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I was looking at ads for an HP140B and saw this one:
Is there a way to have the calibrator signal displayed without using the vertical amplifier's input connections?
I have one of these scopes that I hadn't used for several years so I pulled it onto the desk and I just don't see if/how there's a way to do that. Anyone know?
Thanks,
Barry - N4BUQ
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No, the calibrator is a separate circuit (schematic typically has it on the same page as the power supply). It has to be externally connected to a ¡®scope input. All my HP scopes are that way. I think Tek made scopes with a switch you could push to internally connect the calibrator¡ªbut I¡¯ve never had one so I¡¯m not sure.?
On Fri, Mar 22, 2024 at 7:51?AM n4buq < n4buq@...> wrote: I was looking at ads for an HP140B and saw this one:
Is there a way to have the calibrator signal displayed without using the vertical amplifier's input connections?
I have one of these scopes that I hadn't used for several years so I pulled it onto the desk and I just don't see if/how there's a way to do that.? Anyone know?
Thanks,
Barry - N4BUQ
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I asked the seller and was told that it comes up that way and that's why they're selling it "for parts".? It must be some sort of modification to either route the calibrator directly or, perhaps, something added to the vertical amplifier.? Who knows but it did catch my eye.
BTW, I have several Tektronix scopes and none of them do that but, perhaps, there are some models that do.? I don't know.
Thanks, Barry - N4BUQ
No, the calibrator is a separate circuit (schematic typically has it on the same page as the power supply). It has to be externally connected to a ¡®scope input. All my HP scopes are that way. I think Tek made scopes with a switch you could push to internally connect the calibrator¡ªbut I¡¯ve never had one so I¡¯m not sure.?
On Fri, Mar 22, 2024 at 7:51?AM n4buq < n4buq@...> wrote: I was looking at ads for an HP140B and saw this one:
Is there a way to have the calibrator signal displayed without using the vertical amplifier's input connections?
I have one of these scopes that I hadn't used for several years so I pulled it onto the desk and I just don't see if/how there's a way to do that.? Anyone know?
Thanks,
Barry - N4BUQ
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Looking at it again, if that is truly a 10us/div sweep time, then that's not the internal calibrator.? It appears to be about 14us and the calibrator should be line frequency so that just adds to the mystery.? I have no intention of buying it but thought it was interesting.
Barry - N4BUQ
I asked the seller and was told that it comes up that way and that's why they're selling it "for parts".? It must be some sort of modification to either route the calibrator directly or, perhaps, something added to the vertical amplifier.? Who knows but it did catch my eye. BTW, I have several Tektronix scopes and none of them do that but, perhaps, there are some models that do.? I don't know. Thanks, Barry - N4BUQ No, the calibrator is a separate circuit (schematic typically has it on the same page as the power supply). It has to be externally connected to a ¡®scope input. All my HP scopes are that way. I think Tek made scopes with a switch you could push to internally connect the calibrator¡ªbut I¡¯ve never had one so I¡¯m not sure.?
On Fri, Mar 22, 2024 at 7:51?AM n4buq < n4buq@...> wrote: I was looking at ads for an HP140B and saw this one:
Is there a way to have the calibrator signal displayed without using the vertical amplifier's input connections?
I have one of these scopes that I hadn't used for several years so I pulled it onto the desk and I just don't see if/how there's a way to do that.? Anyone know?
Thanks,
Barry - N4BUQ
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Yeah, I was looking at that one, too. ?I see that the vertical plug in is in 'chop' mode; perhaps the camera exposure is very short and the vertical position is separated, so we're seeing it alternate between the two traces and as a result it looks like a square wave. -Pat
?
> ------ Original Message ------
> From: n4buq@...
> To: [email protected]
> Sent: Friday, March 22nd 2024, 12:20 PM
> Subject: Re: [HP-Agilent-Keysight-equipment] HP 140B Calibrator
? I asked the seller and was told that it comes up that way and that's why they're selling it "for parts".? It must be some sort of modification to either route the calibrator directly or, perhaps, something added to the vertical amplifier.? Who knows but it did catch my eye. ? BTW, I have several Tektronix scopes and none of them do that but, perhaps, there are some models that do.? I don't know. ? Thanks, Barry - N4BUQ ? No, the calibrator is a separate circuit (schematic typically has it on the same page as the power supply). It has to be externally connected to a ¡®scope input. All my HP scopes are that way. I think Tek made scopes with a switch you could push to internally connect the calibrator¡ªbut I¡¯ve never had one so I¡¯m not sure.?
