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Re: Thoughts on upgraded(?) replacement parts for vintage equipment

 

The test equipment in my garage lab I consider tools, and as such is subject to change (purchase, sale, exchange, repair, give away, etc.).? It is not a collection of museum pieces!? A wise person once said that we should love people and use things and not the other way around.? Collecting goes against that great advice.? I have absolutely no qualms about modifying any piece of test equipment I own if it improves its performance.? Can't be sentimental about it.? ? ? ? Jim Ford, Laguna Hills, California, USA?
Re: Thoughts on upgraded(?) replacement parts for vintage equipment

 

On Tue, Oct 8, 2024 at 06:45 AM, Ed (scskits) wrote:
The big problem with these boards was not the board, but the metal shield.
I never had that re-manufactured.
?
I am thinking that it won't make much of a difference not to have them and I have more shields than cards anyway.? Not enough, but enough to do the ones that I will sell anyway.? In the unlikely event it matters, it is not that expensive to have blanks laser cut.? I have a small metal brake to do the major bends and use small glue-on holders for the side board supports instead of the "V" bend.? One box is missing the overall shield, which sucks, but again it will probably not make much difference and I'll use that one as a personal item - I will just use it for local reference distribution and the case itself should provide enough shielding for my needs.
?
Hal
Re: Thoughts on upgraded(?) replacement parts for vintage equipment

 

?
?
Perhaps the most significant area of instrumentation Restoration Retrofit,?
?(other than power supply & amplifier issues),? would be displays:
?
Older instrument LCD, LED, Vacuum Fluorescent VFD, & CRT's, (both Vector & Raster scan) problems plague us all.
?
Having? *low cost*?? *open source* ? programmable retrofit display modules to replace the custom, older VFD , LCD, CRT & some LED display modules would certainly be helpful.
?
Fragile VFD vacuum leak, filament burnouts are increasing.
?
Vector CRT to LCD display replacements have been discussed, but are a challenge to implement
? ( long list of affected instruments: Hp 9100, Tek 576 CRT's,? ).
?
The HP 8665 (VFD) & the? Wiltron 6747b (LCD) ..... series? display issues are haunting.
?
?? - feel free to Add your favorite instrument model # display issue? !! ).
?
There are scattered examples of such replacement display module projects for older equipment on the Web, GitHub, etc.,
?-- but more needs to be done.
?
Not certain if there is a comprehensive List of available, successful display replacements? projects ??
?
?
?
HP? 70911 CLIP / Circuit diagram the 100 Mhz wide IF unit

 

Looking for HP? 70911 CLIP / Circuit diagram the 100 Mhz wide IF unit ?

?

It is a unit that is part of the HP 70000 spectrum analyser system

?

Hopefully someone has it in either paper format or PDF ?

If only in Paper we could then arrange for it to be scanned for witch I will pay for

?

Regards Paul?
Re: Thoughts on upgraded(?) replacement parts for vintage equipment

 

Already did the 5087A boards a couple years back.
The big problem with these boards was not the board, but the metal shield.
I never had that re-manufactured.
?
ed
Re: Boonton 92BD Troubleshooting

 

Yes, the 92B is electro-mechanical.? I think the issue when these choppers go bad is timing problems.? Probably from metal fatigue.?
70420A Phase Noise Test Set or any version of E5500

 

Just a quick question hear has any one got or used a 70420A Phase Noise Test Set or any version of E5500 as We are currently lacking anything about the E5500?

What exactly was included in the E5500 package / configuration?

?

There should be the manuals for the 70420A Phase Noise Test Set

It would be good to find the operating instructions, Service manual and the CLIPS

?

Also there should be the manuals for the software and the program to ran on a HP computer ?also training notes for the? system

?

All comments welcome? Paul South coast UK
HP 37741A DS1 Test Set

 

Does anybody have the calibration software for this antique. ?It comes up saying that the saved data is corrupted and passes all other tests.
Battery was leaking and dead, so it was replaced, but there must be some BB RAM that lost it's load.
The manual refers to HP 15726A MSDOS based software for calibration. ?It appears to be unobtanium from the usual suspects.
?
--
Tim Wright
Senior Engineer
Cumulus Media Chicago - WLS-AM
AL7DS
Re: Agilent 34461A schenmatic

 

开云体育

You are right!

