LC575 Cuda/Egret chip

[noodlepringle]

I have an LC575 board that I sent to the great Bruce Rayne here in Australia to repair for me that suddenly died in the Colour Classic I had it in.

After a fair amount of troubleshooting he's let me know that it's the cuda/egret chip that's at fault and that he doesn't have a spare board to pull it from. The rest of the board is nice and clean and was running super well before this happened.

So I'm on the hunt for one. Does anybody have an LC575 board that's dead in some other way that I could buy to harvest the Cuda/Egret chip from? Does anybody know if cuda/egret chips between similar boards can be swapped? Or does it need to be only from an LC575?

I'd be so grateful for any help here - it was really getting into coding some software using the Retro68 build chain to build an interface with various microcontrollers I have doing things around the house (my style of smart home = chitty chitty bang bang meets 21st century) - it was a hoot! (plus monkey island 2 runs terribly on a standard colour classic mainboard)


Bit of backstory of how this happened:
I had a Colour Classic that I'd used on and off for years, but of course the board that came with them was anemic and hard to do much with (so little ram! such a slow processor even for its time!). Out of the blue one day a local guy was selling an LC575 that looked like it had been dropped and wasn't running, but the board was unharmed, so I bought it and slipped it into the mac and off I went.

This LC575 board was running well for bit more than 6 months I think when I decided to order one of the SCSI2SD boards (I think it was a v5.5 that sources power from the SCSI port to run, no other cables needed). I plugged it in, but had problems getting it recognised, so I used a utility and a boot disk to scan the scsi bus. It briefly saw the drive, then the system locked up hard frozen, cursor wouldn't move.

When I rebooted, I got the chime, but no screen, no hard drive activity no matter what.

I know that this Colour Classic needed an analog board recap at some point soon, but it wasn't so bad yet, just a slight distortion in the CRT image, and I'd checked the analog board for anything super obvious like bulging/leaking caps. The recap was going to be next on the list.

I wonder if maybe the added weight of power requirement for the SCSI2SD caused it to become overwhelmed and find a way to kill the cuda/egret chip? I'm just not familiar enough with the hardware to know why this would have happened.

So my understanding is that this chip handles the POST and is the intermediary with ADB and SCSI etc too, and that's why the chime, but nothing beyond that.

 

[cheesestraws]

Yeah, the way to think of the Egret is that it does the "housekeeping" of running the computer. The problem is that these chips are obviously Apple-specific and there's no reliable source of spares for them as far as I know other than other boards. They're have a reputation for dying, so I wouldn't blame yourself or anything you did particularly.

 

[Byrd]

What's the part no. of the Egret chip? I'm in Melbourne, I have a very flaky LC575 board but some other boards like a parts 7100, Centris 610 that might have the chip.

 

[mg.man]

After a fair amount of troubleshooting he's let me know that it's the cuda/egret chip that's at fault

Do you have the Apple P/N? Is it 341S0788 by chance?

 

[mg.man]

<snap>

 

[joshc]

Egret chips are on utsource and I have some spare, but I don't know if they are definitely the correct one for the 575 board.

Search 341S0788, 341S0788 distributor|,buy 341S0788, in stock,Darlington, Capacitor, find chips, electronic component, diode, Transistors, Sensors, IGBT, IC chip at utsource.

The 341S0788 is a surface mount, low-power, three-phase brushless DC motor driver from STMicroelectronics. It is designed to drive brushless DC motors with a supply voltage of up to 28V and a maximum

utsource.net

I think Egrets are somewhat interchangeable as well, but I haven't confirmed this myself.

 

[mg.man]

This is a pic from my LC575 'board... which is awaiting collection from my folks' in the US...



No "EGRET" silkscreen... but the location is pretty much the same as the Classic II 'boards... *If* that's the one, then, as you say, there are some supplies out there...

 

[joshc]

Yes, that's the Egret.

 

[noodlepringle]

Oh man, you guys are awesome! I just checked in and am blown away by the responses! Thanks so much - what an active and welcoming community! I'll reply directly to everyone now

 

[noodlepringle]

Yeah, the way to think of the Egret is that it does the "housekeeping" of running the computer. The problem is that these chips are obviously Apple-specific and there's no reliable source of spares for them as far as I know other than other boards. They're have a reputation for dying, so I wouldn't blame yourself or anything you did particularly.

Thanks so much for the explanation - I think this is sometimes why I enjoy vintage computers - the standardisation wasn't really there so you get all sorts of interesting exotic stuff like this that definitely piques my interest.

So if I can source a spare, I should probably see if I can source a couple at least as this may happen again?

 

[noodlepringle]

What's the part no. of the Egret chip? I'm in Melbourne, I have a very flaky LC575 board but some other boards like a parts 7100, Centris 610 that might have the chip.

I've emailed the guy looking at my board for me (I'm just SW of Ballarat, and Bruce is in Sydney) and I'll let you know as soon as I hear back from him about the part number of the chip. I was hoping that these are interchangeable between boards, it would suck if they're like a microcontroller with firmware particular to the board.

I'll definitely keep you posted, and thanks so much!

 

[noodlepringle]

Do you have the Apple P/N? Is it 341S0788 by chance?

I've emailed him and I'll let you know as soon as I hear back

 

[noodlepringle]

Egret chips are on utsource and I have some spare, but I don't know if they are definitely the correct one for the 575 board.

Search 341S0788, 341S0788 distributor|,buy 341S0788, in stock,Darlington, Capacitor, find chips, electronic component, diode, Transistors, Sensors, IGBT, IC chip at utsource.

The 341S0788 is a surface mount, low-power, three-phase brushless DC motor driver from STMicroelectronics. It is designed to drive brushless DC motors with a supply voltage of up to 28V and a maximum

utsource.net

I think Egrets are somewhat interchangeable as well, but I haven't confirmed this myself.

Well that's super interesting! If this turns out to be true, I'll buy a fistful of them to make sure I'm covered in future if they're known for being flaky. I was hoping they'd be a general processor rather than a firmware filled microcontroller particular to each board. I'll wait to hear back from Bruce to double check the part number on the board

 

[noodlepringle]

This is a pic from my LC575 'board... which is awaiting collection from my folks' in the US...

View attachment 32926

No "EGRET" silkscreen... but the location is pretty much the same as the Classic II 'boards... *If* that's the one, then, as you say, there are some supplies out there...

Excellent! That looks positive - I'll double check and make sure Bruce can confirm it's the same chip

 

[trag]

I've swapped the 341S0060 onto a board that had the 341S0788 (or maybe the other way around) and never noticed a difference. There might be one, but I didn't stumble across it.

I was in the habit of thinking of the 0788 as being newer -- on newer boards, but I just examined a PM7300 board which has the 0060.

Yet, if you look at this photo of half of a Umax S900 board, (left end of 5th PCI slot) you'll see that it has an 0788 installed.

Both the PM7300 and the Umax S900 are from the same family of machines and use the same chipsets, yet one was built with a 341S0060 Egret and one was built with a 341S0788 Egret (CUDA?)

I don't know what it means, but it seems to indicate that they are pretty interchangeable.