?
?
?
On Fri, Mar 22, 2024 at 7:51?AM n4buq < n4buq@...> wrote: ? I was looking at ads for an HP140B and saw this one:
Is there a way to have the calibrator signal displayed without using the vertical amplifier's input connections?
I have one of these scopes that I hadn't used for several years so I pulled it onto the desk and I just don't see if/how there's a way to do that.? Anyone know?
Thanks,
Barry - N4BUQ
?
?
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I think it's because the trace brightness is high and the display is in 'chop' mode. It could be that the trace blanking is not fully working.
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The calibrator has to be connected externally on these
.
It's in "chop" mode with a fast sweep, should be using "alt" mode instead, chop is for slower sweep speeds.
David
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I did not realize chop mode would do that.? I just tried it with my 140B with a 1404A vertical plugin and I can see a similar effect at high sweep speeds (although it isn't as well-defined as the one in the ad).
I have 7000-series Tektronix scopes and they won't do that.? I'll have to look to see what the chop frequencies are used in those.
Barry - N4BUQ
The calibrator has to be connected externally on these
.
It's in "chop" mode with a fast sweep, should be using "alt" mode instead, chop is for slower sweep speeds.
David
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The screen photo's in that HP140B add, appear to show a Z axis problem (blanking, or not.)
The impression of a square wave I think, is caused by the timebase triggering on the incoming power line frequency (50/60Hz) with the sweep speed high enough (10uS/div) to see the vertical A/B "chop" signal, with the brightness turned up high enough to see the low duty trace, but the sweep blanking might not be functioning correctly, and/or the CRT bias setting is out of adjustment.
Probably fixable, the rest of it looks clean, save for a dent in the top cover.
Shame it's not in the UK, but I do know West Chester PA from trips over there for the past day job.
--
Sent from a MicroSoft free zone:
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Well, I am the buyer. Hope I did not get burned, considering the cost of shipping to the west coast from Pennsyltucky (as my father called it). We shall see what turns up on my doorstep in the next couple of weeks.?
The screen photo's in that HP140B add, appear to show a Z axis problem
(blanking, or not.)
The impression of a square wave I think, is caused by the timebase
triggering on the incoming power line frequency (50/60Hz) with the sweep
speed high enough (10uS/div) to see the vertical A/B "chop" signal, with
the brightness turned up high enough to see the low duty trace, but the
sweep blanking might not be functioning correctly, and/or the CRT bias
setting is out of adjustment.
Probably fixable, the rest of it looks clean, save for a dent in the top
cover.
Shame it's not in the UK, but I do know West Chester PA from trips over
there for the past day job.
--
Sent from a MicroSoft free zone:
|
On Fri, Mar 22, 2024 at 09:35 PM, Dave_G0WBX wrote:
The screen photo's in that HP140B add, appear to show a Z axis problem
(blanking, or not.)
The impression of a square wave I think, is caused by the timebase
triggering on the incoming power line frequency (50/60Hz) with the sweep
speed high enough (10uS/div) to see the vertical A/B "chop" signal, with
the brightness turned up high enough to see the low duty trace, but the
sweep blanking might not be functioning correctly, and/or the CRT bias
setting is out of adjustment.
Probably fixable, the rest of it looks clean, save for a dent in the top
cover.
Shame it's not in the UK, but I do know West Chester PA from trips over
there for the past day job.
--
Sent from a MicroSoft free zone:
The Z axis switch on the back of the 140B seems to be set to external, this might explain the other issue. If you want one of these, look out for the 140A which turn up occasionally over here in the UK, also there is a 141A available at the moment, price is a bit higher than they normally go for. I recommended collection in person for these older scopes, to avoid damage to the frame handles or CRT, but it's not always possible. David
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I completely missed that.? Good catch.? Hopefully when Jeremy gets it, all it will take to get it working properly is flicking a few switches.? It will be interesting to see what he finds.
I need to replace that switch on mine.? The "handle" on it is broken.? Simple fix but not too worried about it for the moment.
