That's known as improving your image!
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On 4/22/2024 7:19 PM, Tom Lee via groups.io wrote: That's almost image amplification!
--
Prof. Thomas H. Lee
Allen Ctr., Rm. 205
420 Via Palou Mall
Stanford University
Stanford, CA 94305-4070
On 4/22/2024 4:15 PM, John Miles wrote:
I¡¯d hate to get by without the E4406A, that¡¯s for sure.? It sees a lot of use these days looking at L-band signals.
But speaking of image rejection¡ LOL! You get 60-80 dB with the MXA, 45-55 dB with the SM435C, and a whopping 0 dB with the E4406A. ?
-- john, KE5FX
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That's almost image amplification!
--
Prof. Thomas H. Lee
Allen Ctr., Rm. 205
420 Via Palou Mall
Stanford University
Stanford, CA 94305-4070
On 4/22/2024 4:15 PM, John Miles wrote:
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I¡¯d hate to get by without the E4406A,
that¡¯s for sure.? It sees a lot of use these days looking at
L-band signals.?
?
But speaking of image rejection¡ LOL!? You
get 60-80 dB with the MXA, 45-55 dB with the SM435C, and a
whopping 0 dB with the E4406A. ?
?
-- john, KE5FX
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I¡¯d hate to get by without the E4406A, that¡¯s for sure.? It sees a lot of use these days looking at L-band signals.? ? But speaking of image rejection¡ LOL!? You get 60-80 dB with the MXA, 45-55 dB with the SM435C, and a whopping 0 dB with the E4406A. ? ? -- john, KE5FX ?
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From: [email protected] < [email protected]> On Behalf Of hardyhansendk via groups.io Sent: Monday, April 22, 2024 1:07 PM To: [email protected]Subject: Re: [HP-Agilent-Keysight-equipment] N9020A ? Hi John You are right¡the top notch versions from signal hound are very impressive ¨CI were referring to their models matching the price---below 2k¡all have a price .As jeremy points to--- we just experience ?a great new ??deal as we had with E4406A (recall you bought two-- Still in use? )The ?MXA are not the best ¡ but great value below 2k¡¯ Hardy
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Re: Is it worth looking for a R/3*2 Instrument Controller? - Feedback request
Hi Tony:
When I was working many decades ago the cost of any of the HP RMB controllers was very high.? Then Sun came out with a diskless node workstation.
HP responded with the 318 Diskless Unix Workstation and I ended up buying a number of them for use a RMB instrument controllers.? These cost way less.
--
Have Fun,
Brooke Clarke
axioms:
1. The extent to which you can fix or improve something will be limited by how well you understand how it works.
2. Everybody, with no exceptions, holds false beliefs.
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Re: HP 140B LVPS -12.6V Not Working
I would've guessed that the dot marks the collector. At least that
was the convention used on all the parts I encountered as a kid. The
literature of the day often referred to "the collector dot". But of
course that doesn't mean that other companies/countries followed
that convention, so I'm curious: Are you just guessing (say, based
on a quick DMM diode check, in which case you're rolling the dice),
or did you cross-check with some circuit-tracing against a
schematic?
And if you're talking about a TO-92, there is no standard pinout.
Parts of US design generally follow EBC, UK parts often follow CBE
(making it easy to swap with US parts by simply installing the other
way around), Japanese parts are frequently BEC (I've also
encountered ECB), but "generally" does mean "not always" here. You
have to check, don't assume.
Tom
--
Prof. Thomas H. Lee
Allen Ctr., Rm. 205
420 Via Palou Mall
Stanford University
Stanford, CA 94305-4070
On 4/22/2024 3:38 PM, n4buq wrote:
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Something about this is confusing
me.? Looking at the board, the transistors and diodes all have
a dot at one lead.? I was thinking that dot indicated the
emitter and for some transistors, that holds.? It agrees with
the 2n3409 I replaced and most of the metal-hat transistors.?
With the flat of the 2n3904's TO92 facing me, left to right is
EBC.? For Q484, though, the diode across BE (I can't read it
very well but I think that's CR485 or CR486) is connected to
the center lead and the right-hand lead (facing the
transistor's flat).? Do those not follow the same convention
as, say, a 2n3904?? I'm used to either EBC being left-to-right
facing the flat or, possibly, B on the left or right, but this
is puzzling to me.
