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Re: Run old 120 V equipment via a 230 V transformer or converter?

 

I would use a 100VA rated IRON step down transformer or at a push, an auto-transformer.

Harmonics of a switcher might get into the Q measurement circuitry and cause unforeseen problems.

Pete
G4GJL?

On Wed, Aug 17, 2022 at 1:45 PM Dr. David Kirkby, Kirkby Microwave Ltd <drkirkby@...> wrote:
I bought an old Boonton 160-A Q-meter that's designed to run from the American 120 V system. However, I want to use it in the UK, where the main voltage is nominally 230 V, and mine is pretty close to that, after getting it dropped by 5% as it was going too high.

It's made in the mid 1930's, which pre-dates the invention of the transistor, so the Q-meter obviously does not have a SMPS. There's a transformer in there, to drop down the voltage for some of the tubes, which run as low as 2.x on the heater. I believe there's a voltage stabiliser, which I think runs works off the AC directly. I forget the operating frequency of these, but they will run from 50 Hz.

I'm wondering if it's a good idea to run this with a 230 -> 120 V transformer, or whether one of these converters would do, which I assume are some sort of switch mode supply. It takes 75 W, so I assume one rated at 200 W would be up to the job (Chinese Watts are a bit different to English ones).

Dr David Kirkby Ph.D
Email: drkirkby@... Web:
Kirkby Microwave Ltd (Tel 01621-680100 / +44 1621-680100)
Stokes Hall Lodge, Burnham Rd, Chelmsford, Essex, CM3 6DT.
Re: HP 8753D flakey step attenuator

 

The last time I worked on my 6GHz 8753D, I ended up with an attenuator issue as you describe.? I found an reasonably-priced used replacement on that auction site, but I decided that since I had nothing to lose, I may as well open her up and see what I could do.? It was a pretty straight forward fix, but unfortunately I can't recall exactly what I did to it.? Seems it was something with a contact finger popping off it's little tit, and I had to CA it back on, or melt the tit more to hold it, or something like that.? It wasn't too difficult, and I have large hands and fat fingers.
Re: Run old 120 V equipment via a 230 V transformer or converter?

 

I recall reading in the manual about a switch one can throw if the line voltage is higher or lower than normal. Looking underneath I see this. There’s no position for “normal” voltage - only higher or lower than normal. It looks like the transformer can probably be reconfigured to run on 230 V, but at this point I don’t want to open it up, in case it’s not as described in the auction. I have a 500 VA transformer.?



On Wed, 17 Aug 2022 at 13:44, Dr. David Kirkby <drkirkby@...> wrote:
I bought an old Boonton 160-A Q-meter that's designed to run from the American 120 V system. However, I want to use it in the UK, where the main voltage is nominally 230 V, and mine is pretty close to that, after getting it dropped by 5% as it was going too high.

It's made in the mid 1930's, which pre-dates the invention of the transistor, so the Q-meter obviously does not have a SMPS. There's a transformer in there, to drop down the voltage for some of the tubes, which run as low as 2.x on the heater. I believe there's a voltage stabiliser, which I think runs works off the AC directly. I forget the operating frequency of these, but they will run from 50 Hz.

I'm wondering if it's a good idea to run this with a 230 -> 120 V transformer, or whether one of these converters would do, which I assume are some sort of switch mode supply. It takes 75 W, so I assume one rated at 200 W would be up to the job (Chinese Watts are a bit different to English ones).

Dr David Kirkby Ph.D
Email: drkirkby@... Web:
Kirkby Microwave Ltd (Tel 01621-680100 / +44 1621-680100)
Stokes Hall Lodge, Burnham Rd, Chelmsford, Essex, CM3 6DT.



--
Dr. David Kirkby,
Kirkby Microwave Ltd,
drkirkby@...

Telephone 01621-680100./ +44 1621 680100

Registered in England & Wales, company number 08914892.
Registered office:
Stokes Hall Lodge, Burnham Rd, Althorne, Chelmsford, Essex, CM3 6DT, United Kingdom
Re: HP 3335A PSU woes PMD12K60.

 

Thank you for the suggestions, I had already ordered the MJ3001 based on its datasheet, which arrived today at a really good price. All I need now is more time to work on it as the bench is already overflowing with projects. I have no doubt there will be more faults/issues with the 3335 before it is done so watch this space as they say. Karl
Re: New keyboard for an HP-8712B

 

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Hello Conrad,

Try 08711-60101.

The circuit board itself is a very simple thing.? What is wrong with it?

Here is the manual for the front panel

Tom
N3AJA

On 8/17/2022 7:32 AM, Conrad, PA5Y wrote:

Can someone tell me the part number of the PCB that sits behind the keyboard membrane please, maybe I can find one.

