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Back again, but this time with less power supply woes.? (thanks again for the help!)?
?I took my "new machine" for a little ride last night, I set it to 100mhz and was able to capture the attached image.? ?It felt REALLY good to see!? ? Ran it for an hour or so like this, flipped it off and ate dinner and came back to ONLY noise floor - no signals anymore.? ? ?I've got a little telescoping antenna hooked to it, and i did try to run the calibrator into it but AFTER i noticed problems.? ? ? A little confused, power supplies look OK.? ? Do I start digging into the attenuator / first mixer then?? ? Going to read the manual some more, that thing is THICK but figured I'd put a call out to the experts.? ??
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Some things I've found while working through the front panel controls section of the manual:? Scan Width - #6 "turn scan width per div to 10mhz", result "LO Feedthrough, 30mhz signal, 2nd harmonic".? ?I do not see these, any of them, just continued noise floor.??
The rest of the steps seem relatively meaningless but one call-out I'd make, Step 12 "Reduce Bandwidth?+ Scan time", result "should be stable and viewable"...? ?
I wouldn't quite call it stable while turning the knob, between the detent I see seemingly random spikes on the screen, until the next detent.? ?might be some sort of switching noise or crosstalk though.??
I do not see a 30mhz calibrator signal, I've never tried to verify this until last night either.? ?I'll begin to read up on this and Scan width circuitry next..??
On Fri, Sep 20, 2024 at 10:46?AM Bill Berzinskas via <bberzinskas= [email protected]> wrote:
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Hi Bill,
?
When I first read your post I thought you did some very low frequency stuff.?
Actually you're referring to MHz (Megahertz), not mHz (Millihertz).
?
Since you left the unit running for a while until the fault condition appeared: did you re-check once it was cold again? Like after 24 hours?
?
cheers
Martin
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I did re-check, and I've since gotten more?problems in?this?area...? ? ? :-D? -10v supply is no longer happy..?? Lot of people saying it might be the mixer diodes, so I may check those w/ my old analog meter today after I look? over MORE POWER SUPPLIES....? ??
Hi Bill,
?
When I first read your post I thought you did some very low frequency stuff.?
Actually you're referring to MHz (Megahertz), not mHz (Millihertz).
?
Since you left the unit running for a while until the fault condition appeared: did you re-check once it was cold again? Like after 24 hours?
?
cheers
Martin
|
Some analog VOMs put out enough current to fry a mixer diode.
toggle quoted message
Show quoted text
I did re-check, and I've since gotten more?problems in?this?area...? ? ? :-D? -10v supply is no longer happy..??
Lot of people saying it might be the mixer diodes, so I may check those w/ my old analog meter today after I look?
over MORE POWER SUPPLIES....? ??
Hi Bill,
?
When I first read your post I thought you did some very low frequency stuff.?
Actually you're referring to MHz (Megahertz), not mHz (Millihertz).
?
Since you left the unit running for a while until the fault condition appeared: did you re-check once it was cold again? Like after 24 hours?
?
cheers
Martin
|
Its a simpson 260, open to hearing any tips before i go in!
Some analog VOMs put out enough current to fry a mixer diode.
I did re-check, and I've since gotten more?problems in?this?area...? ? ? :-D? -10v supply is no longer happy..??
Lot of people saying it might be the mixer diodes, so I may check those w/ my old analog meter today after I look?
over MORE POWER SUPPLIES....? ??
Hi Bill,
?
When I first read your post I thought you did some very low frequency stuff.?
Actually you're referring to MHz (Megahertz), not mHz (Millihertz).
?
Since you left the unit running for a while until the fault condition appeared: did you re-check once it was cold again? Like after 24 hours?
?
cheers
Martin
|
Take a silicon diode or a shottkey diode.? Put a current meter in series with it and measure the resistance.? Now you know how much (at a minimum) your meter will dump into the diode.
Try the same with a cheap digital meter.
Harvey
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Show quoted text
On 9/21/2024 11:37 AM, Bill Berzinskas wrote: Its a simpson 260, open to hearing any tips before i go in!
On Sat, Sep 21, 2024 at 10:57?AM Dave Wise via groups.io <> <d44617665@...> wrote:
Some analog VOMs put out enough current to fry a mixer diode.
------------------------------------------------------------------------
*From:* [email protected]
<[email protected]> on behalf of Bill
Berzinskas <bberzinskas@...>
*Sent:* Saturday, September 21, 2024 7:48 AM
*To:* [email protected]
<[email protected]>
*Subject:* Re: [HP-Agilent-Keysight-equipment] HP 8554B, no RF
after first successful run...
I did re-check, and I've since gotten more?problems
in?this?area...? ? ? :-D? -10v supply is no longer happy..
Lot of people saying it might be the mixer diodes, so I may check
those w/ my old analog meter today after I look
over MORE POWER SUPPLIES....
On Sat, Sep 21, 2024 at 5:27?AM Martin via groups.io
<> <musaeum@...> wrote:
Hi Bill,
When I first read your post I thought you did some very low
frequency stuff.
Actually you're referring to MHz (Megahertz), not mHz
(Millihertz).
Since you left the unit running for a while until the fault
condition appeared: did you re-check once it was cold again?
Like after 24 hours?
cheers
Martin
|
For the x1 and x100 ohm ranges the 260 outputs 1.5 vdc, on the x10000 it outputs 9vdc! On the x1 range the short circuit current is 125 ma, on the x100 it¡¯s 1.25 ma, on the x10000 it¡¯s 75 ua. Danger, Will Robinson, danger!
toggle quoted message
Show quoted text
On Sep 21, 2024, at 8:37?AM, Bill Berzinskas via groups.io <bberzinskas@...> wrote:
? Its a simpson 260, open to hearing any tips before i go in!
Some analog VOMs put out enough current to fry a mixer diode.
I did re-check, and I've since gotten more?problems in?this?area...? ? ? :-D? -10v supply is no longer happy..??
Lot of people saying it might be the mixer diodes, so I may check those w/ my old analog meter today after I look?
over MORE POWER SUPPLIES....? ??
Hi Bill,
?
When I first read your post I thought you did some very low frequency stuff.?
Actually you're referring to MHz (Megahertz), not mHz (Millihertz).
?
Since you left the unit running for a while until the fault condition appeared: did you re-check once it was cold again? Like after 24 hours?
?
cheers
Martin
|
toggle quoted message
Show quoted text
For the x1 and x100 ohm ranges the 260 outputs 1.5 vdc, on the x10000 it outputs 9vdc! On the x1 range the short circuit current is 125 ma, on the x100 it¡¯s 1.25 ma, on the x10000 it¡¯s 75 ua. Danger, Will Robinson, danger! On Sep 21, 2024, at 8:37?AM, Bill Berzinskas via <bberzinskas=[email protected]> wrote:
? Its a simpson 260, open to hearing any tips before i go in!
Some analog VOMs put out enough current to fry a mixer diode.
I did re-check, and I've since gotten more?problems in?this?area...? ? ? :-D? -10v supply is no longer happy..??
Lot of people saying it might be the mixer diodes, so I may check those w/ my old analog meter today after I look?
over MORE POWER SUPPLIES....? ??
Hi Bill,
?
When I first read your post I thought you did some very low frequency stuff.?
Actually you're referring to MHz (Megahertz), not mHz (Millihertz).
?
Since you left the unit running for a while until the fault condition appeared: did you re-check once it was cold again? Like after 24 hours?
?
cheers
Martin
|
Martin