do you notice stand out features of equipment that is troublesome? - Page 1
Forum section: electronics / projects

author: coppercone2
author_rank: Super Contributor
timestamp: June 07, 2025, 09:08:23 pm
content: Did you ever notice a trend that takes a while to see about design features that are like a indicator that something is going to be breaking down all the time and annoying?I noticed I really don't like the little (DIP CHIP) 7 segment red displays. I got rid of my keithley 616 and a lambda dual power supply that were constantly giving me trouble. And another lambda before that. And a alarm clock, a multimeter too. Usually I fix it once and then something else (much harder to track down) breaks and I throw them out. And the microwave sweeper that has been a perpetual nusience. And two thermocouple meters.If it has a analog dial or a LCD/modern its usually fine, but something about these DIP chip sized seven segment displays makes a design haunted and they are always awful to work on mechanically. If it has a big 7 segment display its usually better, but once I see the little digits I am like inclined to avoid it for superstitious reasons. And I see things I don't like, for instance lack of decoupling at the end of a cable harness and stuff that to me is common circuit protection.Like at this point there is enough experience to tell me not to get things with small red 7 segment displays because of the history I have with them. Big seven segment display equipment is a little better usually but not so much, but I hardly noticed the same trend as with the little 74 gate sized 7 segment displays.I think that these little displays make some kind of field or potential which makes failures more likely in equipment connected to them, yet undiscovered. Perhaps some sort of terahertz radiation.

author: jpanhalt
author_rank: Super Contributor
timestamp: June 07, 2025, 09:17:12 pm
content: Of course, otherwise it wouldn't stand out.

author: coppercone2
author_rank: Super Contributor
timestamp: June 07, 2025, 09:21:30 pm
content: I know alot of people are gonna try to cover for their little cute 7 segment displays but there is nothing good for them and you are probobly under the influence of their forces

author: TimFox
author_rank: Super Contributor
timestamp: June 07, 2025, 09:40:56 pm
content: I like large seven-segment red LED readouts, despite their power consumption.They are much easier to read in difficult lighting conditions, and good ones are very long-lived.

author: coppercone2
author_rank: Super Contributor
timestamp: June 07, 2025, 09:51:05 pm
content: I just don't see this correlation with 7 segment large display containing equipmentits the ones that have the small ones in the dip chip form factoralso a DC load can be added to list of malfunctioned 7 mini segment display equipmentI feel like 90% of what I scrapped has mini 7 segment displays (red). those display elements hold a curseLike I made this rule that if it has a red seven segment mini display, its not fixing easily, and its worth under some dollar value, just get rid of the fucking thing. I feel like I am wasting my weekendsthe thermal RMS meter and the sweeper I might make a exception too but never again am i going to spend time on a non unique meter or power supply that has the little 7 segment display on it with the shitty little 3.5 digit ADC chip. the hell with this DC load too. They always have way too much hard ware in them (tricks like washer stacking, threaded rod games, etc instead of having a larger specific part that is better suited. i.e. 10 stack of standoffs instead of 1 big standoff. it just says something about the designer. If you can't afford a 2 inch standoff then you probobly also could not allocate the proper budget for a electronics parts BOM and its going to hell because its lacking 2 passives in the design).That's the other thing I noticed too, when you get more then 2 washers/nuts/standoffs (duplicates) stacked to do something, its abadsign. I don't mean a nut, washer and lockwasher, I mean if its like 2 nuts and 4 washers on 1 bolt just to get the correct spacing. Or 10 pipe segments instead of a larger one. I started to think the cheapness is not ending with the mechanical hardware choices.

author: macronpio
author_rank: Newbie
timestamp: June 27, 2025, 09:12:45 am
content: Quote from: coppercone2 on June 07, 2025, 09:08:23 pmWhat to Look For InsteadLCD displays or VFDs: Often come with better power management and are more likely in modern or well-thought-out gear.Analog meters: While old-school, they're often part of more robust designs that prioritize durability.Modular design: Devices with separated display boards, better shielding, and modern connectors are easier to maintain.Clear decoupling and grounding strategy: A sign of careful design.