?

?

De?: [email protected] <[email protected]> De la part de Ozan
贰苍惫辞测é?: 7 octobre 2024 15:39
??: [email protected]
Objet?: Re: [HP-Agilent-Keysight-equipment] Agilent 34461A schenmatic

?

U1005 is a TI TPS54040A. Package information page of datasheet shows "5404A" as device marking, which matches the picture.

Ozan

?

?

?

On Mon, Oct 7, 2024 at 11:37 AM, Yves Tardif wrote:

?

As specified in the last email, I don't have the part numbers unfortunately, only the marking codes or the Keysight part numbers. Also, I can't find these part numbers on the Keysight website.

?

If I were in your situation, I would first look for a 1.3MHz 8 pin switcher with the same package.

And from the circuit and the coil value, I would try to see if the pin out seems compatible, and if the installed coil would be compliant with a 1.3MHz operating frequency.

?

A friend of mine probably has a 34461A that he could lend me, but don't expect to have more details on the part numbers, but I could take the waveforms at the switcher pins.

I am not absolutely sure that the switcher of the 34461A and 34465A are identical because I do not have a detailed photo of this section for the 34461A, but the coil value is the same.

?

?

?

?

De?: [email protected] <[email protected]> De la part de Keith Harvey
贰苍惫辞测é?: 7 octobre 2024 14:06
??: [email protected]
Objet?: Re: [HP-Agilent-Keysight-equipment] Agilent 34461A schenmatic

?

Hi Yves,

?

Thank you for the insight.

?

If you have the Agilent part numbers for the components I listed, that might prove helpful.

?

Regards,

Keith Harvey

From: [email protected] <[email protected]> on behalf of Yves Tardif <yves_tardif@...>
Sent: Monday, October 7, 2024 11:58 AM
To: [email protected] <[email protected]>
Subject: Re: [HP-Agilent-Keysight-equipment] Agilent 34461A schenmatic

?

Hi Keith,

?

I checked my 34410A and my 34465A, and unfortunately, I don't have a 34461A.

However, they all have the same function to perform, that is to say from +10V, provide a voltage of +3.3V, +1.2V and possibly +2.5V.

A switcher lowers a DC voltage from about +10V to +3.3V, the frequency of the switcher is about 1.3MHz for both instruments.

The 34461A has the same part numbers as the 34465A, there is a very good chance that the 34465A and 34461A have the same circuit for the section concerned.

?

I don't know if this can help you, but you have an idea of ??the damaged circuit.

I don't have the part numbers unfortunately, only the marking codes or the Keysight part numbers.

?

I repaired a 34461A a few months ago, the +3.3V switch was not damaged, but there was a short circuit on the +3.3V line caused by a faulty capacitor.

?

Waveform measured at output switcher connected to coil.

?

Yves

?
Re: Agilent 34461A schenmatic

 

开云体育

?

痴辞颈濒à!

?

De?: [email protected] <[email protected]> De la part de Keith Harvey
贰苍惫辞测é?: 7 octobre 2024 15:18
??: [email protected]
Objet?: Re: [HP-Agilent-Keysight-equipment] Agilent 34461A schenmatic

?

Do you have the full schematic for the 34410a?

From: [email protected] <[email protected]> on behalf of Yves Tardif <yves_tardif@...>
Sent: Monday, October 7, 2024 12:37 PM
To: [email protected] <[email protected]>
Subject: Re: [HP-Agilent-Keysight-equipment] Agilent 34461A schenmatic

?

?

As specified in the last email, I don't have the part numbers unfortunately, only the marking codes or the Keysight part numbers. Also, I can't find these part numbers on the Keysight website.

?

If I were in your situation, I would first look for a 1.3MHz 8 pin switcher with the same package.

And from the circuit and the coil value, I would try to see if the pin out seems compatible, and if the installed coil would be compliant with a 1.3MHz operating frequency.

