Meatball wrote on 2022-01-16, 20:43:

Lots of “work” to do today testing recent hardware pickups and validating a few problems (such as fan headers and a SCSI CD Drive) on existing hardware.

There was a time when my kitchen looked like that.

Now it's all been relegated to the basement, where I reconstituted a Gateway 2000 486/33

Among other things, I'm working on the cache for a DEC 4/33 (66 upgrade) - I might work on it a bit later tonight.

Jed118 wrote on 2022-01-16, 23:14:

There was a time when my kitchen looked like that. […]
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Meatball wrote on 2022-01-16, 20:43:

Lots of “work” to do today testing recent hardware pickups and validating a few problems (such as fan headers and a SCSI CD Drive) on existing hardware.

There was a time when my kitchen looked like that.

Now it's all been relegated to the basement, where I reconstituted a Gateway 2000 486/33

Among other things, I'm working on the cache for a DEC 4/33 (66 upgrade) - I might work on it a bit later tonight.

Awesome... one of these days I will actually put together and keep it together a PC as nice as yours instead of testing the hardware and then putting everything away in a storage room.

Shreddoc wrote on 2022-01-16, 23:01:

The simple presumption is that, if such period hardware in viable condition is common, then ordinary market forces would flood t […]
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TrashPanda wrote on 2022-01-16, 06:04:

Sat back and watched an Auction for a 386 machine go for a whopping $400 AUD ...thats just the box, no cables, monitor, paperwork or accessories. Saw nothing particularly special about it either, 4mb of ram and a 10meg HDD that was just a nasty Maxtor IDE with a rather common 386SX in it.

I really dont get the stupid prices junk is selling for, especially junk as common as cockroaches, its only saving grace was a working 5.25 drive in it but that alone isn't worth 400 dollars.

The simple presumption is that, if such period hardware in viable condition is common, then ordinary market forces would flood the market with this so-called common junk, and prices would fall. There is no shortage of desperate people out there, who would instantly leap at the opportunity to turn junk into good money.

The very fact that isn't happening, is the best proof we currently have that such period hardware in viable condition is, in fact, not common at all. Anecdotal handfuls of the stuff scattered here and there is mere tiny peanuts, at the scale of humanity's 8 billion.

I can go into my local PC recycler right now, and their current regular throughput involves literal shelves and shelves full of dozens if not hundreds of HP/Dell/etc 2000's and 2010's generic black boxes... and along with that, at most a mere handful of pre-Pentium PCs, if even that.

Comes a point with every limited production in history, and in this case especially, with the computer industry being so comparatively tiny pre-1995 - that a couple/few decades after production ceases, most of the product has been used, stored (for a limited time), (then eventually) thrown out, trashed, gone.

With old stuff of any description, there's a bit of hysteresis or a yoyo effect on pricing as it goes upward. There will be one or two items hitting "headline" prices, which then wakes up the market and has everyone digging in their basements and closets such that temporarily supply is increased. So then we get a slight glut and prices fall after the early birds make bank, however, all that is more or less "consumed", it's still out there but has mostly reached it's forever homes, not a lot destined for resale when prices high. So after that glut is taken up, then prices take a steady upward march as less and less pieces get discovered and only of the few previous sales shake out again for modest profits, or 'coz ppl got bored of it, or have to liquidate for other reasons. That's where most of the Voodoos are now I think, with only maybe the Banshees still in a bit of a transition where ppl starting to care about them and dig them out. Pentium to PIII class is probably entering the yoyo zone now, there's been awareness of 486 and prior being maybe "worth something" for a couple of years now and most of those should be shaken out of the woodwork.

I gave up on this NEC SCSI drive. I tried 3 different HBAs (one DTC, one Media Vision Pro Audio Spectrum, and finally the Adaptec AHA-2940UW). The former 2 ignore the drive completely, and the latter hangs up during scan. I tried reversing the cable (only had 2 ends), changing SCSI IDs (1 and 3). Nothing. There’s no setting for termination, so it must be passively terminated internally. I looked for some information on the jumpers, but only the 1st three are usable (for ID). The rest are factory reserved for testing).

I reached out to the eBay seller to see if it can be replaced. This person seems to be a good guy (even if I can’t get a replacement).

I have a small mountain of synthesizers that I have been going through by recording various tracks so that I can compare their outputs. I've read a lot of information about different versions are based on what and other firmware oddities so I want an actual record that I can quickly pull out and listen to so that it can confirm some things for myself. Some of my assumptions based on model numbers were wrong and have led to the purchasing of duplicate units with different casings. I want to identify these so I can sell them off to optimize the size of my collection.

This has involved a rabbit hole of purchasing hardware, setting up software, and learning about the nuances of synthesizers such as having to reset them between tracks so that configuration from a previous file doesn't bleed into the next.

