Preserving 386 PC long term

[mechaniputer]

I already removed the battery back on the day of the original posting. I'll try to clean up the corrosion with vinegar as suggested.

 

[oldpcguy]

Yes, exactly right. This machine has particular nostalgic value and was the first computer I ever used. I'm now a computer science professor and would like to keep this exact machine going as long as I can. If the general concensus is that it's fine to wait until something blows and then probably be able to fix it, I'm willing to accept that. But also open to suggestions for more proactive routes.

Apparently several people here do not preventative maintenance / repairs on their vehicles and wait for something to fail before performing any work.

Here's my opinion. If it were just a generic PC with no sentimental attachment then I would say don't go through the effort / expense of recappnig the power supply. However, since it does, and you're willing to go through the effort / expense, then why not? Find a recapping service and, if the price is right, have it done. There's very little risk in doing so.

 

[Chuck(G)]

FWIW, I do maintenance on our vehicles and other equipment, as well as computer gear. But given the fragile nature of computer systems, I'd rather wait until a single component fails before picking up the soldering iron. Many custom ICs, for example, are unobtainium after a couple of decades; inadvertently damaging one can result in creating nothing more than e-waste when one previously had a functional computer.
After all, a 386 system isn't that old--and old systems are infinitely more repairable than modern ones with their tons of SMT and custom silicon--and lead-free solder.

 

[NeXT]

I'm speaking here from experience (at least on refurbishing a 486sx for 24/7 service) that the only maintenance I did to get a machine rebuilt so that it would remain reliable in operation but locked away in a basement was replacement of the PSU fan (and I used a 24v fan undervolted at 12v to extend the useful life), a full recap of the PSU (careful here. A shotgun recap without knowing the ECR of the original cap will cause problems when replacing them with modern low ESR capacitors), a larger passive heatsink (and a 486sx at 33mhz gives off damn near not enough heat to really need a heatsink) and repalcement of the rechargable CMOS battery with a diode protected BR-2/3A lithium 3V battery. The original hard drive is still in the machine but it now runs off a 256mb Disk on a Module and it's now been in service with not much more than a few power interruptions for two years.
I did not recap the motherboard. A recap of the motherboard was too high a liability for a board outside of the early 2000's capacitor issues and the board as-is was passing burn-in tests. Plus even with a recap there was nothing that said I would be back here having to recap again in 20 years, so why risk damage to the plated vias?

 

[modem7]

Find a recapping service and, if the price is right, have it done. There's very little risk in doing so.

For those who decide, for whatever reason/s, to avail themselves of the service, some considerations:

- Instruction to provider on scope. For example, only aluminium electrolytics.

- Is the service provider going to use the correct replacement parts? One example: They may simply use some 'replacement cap list for {object}' that is on the internet, not knowing that the {object} comes in slightly different variations, with some capacitors being of different values to values in the list, different for a good reason. (Fix: Instruction to provider is to 'replace same with same'.)

- Is the service provider going to test the {object} before shipping it back? If not (the likely case), and for some reason, the {object} no longer works (it was before), what is the resolution plan ?

- If the {object} is fully or partially analog, will the {object} require realignment on return?

 

[oldpcguy]

FWIW, I do maintenance on our vehicles and other equipment, as well as computer gear. But given the fragile nature of computer systems, I'd rather wait until a single component fails before picking up the soldering iron. Many custom ICs, for example, are unobtainium after a couple of decades; inadvertently damaging one can result in creating nothing more than e-waste when one previously had a functional computer.
After all, a 386 system isn't that old--and old systems are infinitely more repairable than modern ones with their tons of SMT and custom silicon--and lead-free solder.

We're not talking about custom ICs. We're not talking about FPGA chips. We're not talking about PGA chips. In fact we're not even talking about multi-pin through hole ICs. We're talking run of the mill, two leg, through hole capacitors. Unless there's some special circumstance these things a dirt easy to replace with minimal, dare I say almost no risk, to replacing them. Especially for someone who does it as a service.