?

A friend of mine probably has a 34461A that he could lend me, but don't expect to have more details on the part numbers, but I could take the waveforms at the switcher pins.

I am not absolutely sure that the switcher of the 34461A and 34465A are identical because I do not have a detailed photo of this section for the 34461A, but the coil value is the same.

?

?

?

?

De?: [email protected] <[email protected]> De la part de Keith Harvey
贰苍惫辞测é?: 7 octobre 2024 14:06
??: [email protected]
Objet?: Re: [HP-Agilent-Keysight-equipment] Agilent 34461A schenmatic

?

Hi Yves,

?

Thank you for the insight.

?

If you have the Agilent part numbers for the components I listed, that might prove helpful.

?

Regards,

Keith Harvey

From: [email protected] <[email protected]> on behalf of Yves Tardif <yves_tardif@...>
Sent: Monday, October 7, 2024 11:58 AM
To: [email protected] <[email protected]>
Subject: Re: [HP-Agilent-Keysight-equipment] Agilent 34461A schenmatic

?

Hi Keith,

?

I checked my 34410A and my 34465A, and unfortunately, I don't have a 34461A.

However, they all have the same function to perform, that is to say from +10V, provide a voltage of +3.3V, +1.2V and possibly +2.5V.

A switcher lowers a DC voltage from about +10V to +3.3V, the frequency of the switcher is about 1.3MHz for both instruments.

The 34461A has the same part numbers as the 34465A, there is a very good chance that the 34465A and 34461A have the same circuit for the section concerned.

?

I don't know if this can help you, but you have an idea of ??the damaged circuit.

I don't have the part numbers unfortunately, only the marking codes or the Keysight part numbers.

?

I repaired a 34461A a few months ago, the +3.3V switch was not damaged, but there was a short circuit on the +3.3V line caused by a faulty capacitor.

?

Waveform measured at output switcher connected to coil.

?

Yves

34410A schematic .pdf
34410A schematic .pdf

Re: Thoughts on upgraded(?) replacement parts for vintage equipment

 

As a collector of vintage equipment, I prefer to keep things original where possible, of course this isn't always possible and substitute parts are sometimes needed. Annoyingly there are plenty of used spares around, but they always seem to end up with the rip-off scammer type sellers, trying & failing to flog piles of used plated boards as Au scrap, often at silly prices, if they were worth the asking prices they wouldn't be listed on ePay.
?
Damaged boards are not a problem to me, I have made some replacement boards for my 5245L & 5264A and tried to keep the track & component layout close to the original, only major difference is the modern solder mask that the originals didn't have, removing this is possible but the PCB house then ask for extra charges, to have the fools-gold plating all over (they don't add this under the mask).
?
David
Re: Agilent 34461A schenmatic

 

U1005 is a TI TPS54040A. Package information page of datasheet shows "5404A" as device marking, which matches the picture.
Ozan
?
?
?
On Mon, Oct 7, 2024 at 11:37 AM, Yves Tardif wrote:

?

As specified in the last email, I don't have the part numbers unfortunately, only the marking codes or the Keysight part numbers. Also, I can't find these part numbers on the Keysight website.

?

If I were in your situation, I would first look for a 1.3MHz 8 pin switcher with the same package.

And from the circuit and the coil value, I would try to see if the pin out seems compatible, and if the installed coil would be compliant with a 1.3MHz operating frequency.

?

A friend of mine probably has a 34461A that he could lend me, but don't expect to have more details on the part numbers, but I could take the waveforms at the switcher pins.

I am not absolutely sure that the switcher of the 34461A and 34465A are identical because I do not have a detailed photo of this section for the 34461A, but the coil value is the same.

?


?

?

De?: [email protected] <[email protected]> De la part de Keith Harvey
贰苍惫辞测é?: 7 octobre 2024 14:06
??: [email protected]
Objet?: Re: [HP-Agilent-Keysight-equipment] Agilent 34461A schenmatic

?

Hi Yves,

?

Thank you for the insight.

