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Forum section: electronics / testgear

author: Ground_Loop
author_rank: Frequent Contributor
timestamp: October 10, 2021, 10:58:41 am
content: Do any of you keep any of your test gear powered up continuously? I have a few instruments that have a standby mode while plugged in, but my HP 4277 has no standby mode. I use this surprisingly often and it really likes to be warmed up. This got me thinking about leaving it powered up all the time, but of course that raises concerns as well.

author: wn1fju
author_rank: Frequent Contributor
timestamp: October 10, 2021, 12:25:39 pm
content: I am just the opposite. I don't leave anything powered up continuously, even in standby. After having a few Rifa caps explode while I was away, I am now afraid to do so. Even though I subsequently ripped every piece of test equipment I had apart and replaced all the Rifas (about 70 in total), I prefer only to turn things on when I am in close proximity to my lab. Sure, pieces like ovenized counters or voltage calibrators really should be powered up for extended periods of time, I'll accept the inaccuracies of only letting them warm up for a few hours.

author: Brumby
author_rank: Unknown
timestamp: October 10, 2021, 12:53:26 pm
content: I'm not big into high resolution measurement, but I do have a couple of items that benefit from a long warm up - and they get switched on well before I need them at their best.I have a master switch for all my test gear, I have another for all my computer setup and I have a third for my desk lighting. All are off unless I am using the relevant gear.

author: AVGresponding
author_rank: Super Contributor
timestamp: October 10, 2021, 02:15:02 pm
content: I'm RCBO protected so I don't worry about RIFAs beyond the inconvenience.I don't like leaving VFD or nixie gear on for extended periods, I prefer to use LED and LCD display items if I'm doing something that requires a long time.If I ever finish building my dual 584 v-ref the intention is to leave that on permanently.

author: bob91343
author_rank: Super Contributor
timestamp: October 11, 2021, 03:27:30 am
content: I leave my HP counter and signal generator plugged in 100% of the time to keep the crystal ovens warm. Everything else, I switch off when not in use, although there are times when I forget and stuff runs for days. It hasn't hurt anything except for a cheap 12V supply intended for CB radios. In that case, the power transformer blew itself up and isn''t repairable. I replaced it with another cheap power supply of similar type but this one has a power switch so I shut it off. If I remember.

author: bdunham7
author_rank: Super Contributor
timestamp: October 11, 2021, 05:04:10 am
content: I have a power strip with a master switch which is usually turned off at night and when I leave the house. The only time something stays on is when there's a specific reason--for example, I left a calibrator on for a few hours when we went out today because I wanted to finish adjusting it. I don't have too many things that benefit from extended warmups, but if I'm going to be using one and I really need that last decimal place, then I have to plan ahead. I know some people leave a lot of equipment--even soldering irons--on all day, but even when I'm using them, I don't like to leave them on because I'll burn a cord, burn myself or forget them altogether and start a fire.How far off is your LCR meter if you give it say 15 minutes warmup as opposed to 24 hours? I have very few pieces of test equipment that need extended warmups to at least be in spec. Some might require a bit longer to be at their absolute best, but that just requires planning.

author: Berni
author_rank: Super Contributor
timestamp: October 11, 2021, 05:51:21 am
content: Running 24/7 is mostly for frequency and voltage references. Those usually have a warm standby mode anyway.It is debatable if it's better for equipment to run continuously or to experience the cycling of going on and off. Both have a chance of braking sometime. Like electrolytic caps like having voltage applied to them because it freshens up the insulating layer, yet at the same time they dry out faster when running hot.There are also LCR meters with ovenised parts inside. For example the high freqency 1GHz version of this LCR meter has the directional coupler on the test port ovenised. A lot of really precise gear likes a bit of a warmup, but it's not like its unusable before it warms up. If you just need a reading within say 1% then just use it straight away. Its only once you go chasing those ppms that it becomes important, and at that point you might even need to let your cables and DUT stabilize to get a good reading, so the equipment will be warmed up by then anyway.Also if you find yourself using a LCR meter really often then it might be beneficial in also getting yourself a smaller handheld one. With the advancements in tech these small things can be surprisingly accurate while being more convenient to use due to being portable and not having loud fans. No warmup required since they don't get warm in the first place.

author: mansaxel
author_rank: Super Contributor
timestamp: October 11, 2021, 05:53:39 am
content: My bench has a master contactor. There are outlets at the bench that are non-switched, but they're reserved for things like battery chargers et c. I have things that need warming up, first and foremost my VTVM collection and their brother-in-law the (also hollow-state) 428b. They don't give anything near sensible values until they're cozy and warm. OTOH, I don't ever want to run them unless present. "Worth waiting for", as the beer advert says. The second area where warm-up would be essential is standards, and in my case mostly frequency. I've taken care of that by running my Meinberg GPSDO 24/7, which also makes sense since it is my NTP server. This means that frequency counters et c. will have a very stable and warmed-up reference to lock on to. A compromise, of course, but one that I'm OK with.

author: Gyro
author_rank: Super Contributor
timestamp: October 11, 2021, 09:07:59 am
content: Quote from: AVGresponding on October 10, 2021, 02:15:02 pmThat doesn't give you any protection against Rifas used as X-caps. It might give some protection against the Y cap ones, but it's usually the bigger, lower voltage rated X-cap ones that burn. The ones embedded in IEC plug AC line filter are before any internal mains fuse*, so that only leaves the plug fuse.*... and before any power switch on the equipment - I've had them blow on plugged-in but turned off equipment.I too have a lab bench isolator switch.