?

Regards Conrad

?

From: [email protected] <[email protected]> On Behalf Of Conrad, PA5Y via groups.io
Sent: 16 August 2022 22:07
To: [email protected]
Subject: [HP-Agilent-Keysight-equipment] New keyboard for an HP-8712B

?

Hello all, I have an HP8712B that has very unreliable soft keys, I tried to clean them, and it made no difference.? I see the replacement membrane keyboards on eBay from China but I don’t think that will help. It is the assembly behind the membrane that needs to be replaced I expect.

?

Can anyone help me locate a complete keypad assembly?

?

Regards

?

Conrad Farlow PA5Y, Eindhoven

Re: Run old 120 V equipment via a 230 V transformer or converter?

 

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Hammond Manufacturing has a line of 230VAC to 115VAC 50Hz/60Hz isolation transformers rated between 100VA to 1000VA

Chuck



On 8/17/2022 8:44 AM, Dr. David Kirkby, Kirkby Microwave Ltd wrote:
I bought an old Boonton 160-A Q-meter that's designed to run from the American 120 V system. However, I want to use it in the UK, where the main voltage is nominally 230 V, and mine is pretty close to that, after getting it dropped by 5% as it was going too high.

It's made in the mid 1930's, which pre-dates the invention of the transistor, so the Q-meter obviously does not have a SMPS. There's a transformer in there, to drop down the voltage for some of the tubes, which run as low as 2.x on the heater. I believe there's a voltage stabiliser, which I think runs works off the AC directly. I forget the operating frequency of these, but they will run from 50 Hz.

I'm wondering if it's a good idea to run this with a 230 -> 120 V transformer, or whether one of these converters would do, which I assume are some sort of switch mode supply. It takes 75 W, so I assume one rated at 200 W would be up to the job (Chinese Watts are a bit different to English ones).

Dr David Kirkby Ph.D
Email: drkirkby@... Web:
Kirkby Microwave Ltd (Tel 01621-680100 / +44 1621-680100)
Stokes Hall Lodge, Burnham Rd, Chelmsford, Essex, CM3 6DT.




-- 
See Early TV at:

Re: Run old 120 V equipment via a 230 V transformer or converter?

 

On 2022-08-17, at 14:44, Dr. David Kirkby, Kirkby Microwave Ltd <drkirkby@...> wrote:

50 Hz.
US systems of this age may be designed specifically for 60 Hz operation.
The longer periods of 50 Hz power may push the device’s transformers into saturation a bit, so the transformers might run hot.
(With high-quality devices, one would expect enough margin to cover 50 Hz, but you never know.)

And, of course, the power line frequency may be driving some internal circuitry such as a clock (maybe not with a device of this age, unless you find a synchronous motor anywhere).

Grü?e, Carsten
Re: Run old 120 V equipment via a 230 V transformer or converter?

 

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I have yet to see a cheap converter that puts out a decent sine wave!

Hard to go wrong with a transformer...


Yours

Tommy

2022-08-17 14:44 skrev Dr. David Kirkby, Kirkby Microwave Ltd:

I bought an old Boonton 160-A Q-meter that's designed to run from the American 120 V system. However, I want to use it in the UK, where the main voltage is nominally 230 V, and mine is pretty close to that, after getting it dropped by 5% as it was going too high.
?
It's made in the mid 1930's, which pre-dates the invention of the transistor, so the Q-meter obviously does not have a SMPS. There's a transformer in there, to drop down the voltage for some of the tubes, which run as low as 2.x on the heater. I believe there's a voltage stabiliser, which I think runs works off the AC directly. I forget the operating frequency of these, but they will run from 50 Hz.
?
I'm wondering if it's a good idea to run this with a 230 -> 120 V transformer, or whether one of these converters would do, which I assume are some sort of switch mode supply. It takes 75 W, so I assume one rated at 200 W would be up to the job (Chinese Watts are a bit different to English ones).
?
?
?
Re: Run old 120 V equipment via a 230 V transformer or converter?

 

Hi David,

No question. ?Always use a transformer for this old equipment.

Take care,

Larry
AC9OX
Run old 120 V equipment via a 230 V transformer or converter?

 

I bought an old Boonton 160-A Q-meter that's designed to run from the American 120 V system. However, I want to use it in the UK, where the main voltage is nominally 230 V, and mine is pretty close to that, after getting it dropped by 5% as it was going too high.