?

If you have the Agilent part numbers for the components I listed, that might prove helpful.

?

Regards,

Keith Harvey

From: [email protected] <[email protected]> on behalf of Yves Tardif <yves_tardif@...>
Sent: Monday, October 7, 2024 11:58 AM
To: [email protected] <[email protected]>
Subject: Re: [HP-Agilent-Keysight-equipment] Agilent 34461A schenmatic

?

Hi Keith,

?

I checked my 34410A and my 34465A, and unfortunately, I don't have a 34461A.

However, they all have the same function to perform, that is to say from +10V, provide a voltage of +3.3V, +1.2V and possibly +2.5V.

A switcher lowers a DC voltage from about +10V to +3.3V, the frequency of the switcher is about 1.3MHz for both instruments.

The 34461A has the same part numbers as the 34465A, there is a very good chance that the 34465A and 34461A have the same circuit for the section concerned.

?

I don't know if this can help you, but you have an idea of ??the damaged circuit.

I don't have the part numbers unfortunately, only the marking codes or the Keysight part numbers.

?

I repaired a 34461A a few months ago, the +3.3V switch was not damaged, but there was a short circuit on the +3.3V line caused by a faulty capacitor.

?

Waveform measured at output switcher connected to coil.

?

Yves

?
Re: Thoughts on upgraded(?) replacement parts for vintage equipment

 

I seem to recall that somebody came up with a replacement chopper for the Fluke 332 calibrator. That might be a good starting point. You can find it if you dig around in the 332 threads on eevblog.

I think one of the biggest problems with replacement technology is the short commercial lifetime of replacement parts. That design, for example, is a few years old and I don't think any of the opamps used are still available.

Similarly, there was a design for the Tektronix U800 that came out of a university that was about 80% functional. Most of those parts are not currently available. Dr. Ram took that work, reworked it so it is a 100% drop in replacement and is selling those on ebay. Kudos to him for that (and disclaimer, I did buy one) but once he decides to quit support that design is lost as well.

I wish we could get something set up so that if people want to make money on a reengineered solution they can, but when they want to drop it (or die) the design info would go open source. Knowing I wouldn't be orphaned again would actually encourage me to buy those solutions.

Paul

On Mon, Oct 07, 2024 at 10:18:43AM -0700, Harold Foster wrote:
Jared- Your very nice work on the 3400A is what inspired me to start thinking of upgrading various parts of the equipment I have.? I have a few Fluke 343's in the que and I keep hoping someone will jump on the chopper portion - otherwise I'll wind up going down that rabbit hole and I have too many other things (mostly Honey-Do's, sigh) to work on first.

Hal
--
Paul Amaranth, GCIH | Manchester MI, USA
Aurora Group of Michigan, LLC | Security, Systems & Software
paul@... | Unix/Linux - We don't do windows
Re: Boonton 92BD Troubleshooting

 

Correct me if I'm wrong, but the Boonton 42B/92B chopper is electro-mechanical, no chopper lamps are mentioned in the manual, not sure if you meant something else using lamps (such as HP stuff, which this definitely isn't). The failure method is going to be chopper switch contact wear isn't it or the coil going open circuit?
?
Also the cable is described in a manual as a "special low-noise design", some pictures of the cable here;
?
David
?
On Sat, Oct 5, 2024 at 10:37 PM, Michael A. Terrell wrote:

I currently have very poor vision, so I missed tat part. I've had eye problems my whole life, but I now have cataracts and hav? been unable to have the surgery. These units have fa outlived their design life and the chopper is always suspect because the lamps weren't rated for a very long useful life. I would add a sub board with the modern circuit, rather than mess with reusig badlt aged lamps., but that choice is yours. I repaired equipment for? daily use in production, along with my opersoal shop.? so the equipment had to meet all specifications at outr in house Metrology lab. I prefer to repair a fault, just once. My work centered on testing and calibrating boards made in house for our products, but I ofteny worked with the lab to find was to repair equipment that there were few or no spare parts.