If anyone knows where I could locate a CRT socket cover for one of these scopes, I'd be interested.? I see where those cost $0.15 in 1974 but I figure a replacement would run at least twice that now.? :-)? I suppose I could print one if it came down to it.
Thanks,
Barry - N4BUQ
The Z axis switch on the back of the 140B seems to be set to external, this might explain the other issue.
If you want one of these, look out for the 140A which turn up occasionally over here in the UK, also there is a 141A available at the moment, price is a bit higher than they normally go for.
I recommended collection in person for these older scopes, to avoid damage to the frame handles or CRT, but it's not always possible.
David
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Thank you - I was beginning to waver. ?The high shipping cost to me even in CT and much closer to PA was a big part of the deterrent. ?(That and I already have a 140A in my repair queue.) ?Hope it winds up being a setting when you get it, Jeremy. -Pat
?
> ------ Original Message ------
> From: jn6wfo@...
> To: [email protected]
> Sent: Friday, March 22nd 2024, 07:38 PM
> Subject: Re: [HP-Agilent-Keysight-equipment] HP 140B Calibrator
? Well, I am the buyer. Hope I did not get burned, considering the cost of shipping to the west coast from Pennsyltucky (as my father called it). We shall see what turns up on my doorstep in the next couple of weeks.?
? ?
?
The screen photo's in that HP140B add, appear to show a Z axis problem?
(blanking, or not.)
The impression of a square wave I think, is caused by the timebase?
triggering on the incoming power line frequency (50/60Hz) with the sweep?
speed high enough (10uS/div) to see the vertical A/B "chop" signal, with?
the brightness turned up high enough to see the low duty trace, but the?
sweep blanking might not be functioning correctly, and/or the CRT bias?
setting is out of adjustment.
Probably fixable, the rest of it looks clean, save for a dent in the top?
cover.
Shame it's not in the UK, but I do know West Chester PA from trips over?
there for the past day job.
--?
Sent from a MicroSoft free zone:
?
|
I¡¯ve had numerous 140s and even a 143 (huge!) but never a 140B. I really don¡¯t need this one, it¡¯s more like the ¡°good cardboard box¡± we hate to throw away (because it¡¯s a really nice box). This 140B is a newer model (1971 by the serial prefix) and looks fairly clean, which is unusual. So I¡¯ll let the group know what it is when it gets here.?
Thank you - I was beginning to waver.? The high shipping cost to me even in CT and much closer to PA was a big part of the deterrent. ?(That and I already have a 140A in my repair queue.) ?Hope it winds up being a setting when you get it, Jeremy. -Pat
? > ------ Original Message ------
> From: jn6wfo@...
> To: [email protected]
> Sent: Friday, March 22nd 2024, 07:38 PM
> Subject: Re: [HP-Agilent-Keysight-equipment] HP 140B Calibrator
? Well, I am the buyer. Hope I did not get burned, considering the cost of shipping to the west coast from Pennsyltucky (as my father called it). We shall see what turns up on my doorstep in the next couple of weeks.?
? ?
?
The screen photo's in that HP140B add, appear to show a Z axis problem?
(blanking, or not.)
The impression of a square wave I think, is caused by the timebase?
triggering on the incoming power line frequency (50/60Hz) with the sweep?
speed high enough (10uS/div) to see the vertical A/B "chop" signal, with?
the brightness turned up high enough to see the low duty trace, but the?
sweep blanking might not be functioning correctly, and/or the CRT bias?
setting is out of adjustment.
Probably fixable, the rest of it looks clean, save for a dent in the top?
cover.
Shame it's not in the UK, but I do know West Chester PA from trips over?
there for the past day job.
--?
Sent from a MicroSoft free zone:
?
|
Have you had any of those models where one or both of the plugins is very difficult to remove?? I thought I would never get the amplifier out of mine and ended up having to remove the bottom cover just to get enough push to free it.? I suspect it is the alignment pin that's too tight in the hole but it could also be the connector.? I tried a bit of sanding with a 1/4" dowel and some silicon carbide paper to smooth the surface of the hole and I think that helped but it is still rather tight.