author: eutectique
author_rank: Frequent Contributor
timestamp: June 27, 2025, 11:27:50 am
content: Quote from: macronpio on June 27, 2025, 09:12:45 amGPT section is here:https://www.eevblog.com/forum/chatgptai/

author: 5U4GB
author_rank: Super Contributor
timestamp: June 27, 2025, 11:43:36 am
content: Quote from: coppercone2 on June 07, 2025, 09:08:23 pmYou mean when it says "British Leyland" on it?

author: tooki
author_rank: Super Contributor
timestamp: June 27, 2025, 12:07:53 pm
content: Quote from: coppercone2 on June 07, 2025, 09:08:23 pmDon’t confuse correlation and causation!The DIP-size LED displays had a fairly short period of popularity, all things considered, so what they really are, more than anything, are indicators of devices made during a particular, somewhat narrow stretch of time. Meanwhile, other, unrelated failures that also affect devices of the same generation will occur. (For a different example, consider how devices from the late 90s/early 00s suffer from capacitor plague. It has nothing to do with what speed CPUs are in them, for example, but is simply an artifact of their time of manufacture.)

author: David Hess
author_rank: Super Contributor
timestamp: June 27, 2025, 06:32:59 pm
content: I notice features that are not present. The rotary selector on multimeters should have an off position at both extremes. Banana jacks should have 3/4" spacing.For displays, I prefer LEDs, then LCDs, and then VFD, and TFT LCDs before OLED.For LED displays, I prefer the older style of thin segments as shown below, although the camera position does not show them to best effect here.

author: jpanhalt
author_rank: Super Contributor
timestamp: June 27, 2025, 07:48:44 pm
content: Quote from: David Hess on June 27, 2025, 06:32:59 pmWhy does the rotary switch need two offs, if there is a master on/off switch? That sounds like a "feature" designed to wear the rotary switch out.

author: CatalinaWOW
author_rank: Super Contributor
timestamp: June 27, 2025, 08:45:03 pm
content: My HP calculator with tiny 7 segment displays still works fine after about fifty years. It isn't the displays.What it is is cheap shit, designed twenty years after the technology was introduced, using the dregs of production because anyone doing good work has moved on to other things.Applies to displays, through hole components, and many other things.

author: coppercone2
author_rank: Super Contributor
timestamp: June 27, 2025, 08:48:20 pm
content: Maybe there is a exemption to be made, that is, portable electronics with the correctly sized DIP chip display are OK. But when its bench top equipment....

author: srb1954
author_rank: Super Contributor
timestamp: June 27, 2025, 10:40:52 pm
content: Quote from: CatalinaWOW on June 27, 2025, 08:45:03 pmWhat model Hp did you have? With my model HP45 the LED segments winked out one by one and, within 4 years from new, about half had gone. I know that other people had the same problem with their HP calculators of that vintage.I assume the failures were due to corrosion of the wire bond contacts as the LED modules appeared to just have bare LED die on the backing PCB with no overcoat or epoxy fill to provide environmental protection.

author: Analog Kid
author_rank: Super Contributor
timestamp: June 28, 2025, 01:13:55 am
content: Quote from: jpanhalt on June 27, 2025, 07:48:44 pmThat's why I prefer my el cheapo Harbor Freight DMMs to my slightly higher-end Klein.The HFs have a slide switch for power, so I don't need to change the mode every time I turn the damn thing on and off.Go ahead, laugh. I know this isn't the best test equipment in the world. I'm a hobbyist.

author: CatalinaWOW
author_rank: Super Contributor
timestamp: June 28, 2025, 04:38:20 am
content: Quote from: srb1954 on June 27, 2025, 10:40:52 pmYour question made me think back and I realized I spoke inaccurately. My first was an HP-45 and I sold it (still working perfectly) a few years later and bought an HP-65, which is still chugging along. The card reader gave up sometime in the 1980s and I used it less and less over time as I got new calculators and then desktops and now smartphones, but the display was still good when I last checked it about four or five years ago.Reliability of these calculators was a great source of debate back in the day. Consumer reports rated the HPs as far less than similar TI calculators of the era. They did simulated use testing which included drops on a concrete floor and other handling errors. The lighter TI calculators did better in these tests. In the group of engineers I worked with the real life results were reversed. The keyboards on the TI calculators started getting unreliable after a year or two, while few engineers dropped either brand of these expensive calculators on anything, let alone a concrete floor.

