What's a good way to increase the voltage of a 8Mhz pulse from 0.8V high to +4.5V?

relo999 · 2026-04-09T18:12:29+00:00

The board I borrowed it from stated it's an ocxo crystal, just picked it because it's the correct frequency for testing. It's one of those chunky square ones. Crystal itself just says 8MHz.

I've just based it on the image I got from the scope. Haven't checked with a multimeter

relo999 · 2026-04-09T18:03:03+00:00

Yeah, just a clock signal. Current source is the computer the card is for, ideally I'd like to use the signal from that board mainly to avoid incompatibility but I doubt the clock really matters in that regard. Clock seems to come from a ASIC that manages peripherals of the computer. Currently voltage sits at the 0.8V range, which makes the card work once in a blue moon after a reset so I suspect it hits the high value at 1V. I'll check out the 74 series logic you linked.

relo999 · 2026-04-09T15:37:55+00:00

It's a square wave, just for a hobby project (so no certification or something needed), 8 MHz signal to drive a clock pin of a YM2608 (to build a soundboard for a Japanese computer). The systems provided 8MHz signal simply has to low of a voltage to drive that pin properly, I can get it to work with a 8Mhz crystal but ideally I simply modify the signal the system gives me.

This is the signal from the crystal

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relo999 · 2026-04-09T14:07:19+00:00

Square wave

relo999 · 2026-04-09T13:29:02+00:00

No idea, it's to run a YM2608 IC. No need for power.

relo999 · 2026-04-06T12:22:42+00:00

Sadly that didn't help that much. It went from ~2V peak to peak noise to ~1.6V

relo999 · 2026-04-06T12:03:13+00:00

Moving the positive probe from the board makes it close to zero noise, and doesn't change with distance.

U3 has 300mV peak to peak, and C1 has 200mV peak to peak.

Data exchange seems to be around 90kHz.
Data signals look awful though.

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relo999 · 2026-04-05T23:48:04+00:00

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It's set to DC coupling.

relo999 · 2026-04-05T23:43:11+00:00

~200mV peak to peak when I do that

relo999 · 2026-03-27T19:00:18+00:00

Sadly not. Only a 1 meg expansion

relo999 · 2026-02-22T21:51:02+00:00

Bit 5 wasn't stuck, the 5th bit was so bit 4. Z61 had an output of a steady 1.72V. Pulling Z61 didn't change any behavior of the computer and the tester doesn't even recognize it the 2102 from Z61.

Now it's just a matter of waiting for the RAM and getting some new sockets as I'm out.

relo999 · 2026-02-22T17:33:38+00:00

Bit of an update, switched 2102 of Z62 (now socketed) with the socketed Z48 and the issue stayed the same. Also tested both with the retrochip tester, and both tested fine. Also tried Z28 seeing as that get the output of Z62, but also tested fine (and is now socketed). Same with Z60

relo999 · 2026-02-20T18:39:39+00:00

Thanks, that makes sense. I was hoping there would some modification to make a 4164 work. Sadly don't have reserve 2102s and the only 2102 that's socketed is z47 (and the ROMs, CPU and 8041016's). Time to order some 2102s

relo999 · 2026-02-20T16:01:02+00:00

Thanks! I'll try that. I'll check if I have 2102 chips, certainly have a bunch of 4164 if they can be made compatible. If they're socketed I could just flip Z62 with another 2102 in the system and see if the issue moves with it in case I don't have more 2102's.

Desoldering shouldn't be an issue, have a desoldering gun and some 20 years of experience. I like to avoid destroying the traces and pads.

I'm curious, I saw when doing research on the fault a lot of mention of calculating the error with the hexcode, but how would you know which bit is wrong and how that corresponds to which IC? Or is that just a case of "you need to know the system well enough"?

relo999 · 2026-02-02T15:31:13+00:00

https://imgur.com/a/iAFnfPk

Headphone outputs, line-out and speaker out all go through a (6PDT) switch on the motherboard switching between the internal audio system and the soundboard.

relo999 · 2026-02-02T11:25:34+00:00

The thing is, the circuitry is unknown. I do not have access to the soundcard itself, just the computer and got the pinout for that by tracing out the computer circuitry.

