HP 5314A Universal Counter Teardown - Page 1
Forum section: electronics / testgear

author: theatrus
author_rank: Frequent Contributor
timestamp: June 20, 2014, 01:09:09 am
content: Got this unit for free recently, and decided to do a teardown. It is functional, but the buttons on the unit are absolutely terrible (hard to push, don't stay pushed, etc etc). Even after some contact cleaner - need to do a bit more work on that.Click the image to embiggen.The inside gets the "whole lot of nothing" award, presumably for the battery option:Power supply, note the internal voltage range switch:The actual counter is tucked behind the front panel:Removing the knobs (which had the set allen screws very stuck) shows the main board. Random note: the fat left 7-segment is inverted in order to put the "dot" next to the gate indicator on the front panel. A second LED is added for the Overflow indicator. The far right dot is used to indicate microseconds, and kilohertz just is indicator-less. Thats some creative cost cutting!I miss old package markings sometimes - a transistor:I can't find a datasheet on the main ICThe frequency reference / oscillator with the tuning adjustment.There are a number of these resistor packs throughout the board:I'm also unsure of what to make of this fuse - looks like a cotton string wrapped element with a spring? First I've seen of this particular construction.Main pass transistor of the power supply:

author: Flump
author_rank: Frequent Contributor
timestamp: June 20, 2014, 01:26:40 am
content: Nice counter theatrus, I hope you can fix the buttons,is that the only problem with it ?lovely pictures

author: theatrus
author_rank: Frequent Contributor
timestamp: June 20, 2014, 01:56:47 am
content: Quote from: Flump on June 20, 2014, 01:26:40 amEffectively - I haven't done all the ranges on both channels, but it does seem to be functional.Its all about lighting. In this case, off camera white ceiling bounce flash

author: skennedy
author_rank: Contributor
timestamp: June 20, 2014, 02:12:03 am
content: Amazing photos. I found the main intersil chip from the HP part number 1820-2187 to be a ICM7226A datasheet:http://www.intersil.com/content/intersil/en/products/timing-and-digital/counters-time-base-ics/counter-time-base-ics/ICM7226A.html. Looks like it does it all. I am pretty impressed by how little is in this counter. I have a 5316A that I bought a while ago and it has a lot more going on inside. I suppose this is how HP got the price down for this model.

author: theatrus
author_rank: Frequent Contributor
timestamp: June 20, 2014, 02:45:10 pm
content: That does look like a pretty much all-in-one.I found the schematics and block diagram at the end of this scanned service manual:http://exodus.poly.edu/~kurt/manuals/manuals/HP%20Agilent/HP%205314A%20Operating%20&%20Service.pdfReadability is pretty terrible but it can be deciphered.

author: SeanB
author_rank: Super Contributor
timestamp: June 20, 2014, 05:14:08 pm
content: Wet slug tantalums in a good case ( glass frit seal which essentially lasts till the end of time) and a slow blow fuse with the resistance wire time delay element inside it to heat it up to melting when subjected to prolonged overload.Lovely, and I like the Intersil house coded parts for HP. You get a variant that does timekeeping in the same package, and you can preset the count as well with the display drive. ICM 7227.

author: PaulAm
author_rank: Frequent Contributor
timestamp: June 20, 2014, 06:36:25 pm
content: HP used that case for a number of instruments of that era (the reason for all the empty space). I have a 3466a DMM and a 5004a signature analyzer in that case. The buttons/switches are also used on the 3466a.The white silkscreen on the LED window is not very durable. I have a parts 3466a with all of the white legends worn off. Even if it worked, it would be unusable.HP may also have offered that unit in a more standard box shaped case. The clamshells do not stack well. I see the handle is missing; somebody probably took it off to make it stack better.

author: theatrus
author_rank: Frequent Contributor
timestamp: June 20, 2014, 06:38:40 pm
content: I took the handle off for disassembly.The buttons are working better with very light lubrication, but still having issues staying depressed.

author: PA0PBZ
author_rank: Super Contributor
timestamp: June 20, 2014, 07:11:06 pm
content: To compare some quick and dirty shots of my 5315A, just a little bit more inside including the C input:Anyone know where to get the knobs? 2 are broken

author: theatrus
author_rank: Frequent Contributor
timestamp: June 21, 2014, 05:37:23 am
content: A fused BNC? That's a new one to me

author: MudMan
author_rank: Contributor
timestamp: October 27, 2016, 08:41:33 pm
content: I got a used 5314A and need a readable schematic. I downloaded the manual from Keysight and also searched the Internet, but all I found was unreadable. Anybody out there who can help me?

author: villas
author_rank: Newbie
timestamp: October 28, 2016, 02:56:32 pm
content: I've got one earlier this year. Mine came with original battery (dead as expected) with '79 date code on it.Led display became orange, but still readable.