Identification: FE-5680A Frequency Standard  - Page 1
Forum section: electronics / general

author: NivagSwerdna
author_rank: Super Contributor
timestamp: January 27, 2016, 11:13:27 pm
content: I just bought a frequency standard from EBAY for a bit of amusement...It is labelled as FE-5680A and has a DB9 connector but unfiortunately it appears to be riveted to a base plate so I can't easily get inside to inspect.Is there any way to identify which version it would be? I assume Pin 1 is 15V, Pins 2&5 are GND... but how can I work out if it is fixed or programmable (hoping for programmable)?Thanks in advance

author: NivagSwerdna
author_rank: Super Contributor
timestamp: January 27, 2016, 11:18:43 pm
content: Better picture of serial#

author: edpalmer42
author_rank: Super Contributor
timestamp: January 27, 2016, 11:47:41 pm
content: Those aren't rivets. They're allan screws. It took me a few minutes to figure it out.

author: jwm_
author_rank: Frequent Contributor
timestamp: January 27, 2016, 11:55:39 pm
content: figure out if it has an onboard 5v converter or not, some require an external 5v supply, others blow up a bit if you try to feed them one. Or at least the tantalums do. You can look on the board to see if the 5v is populated or not. Or just try at 15v first.

author: NivagSwerdna
author_rank: Super Contributor
timestamp: January 28, 2016, 12:05:48 pm
content: Quote from: edpalmer42 on January 27, 2016, 11:47:41 pmYou are joking! My old eyes! Thanks will have a closer look tonight!

author: Brumby
author_rank: Unknown
timestamp: January 28, 2016, 01:06:13 pm
content: Quote from: edpalmer42 on January 27, 2016, 11:47:41 pmActually, I think they might be torx ....

author: mojoe
author_rank: Frequent Contributor
timestamp: January 28, 2016, 04:18:53 pm
content: Usually, those ebay vendors tell you which type you have and list the pinout. Some are software tunable in frequency, some are fixed 10 MHz. A few only put out a PPS signal. As mentioned, some (most) need +15V and +5V, some only +15V. Do some Googling and you will find several sites that document the various types and their pinout. If you put voltage on the wrong pins, you could damage things.As for the "rivets", yes, they are screwed into the circuit board. I used an Allen key on mine and reused them to mount the rubidium in a chassis.

author: edpalmer42
author_rank: Super Contributor
timestamp: January 28, 2016, 06:46:38 pm
content: Quote from: Brumby on January 28, 2016, 01:06:13 pmIt takes a magnifying glass to be sure, but they are Allan, not torx. There's a dimpled pattern on the top that kind of makes it look like torx. Actually, a T6 bit fits fairly well, but the bit that really fits came from a set of precision screwdrivers. It's labelled as #1 and measures as 0.0617 (~1/16) inch or ~1.6 mm.

author: pelule
author_rank: Frequent Contributor
timestamp: January 28, 2016, 08:07:43 pm
content: I found this (unfortunately German, but may help):http://www.sprut.de/electronic/referenz/frequenz/rubidium/rubidium.htmlBRPeLuLe

author: NivagSwerdna
author_rank: Super Contributor
timestamp: January 28, 2016, 11:11:15 pm
content: Making some progress. The 'rivets' were indeed Hex (1.5mm)? screws, so although very crusty they came out, and there was no sign of Flynn from "In like Flynn" fame until I discovered the secret second screw under the serial number label!The internals are nothing like Dave's tear-down, looks like mine is a very early model. There is 1998 on one of the circuit boards.Anyway, it's an amazing triple decker affair see photo...

author: NivagSwerdna
author_rank: Super Contributor
timestamp: January 28, 2016, 11:20:21 pm
content: I see a number of interesting features...it's got buttons!It's got a AD9830A (with a very dodgy looking bit of wire bodge that goes very close to some vias)It has a board dated "November 1998"It has a board that has a DS80C320 on the top and a PSD301 on the bottom!

author: NivagSwerdna
author_rank: Super Contributor
timestamp: January 28, 2016, 11:32:01 pm
content: I didn't recognise the part but it's got a SP233ACT! Looking hopeful.

author: NivagSwerdna
author_rank: Super Contributor
timestamp: January 28, 2016, 11:39:40 pm
content: Quote from: pelule on January 28, 2016, 08:07:43 pmWow! Thanks! That is very close to mine. I seem to have an extra board with two microcontrollers on it. I guess I need to apply 15v and see what happens! That link is really useful. Danke!

author: NivagSwerdna
author_rank: Super Contributor
timestamp: January 28, 2016, 11:47:23 pm
content: After reading thehttp://www.sprut.de/electronic/referenz/frequenz/rubidium/rubidium.htmlpage I can see it looks like I have an early PIC based DDS board and that under the label is probably a SP233ACT, however I can also see I have the dual controller board which also has a SP233ACT! Very confusing!

author: uncle_bob
author_rank: Unknown
timestamp: January 29, 2016, 02:18:41 am
content: HiJust to add more to the confusion ...As you have figured out, that's a very *old* version of the 5680. There have been many changes to the design since that old beast. They have a "rated life" of about 7 years. Your part is at least twice that. It may have zero running hours on it and will run for a long while. It may have spend it's life 100% on power and be on its last legs. No way to know until you get it running.Once you know it works, it needs a heatsink. Yes that sounds crazy. It's true. Without heat sinking they don't last long. A fan also works, just be careful of magnetic fields.Like anything else that's been through the scrap reclamation process, it may need a bit of repair simply to fix damage done in the removal process.Lots of fun!Bob