Any issues using 732A vertically? - Page 1
Forum section: electronics / general

author: essele
author_rank: Frequent Contributor
timestamp: September 07, 2020, 07:46:26 am
content: As I'm slowly filling my home lab and emptying my wallet I'm starting to get a bit pushed for space. The only space I have for my 732A is on the floor under the bench. Apart from the inconvenience of it being at my feet, I'm really worried I'm going to damage the front terminals at some point.With a right-angled IEC cable it would fit vertically under the bench on it's rear feet where it would be a bit more out of the way.I know there are some reference variations based on orientation, but are there any other reasons this might be a bad idea?My logic is that these things were designed to be shipped live, so orientation shouldn't be a major issue ... just not sure if it will have an impact being used in a different orientation.Lee.

author: jfphp
author_rank: Regular Contributor
timestamp: September 07, 2020, 09:50:45 am
content: The lead batteries must be charged verticaly if I remember (have a look at the Yuasa datasheet) and the ventilation of the charger plug in is not correct (conduction). Not allowed by the manual.

author: Andreas
author_rank: Super Contributor
timestamp: September 07, 2020, 10:03:28 am
content: Quote from: essele on September 07, 2020, 07:46:26 amI would not bet on this.At least a LM399 (heated reference) has some kind of memory.I accidently put my LM399#2 in a wrong orientation (head over heels) on my table.On day 920 I recognized a deviation > 1 ppm in my daily checks and put it back to normal orientation.It needed around 3 weeks to get back to the old value.So in which orientation do you want to calibrate the device?Of course I think that the effect is larger with heated references (especially LM399) than with lower temperature references.with best regardsAndreas

author: Dr. Frank
author_rank: Super Contributor
timestamp: September 07, 2020, 11:33:27 am
content: The LTZ1000 references show a pronounced orientation shift of up to several ppm.. I would expect that as well for the LTFLU, maybe also for the SZA263, depending on how old your 732A is.Therefore, all these references should be operated always in the intended orientation.Frank

author: Grandchuck
author_rank: Super Contributor
timestamp: September 07, 2020, 12:02:10 pm
content: I have noticed the shift due to orientation with my LTZ1000 references.

author: branadic
author_rank: Super Contributor
timestamp: September 07, 2020, 01:58:19 pm
content: Personally I would expect such a behavior only from LMx99 and LTZ, with onchip heater. But since 732A has the non-heated reference SZA263/LTFLU inside a big oven, I would expect much more equal heat distribution inside the oven. However, it would be nice to see some real world measurements on this.-branadic-

author: essele
author_rank: Frequent Contributor
timestamp: September 07, 2020, 05:31:14 pm
content: So I’ve already replaced the batteries with Power Sonic ones, and they suggest they can be used in any orientation (although upside-done usage is not recommended.)I’ll need to look at the cooling side of things.It does sound like this might be a useful experiment ... I can collect a good few weeks data, then move it and see if I get any significant change:(Just need to finish my GPIB setup first)Lee.

author: Dr. Frank
author_rank: Super Contributor
timestamp: September 07, 2020, 07:11:31 pm
content: That would be great, much appreciated!By the way, I have plenty of room in my volt-nuts lab to set the 732A horizontally, and also on table top level.So, if you're in trouble, I could give it a good home, alternatively.Frank

author: lukier
author_rank: Unknown
timestamp: September 07, 2020, 07:14:57 pm
content: So I did a quick test, received 732A recently and it has been running on AC, while I wait for parts to do the refurbishment (batteries, caps etc).I've been logging it for a while and it seems quite stable, most variations come from 3458As tempcos. 3458A#1 (golden, excellent ADC) logs 10V output, 3458A#2 (meh, opposite tempco of ADC, a bit drifty but still within SN18 specs) logs the 1V output and DMM6500 logs the thermistor.Few hours ago I put 732A on its side and it had some effect on the oven temperature (I guess related to the physical locations of heaters and thermistors), however the output barely changed IMHO.Plots from Grafana for the last couple of hours:(blue annotation is when I flipped the 732A)

author: essele
author_rank: Frequent Contributor
timestamp: September 08, 2020, 11:58:05 am
content: Quote from: Dr. Frank on September 07, 2020, 07:11:31 pmThanks for the offer Frank, I'll bear that in mind ... although I must say I favour evicting one of my kids from their spacious bedroom