|
My HP-3336C until today has always worked beautifully.
This morning I switched it on, connected to an HP-3586C, just to let them both warm a bit up. Frequency set to 7.3 MHz, amplitude -33 dBm. All was ok for a couple of hours, the 3586 declared -33.05 dBm, within specs. All of a sudden, the amplitude displayed on the 3586 went to -38.73 dBm.... Just to diagnose which of the two was the culprit, I checked the amplitude with a W&G SPM19, and it too declared -38.7 dBm (plus or minus a couple of hundredths of a dB). I even used a different cable, just in case... So the culprit is the 3336C... Suggestions on how and what to check to find the reasons of the problem are gratefully accepted... Thanks Alberto |
|
Hi Alberto,
toggle quoted message
Show quoted text
There is an electrolytic capacitor in the "C" that is in backwards. It works for a long, long time, and then quits, messing up the amplitude of the generator. The capacitor A4C113, a 10uf electrolytic is backwards on both the schematic, and the circuit board markings. -Chuck Harris Alberto di Bene wrote: My HP-3336C until today has always worked beautifully. |
¿ªÔÆÌåÓýThere is an electrolytic capacitor in the "C" that is in backwards. Chuck, ?? thanks indeed. Without your input, I would have never guessed that.... That 3336C has been in use for years, without problems... all of a sudden that capacitor has realized that its life was upside down... :-) TNX Alberto |
|
Alberto,
toggle quoted message
Show quoted text
I was clued into this problem by another member (whose name eludes me at the moment), but found that sure enough it was affecting my 3336C. -Chuck Harris Alberto di Bene wrote: /There is an electrolytic capacitor in the "C" that is in backwards.//Chuck, |
|
Interestingly enough, the C113 error, in the documentation anyway, was corrected in 1980, as can be seen in a proper version of the 1983 service manual.
I say "proper" version because many of the online 3336ABC manuals don't seem to be quite what they claim to be.
As far as I can tell, the October 1979 Ops and Service manual from the HP site is as it should be, although it does contain the C113 error, and their July 1983 Ops manual and June 1983 Service manual also look to be ok, although the latter has no schematics.
And that's where the problems creep in, there are what claim to be full 1983 Ops and Service manuals available online but so far all of those I've seen are actually cobbled together from the manuals on the HP site, or perhaps elsewhere, and contain a mixture of 1983 text and 1979 schematics.
I'm assuming the text is all from the 1983 versions anyway, can't say I've checked it all:-), but in the online versions I've seen the schematics in section 8 are all still dated 1979 and the section ends with page 8-43/8-44, section 8 looks to have been lifted straight out of the 1979 Ops and Service manual.
In my June 1983 HP printed version the schematics in section 8 are all dated 1980, that section now extends to page 8-143/8-144, and the C113 error is corrected, although there is a manual change note with quite a few other schematic corrections listed.
There was a time I would have just dived straight in and scanned this, I might still try but there's a lot of work there and I can't see it happening anytime soon these days, or perhaps Dave at Artek might have the correct 1983 version?
Nigel GM8PZR
Re: Seeking advice for an HP-3336C
From: Chuck HarrisDate: Fri, 31 Jan 2020 06:59:57 PST Hi Alberto, There is an electrolytic capacitor in the "C" that is in backwards. It works for a long, long time, and then quits, messing up the amplitude of the generator. The capacitor A4C113, a 10uf electrolytic is backwards on both the schematic, and the circuit board markings. -Chuck Harris |
¿ªÔÆÌåÓýAs far as I can tell, the October 1979 Ops and Service manual from the HP site is as it should be, although it does contain the C113 error, and their July 1983 Ops manual and June 1983 Service manual also look to be ok, although the latter has no schematics. My PDF version of the October 1979 Ops and Service manual reports this : Thanks Alberto |
|
I was looking up how to fix an attenuator problem on my HP 3336C and came across this thread and thought I'd check my unit and found it has C113 installed correctly (metal can end towards R134).? SN starts as 1932A....
What I find interesting is for ones incorrectly installed, it lasts a long time before becoming a problem.? I thought tantalums failed quickly and spectacularly with any reverse voltage applied.?? Lastly, I don't see polarity markings on my PCB for which end is positive for this cap other than the positive end of C113 is going to a square vs round solder pad,? Is that what's being referred to as the polarity markings? Dave |
