Aging Solid State Electronics - R&R question

[DataCruncher]

Is there a way to test components still attached on-board, or must certain types be removed in order to attain accurate readings?
And when searching for weak-links, which parts would be first to consider.
Capacitors?

[YzzzR1]

Definitely start with the caps as they end to dry out. Is this for audio gear?

I'm considering this rebuild kit for an old Sansui integrated amp I'm thinking of restoring. If you don't know, Avery Fisher is a long time respected audio guy and has rebuild kits for a lot of different gear.

https://www.ebay.ca/itm/155126508123?ha ... BM3N73l5Nh

[DataCruncher]

Definitely start with the caps as they end to dry out. Is this for audio gear?

I'm considering this rebuild kit for an old Sansui integrated amp I'm thinking of restoring. If you don't know, Avery Fisher is a long time respected audio guy and has rebuild kits for a lot of different gear.

https://www.ebay.ca/itm/155126508123?ha ... BM3N73l5Nh

It's a mother board which operates components on a gantry, however am too an audiophile. Sansui, great brand
The MOBO is still operational, though I'm getting a slight deviation that probably only I would ever notice, and it's buggin' me.
That said, I can get a 3rd party one in as backup in case I fubar this one. Just not aware of their standards and components quality.

Q:
Can caps be tested in place do you know?
And I've seen some high quality caps that are said to offer longer lifespans.
Your thoughts?

What age is your Amp, and how are the rheostats holding up?

+++

Also noticed his comment:
" I am extremely particular about the quality of the parts provided with this kit. Knowing how many bogus/fake caps, diodes, resistors etc. out there, I source all the parts from reputable whole-sellers and buy them in bulk."

(good to know)

[Jlabute]

Electrolytic capacitors tend to have a relatively short life in comparison to everything else, and specifications show their lifespan is directly related to temperature. Usually rated in thousands of hours, you can expect their rated values to decrease over time. They are on motherboards, LED bulbs, etc. Noise suppression components suffer damage from dirty power. Old power-supplies are also suspect because without healthy filtering capacitors and noise suppression MOVs, more noise will go to your motherboard.


So called solid state capacitors have a longer life but that benefit diminishes as temperature increases. As far as transistors and FETs and microprocessors etc go, they can suffer damage from noise over time.

[DataCruncher]

Electrolytic capacitors tend to have a relatively short life in comparison to everything else, and specifications show their lifespan is directly related to temperature. Usually rated in thousands of hours, you can expect their rated values to decrease over time. They are on motherboards, LED bulbs, etc. Noise suppression components suffer damage from dirty power. Old power-supplies are also suspect because without healthy filtering capacitors and noise suppression MOVs, more noise will go to your motherboard.


So called solid state capacitors have a longer life but that benefit diminishes as temperature increases. As far as transistors and FETs and microprocessors etc go, they can suffer damage from noise over time.



CE67894A-11D1-4CCC-A2BA-5395707D1B1F.png

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Then would it be prudent to swap out the power supply as well? (24vdc)
The main board I'm considering the service on has 22 caps (and there are other boards involved). My understanding is that there is an oil which may tend to dry out - thus causing it to short.

And I do prefer the old tech over the SMD devices. Easier to see, read and handle.

I've also noticed a difference in the solder. Can you offer insight on that, as I've experienced issues with doing R&Rs whereby it was difficult to pool and bond the new solder to the old, not to mention heating and removal of some components.

Should mention as well, that electronics has been a long time hobby of mine.
(Have a few Arduino boards on hand, though just haven't had the opportunity to set them up.)

[DataCruncher]

Just came across this: High Quality Solder Flux 10cc NC-559-ASM-UV solder paste For Phone LED BGA SMD PGA PCB

--- and

Basic Knowledge about SMT soldering Process
hot air furnace
https://www.raypcb.com/smt-soldering-process/

[DataCruncher]

Failure Modes

Electrolytic capacitors are not perfect. It is possible for them to fail at doing their job, which could lead to leakage and bulkage. Fortunately, you can investigate the failure modes to figure out the reason why the capacitor failed. Since most electronic devices have a Low Equivalent Series Resistance (ESR) when using an electrolytic capacitor, then a High ESR is one failure mode. You can use an ESR meter to test and see whether this is the case.

If the proper amount of ESR is measured on the metering tool, then you might have a low capacitance failure mode. To verify this, you’ll need to use a capacitance meter to find out what the capacitance level is at. However, sometimes the failure might be related to the capacitor not opening, which means that the electric flow cannot be distributed properly to the circuits. Only an experienced technician can diagnose this problem.

If none of these failure modes exists, then you have a short in the capacitor. This is the worst of them all because it means your capacitor is damaged and will need to be replaced.

