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Hm. I'll bet it's actually the FD7201 that's toasty, then. Is the PCB that contains it single-sided? Does the signal from pin 48 go through the FD7201?... or is this the 2SB941 you were talking about in the very beginning? If it is the same transistor, you should just be able to replace it. The 2SB...

It goes right into the drive.

Pin 48 looks like it's held low, pin 47 is high (5V), 46 is also high and 45 is also held high. It looks like all of $4032 is held high then. And the strange thing is that despite all this, my disks still load perfectly fine and the BIOS also behaves fine; it responds when I press the various switch...

Is there a possibility the drive controller is causing it? I can't find any pinout information for the FD7201 so I'm really grasping at straws right now.

OK, so I looked at pins 49 and 50 (both related to $4025) of the 2C33 and they're both showing 5V meaning they're held high. Shit...

Given the above schematic, I have no idea where this 4001 or 4013 you're mentioning is. They're on the power PCB, right next to the power connector for the disk drive. Here's a picture along with another pic of the underside of the board: http://i18.photobucket.com/albums/b144/ApolloBoy/NES/DSCN106...

Is there only the one PCB in the drive itself? can you take it out non-destructively? If so, a picture of both sides of the PCB will give me the best ability to guess. The drive is exactly the same as used in the FDS so it only has a single PCB inside with the drive controller chip and supporting c...

That's part of my problem, I can't seem to find jack shit for the FDS schematic-wise. All I know at this point is that the 2C33 commands the disk drive, which is why I'm listing it as a possible suspect. Really hoping that's not the case considering I'd have to cannibalize an FDS RAM adapter for one.

Anyone?

It looks I have a more serious problem on my hands now, the disk drive head won't stop moving and nothing except disconnecting it helps. Even having the cartridge mode selected does nothing. EDIT: Did a little poking around and I think I've narrowed it down to the culprits. I'm thinking one of the l...

The voltage shouldn't matter as much as the current supplied by the adaptor. The Twin needs 1.25A (says on the adaptor) and that's just with the FDS+Fami (not including the NESRGB). How much current can your universal adaptor supply? The new PSU I got puts out 1.5A, whereas the Genesis PSU I was us...

Oookay, so using a 10V PSU on a Twin Fami with an NESRGB installed wasn't necessarily a good idea. While playing Zelda on the FDS after 40 minutes or so, the screen started flickering and the disk drive started moving (!) even when unprompted to do so. The heat sink for the 2SB941 power transistor a...

I have a Twin Fami coming in the mail soon, and while I mod it for the NESRGB, I also plan to change out the power jack so I can use a model 1 Sega Genesis/SMS power supply. When I had a Turbo Twin Fami, I actually added such a power jack and it worked just fine using that particular PSU. However, w...

blargg wrote:The 7805 regulator has three pins. Looking at the front, the left pin is the input, center ground, and right output. What's the voltage between the left and center pins (can also use the heat sink as ground)?

Aren't you supposed to test from the output pin as opposed to the input?

TKempkes wrote:This exact thing happened to me when cleaning an Atari 2600 motherboard with alcohol. Kept at it and it eventually all came off. Not sure what it was.

Sounds like solder flux to me, Atari usually coated the undersides of 2600 motherboards with it.