And 15,734 Hz in the US (NTSC).

--
Prof. Thomas H. Lee
Allen Ctr., Rm. 205
420 Via Palou Mall
Stanford University
Stanford, CA 94305-4070

Thanks! very good. The ~ 17 ohms is the lamp and dropping resistor? inside the manual fine tune encoder. Im seeing another 10 ohms cold load thru the Gpio boards apparently to or from the Xtal Oven oscillator.

This should give you the information you need.

Steve

Hi Dave,

Just checked my 8660C s/n 03700 something.? ? ?I measure 16.2 ohms to the chassis.? ?My 8660 has and 8660D power supply.....long story.? ?

I have not unplugged and removed from a rack my 8660 in about 20 years!?

92 means a wire colored white-red (white with a red stripe I guess).? ? HP used the standard color code on wiring.? ? Red usually meant a positive voltage with respect to chassis, black chassis,? violet a negative voltage with respect to the chassis, etc..?
??
I repaired the last 8660 and plug-ins before the eastern region repair center became a calibration-only hub and consolidated the full service centers to Roseville CA.? ?At one time we had maybe 50-60 techs.? ? ??

I continue to work on HP instruments as a volunteer at the Antique Wireless Assoc. in Bloomfield, NY.? ? Haven't seen any 8660's come thru as donations from estates but plenty of 8640s.? ?Also just fixed up an HP410B and before that an HP 204 (or 209).? ? Now retired (from Harris).? working on the old HP instruments has been a blast from the past after working for HP for >24 years.? See plenty of other old common HP units.? ?

??

Thank you Robert and Don,

Fortunately the device does have 24VDC written on it, so I can be sure of that spec. +30dBm continuous suits me well, I stay firmly under +10dBm or so in my experiments.

John.

Oh! Yes. PAL. Everything in the world is not according to U.S. standards (NTSC= naught twice the same colour)

Might it be worth repairing as to the cost of Yig units? Thousands of dollars?

Hi Dave,?

That's a great question. There is no way of really knowing if a shorted coil in the YTX caused an overcurrent damaging the A6A12, or if an overcurrent in the A6A12 caused a shorted coil in the YTX. It could have been a failure upstream of R106 that caused the damage. In fact, the more I think about it, I'm inclined to think that was the case. Failure of that coil seems unlikely given how well protected and low power it is. It seems more likely that something in the current regulating circuity shorted, sending high power levels through R106, burning it and overheating the coil. Chicken and egg question, I suppose. As such, I have no intention of attempting to replace the resistor and re-use the driver card. It's going straight into the parts bin.

Also, I did not notice any difference in sweep speed.?

It was a thread I had read a few weeks ago on the EEV blog that made me think of the coil being damaged:

I should pull the old YTX apart some time, it's not like it will ever be going back into service.?

?

?

?

Chassis parts would be useful to someone.? So would the connectors and switches.

Hi everybody,

I recently acquired two broken Agilent oscilloscopes. The first one is a 54825A. I was able to fix that one as it only had a bad CMOS battery and leaky caps on the mainboard.

The second one is a 54832B and it had a very hard life. It came completely beat up with a severely bent housing. Of course it didn't start at all. After I removed the cable going from the PCB where all the fans are connected to to the mainboard, it started up and booted into XP. There it even opened in the infiniium application but it didn't show any traces. All were empty.

Well I had a look at the application board and at some the screw holes there are tiny cracks. I saw one severed trace that I fixed but unfortunately it didn't help. Half of the time the oscilloscope wouldn't start at all and the other half the oscilloscope would boot but not start the infiniium app. It would crash out with the typical "this program has expirienced a problem" Windows XP message.

So I'm not sure how to proceed. Since the PCB is a multilayer board, I don't know if any internal traces got severed. Does anybody have some ideas or know where to get a reasonably priced acquistion board?

Kind regards,
Milad

You can find the pin outs, schematics, specs, for the 33320 through 33323 series attenuators in the older HP, Agilent Microwave Accessories catalogs. You may find some of them posted on this forum site. The PN seams familiar to me and may be the attenuator used in the 8566B. Check the manual for the 8566B for this PN. If this is the case then it is a 70dB attenuator (10, 20, 20, 20 dB sections), 0-22GHz, 1W max input, atten. drive should be +15VDC (think current). There were several different part nos. used in the 8566 spectrum analyzers, but all are equivalent.