 

[oldpcguy]

I did not recap the motherboard. A recap of the motherboard was too high a liability for a board outside of the early 2000's capacitor issues and the board as-is was passing burn-in tests. Plus even with a recap there was nothing that said I would be back here having to recap again in 20 years, so why risk damage to the plated vias?

What made it too high of a liability? Maybe if you're talking about SMD caps (which aren't that difficult to replace either) but two leg, through hole?

 

[Chuck(G)]

We're not talking about custom ICs. We're not talking about FPGA chips. We're not talking about PGA chips. In fact we're not even talking about multi-pin through hole ICs. We're talking run of the mill, two leg, through hole capacitors. Unless there's some special circumstance these things a dirt easy to replace with minimal, dare I say almost no risk, to replacing them. Especially for someone who does it as a service.

Just saying that the old boards can get touchy. If the service botches the job, will they make good with an exact replacement? If not, why take the risk? Or will they take the universal mulligan and say "damaged in shipping".

 

[modem7]

Preventative maintenance (PM) is a large subject. There are even books written on the subject.

I don't pretend to have expertise, but to me, the following two statements are a gross oversimplification:
- "It it isn't broke, don't fix it."
- "Replace it because it's just going to break later on."

As I see it, the two main questions re PM are:
1. What is it that I am aiming to prevent?
2. Why am I aiming to prevent it (e.g. safety, reduce operational downtime, economic only, performance, criticality, ...)

'Different courses for different horses' comes into the equation. I know that the battery in my car will last between approx. 3 to 5 years. But I do not replace the battery every two years, and that is because it is expensive for me. I am going to wait until there are signs of failure. For me, if the battery just dies on me, my plan is to call in a mobile battery replacement service, but I do expect signs of imminent failure beforehand. Large mining companies with specialist vehicles probably do routinely replace the battery on a certain act of PM - they can easily afford it and it makes economic sense to do so. Am I going to get the air filter changed occasionally? Yes.

What would I do if I bought another 40 year old IBM PC from eBay ?

I know that the 'RIFA' capacitor in its power supply is a known high failure rate part, due to age. I know that if it fails, there will be smoke and a foul odour. There may even be some superficial damage (example). Does that concern me (repeat: me)? No, but I accept that it concerns others. If I happen to be in the power supply, I will replace the 'RIFA' capacitor whilst I am there. Until then, I (repeat: I) am happy to 'sit and wait'.

Now, had it been the case that failure of the 'RIFA' capacitor usually results in failure damage to other components in the power supply, then I (repeat: I) would see reason (economic) to proactively replace the 'RIFA' capacitor ASAP.

What about those notorious 10µF tantalum caps on the IBM PC motherboard? I know that if the just-acquired IBM PC has been sitting unpowered for many years, that there is a good chance that one (or a few) on the 12V rails is going to fail within hours of me powering up the computer for the first time. Maybe that will happen, maybe it won't. I know that once 'juice' has been flowing through those tantalums for a while, that the likelihood of failure drops VERY significantly, and once that happens, I do not believe that the failure rate is significantly higher than putting in new tantalums. Even if it is, it does not concern me. I (repeat: I) am okay with that situation.

Again, I ask myself the two aforementioned questions.

And if I decide that a particular PM action should/needs to be done, how do I ensure the adequacy/quality of the action?

 

[Chuck(G)]

Given that I don't (easily) see any aluminum wet electrolytics on the subject 386 board (I'll confess that there may one or two hidden by the power supply), that leaves two other types--the dipped tantalum and the ceramic decoupling caps. Like @modem7, it's been my experience that if a tant is going to blow, it's going to do it after sitting idle for years. And when one blows, the damage is easily repaired. Ceramic caps fail very rarely and aren't really worth thinking about. Re-capping the entire board is not likely to improve the long-term survival prospects materially.
Now the power supply is a different matter. SMPSU technology has greatly advanced since the system was new, with better silicon and regulation technology. Electrolytics in these PSUs are likely to age badly, mostly due to internal heating (high ripple frequency) and might well be replaced proactively. Or just junk the guts of the thing and use a modern design in the same box. I've run into my fair share of SMPSUs where the capacitors are little more than empty cans. Most of my older LCD monitors are ones given up as junk because of capacitor failure--inverter failure for the fluorescent backlights is legend. Repairing those was a simple task.