It's made in the mid 1930's, which pre-dates the invention of the transistor, so the Q-meter obviously does not have a SMPS. There's a transformer in there, to drop down the voltage for some of the tubes, which run as low as 2.x on the heater. I believe there's a voltage stabiliser, which I think runs works off the AC directly. I forget the operating frequency of these, but they will run from 50 Hz.

I'm wondering if it's a good idea to run this with a 230 -> 120 V transformer, or whether one of these converters would do, which I assume are some sort of switch mode supply. It takes 75 W, so I assume one rated at 200 W would be up to the job (Chinese Watts are a bit different to English ones).

Dr David Kirkby Ph.D
Email: drkirkby@... Web:
Kirkby Microwave Ltd (Tel 01621-680100 / +44 1621-680100)
Stokes Hall Lodge, Burnham Rd, Chelmsford, Essex, CM3 6DT.



IMG_1104.jpeg

Re: New keyboard for an HP-8712B

 

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Can someone tell me the part number of the PCB that sits behind the keyboard membrane please, maybe I can find one.

?

Regards Conrad

?

From: [email protected] <[email protected]> On Behalf Of Conrad, PA5Y via groups.io
Sent: 16 August 2022 22:07
To: [email protected]
Subject: [HP-Agilent-Keysight-equipment] New keyboard for an HP-8712B

?

Hello all, I have an HP8712B that has very unreliable soft keys, I tried to clean them, and it made no difference.? I see the replacement membrane keyboards on eBay from China but I don’t think that will help. It is the assembly behind the membrane that needs to be replaced I expect.

?

Can anyone help me locate a complete keypad assembly?

?

Regards

?

Conrad Farlow PA5Y, Eindhoven

OT: solartron 715x spare parts needed

 

Hi all,
sorry for the OT, but I think some people here might have the right
spares (If I'm lucky).
I am repairing a Solartron 7151 multimeter, it was cheap enough that I
decided to give it a try.
Unfortunately someone was inside it before and there're a few parts
missing on the analog pcb (PCB1). Most of them are easily replaceable
but one reed relay and PTFE variable capacitor.
Does anyone have one of these multimeters (7150/7151 should have the
same PCB1) and can sell me the parts I need?
The relay is a Coto 4000-0002 btw.

Thanks
Frank IZ8DWF
Re: "ADDITIONAL STANDARDS ARE NEEDED" when using E-Cal

 

Wayne -
Very nicely done - you have been busy :-)

Cheers !

Bruce

Quoting Wayne ZL2BKC <w.knowles@...>:

Hi Dan,

Some additional information that may help you troubleshoot your suspect ECal until has been uploaded.?? Using an Arduino you can manually activate each of the gate signals to confirm correct behavior.
I thought I took better notes about which of PIN switches were activated and the voltage levels for the low band unit. (The high band one uses an easy 1:1 mapping but the low band one has some SPDT switching at play.? If you end up down that rabbit hole I can document the next level down.

Search for the 85062 folder in the files section and look for HP85062 ECal Interface.zip

--
Wayne
Re: "ADDITIONAL STANDARDS ARE NEEDED" when using E-Cal

Wayne ZL2BKC
 

Hi Dan,

Some additional information that may help you troubleshoot your suspect ECal until has been uploaded.?? Using an Arduino you can manually activate each of the gate signals to confirm correct behavior.
I thought I took better notes about which of PIN switches were activated and the voltage levels for the low band unit. (The high band one uses an easy 1:1 mapping but the low band one has some SPDT switching at play.? If you end up down that rabbit hole I can document the next level down.

Search for the 85062 folder in the files section and look for HP85062 ECal Interface.zip

--
Wayne
File /All HP, Agilent and Keysight instruments in folders by part numbers/A 80000 to 89999/85062/HP65062 ECal Interface.zip uploaded #file-notice

Group Notification
 

The following files and folders have been uploaded to the Files area of the [email protected] group.

By: Wayne ZL2BKC <w.knowles@...>

Description:
Arduino interface to control HP ECal Modules plus some additional reverse engineering notes
Re: HP 8753D flakey step attenuator

 

"Jeff Keyzer" <jeff@...> writes:

I have an HP 8753D with the internal 50 ohm test set (6GHz) and what I
suspect is an intermittent step attenuator.

If I connect a short cable between ports 1 + 2, I will occasionally see a
steep rolloff in the uncorrected S21 below about 300kHz. Cycling the power
ranges manually a few times usually fixes it. Sometimes leaving the analyzer
alone for a few minutes or giving it some "percussive maintenance" will fix
it as well, so I believe that the mechanical step attenuator may be dirty
and is not always making contact. Certain ranges are more affected than
others, so I suspect that one of the stages is going bad.

