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Re: Hp8640b
What about the small bit of plastic on each side of the cam closest to the pin that has worn away on each side creating a small ramp....? What do you suggest to use as a cleaning agent or solvent? I
By Dave . · #129068 ·
Re: Hp8640b
The stacked plates of the eight-turn stop should be free to rotate with respect to each other to the limits of their respective dogs. Sounds like yours have frozen together into a single rigid lump.
By Dave Wise · #129067 ·
Hp8640b
Hello all, I recently acquired a hp8640b.. With a quick.? Checkout all seems to function...EXCEPT a detent in the frequency generator...when it hits this plastic (cog) it makes it very difficult to
By Dave . · #129066 ·
Re: HP-8753E Power Cycles at Start Up
Thanks Dan; this problem is happening on an 8753B and an 8753E with old capacitors. What you experienced is exactly why I don't want to replace the capacitors without a reason. The last thing I need
By peter bunge · #129065 ·
Re: HP-8753E Power Cycles at Start Up
Re: Power Supply for 8753E Peter: Take a look at the + and - 15V supplies. If the filter cap there draws too much peak current during cycle peaks, the current limit shuts down the supply. I found this
By Daniel Nelson · #129064 ·
Re: HP-8753E Power Cycles at Start Up
Peter: After putting in a new SMPS (Newer SMPS), I have had no failures. I would like to repair the SMPS I pulled but it has not failed yet. This is why I think its a current sense problem. Rich
By Rich Miller · #129063 ·
Re: HP-8753E Power Cycles at Start Up
Rich, Mine are all Sprague and the more I test the less I think they are the problem, but..... I should test one. Right now it is running rock solid. Has your's failed again? You said you had
By peter bunge · #129062 ·
Re: HP-8753E Power Cycles at Start Up
Peter: While I cannot answer your question directly, the capacitor's in mine are Nippon¡¯s. I have seen those last forever without fault. They were sparing no expense in this department when making
By Rich Miller · #129061 ·
Re: HP-8753E Power Cycles at Start Up
With my 'scope on EN of the reset timer I loaded the 5v with an extra 500 mA and the higher voltage supplies with 100 mA. The voltage did not change from the +3v so it would need a short somewhere to
By peter bunge · #129060 ·
Re: 54542 won't start, just checking if anyone had this problem before digging in
The PSU in my HP 54542C just failed, but only partially. Just started diagnosing, digital supply is fine, scope runs but no A/D or some other analog bits, so seems like one of the analog supplies.
By Bill E · #129059 ·
Re: Large assortment of H-P parts available
LibreOffice / OpenOffice can read xls(x).
By Toby · #129058 ·
Re: HP 5086-7906 YTO
What style of output connection is on this YTO? Not whether it's SMA, but how it's mounted to the body. If it's a barrel type screwed into a threaded hole and locked with a nut, you can as a last
By Ed Breya · #129057 ·
Re: Large assortment of H-P parts available
Am 29.08.2022 um 20:03 schrieb greenboxmaven via groups.io:
By DF6NA Rainer · #129056 ·
Re: Large assortment of H-P parts available
Could you please repost the list of equipment in PDF format, so eveyone can read it? Thamks, Bruce Gentry. KA2IVY
By greenboxmaven · #129055 ·
Re: Large assortment of H-P parts available
I've uploaded an inventory of what we've found so far. The list is shorter than we thought. More parts may be uncovered in the future.
By Bob Haas · #129054 ·
Re: HP 5086-7906 YTO
Today I tried to power the YTO 5086-7906, that of the 8563E, externally to the analyzer. Granted that I have checked all the components of the small PCB on the oscillator, I noticed that the current
By @Picol · #129053 ·
Re: HP-8753E Power Cycles at Start Up
My mistake.The reset timer is a 555 and the EN (on my unit) is at 3v well above the 1.7v trip oint (1/3 of 5v). Can anyone figure where the 3v comes from? R21 and R20 both connect to 5v. I guess the
By peter bunge · #129052 ·
Re: HP-8753E Power Cycles at Start Up
The 5v supply MUST have a load on it or the other supplies will not be regulated correctly (in the manual). I am running it connected to the 8753B and an easy test is to 'scope the trip EN to the
By peter bunge · #129051 ·
Re: HP-8753E Power Cycles at Start Up
Hey Rich, your thread and the more we learn the better. The trip point seems to be that heavy current through the over current detection transformer causes enough rectified DC to activate the reset
By peter bunge · #129050 ·
Re: HP-8753E Power Cycles at Start Up
Not to pile on - I have run the supply outside the case for over an hour. I see no ripple which would alarm me or make me suspect I have a bulk capacitance issue. I too am leaning towards overload
By Rich Miller · #129049 ·
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