Re: Commodore 64 video problems

Posted on 2021-10-15, 10:03

by

by Deunan

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Remove means exactly that, there should be no wires or breaking anything. These parts are located inside the metal box of the TV modulator, and could be SMD (if only because these take less space).

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Re: Gotek like Optical Driver Emulator - Is it possible?

Posted on 2021-10-14, 21:03

by

by Deunan

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

cheeky, probably same reason ordering gdemu is a smooth and easy experience :) Depends who you ask I guess. I'd argue I have a few happy customers, I take you aren't one. FYI you can hack together an IDE interface with a decent AVR, you don't need ESP32 cores for that. It's not fast and doesn't …

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Re: Gotek like Optical Driver Emulator - Is it possible?

Posted on 2021-10-14, 11:12

by

by Deunan

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

you mean like this https://cdn.hackaday.io/files/20774888794816/NetPi-IDE_PoC_schematic.pdf? not quite dumb, but not rocket science either. Lets not make a big deal out of a couple 245 buffers. Take another look. I think you missed an FGPA - with all the logic in it. So no, not just a couple of ' …

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Re: Gotek like Optical Driver Emulator - Is it possible?

Posted on 2021-10-14, 10:06

by

by Deunan

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Just a reminder that SCSI was introduced in '86 and predates ATA. Also, what SCSI level, surely not the Ultra modes? If you keep to SCSI-1, or subset of SCSI-2, then I'd argue it is easier. Reason being each transaction is always ack'ed so if you can't keep up it will simply slow down the transfer, …

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Re: Gotek like Optical Driver Emulator - Is it possible?

Posted on 2021-10-14, 08:59

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by Deunan

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

I have an ESP32 developer board that has both 3.3V and 5V inputs. No magic smoke has escaped using just 5V. I've also powered Pis without issue with 5V through the GPIO. I think you are confusing powering something with 5V vs having 5V I/O. Not the same thing. Also any ESP32 dev board you might …

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Re: Gotek like Optical Driver Emulator - Is it possible?

Posted on 2021-10-13, 23:08

by

by Deunan

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Thanks for being another voice of reason in the thread. 2-4X should work for the really old retro PCs. For you. It would work for you. Not all people with retro PCs. What is a "retro PC" anyway, I've just had a discussion on P4 mobo capacitors and these systems already had SATA on them. And while …

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Re: Gotek like Optical Driver Emulator - Is it possible?

Posted on 2021-10-13, 17:36

by

by Deunan

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

The ATA/ATAPI glue logic is difficult to get right, yes, especially for high-speed modes. But there're also more subtle issues that people who never tinkered with such things don't even consider. First, the interface is 5V based, and all modern PLDs and FPGAs are 3V3. Not even 5V tolerant, and that …

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Re: Commodore 64 video problems

Posted on 2021-10-13, 17:17

by

by Deunan

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Yes. In fact if you take all of those out then S-Video will be the only thing you'll have. If you want to try and mod the modulator then you can either remove (actually, just lifting one pin is enough) C6 or R8, that's the minimal change required to disable mixing of the luma and chroma signals. …

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Re: Commodore 64 video problems

Posted on 2021-10-13, 12:45

by

by Deunan

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

In essence, this: https://github.com/tebl/C64-Modulator-Replacement/blob/master/gallery/modulator_simple.png This is just a part of the original C64 circuit inside the modulator box. I strongly suggest getting rid of composite mixing, so at minimum C6 should not be populated. This will let you have …

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Re: Recapping Capacitor List

Posted on 2021-10-13, 10:07

by

by Deunan

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Yeah, just flatten it and make sure it didn't move too close to any other traces nearby, this looks to be the low voltage section so little cause for concern. If you feel there's enough damage done and too little copper left then just slap a piece of wire on top and solder it to nearby pins, or …

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Re: Gotek like Optical Driver Emulator - Is it possible?

Posted on 2021-10-13, 09:07

by

by Deunan

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Speaking of interfaces, I like simple. But I do understand that one-button solution would not work well on a PC where there's so many different program with their own GUIs and possible even different graphics cards. So there needs to be some external interface on the device with its own display. And …

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Re: SyQuest SQ3270S (SCSI) problem

Posted on 2021-10-12, 20:55

by

by Deunan

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Just a random idea, since I have very little experience with SCSI. Is the cable terminated on the card's end? I once had some issues that were resolved by properly terminating the bus on both ends (the other end was a disk with internal terminator pack, like what you have).

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Re: Recapping Capacitor List

Posted on 2021-10-12, 20:45

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by Deunan

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

The point of writing 'low ESR' is to prevent confusing people, who don't need to be made aware of the minutia. I don't want to be nitpicking but that is exactly what I am against. We say "go low ESR everywhere, can't hurt" and it becomes a gospel, we already are at a point where "recap everything" …

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Re: Recapping Capacitor List

Posted on 2021-10-12, 19:07

by

by Deunan

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

See, this is why I don't like just saying "low ESR caps for PSU". Surely the output filters, possibly also the big primary side ones (but that's not critical), but what is the point of putting low ESR caps in PWM controller supply rail? Or POWER_GOOD circuit where there's often an electrolytic used …

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Re: Gotek like Optical Driver Emulator - Is it possible?

Posted on 2021-10-12, 16:26

by

by Deunan

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Ha, I was that naive too. Turns out though that people don't like to read (or even think) and also expect you to be answering their questions within few hours, no matter where you live and what day it is. And if you dare to "dissapoint" them even once... Let's just say there's no shortage of so- …

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Re: Recapping Capacitor List

Posted on 2021-10-12, 14:03

by

by Deunan

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

I'm not againt replacing capacitors, the bad ones have to go, that much is obvious. All I'm saying is recapping whole PCBs has become almost a religion that cures any and all problems you might have. Not only is that not true, and you learn nothing from it (other than soldering, maybe), it can be …

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Re: Commodore 64 video problems

Posted on 2021-10-12, 13:21

by

by Deunan

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

By coincidence, I also tinker with the C64 at the moment. Well, it's true that the main issue with using S-Video output on C64 is cross-talk between luma and chroma. But the reason why this cross-talk exists it due to modulator, it needs to combine the two to make a TV singal out of it. The …

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Re: Gotek like Optical Driver Emulator - Is it possible?

Posted on 2021-10-12, 11:57

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by Deunan

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Yes, I did make a few toys so I'd like to think I know what it takes to make an ODE. Both from HW/SW as well as sales point of view. Basically it boils down to: - low price - quality - support Pick any 2.

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Re: ACTION REWIND: a clone of the original IBM PC Action Replay card

Posted on 2021-10-12, 11:46

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by Deunan

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

I have a few strange questions, feel free to ignore or answer via PM if you don't want to spill any "company secrects". Is that EPM7128STC100? Last time I checked it was rather difficult to buy in any decent amounts (100+) and still kinda expensive for what it is. Not to mention already obsoleted by …

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Re: Gotek like Optical Driver Emulator - Is it possible?

Posted on 2021-10-12, 09:05

by

by Deunan

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Yes, conflicting user expectations are pretty much assured for a platform like PC. Some people will also say a digital audio output is a must, since it's a new device (even if emulating old hardware), there will be a small war about what kind of output that should be, coax or optical, the result …

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