On Sat, Oct 5, 2024 at 3:30?PM Bill Berzinskas via <bberzinskas=[email protected]> wrote:
@Michael T -
I mentioned that the recorder port is presenting 13.5v always, so there may be something there to look at.? ?If i remove either the chopper or shaping amp boards, it returns to zero.??
This is why it leads me to believe the digital part is ok, its just passing around signals from further up in the chain, i assume.? ? Will dig into it further, still digesting the schematic and manual, tracing through what i can when i have time.? ?

I do think the chopper is passing through to the board and into the circuit but i'm not seeing anything coming OUT of it into the shaping amp, might be the opamp on the output side, tbd.? ?

Either way, I'll cross post to the other group if I get a chance today.??


@Curt, mines the opposite and pined on the high stop.? ?One thing that's driving me mad, the only subsection of the block diagram besides the actual board labels is the lone word "chopper".? I'd love to understand more specifically WHERE the attenuator, 2nd amplifier, sync detector actually reside.? ??


On Sat, Oct 5, 2024 at 3:21?PM Curt Helstrom via <cahelstrom=[email protected]> wrote:
I have repaired two 92B's with this technique.? It appears that as the choppers age, their timing effects the meter's operation (both of mine
showed meter pined to the negative stop).? What I did was to swap the cathodes of CR207 and CR213, that is I connected CR207 cathode to
the original connection point of the CR213 cathode and vis versa, connected the cathode of CR213 to the original connection point of CR207.
?
This changes the timing of when the synchronous detector measures the signals coming from the chopper through the amplifiers, and compensates
for the delays caused by an aging chopper.
?
As mentioned, I've repaired two 92B's with this technique, both meeting all specifications after this modification.
?
Hope this helps in your efforts to repair your meter.

?

?

?

?
Re: Agilent 34461A schenmatic

 

开云体育

Do you have the full schematic for the 34410a?

From: [email protected] <[email protected]> on behalf of Yves Tardif <yves_tardif@...>
Sent: Monday, October 7, 2024 12:37 PM
To: [email protected] <[email protected]>
Subject: Re: [HP-Agilent-Keysight-equipment] Agilent 34461A schenmatic
?

?

As specified in the last email, I don't have the part numbers unfortunately, only the marking codes or the Keysight part numbers. Also, I can't find these part numbers on the Keysight website.

?

If I were in your situation, I would first look for a 1.3MHz 8 pin switcher with the same package.

And from the circuit and the coil value, I would try to see if the pin out seems compatible, and if the installed coil would be compliant with a 1.3MHz operating frequency.

?

A friend of mine probably has a 34461A that he could lend me, but don't expect to have more details on the part numbers, but I could take the waveforms at the switcher pins.

I am not absolutely sure that the switcher of the 34461A and 34465A are identical because I do not have a detailed photo of this section for the 34461A, but the coil value is the same.

?

?

?

De?: [email protected] <[email protected]> De la part de Keith Harvey
贰苍惫辞测é?: 7 octobre 2024 14:06
??: [email protected]
Objet?: Re: [HP-Agilent-Keysight-equipment] Agilent 34461A schenmatic

?

Hi Yves,

?

Thank you for the insight.

?

If you have the Agilent part numbers for the components I listed, that might prove helpful.

?

Regards,

Keith Harvey

From: [email protected] <[email protected]> on behalf of Yves Tardif <yves_tardif@...>
Sent: Monday, October 7, 2024 11:58 AM
To: [email protected] <[email protected]>
Subject: Re: [HP-Agilent-Keysight-equipment] Agilent 34461A schenmatic

?

Hi Keith,

?

I checked my 34410A and my 34465A, and unfortunately, I don't have a 34461A.

However, they all have the same function to perform, that is to say from +10V, provide a voltage of +3.3V, +1.2V and possibly +2.5V.

A switcher lowers a DC voltage from about +10V to +3.3V, the frequency of the switcher is about 1.3MHz for both instruments.

The 34461A has the same part numbers as the 34465A, there is a very good chance that the 34465A and 34461A have the same circuit for the section concerned.

?