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Re: HP 140B LVPS -12.6V Not Working
The problem is there is no -12.6V.? That sits a zero and I can't determine why.? There is sufficient voltage at the collector of Q481.? If Q481 were open that could cause it.? If -12.6V was overloaded, then Q483 should be shutting down Q481 but I can't see where either is the case. I've checked the resistors - at least in circuit - and I don't find anything wrong there but until I can get something going for -12.6V, nothing is checking out correctly.
Thanks, Barry - N4BUQ
You should have more than 0.7V across BC of Q484 in normal operation, E is connected to the -12.6V output, B should be approx -12V and C +2V.
Another common problem is some of the larger film resistors, they either drift up in value or go open circuit, this is a problem in the 140, 141, 180, 181 etc series. R485 & R489 are probably most likely to suffer from this in the circuit part you posted, as they have 90+ volts to drop. Had this with that 180A in the horizontal section, both 22.1k resistors had been cooked and gone up in value.
David
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Re: HP 140B LVPS -12.6V Not Working
Something about this is confusing me.? Looking at the board, the transistors and diodes all have a dot at one lead.? I was thinking that dot indicated the emitter and for some transistors, that holds.? It agrees with the 2n3409 I replaced and most of the metal-hat transistors.? With the flat of the 2n3904's TO92 facing me, left to right is EBC.? For Q484, though, the diode across BE (I can't read it very well but I think that's CR485 or CR486) is connected to the center lead and the right-hand lead (facing the transistor's flat).? Do those not follow the same convention as, say, a 2n3904?? I'm used to either EBC being left-to-right facing the flat or, possibly, B on the left or right, but this is puzzling to me.
Thanks again, Barry - N4BUQ
With the different variants of the 4-071 you need to make sure the leads are in the right configuration, one of the old 4-071 variants has leads formed to get the base in the middle. TI is Texas Instruments, the 001 is a date/batch code, the Motorola ones usually have EBC marked on them.
David
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Is it worth looking for a R/3*2 Instrument Controller? - Feedback request
Hey All,
I've always wondered if I should try to acquire one of the R/3*2 Instrument Controllers (332, 362, 382)
If anyone has one, would you be able to provide some feedback on how you use it and why you keep it? I've always liked the idea of having one in my rack and I've just started working with the hobbyist license for HT BASIC so I can get a handle on what using the original HP BASIC would be like but I'm just wondering if it is worth trying to acquire and piece together one of these seeing that the ones I can find today are all broken or missing things like keyboards etc or if I should just give it a pass and keep working on HT BASIC for Windows.
Would love to hear your thoughts.
TonyG
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Re: HP 140B LVPS -12.6V Not Working
You should have more than 0.7V across BC of Q484 in normal operation, E is connected to the -12.6V output, B should be approx -12V and C +2V.
Another common problem is some of the larger film resistors, they either drift up in value or go open circuit, this is a problem in the 140, 141, 180, 181 etc series. R485 & R489 are probably most likely to suffer from this in the circuit part you posted, as they have 90+ volts to drop. Had this with that 180A in the horizontal section, both 22.1k resistors had been cooked and gone up in value.
David
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Re: Agilent E4404B Spectrum Analyzer With Dead PSU Repair
On 4/22/24 14:07, Jim Ford wrote: But I don't replace old RIFAs on sight anymore.? Too much collateral damage by a ham-fisted engineer with a soldering iron in his hand, and explosions are rare here in 120 VAC land.? Those in 240 VAC land risk explosions, though. Uh, I've had three go so far just this year. The risk is surely higher in 240V-land, but I strongly advise replacing them on sight here too. -Dave -- Dave McGuire, AK4HZ New Kensington, PA
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On 4/22/24 14:51, Peter Gottlieb wrote: So what options should I look for in one of these MXA units? I'm not sure yet. I asked from an ebay seller and got out of focus photos:
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Re: Agilent E4404B Spectrum Analyzer With Dead PSU Repair
having had quite a few
go here in 120 VAC land...if I am in the equipment I replace (or at least remove )
especially if easy access and they are yellow before the stench
and mess....I cannot stand the stench or the mess which is the
worst part. btw the stench is not so bad in summer or when
weather allows windows and doors open...winter is another
matter...and when do they like to fail.......
