on the +5v. New frame cost me less than $100 and problem fixed.  Thanks for posting.   

Jerry

[K9DTV]

Today I received four DLP cards for the 7095x OSA.
The DFB, FP, and LED
OPT 51 EDFA ASE
OPT 52 EDFA TIME
OPT 53 EDFA NOISE GAIN PROFILE

Easy to install and use, not used the EDFA as I have no doped fiber YET!

The 70k System just gets more and more useful everyday it seems.
 

[materialsguy]

Firmware Files Uploaded:

I have uploaded 70900A Local Oscillator firmware A.01.00 to the groups.io files section https://groups.io/g/hp70000/files
and to KO4BB.  This is an early version of the firmware with the old menu system for the integrated CPU/ROM board (70900-60078). This board used six AM27C512 EPROMS.

-materialsguy

[coppercone2]

my b fm reciever still bad because someone sent me the wrong floppy drive on ebay and I gave up 

[cncjerry]

I'm trying to find the original module list prices for the MMS system.  I'll admit to not searching too hard, 20 minutes on "the google" but if someone has a pointer, it would be appreciated. Thanks

Jerry

[coppercone2]

be ready for your time travel trip to 1985?

[materialsguy]

"I'm trying to find the original module list prices for the MMS system.  I'll admit to not searching too hard, 20 minutes on "the google" but if someone has a pointer, it would be appreciated. Thanks"

Now this is interesting.  I was going to direct you to the HP Archive catalog section, but I see that the 1997 T&M catalog PDF version has no pricing.  I know that the printed version (a book, really) does have pricing. I can scan some pages for you if you like.

Or are you trying to go back even further? 

The 1986 catalog has pricing for the HP 70k system: http://hparchive.com/hp_catalogs

Shaun M.