I don't know if this can help you, but you have an idea of ??the damaged circuit.

I don't have the part numbers unfortunately, only the marking codes or the Keysight part numbers.

?

I repaired a 34461A a few months ago, the +3.3V switch was not damaged, but there was a short circuit on the +3.3V line caused by a faulty capacitor.

?

Waveform measured at output switcher connected to coil.

?

Yves
Re: Agilent 34461A schenmatic

 

开云体育

?

As specified in the last email, I don't have the part numbers unfortunately, only the marking codes or the Keysight part numbers. Also, I can't find these part numbers on the Keysight website.

?

If I were in your situation, I would first look for a 1.3MHz 8 pin switcher with the same package.

And from the circuit and the coil value, I would try to see if the pin out seems compatible, and if the installed coil would be compliant with a 1.3MHz operating frequency.

?

A friend of mine probably has a 34461A that he could lend me, but don't expect to have more details on the part numbers, but I could take the waveforms at the switcher pins.

I am not absolutely sure that the switcher of the 34461A and 34465A are identical because I do not have a detailed photo of this section for the 34461A, but the coil value is the same.

?

?

?

De?: [email protected] <[email protected]> De la part de Keith Harvey
贰苍惫辞测é?: 7 octobre 2024 14:06
??: [email protected]
Objet?: Re: [HP-Agilent-Keysight-equipment] Agilent 34461A schenmatic

?

Hi Yves,

?

Thank you for the insight.

?

If you have the Agilent part numbers for the components I listed, that might prove helpful.

?

Regards,

Keith Harvey

From: [email protected] <[email protected]> on behalf of Yves Tardif <yves_tardif@...>
Sent: Monday, October 7, 2024 11:58 AM
To: [email protected] <[email protected]>
Subject: Re: [HP-Agilent-Keysight-equipment] Agilent 34461A schenmatic

?

Hi Keith,

?

I checked my 34410A and my 34465A, and unfortunately, I don't have a 34461A.

However, they all have the same function to perform, that is to say from +10V, provide a voltage of +3.3V, +1.2V and possibly +2.5V.

A switcher lowers a DC voltage from about +10V to +3.3V, the frequency of the switcher is about 1.3MHz for both instruments.

The 34461A has the same part numbers as the 34465A, there is a very good chance that the 34465A and 34461A have the same circuit for the section concerned.

?

I don't know if this can help you, but you have an idea of ??the damaged circuit.

I don't have the part numbers unfortunately, only the marking codes or the Keysight part numbers.

?

I repaired a 34461A a few months ago, the +3.3V switch was not damaged, but there was a short circuit on the +3.3V line caused by a faulty capacitor.

?

Waveform measured at output switcher connected to coil.

?

Yves
Re: Agilent 34461A schenmatic

 

开云体育

I just discovered the partial schematic you attached.
Thank you! That will be of great assistance.

From: [email protected] <[email protected]> on behalf of Keith Harvey <keithh534@...>
Sent: Monday, October 7, 2024 12:05 PM
To: [email protected] <[email protected]>
Subject: Re: [HP-Agilent-Keysight-equipment] Agilent 34461A schenmatic
?
Hi Yves,

Thank you for the insight.

If you have the Agilent part numbers for the components I listed, that might prove helpful.

Regards,
Keith Harvey
From: [email protected] <[email protected]> on behalf of Yves Tardif <yves_tardif@...>
Sent: Monday, October 7, 2024 11:58 AM
To: [email protected] <[email protected]>
Subject: Re: [HP-Agilent-Keysight-equipment] Agilent 34461A schenmatic
?

Hi Keith,

?

I checked my 34410A and my 34465A, and unfortunately, I don't have a 34461A.

However, they all have the same function to perform, that is to say from +10V, provide a voltage of +3.3V, +1.2V and possibly +2.5V.

A switcher lowers a DC voltage from about +10V to +3.3V, the frequency of the switcher is about 1.3MHz for both instruments.

The 34461A has the same part numbers as the 34465A, there is a very good chance that the 34465A and 34461A have the same circuit for the section concerned.

?