I can't find information about the step attenuator in the service manuals,
where can I find more information? I'd like to know the part #, how
difficult it is to extract from the VNA, and if anyone has had any luck
cleaning or repairing these.
I've read that HP considered these non-serviceable items so you're
unlikely to find service manual information other than electrical
connections to the attenuator. However, in many cases they are
repairable and definitely worth the attempt.

I don't have any experience with the HP 8753D, but I would probably just
open the unit up and take a look if you can't find much in the
manual. I'd expect it to be right next the the RF connector, so probably
at the front. If you take a picture of the label on the attenuator
people on this list can probably help out. I "repaired" an HP 33321
attenuator in my HP 8663A a few months back. Unfortunately, I neglected
to take notes on the process but I did take pretty detailed pictures and
I think I could remember from those if you need some assistance.

You can sometimes implicate the attenuators without opening the
unit. For instance, in my unit it would jump up by 20dB or something
when I would decrease the power 1dB for some levels. The attenuators
work (at a very high level) by switching in attenuation pads. These are
often 1, 5, 10, 20, 40 dB (probably others too, but you get the
idea). They achieve the desired attenuation through combinations of
these.

The most common fault (judging by number of posts) seems to be faulty
o-rings. Do a search of those here and maybe on eevblog too. You should
get a bunch of results. There are also youtube videos last I checked
that could prove useful.

In my case the o-rings were totally fine and the switches were just a
bit sticky. Attempting to actuate it electrically didn't do the trick,
but opening it up and actuating it mechanically (many times) worked. I
haven't had an issue with them since.

With anything RF precision like this you do want to be careful when you
open them up. But, with some care it's not difficult to avoid any
damage.

I've tried cycling the attenuator manually a bunch of times and it's still
exhibiting the problem. I was hoping that by exercising it a lot, the
problem would go away. Wishful thinking, I guess.

Thanks in advance for any replies.
Best of luck and hope we can help.

Matt
HP 8753D flakey step attenuator

 

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Hello all,

?

I have an HP 8753D with the internal 50 ohm test set (6GHz) and what I suspect is an intermittent step attenuator.

?

If I connect a short cable between ports 1 + 2, I will occasionally see a steep rolloff in the uncorrected S21 below about 300kHz. Cycling the power ranges manually a few times usually fixes it. Sometimes leaving the analyzer alone for a few minutes or giving it some “percussive maintenance” will fix it as well, so I believe that the mechanical step attenuator may be dirty and is not always making contact. Certain ranges are more affected than others, so I suspect that one of the stages is going bad.

?

I can’t find information about the step attenuator in the service manuals, where can I find more information?? I’d like to know the part #, how difficult it is to extract from the VNA, and if anyone has had any luck cleaning or repairing these.

?

I’ve tried cycling the attenuator manually a bunch of times and it’s still exhibiting the problem.? I was hoping that by exercising it a lot, the problem would go away. Wishful thinking, I guess.

?

Thanks in advance for any replies.

Jeff

?

?
New keyboard for an HP-8712B

 

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Hello all, I have an HP8712B that has very unreliable soft keys, I tried to clean them, and it made no difference.? I see the replacement membrane keyboards on eBay from China but I don’t think that will help. It is the assembly behind the membrane that needs to be replaced I expect.

?

Can anyone help me locate a complete keypad assembly?

?

Regards

?

Conrad Farlow PA5Y, Eindhoven

Re: HP8560E SA Display oddness

 

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Presumably the power supplies have been confirmed good prior to anything else being done.

Nigel

by banging a nail into a piece of wood...

On 16 Aug 2022, at 18:38, Jaap Rusticus <jrusticus@...> wrote:

Hello Dan,
My recently bought 8560E has the same issue. Intensity is at maximum (255). Graticule is a bit dim too. At first I thought it might be the many Elapsed Hours (8869), but I cannot see burning-in effects. I did shift the image up and down, but no effect. So that looks good. I will try to get inside and find the monitor brightnes/bias pot. Must be there I think. I do have the service manual with CLIP from Artek but I still have to have a look at it.
Did you already investigate further?

Jaap PA0JRK
Netherlands

Re: HP8560E SA Display oddness

 

Hello Dan,
My recently bought 8560E has the same issue. Intensity is at maximum (255). Graticule is a bit dim too. At first I thought it might be the many Elapsed Hours (8869), but I cannot see burning-in effects. I did shift the image up and down, but no effect. So that looks good. I will try to get inside and find the monitor brightnes/bias pot. Must be there I think. I do have the service manual with CLIP from Artek but I still have to have a look at it.
Did you already investigate further?

Jaap PA0JRK
Netherlands
22961 - 22980 of 151504