[time-nuts] HP 5370B Leds pulsing slowly, buttons selecting normally, PB ...

Sat Jul 6 09:07:40 EDT 2013

Yeah, I was looking at the local suppliers and comparing items.
They all seem to stop at 10,000uf for the "normal places".
I wonder what CR4 is, It's the -5.2 bridge before C3.
I'd better check it too, must be a reason for the second time that caps failed.
I suppose I could replace CR4 with a higher rated bridge and replace C3 with the 29,000uf
Then I'll have prey to the transformer gods for the 8VAC that supplies CR4 doesn't go open circuit under the strain :)
HP had some odd values for things on occasion, but look at what they achieved for 1970-1990...

-marki

-----Original Message-----
From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com] On Behalf Of Adrian
Sent: Saturday, 6 July 2013 10:55 PM
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] HP 5370B Leds pulsing slowly, buttons selecting normally, PB ...

Mark,

I wouldn't replace a 20V cap with an only 10V rated one, especially when the nominal working voltage is alrady 10V. That would be a very bad idea.
You can always use caps with higher voltage ratings as replacements which is good for reliability, but don't do the other way.

The exotic values HP was using (17.000 uF) are probably near impossible to find, except old stock (not so great with electrolytics) or you go to a manufacturer and get them custom made.
The closest commonly available standard value is 22.000 uF, voltage rating at least 20V (25...35V would be great). 15.000 uF would work as well if available. For higher reliability you may go for a 105°C model.

Don't care too much about the mounting style. For repeated outdoor use and transport you can fix the cap with hot glue and / or binding straps. 
Otherwise I hope your lab isn't moving and shaking enough for the cap to loosen... ;)

Adrian

Mark C. Stephens schrieb:
> Hi Nigel,
>
>
> The only screw type electro can find is 29000uf at 10V. it's the same dimensions.
> Should I risk the strain on the rectifiers (another 10Kuf is rather a lot)?
> Without this timer I am dead in the water so I need to do the right thing here...
>
> That's why I posted on the Agilent group too, I need to be sure that I do the right thing!
>
> By the way, the failed electro measures 39uf :)
>
> I reckon, the line voltage here is 250v and the equipment is set for 240V, that extra 10V on the mains is why I am having so much equipment failure.
> Also the Heat sink on the 5370B got so hot I mounted a 5" fan across it to keep it at a respectable temperature.
>
> How can I drop the Mains to 240V, I have a boat load of gear that needs to be powered concurrently.
> (8566A, 8568B, 3585A, 5335A, 5370B, 8901A, etc, powered on together) we are starting to talk some serious current there.
>
>
> -marki
>
>
> -----Original Message-----
> From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com] 
> On Behalf Of GandalfG8 at aol.com
> Sent: Saturday, 6 July 2013 9:37 PM
> To: time-nuts at febo.com
> Subject: Re: [time-nuts] HP 5370B Leds pulsing slowly, buttons selecting normally, PB ...
>
> As per my reply to the same question on the HP group, you've  identified the problem so just go for a reasonably close-ish equivalent and  replace it!
>   
> Regards
>   
> Nigel
> GM8PZR
>   
>   
> In a message dated 06/07/2013 12:18:44 GMT Daylight Time, marks at non-stop.com.au writes:
>
> C3  (17000uf @ 10v) is open circuit.
> Where am I going to get one of those  from.
>
> I need some advice here, Should I just use modern low ESR solder  lug type soldered directly onto the board?
> Or Should I try and locate a  screw terminal type Capacitor?
>
> Obviously, I want to do the best for  this timer as I rely on it tremendously.
>
>
> -marki
>
> -----Original Message-----
> From:  time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com] 
> On Behalf Of  Mark C. Stephens
> Sent: Saturday, 6 July 2013 8:47 PM
> To: Discussion of  precise time and frequency measurement
> Subject: Re: [time-nuts] HP 5370B  Leds pulsing slowly, buttons 
> selecting normally, PB LEDS scannning and appears  to be reading o/k
>
> Checked the PSU voltages on the PSU card next to the  10811.
> The -5.2 is reading -4.2.
> Took a look with the scope and instead  of a nice flat DC I see a 4V Peak to Peak spike @ 100Hz.
> Trying to track  down a service manual.
> Any ideas on this one guys, if the Pass tranny was  shorted, it would be a lot more than 4.2V unless the overvoltage Zener is able  to sink all that current...
>
>
> -marki
>
>
> -----Original  Message-----
> From: time-nuts-bounces at febo.com  [mailto:time-nuts-bounces at febo.com] 
> On Behalf Of Mark C. Stephens
> Sent:  Saturday, 6 July 2013 8:18 PM
> To: time-nuts at febo.com
> Subject:  [time-nuts] HP 5370B Leds pulsing slowly, buttons selecting 
> normally, PB LEDS  scannning and appears to be reading o/k
>
> I went to use my 5370B todayt  and noticed the LEDS on the display are slowly sort of pulsing bright one  after another.
> Also all the push button LEDS are going on and off one by  one.
> The strangest thing is that it appears to be working o/k via  HPIB.
>
> I don't have extender boards but I do have a signature  analyser.
>
> Could it be something silly like one of the PSU regulator has  gone kaput?
> Has anyone seen this issue  before?
>
>
> -marki
>
> _______________________________________________
> time-nuts  mailing list -- time-nuts at febo.com To unsubscribe, go to 
> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> and follow the  instructions  there.
>
>
> _______________________________________________
> time-nuts  mailing list -- time-nuts at febo.com To unsubscribe, go to 
> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> and follow the  instructions  there.
>
>
> _______________________________________________
> time-nuts  mailing list -- time-nuts at febo.com To unsubscribe, go to 
> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> and follow the  instructions there.
>
> _______________________________________________
> time-nuts mailing list -- time-nuts at febo.com To unsubscribe, go to 
> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> and follow the instructions there.
>
>
> _______________________________________________
> time-nuts mailing list -- time-nuts at febo.com To unsubscribe, go to 
> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> and follow the instructions there.
>

_______________________________________________
time-nuts mailing list -- time-nuts at febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.