Recapped and played a MT-32. It sounds a lot clearer and sharper. I put two higher voltage rated caps at input filter C40, C41 and somehow the voltage regulating MOSFET on the right wall gets hot at the first power up. After some minutes of playing, it cools down to a slightly warm temp. I suppose it's time to replace the MOSFET with a resilient, modern component.

Other than that, it looks to be back in its old place.

Dark Forces every two weeks. That's brutal. Like, sewer garbage brutal.

brownk wrote on 2020-06-20, 08:37:

MT-32_recap.jpg

Recapped and played a MT-32. It sounds a lot clearer and sharper. I put two higher voltage rated caps at input filter C40, C41 and somehow the voltage regulating MOSFET on the right wall gets hot at the first power up. After some minutes of playing, it cools down to a slightly warm temp. I suppose it's time to replace the MOSFET with a resilient, modern component.

Other than that, it looks to be back in its old place.

The current is much higher immediately after power up because the various capacitors in the circuit are charging up. Large capacitors, when they are fully discharged, act almost like a short circuit. So I suspect this behaviour is normal and has nothing to do with the voltage rating of the capacitors. If the old caps were dried up, the inrush currents were probably much lower before the recap.

ShovelKnight wrote on 2020-06-20, 11:01:

The current is much higher immediately after power up because the various capacitors in the circuit are charging up. Large capacitors, when they are fully discharged, act almost like a short circuit. So I suspect this behaviour is normal and has nothing to do with the voltage rating of the capacitors. If the old caps were dried up, the inrush currents were probably much lower before the recap.

Thanks for clearing up, especially the depleted large cap part. It blew some sense into my mind.

I thought new caps were charging up and the voltage regulator was overloaded. Naturally, I was ready for something to pop but everything went ok, fortunately.

Folks recommend running an audio unit about 3~4 days nonstop after a cap replacement to age and check the new caps. I'll probably do that to make sure everything is rock solid.

xcomcmdr wrote on 2020-06-20, 10:49:

Dark Forces every two weeks. That's brutal. Like, sewer garbage brutal.

Nah, I've reached a Zen-like state with those two games. I'm not speedrunner fast, but I also don't have to think much to get through them. It's to the point that both games barely last three hours each for me, even when I watch the cutscenes.

darry wrote on 2020-06-20, 05:00:

Long shot :
Try toggling PCI/VGA Palette Snoop in BIOS .

Unfortunately, no dice - It’s already turned on. I am trying to see if firing up an SVGA/VESA app first will initialize VGA correctly. If that doesn’t work I’ll need to hunt down a cheap single-head Savage4IX/MX PCI card. Barring that, maybe a Vanta TNT2 PCI card. The strange thing is that the VGA init issue only impacts the Igel-J thin client...I don’t see the same artifacts on my Via Epia boards.

Got my VLB 486 setup on the test bench and running. Feels really awsome to get it up and running again as this board was previously in storage.

Anyone get freaked out by these balloon caps though? I sware everytime I see one looking bulgy I imagine it erupting right as a game is getting good. It just looks so...unhealthy? Guess it might be time for a recap soon?

SodaSuccubus wrote on 2020-06-20, 22:06:

Got my VLB 486 setup on the test bench and running. Feels really awsome to get it up and running again as this board was previously in storage.

Anyone get freaked out by these balloon caps though? I sware everytime I see one looking bulgy I imagine it erupting right as a game is getting good. It just looks so...unhealthy? Guess it might be time for a recap soon?

I was just installing a few games into my 486 VLB setup, still need to add a sound card, has been a slow build. Here is a pic from last week when I added a fan to the DX100 ODPR
Re: Intel 486 DX4ODPR100 runs very hot
Those Tantalum caps can blow, usually when you first turn on the computer.

SodaSuccubus wrote on 2020-06-20, 22:06:

Anyone get freaked out by these balloon caps though? I sware everytime I see one looking bulgy I imagine it erupting right as a game is getting good. It just looks so...unhealthy? Guess it might be time for a recap soon?

that's just how they look though 😁

tantalum caps are very durable, as in they don't leak and they last very long... but if they fail, they fail spectacularly ^^

imi wrote on 2020-06-20, 22:30:

SodaSuccubus wrote on 2020-06-20, 22:06:

Anyone get freaked out by these balloon caps though? I sware everytime I see one looking bulgy I imagine it erupting right as a game is getting good. It just looks so...unhealthy? Guess it might be time for a recap soon?

that's just how they look though 😁

tantalum caps are very durable, as in they don't leak and they last very long... but if they fail, they fail spectacularly ^^

Are more recently produced ones as likely to fail after 30 or so years as those from the 80s (and as spectacularly), or have manufacturing techniques improved ?

imi wrote on 2020-06-20, 22:30:

darry wrote on 2020-06-20, 23:14:

that's just how they look though 😁
tantalum caps are very durable, as in they don't leak and they last very long... but if they fail, they fail spectacularly ^^

Are more recently produced ones as likely to fail after 30 or so years as those from the 80s (and as spectacularly), or have manufacturing techniques improved ?