 

[NeXT]

What made it too high of a liability? Maybe if you're talking about SMD caps (which aren't that difficult to replace either) but two leg, through hole?

That board was selected for the job. If it worked, then I recapped it as PM and now it wasn't working I just wasted a dozen or so capacitors and a bunch of my time, plus now I have to put the job on hold until another suitable board could be sourced.

SMD caps are a whole other ordeal. If you have no intention of using the device and store it/put it on display, just pull them and leave a BOM inside the case if leakage is making you lose sleep at night.
When the mac community in their brain-fogged collective finally caught up to everyone else a decade ahead of them on the failures of SMD lytics one of the first choices was to replace them with tantalum because now you no longer had caps to leak anymore.
That worked, but now I'm starting to observe failures that seem to come down to people were sourcing and soldering in the cheapest tantalum capacitors they could find and some are starting to fail.
I just gave up fighting the SMD lytics. There's so much stuff here that's going to end up rotting away because you'll go insane trying to get it all recapped and prepared for future issues, then get screwed over by some other thing nobody expected.

 

[Timo W.]

Apparently several people here do not preventative maintenance / repairs on their vehicles and wait for something to fail before performing any work.

A vehicle can kill you if an important part fails. That comparison is so off that it is just ridiculous and kind of shows a lack of real argumentation.

Also, what's the deal anyway to always fight other people's opinions instead of just respecting them?

Find a recapping service and, if the price is right, have it done. There's very little risk in doing so.

I've seen the work of many "recapping services". No risk? Most of them do a terrible job. And, of course, no one will ever give you any warranty for their work.

What some people don't seem to understand: BECAUSE the system is important to him, he should not mess around with it. If e.g. the mainboard takes damage, you can't just go buy a new identical one and replace it (and if you could, it would lose its uniqueness - no longer being the actual part from his past).

In the end, he can do whatever he wants. Still, my opinion is to use the system, have fun with it, and not take the soldering iron to fix what is not broken.

 

[oldpcguy]

Just saying that the old boards can get touchy. If the service botches the job, will they make good with an exact replacement? If not, why take the risk? Or will they take the universal mulligan and say "damaged in shipping".

Because they work with higher voltages / current power supplies, especially older ones, tend to utilize thicker, heavier traces (at least the ones that I've serviced) compared to a logic board utilizing lower voltages / current to power the logic devices. I would not expect to find thin, closely spaced traces (such as those found for data signals) in a power supply which are much easier to damage. Every power supply I've serviced (granted, not more than half a dozen) has required me to turn up the temperature on the soldering station due to the thicker, wider, heavier traces. For anyone who knows how to replace power supply capacitors there is little to no risk of damage (barring special circumstances).

Why take the risk? As the OP mentioned, if the power supply fails there's the potential for it to send a significant amount of voltage to the logic board, even for a millisecond.

Again, if the OP didn't have a sentimental attachment then I would agree. But he wants to preserve this system, these specific components. Given the very low risk of damage due to two lead, through hole component replacement I think the OPs desire to have it recapped is reasonable (as long as it's performed by someone with the qualifications to do so).

 

[oldpcguy]

A vehicle can kill you if an important part fails. That comparison is so off that it is just ridiculous and kind of shows a lack of real argumentation.

I didn't say anything about "important" parts. There's very little risk of death if someone fails to change the oil. Or air filter. Or replace the timing belt,

Also, what's the deal anyway to always fight other people's opinions instead of just respecting them?

