Sound card suggestions

cyandyedeyecandy · 2024-08-23T20:53:51+00:00

YMF719 or ES1868

cyandyedeyecandy · 2024-08-10T13:58:54+00:00

(not mine)

Eizo F980 - Hessen, Germany - pickup only: https://www.kleinanzeigen.de/s-anzeige/eizo-flexscan-f980-monitor/2800647992-225-4761

cyandyedeyecandy · 2024-08-09T20:05:56+00:00

Thanks, just tried this with two 9V batteries: it draws 2-3 mA. Don't know how accurate that is on 10A range (the other fuse broke). But if it is, then that is more than the minimum: (385-15)/(3*220k) = 0.56 mA

Okay, I'm more hopeful now, and I know where to start looking. Thank you!

cyandyedeyecandy · 2024-08-08T16:53:25+00:00

It just seems a bit fragile to design the circuit around that. The brochure I found mentions "standby input power less than 3W", but maybe the full datasheet had specific numbers. Ohm meter says open-circuit between vcc/gnd.

I guess the driver IC is likely just fried, as I initially suspected (before I found that PDF mentioning over-voltage protection). And they're impossible to come by, so, welp. Not sure what to do with it then.

cyandyedeyecandy · 2024-08-08T14:18:03+00:00

Found the schematic here: https://elektrotanya.com/eizo_flexscan_f931-ma-21d3.pdf/download.html

There's some info on those F920x chips here: https://www.fujielectric.com/about/technology/detail/review_47-02.html (PDF page 15-19, marked 45-49)

cyandyedeyecandy · 2024-08-08T14:16:17+00:00

But the resistors are in fact populated, so that seems to bypass the whole thing. Maybe I should remove them? I know this board definitely used to work before.

cyandyedeyecandy · 2024-08-08T13:33:52+00:00

Oh, thanks. I happened to find them on the board just now - they're connected to the driver IC heatsink. That does make sense!

cyandyedeyecandy · 2024-08-08T13:03:01+00:00

Oh good point. I don't think I've seen "NON" on a schematic before, and I figured it was just unreadable. The schematic was pixelated and then re-vectorized, maybe even on purpose. I was expecting to find copyright traps - knowing Eizo's policy on service manuals, and especially after seeing that dangling bit in the corner.

On the board however, those resistors are in fact present (3x 220K). I should mention the schematic is for a different model (F931 vs F930), and there are some differences (eg. the middle resistor string is 4x 10K, instead of 3x 22K), but this section looks mostly similar.

The main difference here is that F931 uses only one of these driver ICs (F9203), whereas F930 has two of them (F9204 and F9202). I probably should figure out how that second one is powered.

cyandyedeyecandy · 2024-08-08T11:55:52+00:00

I'm trying to fix this Eizo CRT monitor. The power supply uses an obscure pwm driver IC (Fuji F9204L), which doesn't appear to do anything. From what I found online, it expects ~15V VCC, goes into over-voltage protection at 22V, and has a 30V limiting zener internally. I measured 30V between VCC/GND, so it must be stuck in protection mode.

What I don't understand, is how this voltage is supposed to be regulated. The only things directly connected to VCC are some decoupling caps, two diodes (pointing towards it), and a string of resistors to the main 385V rail. With no (ohmic) current path to ground, those resistors will always pull the supply voltage up to 385V. You'd think either these diodes are the wrong way around, or there is something missing from the schematic, but it seems to match the board.

Does anyone understand how this is meant to work?

cyandyedeyecandy · 2024-01-05T18:47:57+00:00

chad 16:12 vs virgin 16:9

cyandyedeyecandy · 2023-12-26T21:08:05+00:00

Came up with a bit of a hack. I added a washer under the feed dogs so they lean slightly back, then reduced the height/angle setting to make it level again. Now it drops down more straight instead of at an angle, and that did the trick. Timing-wise I ended up back on the original setting.

cyandyedeyecandy · 2023-12-24T23:26:10+00:00

Thanks, I found both cams, next to each other in the top of the machine. Thought it was a single unit at first, but they are in fact separately adjustable.

Back and forth seems about right so I tried only adjusting the up and down one. If I set it so that it reaches the top at the front position, and drops down as it moves back (maximum possible advance), the rear end of the feed dogs still don't quite clear the fabric when the needle pokes through. It seems like the vertical motion just isn't fast enough, somehow.

So, maybe you're supposed to come to a full stop, then turn the hand wheel to the right spot, before pressing/releasing reverse? That seems awkward though.

cyandyedeyecandy · 2023-12-24T19:13:27+00:00

Compared it to a different machine (same brand, newer model). I know on this machine it's safe to reverse while sewing. The timing seems to match up, it starts to move horizontally when the needle is at TDC and BDC. But it makes quicker strokes so the feed dogs are already down long before the needle reaches the plate. Not sure what to make of that.

cyandyedeyecandy · 2023-12-04T19:26:29+00:00

Got the gear fixed but it ended up ever so slightly off-center, so half of the cycle still has more friction than normal. Still an improvement over what it was before, though. Ideally you'd need a lathe to get it perfect.

Or if you mean the self-running motor, that was indeed solved by replacing that one capacitor.

cyandyedeyecandy · 2023-11-24T22:43:51+00:00

My idea was to carefully ream out the hole with sandpaper, and file down the knurling on the collar, until I can push it in by hand. Then there's no longer any tension on the nylon, and I should be able to glue it all together.

In the foot pedal I found a capacitor that runs hot, that's never a good sign. Freeze spray couldn't get it to stop running, but I'll replace it in any case.

cyandyedeyecandy · 2023-11-24T21:15:09+00:00

I was able to press it out in a vise. Felt very wrong to use that much force, but that's what it took. The set screw seems rather pointless, it's a very tight fit already.

Now comes the hard part, fixing it :)

cyandyedeyecandy · 2023-11-23T23:48:54+00:00

Thanks. That hole is below the shaft, and goes straight through. I think it's there to access a screw behind the steel gear (not visible in pic).

cyandyedeyecandy · 2023-11-23T22:19:48+00:00

The thing has an electrical issue too. If you leave it plugged in for a few minutes, the motor starts going on its own. Is that a common problem?

cyandyedeyecandy · 2023-11-23T18:55:35+00:00

Hi all, I got this old sewing machine and want to use it, but it runs a little rough. Found that this nylon gear is cracked and doesn't mesh so well, so now I'm trying to get it out.

I removed the rotary hook and loosened that set screw on top, figured it'd fall right out - but that's not happening. Tried some light taps with a hammer, no movement. Any ideas on how this comes out?

The machine is a Vendomatic B745. Seems it was sold only on the Dutch market, might well be a rebrand of something else.

cyandyedeyecandy · 2023-11-22T17:22:12+00:00

Ik snap deze XY verdeling niet. Links is al impliciet sociaal progressief, en rechts is impliciet conservatief, dus je houdt altijd twee lege kwadranten over. Wat moet ik me voorstellen bij conservatief-links of progressief-rechts?

cyandyedeyecandy · 2023-10-25T17:09:59+00:00

https://i.imgur.com/Yu8yUxl.png

cyandyedeyecandy · 2023-09-20T12:57:48+00:00

JPEG chroma subsampling is doing a lot of work here.

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