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Lifespan

Electrolytic capacitors are required for all power supplies which use alternating currents and direct currents. As the power demands for electronic components increase each year, it also changes the way in which electrolytic capacitors are designed. The design ultimately determines the lifespan of the capacitor. Some internal components cannot handle the excessive heat that is generated from the input voltage demands. That is why you need to shop around and pick the best capacitor possible that has the longest lifespan.

The minimum lifetime of an electrolytic capacitor is between 1,000 and 2,000 hours, while the better-quality designs have 10,000+ hours of life. You’ll obviously want an electrolytic capacitor with a long lifespan because it means the application will last a long time as well. Capacitor manufacturers calculate the lifespan by considering the maximum rated ambient temperature.

In most cases, the maximum temperature is 105°C. So, if you have an electrolytic capacitor with a 5,000-hour lifetime, then it is possible to increase the lifetime if you can reduce the temperature. Every 10°C drop in temperature will double the lifetime of the capacitor. That means if the temperature is 95°C, then the total lifetime is 10,000 hours. If the temperature is 85°C, then the lifetime is 20,000 hours.

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There are polarized components within electrolytic capacitors because they’re constructed asymmetrically. The reason for this construction is due to their higher voltage operation where one side receives more power than the other side. They have a metal or aluminum anode with an oxidized cover layer, which is the dielectric, and serves as the positive electrode of the capacitor. This is the side which receives most of the input voltage.

The cathode serves as the negative electrode and contains aluminum foil and a liquid electrolyte. This liquid usually consists of a combination of water and sodium borate or boric acid. There are also a few sugars added to prevent evaporation. Make sure you don’t get this liquid in your eyes, mouth, or skin because it is very dangerous to your health. Immediately wash off the liquid if it encounters any part of your body.

The aluminum oxide is what enables the polarity of the electrolytic capacitors. The electric field holds the aluminum oxide in place. When direct current (DC) voltage is being supplied to the electrolytic capacitor, the proper polarity needs to be there. This requires the positive lead and positive terminal to be connected and the negative lead and negative terminal to be connected. If this is not done properly, it will ruin the capacitor.

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Anyone know of a reliable source for quality components in Canada?

[Jlabute]

If the PSU is as old as the motherboard, I would replace it. That’s just what I would do. Everything improves over time, especially semiconductors. I’ve seen cheap old power-supplies kill system components after they aged out.

If you are confident in working with surface mount parts, you will need a good soldering iron, one where you can set the temperature, appropriate tips, wick, and flux, etc. Too much heat and force can cause pads to lift off. Might want to practice on something first? Motherboards are lead free using silver solder which has a higher melting temperature. Lead based solder is easier to work with, and cheaper. I don’t think it matters until they get recycled perhaps. All motherboards are lead free today.

[Urban Cowboy]

I believe the quality of the parts has a huge bearing on longevity.

I have 3 PC's that until recently were running 24/7/365 at 100% CPU load for 15+ years which works out to over 130,000 hrs and haven't had an issue. But then the motherboards were top of the line EVGA, good Corsair PSU's, 12GB Corsair memory, Xeon X5680 processors @3.33Ghz, as well as upgraded Corsair H115 all in one water coolers. Components all installed in Corsair full size ATX towers so they have decent air flow.

These things have been reliable beyond belief and still more than meet my needs these days. The only possible drawback I can admit to is that I can't install Windows 11 on these units but it's not as if I need it.

[Catsumi]

Lead fumes, please take caution

https://www.ccohs.ca/oshanswers/chemica ... /lead.html

[TylerM4]

As others have already said - capacitors, especially electrolytic are the most likely component to fail. Unless what you're working on is really old and uses the old tube style transistor.

In regard to testing components while still installed in the board - the answer is essentially "no, you can't do that". You "sorta" can if you truly understand the circuit the component is a part of. But at that point, it's more a matter of you testing the circuit vs the component. And even then, In many cases you need to remove the component to confirm it's the cause of the bad circuit.

The sad reality is that most electronic failures result in "throw away and buy new" as being the best approach. Even if you have the knowledge, skill, and tools to repair modern electronics - most will "check the common or easy stuff" and throw away if unsuccessful unless it's something very expensive or hard to replace. There's a reason why electronics repair shops don't really exist, and when they do (E.G. Cell phone repair places) they replace whole boards/assemblies vs actually repairing the existing circuit board.

[Bsuds]

Cell phone repair places) they replace whole boards/assemblies vs actually repairing the existing circuit board.

This has been going in that direction for many years.

I was trained to troubleshoot down to the component to repair large photocopiers way back in the day. (late 70's)

When we got into the field and actually started to repair them all of a sudden the company decided it was better to just replace the circuit boards.

What a waste of training.

[TylerM4]

This has been going in that direction for many years.