I don't know if this can help you, but you have an idea of ??the damaged circuit.

I don't have the part numbers unfortunately, only the marking codes or the Keysight part numbers.

?

I repaired a 34461A a few months ago, the +3.3V switch was not damaged, but there was a short circuit on the +3.3V line caused by a faulty capacitor.

?

Waveform measured at output switcher connected to coil.

?

Yves
Re: Agilent 34461A schenmatic

 

开云体育

Hi Yves,

Thank you for the insight.

If you have the Agilent part numbers for the components I listed, that might prove helpful.

Regards,
Keith Harvey

From: [email protected] <[email protected]> on behalf of Yves Tardif <yves_tardif@...>
Sent: Monday, October 7, 2024 11:58 AM
To: [email protected] <[email protected]>
Subject: Re: [HP-Agilent-Keysight-equipment] Agilent 34461A schenmatic
?

Hi Keith,

?

I checked my 34410A and my 34465A, and unfortunately, I don't have a 34461A.

However, they all have the same function to perform, that is to say from +10V, provide a voltage of +3.3V, +1.2V and possibly +2.5V.

A switcher lowers a DC voltage from about +10V to +3.3V, the frequency of the switcher is about 1.3MHz for both instruments.

The 34461A has the same part numbers as the 34465A, there is a very good chance that the 34465A and 34461A have the same circuit for the section concerned.

?

I don't know if this can help you, but you have an idea of ??the damaged circuit.

I don't have the part numbers unfortunately, only the marking codes or the Keysight part numbers.

?

I repaired a 34461A a few months ago, the +3.3V switch was not damaged, but there was a short circuit on the +3.3V line caused by a faulty capacitor.

?

Waveform measured at output switcher connected to coil.

?

Yves
Re: Agilent 34461A schenmatic

 

开云体育

Hi Keith,

?

I checked my 34410A and my 34465A, and unfortunately, I don't have a 34461A.

However, they all have the same function to perform, that is to say from +10V, provide a voltage of +3.3V, +1.2V and possibly +2.5V.

A switcher lowers a DC voltage from about +10V to +3.3V, the frequency of the switcher is about 1.3MHz for both instruments.

The 34461A has the same part numbers as the 34465A, there is a very good chance that the 34465A and 34461A have the same circuit for the section concerned.

?

I don't know if this can help you, but you have an idea of ??the damaged circuit.

I don't have the part numbers unfortunately, only the marking codes or the Keysight part numbers.

?

I repaired a 34461A a few months ago, the +3.3V switch was not damaged, but there was a short circuit on the +3.3V line caused by a faulty capacitor.

?

Waveform measured at output switcher connected to coil.

?

Yves

34410a.png
34465A_.png
34410A_schematic.png

Re: Thoughts on upgraded(?) replacement parts for vintage equipment

 

Yes. That was their only Telemetry product they made. The lawsuit cost them millions, and their customer base was very small. We ended up with the rack full of test equipment to do final testing on them.? The softwware only worked under Windows 2.0. The backlights on those LCDs was a high failure item. The tech had a large stack of othwise good, used displays .? These dats there are cheap, LED powered lights that would fit into them, rafter than the electroluminescent source. I've see some about the right size for $5. The can be cut down, with some care.

On Mon, Oct 7, 2024 at 12:48?PM Jeff Kruth via <kmec=[email protected]> wrote:
Was that the SA 930 Telemetry Rcvr? Had one with a bad LCD, didnt even get to make it work, gave up. Jeff Kruth

In a message dated 10/7/2024 10:54:27 AM Eastern Standard Time, terrell.michael.a@... writes:
?
Microdyne serviced the Scientific Atlanta clone of one of our designs We still built a few new units a tear but most of the analog IC were obsolete so I selected modern replacements fr each. The tech had to log the reason for the substitution,? but itt was either accept the update, or wait to locate olsd stock from questionable sources. .S A bought one receiver from us, and copied the entire circuitry, except for the front panel. They replaced the LED displays with an early LCD panel that didn't age well. We sued them, and they lost the case.
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