Fight other people's opinion? I hold a different opinion than the "other people" and people are fighting me for it. Why don't they just respect that I hold a different opinion and leave it at that? Or is it the most popular opinion is the one which is valid and other people's opinions are invalid?

I've seen the work of many "recapping services". No risk? Most of them do a terrible job. And, of course, no one will ever give you any warranty for their work.

What some people don't seem to understand: BECAUSE the system is important to him, he should not mess around with it. If e.g. the mainboard takes damage, you can't just go buy a new identical one and replace it (and if you could, it would lose its uniqueness - no longer being the actual part from his past).

In the end, he can do whatever he wants. Still, my opinion is to use the system, have fun with it, and not take the soldering iron to fix what is not broken.

See, here you are fighting me on my opinion. If I respond am I fighting with you? Or just expressing my differing opinion? (That's a rhetorical question as we already know the answer from your comment above)

As someone who does recapping, including a few power supplies, I find the "other people's" reasoning against proactively recapping a functional power supply weak and I expressed that opinion. Apparently I am prohibited from doing so and must follow the group think.

 

[oldpcguy]

That board was selected for the job. If it worked, then I recapped it as PM and now it wasn't working I just wasted a dozen or so capacitors and a bunch of my time, plus now I have to put the job on hold until another suitable board could be sourced.

I'm having a difficult time understanding why it wouldn't work unless you don't know what you're doing. Below is a picture of an Apple II power supply I recently recapped (all electrolytic capacitors). As you can see it has heavy, thick traces (this is the low voltage side of the PCB. You'd really have to not know what you're doing to damage it. I don't even use my Hakko desoldering tool, just a soldering station and a solder pull-it. IMO the risk of recapping this power supply is very, very, very low.

That said if we weren't discussing a system which has sentimental value then I would agree, no reason to do so. If it should fail and damage the rest of the system so what? Just get replacement parts. But we're not, we're talking about someone who wants to keep this system, these parts. In this instance the parts are irreplaceable so I see recapping as a very low risk way to protect them.

EDIT: Forgot the picture.

 

[tradde]

Everyone will have different views on how to handle this (re-capping or not). I respect your views on doing it as that is your decision. I also respect those that say don't unless it's needed. In the end the OP will have to decide based on all these suggestions and do what he feels is correct. There is no perfect solution here. You do nogt have to follow "the group think".

 

[seaken]

It is always hard to sort out what to do when there are only opinions and no empirical data supporting one way or the other. To @mechaniputer, you have a working computer, right? Are you willing to risk it becoming a non-working computer after turning it over to an unknown "service" company? What if something does go haywire while recapping?

If I were you I would take it into my own hands and learn to solder and repair the caps. And then only do so when necessary. If it's working now it will probably be fine. But if you prepare yourself to fix it if it does break then you will be better off. If you send it out send it to someone who respects your views on it's value and who will protect your interests and not just be careless. You may have to do quite a bit of research to find such a service for that equipment.

I have a couple of systems that I would like to have working. Both were among the first computers I owned. I made an attempt at fixing the batteries on the Tandy 1400FD laptop but it did not fix the machine. I am hesitant to try soldering until I know more about what I am doing. It would be a shame to send the wrong voltages to the wrong place on accident because I didn't have enough knowledge. I am still considering what to do and I understand your concerns. But my machine is NOT working. Yours is working. Now would be the time to learn how to repair your own equipment, or learn to live without it working. I can put my original "first purchase" computer on display, even though I can't power it up. I have other PC's in that generation that do work so, for me, it is not that terrible that my "first" doesn't power up.

In the end it's up to you to decide, our opinions aside. Are you willing to spend the money? Are you willing to assume the risk? Do you have the time and inclination to learn to be your own repairman?

Best of luck to you and I hope your 386 keeps on ticking for several more years.