Hi,

From what I have read a v7.xx of 8510C requires 1992 version of 8341B. I am therefore interested in hearing your answer.

I have a 8510C with firmware v7.10 Mar 30, 1995 and a 8341B with firmware 11 May 88. They work fine together with a 8515A.

Also remote control with GPIB works fine with various adapters.

Best regards,
Job

开云体育

Re...

On 09/07/2024 21:01, [email protected] wrote:

During this time I found R106 was burned on my original A6A12. Concerned this could have been caused by a damaged coil in the YTX, I decided the next logical step was replacing the YTX with one from the donor unit. Success! I was able to achieve a full amplitude signal across all tested frequencies.

I wonder if a shorted turn in the YTX device could cause that?

Was there any noticeably different behaviour at faster sweep speeds than slower?

Regards to All.

Dave B.

-- 
Created on and sent from a Unix like PC running and using free and open source software:

Hi.

Glad to help.

IO-Trace is "The" tool to have, for any GPIB/HPIB weirdness you might come across using NI's tools.? (I have no idea if the Agilent/Keysight equivalent systems have a similar tool.)

It works for all traffic going out/in over the GPIB, not only VISA calls, but "old school" board level calls too.
(It might even log calls to other interfaces, if managed by the NI drivers, I'm not sure.)

NI has a good description of how to use it here:-


There are lots of options, many will lead to "HUGE" files being created (they compress very well with the usual file compression tools etc) but they will contain all the info needed to see what's happening.


Re the faulty HPIB board.

"If" your HP machine is one of the products that uses the famous HP "Nanoprocessor" on the HPIB board, check it's local DC power rails.

As usual, they should be clean and stable.? Especially the "bias" pin (38) on the processor, that should have the voltage on (wrt to local 0V on Pin 17) it that is marked on top of the 'processor chip itself.? Typically between -2 and -5V

Pin 39 is the main +5V, and Pin 40 "Vgg" could be +9 or +12V (+- 5%)? Depending on version of Nanoprocessor.

1820-1692 (NP-A) uses +12V?? 1820-1691 (NP-B) uses +9V

(According to the documentation I have dated 11/10/1975.)


It uses an external (on the same board) ROM for the code it runs.

As I recently found on a little HP 3438A DMM I have.

The GPIB board's dedicated PSU rail (it's main +5V!) was bad.? A failed (open) rectifier diode, and the resulting bad electrolytic cap in that case, no doubt due to the excess ripple current, was causing 100% ripple on the +5V!? (It was more like a 50Hz Square Wave!)? Replacing the diode and the cap' (plus another similar cap for the +12V rail, that had not quite failed) restored full operation!

(The DMM circuitry is fully floating with it's own PSU rails, communicating with the HPIB board via opto isolators.)

What I was initially seeing, was partial GPIB activity (using an Arduino or PIC based USB-GPIB device I have, I do not use Windows) it could be addressed, showing the indicator on the front panel, but fail to complete any handshake.? Even in the data streaming "Talk only" mode, it would not do anything!

Quite how the Nanoprocessor survived that abuse for presumably an extended time, I do not know.? HP obviously designed and fabricated those things very well!

(If only a lot of modern stuff was just as forgiving!)


Hope something helps.? The HP8341B is a very nice instrument.? I'm green with envy!? :-)

Regards.

Dave G8KBV.


--
Created on and sent from a Unix like PC running and using free and open source software:

Power handling.
All thase attenuators use tha same atteunuator "cards". Power rating is 1 W average, 100 W peak with maximum pulse width of 10 microseconds.

Note that 10us is much shorter than a quick press of the PTT. These are NOT power attenuators.

Forgot to say,
Common coil voltage options are 24V, 15V and 5V .? Resistances are 190, around 100 and 17 Ohms respectively. Also if there is a ribbon cable connection the colurs are consistent to function whatever the connector.

Well, it took a little longer to get results, but here it goes:
After constructing an adapter board for the FM16W08 (the readily available ones from China do not fit the socket) the patient seems fully cured: all things work as expected, and the settings are remembered.
"Look ma! No batteries!" ;)

For those interested: I have 1 fully assembled FRAM adapter and three bare PCBs left over for sale...

I don't think the uprade is a problem.? AFIK anything working with V6 will work with V7, but the reverse is not true.

Do you have a complete 8510C system now?

Cheers!

Bruce