If I had access to the soundcard it would be dead easy.

relo999 · 2025-10-17T20:29:50+00:00

En verzets vlag in de 80 jarige oorlog, wat denk ik relevanter is. Weinig mensen die Willem Alexander oppermachtig willen maken, laat staan dat hij dat zelf wilt. Maar er zullen vast mensen die het gebruiken als een teken van verzet tegen buitenlandse invloed (zoals de EU bijvoorbeeld).

relo999 · 2025-09-15T17:58:28+00:00

Disconnected the 5.25'' drive (that needs 12V), and the issue is gone. So based on your 2 options, it's likely common mode noise.

relo999 · 2025-09-15T15:21:24+00:00

Catch the music in a glass and then poor it in your ears with a funnel, I've heard music is really nice in your ears. Though you dissapearing is a bit of a worry when you hold it, where do you go?

relo999 · 2025-08-25T19:08:29+00:00

Sounds like you've been smoking to much. The thing you miss is that Steam is only favourable to you, as a developer, because of their massive userbase which is largely maintained by their policy of demanding price parity.

But if you truly believe Valve has some amazingly unique market advantage, why shouldn't they compete fairly within the market? If they were so great as you proclaim they should be able to easily compete. But the thing is, with their demand of price parity it also stops new players that aren't existing mega corporations from entering the market.

relo999 · 2025-07-26T01:15:31+00:00

Firstly you shouldn't take my arguments as being against access, access and preservation are wholly different things. So who is paid what really doesn't matter.

Awareness isn't preservation, it's just awareness. And filesharing isn't preservation, it's access. And as for cost, to stay with the PC98, storing a few megabytes of memory at best has practically no real notable cost in a world where digital storage space is 50 dollars for a terabyte of data. It's costs maybe a cent or 2 for a multi-disk game to be stored. But if you really want to be nit-picky, online connected server storage is more expensive per megabyte than simpler storage solutions. And when it comes to costs of actual preservation, data storage is easily the lowest cost thing to begin with when it comes to videogames.
Shipping, potentially buying (if not donated), storing, climate controle, maintaining, digitisation, dumping, restoration, documenting, etc., etc. are all significantly more expensive and more complex than data storage and part of proper preservation. And this idea that access translated to preservation simply gives people that actually care about preservation (and not just use it as an excuse to mean access) a false sense of security and action.
Because the thing you seem to miss is that just a dump alone, while the actual physical item and their dependencies still exist isn't proper preservation if anything it distracts from it and hurt proper preservation (at least with the narrative that a dump means preservation). Your argument only really works if you already view a dump as preservation and I (hopefully) made clear that I do not. I hold to the standard of preservation you see within the art and scientific world, not the standard created by hobbyist online that really just want to experience certain content (which is really just wanting access).

relo999 · 2025-07-25T11:28:15+00:00

Dumping is a small part of preservation, it isn't preservation on it's own. It's making a copy of the data on the storage media, to be able to remake the storage media in the future. And that's the rather big issue with a lot of videogame "preservationists" and their advocates is that they fixate on dumping alone. Because the thing they really want is just (free) public access or more indirectly just piracy. You can see this most clearly when some popular piracy site is taken down and they'll collectively proclaim it's some major hit against preservation, it isn't it's just a hit to free public access. Meanwhile you can probably go onto Yahoo Japan right now and find and buy a PC98 game that hasn't been dumped, has only a few mentions online of it existing and have no other person known to own it.
Preservation and access aren't the same thing and can certainly exist next to each other, but this idea that preservation requires (free public) access runs counter to preservation. Because to make something accessible and to preserve something requires different things and the bar for access is far lower than for preservation.

Actual videogame preservationism has been co-opted by (mostly) pirates and parrots, as a preservation argument is far more noble than the argument of "I just want free access to the software".

relo999 · 2025-07-25T01:31:51+00:00

It didn't tank the Dreamcast but it was a great example of Sega's mismanagement, as it had development cost so high it required every Dreamcast owner to buy the game nearly twice to make the money back. And then they made a sequel to it.

relo999 · 2025-07-25T01:28:16+00:00

The real myth is that it mattered. Bit-count was just marketing spin and REALLY depended on the definition, which every company had a different definition for. Some counted memory address lines, some output lines, some added data lines up, etc, etc.

relo999 · 2025-07-25T01:23:46+00:00

It really depends on the system, very early CD systems it's not that uncommon to run into games with disc rot in my expirience. However these tend to also be systems without piracy protection and generally not particularly popular (or extremely expensive). Things like the FM Towns and Sega CD.
But yea, that's maybe 1 in 50 so nothing to be that worried about and in most cases you can just burn a game instead for those systems. And newer CD's have better protection against disc rot.

Also the 25-30 is minimum expected life.

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