I think the new ones last the same as the old ones, about 35-40 years or more if used regularly. Like Electrolytics their life span is increased by normal usage, if rarely used they will breakdown internally in 20 years or less and internally short. Electrolytics can last 20-30 years or more but break down in 5 years or less if not used and become open, making them safer but with shorter lifespan than Tants. That is why you see a Tant blow on an old board: has not had power applied for quite a while or often enough and the dialectric breaksdown. That is all I know though have heard that some equipment from the mid-late 70's using Tants still work perfectly 50+ years later.

Horun wrote on 2020-06-21, 01:05:

I think the new ones last the same as the old ones, about 35-40 years or more if used regularly. Like Electrolytics their life span is increased by normal usage, if rarely used they will breakdown internally in 20 years or less and internally short. Electrolytics can last 20-30 years or more but break down in 5 years or less if not used and become open, making them safer but with shorter lifespan than Tants. That is why you see a Tant blow on an old board: has not had power applied for quite a while or often enough and the dialectric breaksdown. That is all I know though have heard that some equipment from the mid-late 70's using Tants still work perfectly 50+ years later.

This.

Be scared of any old computer that hasn't been powered up for years and years. It may be ready to pop 😀

canthearu wrote on 2020-06-21, 07:15:

This.

Be scared of any old computer that hasn't been powered up for years and years. It may be ready to pop 😀

Yup, Famous magic smoke! and most of the time it is caused by the usual suspects 😀 Oh and don't forget to take into account any power grid changes through the years...
Most old PC's I've had were rated to 220 max + an extra bit of headroom of a few %, nowadays we run 230v mains. It's become standard to upgrade some PSU components first before powering up. Even with the extra %, most are already close to 230v max tolerance when the components were brand new... let alone when they faded and degraded...

I have never seen a PSU that was not marked 220-240V.

Horun wrote on 2020-06-21, 01:05:

imi wrote on 2020-06-20, 22:30:

darry wrote on 2020-06-20, 23:14:

that's just how they look though 😁
tantalum caps are very durable, as in they don't leak and they last very long... but if they fail, they fail spectacularly ^^

Are more recently produced ones as likely to fail after 30 or so years as those from the 80s (and as spectacularly), or have manufacturing techniques improved ?

I think the new ones last the same as the old ones, about 35-40 years or more if used regularly. Like Electrolytics their life span is increased by normal usage, if rarely used they will breakdown internally in 20 years or less and internally short. Electrolytics can last 20-30 years or more but break down in 5 years or less if not used and become open, making them safer but with shorter lifespan than Tants. That is why you see a Tant blow on an old board: has not had power applied for quite a while or often enough and the dialectric breaksdown. That is all I know though have heard that some equipment from the mid-late 70's using Tants still work perfectly 50+ years later.

I've been reading up on capacitors lately, and electrolytics could need reforming if unpowered for a very long time, but tantals usually shouldn't according to most of what I found... yet I wonder if this could remedy the failure upon first power up anyways, if you first apply low power to the board so capacitors can reform?

appiah4 wrote on 2020-06-21, 10:05:

I have never seen a PSU that was not marked 220-240V.

How old are the oldest PSUs that you've seen? 😜
I got a couple marked at 230v btw.

Tetrium wrote on 2020-06-21, 13:00:

appiah4 wrote on 2020-06-21, 10:05:

I have never seen a PSU that was not marked 220-240V.

How old are the oldest PSUs that you've seen? 😜
I got a couple marked at 230v btw.

The Tulip PC Compact and the Tulip PC Extend both have PSU's rated at 220 VAC 50 Hz. They are from 1984-1985 ish. They worked fine, for a few seconds 😀

Just got a piece of dream hardware for me, an Apollo 1260 @ 80Mhz. Been playing with that for the last day since I got it. Lots of fun!

download/file.php?mode=view&id=86454

download/file.php?mode=view&id=86453

Shagittarius wrote on 2020-06-21, 16:28:

Just got a piece of dream hardware for me, an Apollo 1260 @ 80Mhz. Been playing with that for the last day since I got it. Lots of fun!

download/file.php?mode=view&id=86454

download/file.php?mode=view&id=86453

Awesome Amiga! 😁 Lots of good games and demos to be had.
I'v always drooled over owning a souped up A1200 but I just can't fathom the ludicrous prices they apparently demand on Ebay.

Damn ! That's a very good piece of Amiga hardware !

Back 8 years ago, I had gotten a Blizzard 1230 IV with 8 Mb of EDO RAM and a FPU for €200.
Now it's around €800.
Don't even think about a Blizzard 1260 or any 68060 based accelerators.

eBay prices are gouged up to eleven and beyond. Disgusting.