¸é±ð²Ô¨¦±ð
Northern California Mtns
On 4/22/24 11:07 AM, Jim Ford via
groups.io wrote:
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Yes, I've bought new RIFA caps to replace the old ones.? WIMA
and Kemet are two other brands that make the safety rated X and
Y caps.
But I don't replace old RIFAs on sight anymore.? Too much
collateral damage by a ham-fisted engineer with a soldering iron
in his hand, and explosions are rare here in 120 VAC land.?
Those in 240 VAC land risk explosions, though.
HTH.
Jim Ford
Laguna Hills, California, USA
"And we know that God causes all things to work together
for the good of those who love God and are called according
to his purpose for them." Romans 8:28 (NLT)
------ Original Message ------
Date 4/22/2024 2:27:58 PM
Subject Re: [HP-Agilent-Keysight-equipment] Agilent E4404B
Spectrum Analyzer With Dead PSU Repair
On 4/22/24 15:22, Allen Hill via
groups.io wrote:
Are RIF caps still used in new
equipment, or have manufacturers found better solutions?
?
The common RIFA capacitor failure is
a materials problem, which was solved long ago. Later RIFA
capacitors do not exhibit the explosion problem. Many
companies manufacture safety capacitors.
?
-Dave
?
-- Dave McGuire, AK4HZ
New Kensington, PA
?
?
?
?
?
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So what options should I look for in one of these MXA units?
There are so many posts in the thread I can't find the one with the link to the well-optioned units.
Peter
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On 4/22/2024 4:48 PM, John Griessen via groups.io wrote: On 4/21/24 22:44, Tom via Metronet wrote:
last I heard, an original X-series can be upgraded to the lates Wintel version just by replacing that module. The RF hardware doesn¡¯t need to change at all. Some of the aliexpress sellers offer a bare metal MXA without all the options for $150.? It could be a parts donor to upgrade an old MXA, but then how to add options?
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On 4/21/24 22:44, Tom via Metronet wrote: last I heard, an original X-series can be upgraded to the lates Wintel version just by replacing that module. The RF hardware doesn¡¯t need to change at all. Some of the aliexpress sellers offer a bare metal MXA without all the options for $150. It could be a parts donor to upgrade an old MXA, but then how to add options?
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The best advice I can offer is to look past the datasheet numbers for the SM435C and look at what is inside the box. It's a low IF receiver that will be prone to image issues just like the little RSP1A SDR receivers although the SM435C will probably offer >50dB image rejection most of the time.
Imagine having a lab spectrum analyser that always showed a mirror image of all signals at maybe -60dBc that were a few tens of MHz away from the real signals. Then try and imagine what happens when you tune the LO. Some signals are going to move as expected and the image signals will behave differently. Some of their other products use a low IF and they do some tricks in DSP to try and boost the image rejection.
I don't think that is going to be feasible on a real time instrument, so I suspect you will have to grin and bear the image reject issue on the SM435C.
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Re: HP 140B LVPS -12.6V Not Working
Yes, it was regarding the 180A repair.
The 2n3904 I replaced has the EBC embossed on the flat and I made sure I placed the new one in correctly.? Unlike the one pictured in the foreground, its base lead is bent forward.? A lot of the Tek gear does that as well.
I measured BE and BC across Q484 while powered up and I get 0.7V drop across each so I'm thinking the transistor may not be the problem but can't say that for sure.? Two diodes does not a transistor maketh.? Still looking...
Thanks,
Barry - N4BUQ
From: "factory" <bobradios11@...> To: "HP-Agilent-Keysight-equipment" < [email protected]> Sent: Monday, April 22, 2024 2:53:54 PM Subject: Re: [HP-Agilent-Keysight-equipment] HP 140B LVPS -12.6V Not Working You might have seen my comments on the eevblog forum and/or the UK vintage radio forum, most recent repair involving the 4-071 was a HP 180A, several got replaced in the PSU, another failed once the PSU board was refitted, and the last I changed was an intermittent one in the HV regulator circuit and causing the trace to disappear once the scope warmed up, this 180A is an extreme example as it had been stored very badly by a previous owner, lots of corrosion/rust etc.