Seaken

 

[Chuck(G)]

Clearly, everyone has a view. I can only speak from experience--that extends more than 45 years of owning my own systems. And I have a bunch of old gear, not just PeaSees. There are some known rogues in the capacitor area, but in general, they're confined to wet electrolytics made after the PCB ban and some film capacitors (e.g. Rifa). I replace the start/run motor caps on my home's heat pump every 5 years, needed or not because a decrease in capacitance can result in eventual compressor problems. That's basically the rated service life of these things. If the caps were the old GE PCB Pyranol ones, that 5 years might well be 10. PCBs were that good--but abuse has led to a global ban. Power utilities have been struggling with that issue for years.

SMPSUs are a major problem, but generally, they don't fail from over-voltage (a good one has a crowbar circuit for that)--they either quit working or the output sags below spec. Repair or replacement generally results in a system working again. It's true that there are some really Muntz-like designs out there, but you pays your money and takes your choice.

 

[NeXT]

I'm having a difficult time understanding why it wouldn't work unless you don't know what you're doing.

I know what I am doing*. That doesn't mean someone else is as good as I am, or that I compared to someone else with considerably more experience and more expensive tools is what you would call "professional".
If it ain't broke, don't fix it.

As Timo also pointed out, recapping services are as Professional** as one believes. I don't offer it as a service, partly because I'm too busy maintaining my own hardware and partly because it's too high liability. You can tell them to learn but then you get into a feedback loop of feeling elitist and people actually trying and making a royal mess, not giving themselves a second chance then blaming you for making them try. Heathkit is pretty blunt about this in their old assembly guides, ironically.
Years ago on 68KMLA (yes I trash them a lot but there's a recurring pattern here) there was a member by the name of Uniserver who offered mac recapping as a paid service. You sent money and shipped the board in and you got a recapped board a few weeks later.
Problem is his work was poor and rarely was it graded as such because ultimately most recapping services exist to have money thrown at them by people who don't want to do it themselves. Some people would send in boards that kinda worked but jailbar'd and would get back boards that were recapped but didn't work at all. Some people sent in boards that didn't work but blew chimes and got back boards that worked but now there was no audio. Others sent boards out and got back a board for their mac, but a different serial number.
This operation ran like this for years because he could screw a pooch six ways from Sunday but if you didn't know better you still only saw the brain-fizzling "I sent my CC 1 board to him and it came back not working but he tried his best so I'm satisfied with this service" testimonials that kept him in business until site staff finally blew the lid on the operation and shadowbanned him. He ruined a lot of boards, made bank and was STILL considered a service until the dirty end.

(for the record my day job outside of the house and on a company payroll is that of a repair tech with a bench, supplied tools and a constant flow of boards that are recapped as per contracted preventative maintenance)

 

[RetroHospital]

After 3 pages, and has Minuszerodegrees stated, there is just no "standard answer".
I've done both "shotgun recapping" or just "leave it like it is" on my systems.

Fully agree with "what are you trying to achieve" here, and I would add "what are your technical skills".

Usually I do a full recap (and not only that but cleaning, aligning, etc) on my unusual/rare/oldest units.
The ones that are unlikely to pop up every day on ebay. I don't care what people say, I want these units to work for the next generations (my children). And yes I'm blindly recapping them, with the best quality parts I can find.

I also do a recap (but not much more than that) on capacitors that are known to leak (surface mounted electrolytics from the 90s, i'm looking at you), but I also try to figure out what they do. If they are part of a power circuit I always replace them, having bad filtering is likely to kill unique fpga or other parts. Sometimes they are just used to filter the audio output - typical on macs - so this is less critical and it's in the "do it when everything else has been fixed" bin. But if it has a chance to leak corrosive juice, it's always worth replacing imho.

For some units I just wait and see. 90s and newer stuff mostly. Stuff that you can easily find on ebay, that has been produced in the hundreds of millions, and that is generally considered e-waste by anyone else but me. It's also usually a good idea to collect spare parts for those "cheaper" systems - while they are cheap.

My 2 cents on the "recapping" debate