I'll be sharing all of my findings and sample recordings in a thread on the Sound subforum once I'm finished.

Fired up the old late DOS machine, started Doom2 and made sure the MIDI interface was hooked up.

Nothing special - other than that it wasn't for me. Walked in on my son proudly showing he'd found Doom on steam and was playing it on his modern computer with 4k monitor and pretty weedy sounding MIDI interpretation. Very proud dad moment, but had to do better than that, so led him downstairs into the retro cave.

Last I heard he was combining MT-32 (with GM 😦 ) and my SO's electric piano while getting killed by everything UAC allowed to infest the worlds with. He'll probably be able to out-play me by the end of the week 😉

dionb wrote on 2022-01-17, 18:21:

He'll probably be able to out-play me by the end of the week 😉

Build him a 386sx25 Doom rig and network it to yours. 🤣

Today I upgraded a Diamond Monster Sound MX300 with some bigger and better caps (Panasonic FR series all the way) and a new op-amp. It was originally equipped with a JRC 074 which is a clone of the TL074. While the TL074 is generally considered a good op-amp, the JRC clone seems to be mediocre at best. So while I was at it, I put in an OPA4134UA. It comes in an SOIC-14 package, so hand-soldering was a bit of a challenge, but it worked out quite well. I am not very experienced with this kind of sound card mods, so I am curious to see (or hear) how much of a difference it makes.
Some might consider it a no-go to make mods like this to a perfectly fine and somewhat rare card, but I have three of them in my collection by now, so I thought it wouldn't hurt to do some experiments with one of them.

BitWrangler wrote on 2022-01-17, 16:22:

Shreddoc wrote on 2022-01-16, 23:01:

The simple presumption is that, if such period hardware in viable condition is common, then ordinary market forces would flood t […]
Show full quote

TrashPanda wrote on 2022-01-16, 06:04:

Sat back and watched an Auction for a 386 machine go for a whopping $400 AUD ...thats just the box, no cables, monitor, paperwork or accessories. Saw nothing particularly special about it either, 4mb of ram and a 10meg HDD that was just a nasty Maxtor IDE with a rather common 386SX in it.

I really dont get the stupid prices junk is selling for, especially junk as common as cockroaches, its only saving grace was a working 5.25 drive in it but that alone isn't worth 400 dollars.

The simple presumption is that, if such period hardware in viable condition is common, then ordinary market forces would flood the market with this so-called common junk, and prices would fall. There is no shortage of desperate people out there, who would instantly leap at the opportunity to turn junk into good money.

The very fact that isn't happening, is the best proof we currently have that such period hardware in viable condition is, in fact, not common at all. Anecdotal handfuls of the stuff scattered here and there is mere tiny peanuts, at the scale of humanity's 8 billion.

I can go into my local PC recycler right now, and their current regular throughput involves literal shelves and shelves full of dozens if not hundreds of HP/Dell/etc 2000's and 2010's generic black boxes... and along with that, at most a mere handful of pre-Pentium PCs, if even that.

Comes a point with every limited production in history, and in this case especially, with the computer industry being so comparatively tiny pre-1995 - that a couple/few decades after production ceases, most of the product has been used, stored (for a limited time), (then eventually) thrown out, trashed, gone.

With old stuff of any description, there's a bit of hysteresis or a yoyo effect on pricing as it goes upward. There will be one or two items hitting "headline" prices, which then wakes up the market and has everyone digging in their basements and closets such that temporarily supply is increased. So then we get a slight glut and prices fall after the early birds make bank, however, all that is more or less "consumed", it's still out there but has mostly reached it's forever homes, not a lot destined for resale when prices high. So after that glut is taken up, then prices take a steady upward march as less and less pieces get discovered and only of the few previous sales shake out again for modest profits, or 'coz ppl got bored of it, or have to liquidate for other reasons. That's where most of the Voodoos are now I think, with only maybe the Banshees still in a bit of a transition where ppl starting to care about them and dig them out. Pentium to PIII class is probably entering the yoyo zone now, there's been awareness of 486 and prior being maybe "worth something" for a couple of years now and most of those should be shaken out of the woodwork.

Good insight. I can see how that effect would be true.

I think your quote "mostly reached .. forever homes" is also an important factor. Many retro enthusiasts already went through the loss of all their (original) old gear, due to life's phases. That is exactly why we are having to re-buy all these things (+ a lot more) now in the modern era, 20+ years later. Because we regret that we no longer have the computers we grew up with and which meant so much to us, especially with hindsight and nostalgia.