I was trained to troubleshoot down to the component to repair large photocopiers way back in the day. (late 70's)

When we got into the field and actually started to repair them all of a sudden the company decided it was better to just replace the circuit boards.

What a waste of training.

Yes, repairing consumer electronics (vs swapping boards/parts) was already a thing of the past by the early 80's except in some niche areas like audio/amplifiers which were relatively easy to understand/troubleshoot.

I had a similar experience going to school to get my Electronic Engineering Technologies diploma. I figured I'd have a career fixing electronics or building my own but quickly realized I'd be buying electronics like everyone else and repairing by swapping boards/parts not IC's and components.

[DataCruncher]

So many helpful replies here, and as I don't know how to multi-quote, I'll address each by name.

@ Jlabute
If the PSU is as old as the motherboard, I would replace it.

Replace it in full, or change caps and see how much longer I can go?
(PS $634. USD)

-I’ve seen cheap old power-supplies kill system components after they aged out-

And many have an early death due to dust contamination. As a precautionary measure, I've always attached pre-filters.
Have a 8~12 month schedule of blowing them out (with low pressure) once a year. Also use a vacuum and small hose attachment to get into tight spaces and crevices.

-If you are confident in working with surface mount parts-

Am, just new at servicing lead free boards.
Yes, have had pads lift. Had to build a wire bridge as part of the repair.

-silver solder which has a higher melting temperature-

This is what I'll have to research more, as I've been doing it old-school.
Have the digital dial-in temp solder station with additional heat gun attachment.
Wick is something I have been skipping, but will get some in.

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@ Urban Cowboy

Stupid me, just purchased yet another upgrade and found out it want's Win 11 now.
Can't understand why they don't write 64bit software to be reverse compatible.

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@ Catsumi
-please take caution-

REPRODUCTIVE HAZARD. May cause reproductive effects in men and women. Has been associated with: reduced fertility.
Pondering....good thing or bad?

Joking aside, thanks for the concern Cats, will exercise caution :)

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@ TylerM4
-old tube style transistor-

Not that old, no tubes.
As for caps, are there ever visible signs in the earlier stages of pre- failure?
I've seen them (in past) swell and leak. I would imagine the swell comes before the leak, and wonder if that is an early warning to replace, or way too late.
Not that this particular board is exhibiting such, just a question out of curiosity.

-testing components while still installed in the board-
Good to know.

Had also watched this vid yesterday:
Board Repair Basics #11 - Finding replacement components
https://www.youtube.com/watch?v=weUAiivaYa4
Learned a few new things :)

-remove the component-

If it had only two terminal, could I not snip one side so that it's not fully in circuit, then use a meter with clips?
If I could, that would save some time. And if I did, would the leads create resistance and interfere with accurate readings?

-"throw away and buy new"-

Was considering getting a backup in first, though discovered it's $1,700. USD, therefore, I would like to refurbish if possible.
If I were to fail, then I have no other option.


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@ Bsuds

-it was better to just replace the circuit boards-

That's way over my pay-grade ;)

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New Questions

Would it be prudent to install additional cooling fans - in respect of keeping the cap temps down?


And something I've done in the past with less critical boards was to give them an alcohol bath, to get them really clean. They did work afterwards.
(used to do it too as a quick fix on crackling rheostats as well, till I came across the spray cleaner)

So my question is:
Is it ok to do it on MOBOS, or is there a risk involved. Most components appear sealed, and of course not overlooking, discharging the board before the alcohol scrub.

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Have also been looking over these inexpensive testers.

BSIDE ESR02 Pro Transistor Tester Digital Multimeter Diode Triode Resistor Capacitance Inductance MOSFET NPN Triac MOS Detector

https://www.aliexpress.com/item/1005002 ... pepxSyBmou

East Tester ET430 Multimeter Handheld LCR Digital Bridge Capacitance Inductance Resistance Test 2.8 Inch TFT Display Screen

https://www.aliexpress.com/item/1005004 ... 06364682_6


BSIDE ESR02PRO Digital Transistor Tester Capacitance Inductance Resistance LCR Meter Multimeter SMD Components ESR Measurement

https://www.aliexpress.com/item/4000186 ... kU8FMvL2jR


LCR-TC1 1.8" TFT LCD Display Multi-meter Transistor Tester Diode Triode Capacitor Resistor Test Meter MOSFET NPN PNP Triac MOS

https://www.aliexpress.com/item/1005004 ... BRbB5N5cde


Thoughts?

[Jlabute]

I had a plasma TV give up the ghost years back (5 or 6 years ago??)
Teltronics figured out the problem at a board level. Unfortunately, the boards were no longer available. Thankfully, this was the one time I had an extended warranty taking me to 7 years of coverage. The TV died within a few months of 7 years.