author: coppercone2
author_rank: Super Contributor
timestamp: June 28, 2025, 04:50:41 am
content: I did not mean the display modules fail. They seem fine.I mean the stuff they are in breaks. Its like a sign.my theory is if you put a red DIP led into a product, it will break easieror its like a calling card that some evil engineer design cult leaves on their designs

author: David Hess
author_rank: Super Contributor
timestamp: June 28, 2025, 12:49:56 pm
content: Quote from: jpanhalt on June 27, 2025, 07:48:44 pmThe rotary switch would not, but how many handheld multimeters have a separate control for power?Having an off at both ends allows *less* movement of the rotary switch.

author: jpanhalt
author_rank: Super Contributor
timestamp: June 28, 2025, 02:36:16 pm
content: Quote from: David Hess on June 28, 2025, 12:49:56 pmI don't know how many have separate on/off switches and have no way to find out. I have 2 multimeters that I can find easily:BK Test Bench 391 and top of the line Cen-Tech 7-function multimeter (currently $6.99 at HF). Both have separate on/off and rotary dials. My DE5000, if you consider it a multimeter of sorts, has separate on/off but doesn't have a rotary dial. My Extech LCR has a rotary OFF. It's a 360° rotary with only one OFF. The rotary OFF is a feature I simply do not like. With a 360° switch, it's probably preferable to have only one OFF, as that prevents having to go through OFF.

author: ejeffrey
author_rank: Super Contributor
timestamp: June 28, 2025, 03:12:14 pm
content: From what I can see separate off switches are somewhat common on manual range meters but very rare on auto rangers. Even then plenty of manual range meters have off positions on the range switch.

author: David Hess
author_rank: Super Contributor
timestamp: June 28, 2025, 05:20:24 pm
content: Quote from: ejeffrey on June 28, 2025, 03:12:14 pmMy manual ranging Beckman DM25L has a separate switch for power, but on a manual ranging meter, the rotary switch is going to need 360 degrees of operation to encompass all of the ranges so there are no endpoints.I never had an automatic ranging meter with separate power control, but many like the example DMM916 have enough rotary settings to make off settings at either end of the rotary switch's motion. No current meter does this, and I look for it as a sign of good design.

author: jpanhalt
author_rank: Super Contributor
timestamp: June 28, 2025, 06:23:17 pm
content: I don't use auto-ranging, nor auto-pilots (another thread). That's just me.

author: coppercone2
author_rank: Super Contributor
timestamp: June 28, 2025, 06:46:49 pm
content: rotating it off is alot of work, makes me OK with measuring voltage but too much work to measure currentI think some people develop a distaste for twisting stuff. I avoid it. Too many screws in life time. I also use those corny little electric screw drivers if at all possible.Potentiometer is OK because its very smooth

author: SteveThackery
author_rank: Super Contributor
timestamp: June 28, 2025, 08:10:10 pm
content: The auto power-off on the meter I often use drives me nuts. It requires an actual button press or switch rotate to cancel it, then five minutes later the bloody thing's beeping again.Are there any multimeters that monitor the inputs or display to defer the power-off?

author: pardo-bsso
author_rank: Frequent Contributor
timestamp: June 29, 2025, 06:33:23 pm
content: - Existing.- Blue leds.- Blue displays.- Size that does not fit in my home furniture.- Taller than my doors.- Silent.

author: David Hess
author_rank: Super Contributor
timestamp: June 29, 2025, 09:12:26 pm
content: Quote from: pardo-bsso on June 29, 2025, 06:33:23 pmYea, blue LEDs, or really blue LED displays and indicators, are definitely a problem.At night try to find a deep blue or especially violet advertising sign, and notice how difficult it is to read. Human eyes have excellent color vision, but less so toward the shorter more blue and violet wavelengths where resolution is effectively reduced. This is caused by a combination of optical aberrations which prevent clear focus, and lower resolution.Red has the highest resolution, and green has the highest sensitivity, especially considering how good P31 phosphor is, and both are much easier to read then blue or especially violet. In practice anything between red and green is satisfactory. Those old enough to experience them might remember amber CRTs which were suppose to be easier on the eyes then even P31 phosphor green CRTs.This all adds up to blue LED displays being a curse placed on us by marketing and business majors, who never had to use them. Blue VFDs are acceptable, probably from having less saturation, but barely.