Now that we have obtained those old PCs back again - and with so much less of our own lives remaining in front of us - we are adamant that we will not make the same mistake again. This time, we will keep and fully appreciate the eras of PCs we enjoy. We will not risk being 10-20 years into the future, having a personal retro resurgence, and having to face a 10x market again. I've got what I want, and now I'm keeping it thanks! 😀

I expect that sentiment is echoed by quite a few people like me. Net result: the remaining old gear is actively filtering down to people who intend to keep it, and thus a 'permanent' (human lifespan!) supply reduction is in constant effect.

With the rate of supply reduction for a given item being defined by current trends.

gex85 wrote on 2022-01-17, 20:28:

Today I upgraded a Diamond Monster Sound MX300 with some bigger and better caps (Panasonic FR series all the way) and a new op-amp. It was originally equipped with a JRC 074 which is a clone of the TL074. While the TL074 is generally considered a good op-amp, the JRC clone seems to be mediocre at best. So while I was at it, I put in an OPA4134UA. It comes in an SOIC-14 package, so hand-soldering was a bit of a challenge, but it worked out quite well. I am not very experienced with this kind of sound card mods, so I am curious to see (or hear) how much of a difference it makes.
Some might consider it a no-go to make mods like this to a perfectly fine and somewhat rare card, but I have three of them in my collection by now, so I thought it wouldn't hurt to do some experiments with one of them.

Looks OEM! Very nice.

BitWrangler wrote on 2022-01-17, 19:13:

dionb wrote on 2022-01-17, 18:21:

He'll probably be able to out-play me by the end of the week 😉

Build him a 386sx25 Doom rig and network it to yours. 🤣

No room on his desk with all the Wii-U modding he's doing - not bad for a 9-year old 😉

I had the Amiga500 that I bought on the desk for service today. And yes, it is indeed a full ECS version of the non-Plus machine. Commodore never build this revision with battery, and it can be converted to full Plus if I want to. However this is not for modding at all. I have done a Plus convertion on my first 8a.1 machine.

However as cheap as it was, then it was NOT in working condition, as described by the seller. I suspect the seller had it powered on, but not tested. Power led activating is not the same as working. The machine had two things wrong with it. The first was the trapdoor memory module that was faulty, and the other was the floppy drive. I threw the mem module out and I have saved the drive for later, to see if I can fix it.

I installed a stock PC drive and connected my last PC-Amiga floppy drive converter cable between the drive and the board. And I installed an a512 Ram module that Individual computers have manufactured. So now I have a working Amiga500 Rev. 8a.1 with everything working. I will buy a gotek solution for this one, with a bracket that have a fake eject button, and then have the oled and selector switch on top of the grill. And do the same with an RGB-to-HDMI solution. Those two mod are non destructive to the case it self. Going to keep it as close to original as possible.

Ended up running memory test one hour, then watched 10 demo's. 100% stable and no issues.... Sweet!!!! 😜

More synthesizer work today. I finished repairing my Roland SC-55mkII and have to redo a bunch of recording for a larger comparison I'm working on.

I found some corrosion that had occurred due to the epoxy used during manufacturing. I still need to open up and check all of my other synthesizers for damage when I'm finished.

That under-capacitor epoxy or whatever it is, seems to really suck over the long term. Mine did freaky things too.

I still have some doubts about exactly what it is - that is, I would like to definitively know it's chemical composition and purpose.

Tan looking glue that sometimes turns black and becomes conductive and corrosive? That's not epoxy. Epoxy is non-reactive when cured and this is very reason this similar epoxy also used for potting HV transformers windings.

Cheers,

Maybe it's a silicone adhesive. I think its purpose is to dissipate vibrations from large components and redirect them away from the solder joints.

I'm currently playing "find the broken cache chip" with an Elitegroup 4980 (which doesn't seem to want to accept my DX4/120, seeing it as a 100 MHz) and I found a bad one already. Hopefully this will work in my DECpc...

Kahenraz wrote on 2022-01-19, 00:42:

Maybe it's a silicone adhesive. I think its purpose is to dissipate vibrations from large components and redirect them away from the solder joints.

Could be, if they chose the wrong one, it releases acetic acid as it degrades, then the black color would probably be black copper oxide as it eats into traces.

I've examined all of my synthesizers and even my SC-88VL which has a similar layout but uses what appears to be a different kind of adhesive material on this capacitor. You may be correct that this was an error during manufacture of my SC-55mkII.

My much older CM-32L also uses some kind of adhesive under it's large capacitors but they have not caused any corrosion to either the PCB or any traces.

Kahenraz wrote on 2022-01-19, 00:42:

Maybe it's a silicone adhesive. I think its purpose is to dissipate vibrations from large components and redirect them away from the solder joints.

Though sometimes the silicone is used on coils to keep them from vibrating, in this case I think it's just to keep the larger capacitors in place during the wave soldering process.

I think all SC-55mkII use this brown adhesive (at least mine and a few others I've seen do), I never really wanted to mess with it as it works fine but your findings on the other thread are interesting.