Thanks,
Barry - N4BUQ
I¡¯ve had numerous 140s and even a 143 (huge!) but never a 140B. I really don¡¯t need this one, it¡¯s more like the ¡°good cardboard box¡± we hate to throw away (because it¡¯s a really nice box). This 140B is a newer model (1971 by the serial prefix) and looks fairly clean, which is unusual. So I¡¯ll let the group know what it is when it gets here.? Thank you - I was beginning to waver.? The high shipping cost to me even in CT and much closer to PA was a big part of the deterrent. ?(That and I already have a 140A in my repair queue.) ?Hope it winds up being a setting when you get it, Jeremy. -Pat
? > ------ Original Message ------
> From: jn6wfo@...
> To: [email protected]
> Sent: Friday, March 22nd 2024, 07:38 PM
> Subject: Re: [HP-Agilent-Keysight-equipment] HP 140B Calibrator
? Well, I am the buyer. Hope I did not get burned, considering the cost of shipping to the west coast from Pennsyltucky (as my father called it). We shall see what turns up on my doorstep in the next couple of weeks.?
? ?
?
The screen photo's in that HP140B add, appear to show a Z axis problem?
(blanking, or not.)
The impression of a square wave I think, is caused by the timebase?
triggering on the incoming power line frequency (50/60Hz) with the sweep?
speed high enough (10uS/div) to see the vertical A/B "chop" signal, with?
the brightness turned up high enough to see the low duty trace, but the?
sweep blanking might not be functioning correctly, and/or the CRT bias?
setting is out of adjustment.
Probably fixable, the rest of it looks clean, save for a dent in the top?
cover.
Shame it's not in the UK, but I do know West Chester PA from trips over?
there for the past day job.
--?
Sent from a MicroSoft free zone:
?
|
My HP-143A (the large-screen member of the 140 family came in a cardboard box with no padding. Aside from the CRT being broken, the frame members were bent such that the plug-ins were very tight. I eventually managed to free them but it was always a challenge going forward. Replacing the CRT was another matter¡ªtook about a year to track one down. The seller (claimed ¡°a friend¡± packed it for him) refunded most of my money.?
On Sun, Mar 24, 2024 at 10:09?AM n4buq < n4buq@...> wrote: Have you had any of those models where one or both of the plugins is very difficult to remove?? I thought I would never get the amplifier out of mine and ended up having to remove the bottom cover just to get enough push to free it.? I suspect it is the alignment pin that's too tight in the hole but it could also be the connector.? I tried a bit of sanding with a 1/4" dowel and some silicon carbide paper to smooth the surface of the hole and I think that helped but it is still rather tight.
Thanks,
Barry - N4BUQ I¡¯ve had numerous 140s and even a 143 (huge!) but never a 140B. I really don¡¯t need this one, it¡¯s more like the ¡°good cardboard box¡± we hate to throw away (because it¡¯s a really nice box). This 140B is a newer model (1971 by the serial prefix) and looks fairly clean, which is unusual. So I¡¯ll let the group know what it is when it gets here.? Thank you - I was beginning to waver.? The high shipping cost to me even in CT and much closer to PA was a big part of the deterrent. ?(That and I already have a 140A in my repair queue.) ?Hope it winds up being a setting when you get it, Jeremy. -Pat
? > ------ Original Message ------
> From: jn6wfo@...
> To: [email protected]
> Sent: Friday, March 22nd 2024, 07:38 PM
> Subject: Re: [HP-Agilent-Keysight-equipment] HP 140B Calibrator
? Well, I am the buyer. Hope I did not get burned, considering the cost of shipping to the west coast from Pennsyltucky (as my father called it). We shall see what turns up on my doorstep in the next couple of weeks.?
? ?
?
The screen photo's in that HP140B add, appear to show a Z axis problem?
(blanking, or not.)
The impression of a square wave I think, is caused by the timebase?
triggering on the incoming power line frequency (50/60Hz) with the sweep?
speed high enough (10uS/div) to see the vertical A/B "chop" signal, with?
the brightness turned up high enough to see the low duty trace, but the?
sweep blanking might not be functioning correctly, and/or the CRT bias?
setting is out of adjustment.
Probably fixable, the rest of it looks clean, save for a dent in the top?
cover.
Shame it's not in the UK, but I do know West Chester PA from trips over?
there for the past day job.
--?
Sent from a MicroSoft free zone:
?
|
Jeremy Nichols
Cubdriver
factory