With the different variants of the 4-071 you need to make sure the leads are in the right configuration, one of the old 4-071 variants has leads formed to get the base in the middle. TI is Texas Instruments, the 001 is a date/batch code, the Motorola ones usually have EBC marked on them.
David
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It's difficult to compare the SH to the MXA because the MXA is a classic lab spectrum analyser with the emphasis on achieving low measurement uncertainty and excellent spurious free dynamic range. The SH product is all about tuning fast and grabbing and processing data as fast as possible and this comes at the price of reduced spurious free dynamic range and relatively poor input VSWR and poor amplitude flatness vs frequency.
The SH signal path isn't designed to achieve low input VSWR or a flat response and the low IF receiver architecture will inevitably have image reject issues at twice the low IF away. It's usually very difficult to get more than about 50dB image rejection in this respect. This limitation alone is enough to prevent the SH product being considered as a valid lab spectrum analyser. Throw in the poor input VSWR and poor amplitude response and it really can't be compared against a lab analyser (if the person actually wants a general purpose lab analyser that is).
By contrast, if the aim is to use the instrument as a radio receiver and just grab and process signals from an antenna (or maybe a signal generator) then the SH will be very competitive compared to the MXA. The two instruments are aimed at different customer types in my opinion.
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Re: Agilent E4404B Spectrum Analyzer With Dead PSU Repair
Yes, I've bought new RIFA caps to replace the old ones.? WIMA and Kemet are two other brands that make the safety rated X and Y caps.
But I don't replace old RIFAs on sight anymore.? Too much collateral damage by a ham-fisted engineer with a soldering iron in his hand, and explosions are rare here in 120 VAC land.? Those in 240 VAC land risk explosions, though.
HTH.
Jim Ford Laguna Hills, California, USA
"And we know that God causes all things to work together for the good of those who love God and are called according to his purpose for them." Romans 8:28 (NLT)
------ Original Message ------
Date 4/22/2024 2:27:58 PM
Subject Re: [HP-Agilent-Keysight-equipment] Agilent E4404B Spectrum Analyzer With Dead PSU Repair
On 4/22/24 15:22, Allen Hill via groups.io wrote:
Are RIF caps still used in new equipment, or have manufacturers found better solutions?
?
The common RIFA capacitor failure is a materials problem, which was solved long ago. Later RIFA capacitors do not exhibit the explosion problem. Many companies manufacture safety capacitors.
?
-Dave
?
-- Dave McGuire, AK4HZ
New Kensington, PA
?
?
?
?
?
|
Hi John You are right¡the top notch versions from signal hound are very impressive ¨CI were referring to their models matching the price---below 2k¡all have a price .As jeremy points to--- we just experience ?a great new ??deal as we had with E4406A (recall you bought two-- Still in use? )The ?MXA are not the best ¡ but great value below 2k¡¯ Hardy ? ? The SM435C is a damned impressive piece of hardware.? If you are seeing them advertised for ¡°10k$,¡± I¡¯ll take a piece of that action. ? Both it and the N9020B offer 160 MHz of acquisition bandwidth, but you can actually get the data out of the Signal Hound, streamable in realtime over 10Gb Ethernet.? ?And at first glance it looks like the N9020B has about 20 dB worse phase noise than the N9020B.? ? The Signal Hound only goes to 43 GHz, though, where the MXA does 50. ?So there¡¯s that. ? ? -- john, KE5FX ?
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Re: HP 140B LVPS -12.6V Not Working
You might have seen my comments on the eevblog forum and/or the UK vintage radio forum, most recent repair involving the 4-071 was a HP 180A, several got replaced in the PSU, another failed once the PSU board was refitted, and the last I changed was an intermittent one in the HV regulator circuit and causing the trace to disappear once the scope warmed up, this 180A is an extreme example as it had been stored very badly by a previous owner, lots of corrosion/rust etc.
With the different variants of the 4-071 you need to make sure the leads are in the right configuration, one of the old 4-071 variants has leads formed to get the base in the middle. TI is Texas Instruments, the 001 is a date/batch code, the Motorola ones usually have EBC marked on them.
David
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factory
Dave McGuire
