Long Promised- LC575 A/B in CC pictures

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Joined: Dec 20 2003
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One day "real soon now" this will become a complete article, but for now I only have the pictures up. Here's how I fit the LC575 Analog Board into my Takky.

Please don't do this mod to a stock Color Classic, but once you've done the Takky mod there really isn't any going back, so go ahead with this mod and then you'll have a lot easier time replacing your burnt out Analog Board in the future!

Pictures are available from my website at http://www.fenestrated.net/~macman/mac.html

Enjoy!

Tyler

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Joined: Dec 20 2003
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Also, I've got the motherboar

Also, I've got the motherboard from my A/B donor here. It boots and runs fine, but I think it's gotten wet sometime in the past, as there's some white film on the motherboard. Yours for $5 plus shipping, and I'll even spray it off with Chemtronix circuit cleaner!

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Joined: Dec 20 2003
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Thanks!

Another one for the archive.

Stuart

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Stuart Bell,
Developer of the PowerCC site a long time ago.

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Cool. And in a happy coincid

Cool. And in a happy coincidence, I just listed an LC575 a/b for sale.

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AG-Wolf's picture
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I had previously done the Tak

I had previously done the Takky modification to my color classic, enabling my machine to power a PM6500 board with a 350mhz G3 L2 card... Although I need to provide some MUCH improved ventillation, in the mean-time I'm looking to overcome one other obstacle:

If I were to trim down an lc575 a/b, would I need to make any other -electronic- modifications to the board, other than the 5v/10v trace mod?

I'm a little lost because I did a BLITZ takky mod on this color classic like two or maybe even three years ago... and had never touched it since then. I don't remember ANYthing I did to it, I've lost nearly all the documentation and personal notes I made while in the process.... and I have absolutely NO CLUE how I somehow managed to MIRACULOUSLY not only connect a mini-atx power supply to power the 6500 motherboard, but also wire in a relay somewhere and make the entire machine bootable with the keyboard o_O It's like... a total mystery.

I'm aiming to devote a lot of time to this again, and give my 6500's board a permanant home in the Color Classic (then aim on getting a PM9500 or 9600 and g4 card for that), but I'm just trying to find some small answers in the mean time... to sort of give me hope when I finally sit down to work on it again.

I'd appreciate any feedback you can offer... also, can I request higher-resolution, and more specific shots along with the explanation on your site? THe ones you have right now are alright, but pretty small, and I can't get a grasp of where exactly they're depicting; like this "infamous bump" region...is that the front-right corner of the board near potentiometer "PP7" (while looking at the board with the power connector and switch furthest away from you)?

Sorry for all the questions... I just know that if I DO go through with this and it DOES work out, I've got a much more functional machine.... but if I attempt it and screw it up ANYwhere in the process, my once kinda-but-not-really-flaky configuration will be rendered scrap due toe the heavy plastic chassis modification that is also required.

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» Main Mac: PowerMac 6500 inside Color Classic/G3 500Mhz 1MB L2/128Mb Ram/40Gb HD/OS 9.1/ATI Rage 128/OrangeLink USB-FireWire/CSII E-net/TV-FM Tuner

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I didn't make any electronic

I didn't make any electronic modifications to it other than the 5v/10v mod. Where the "bump" actually IS doesn't make much difference compared to what the total width of the board is. If you trim the board down totally enough, it will BARELY fit. I personally think it would be better to remove the "bump" by re-engineering that area of the board, but people have decided in the past that this would be too much work.

If you've got a 575 board to chop up, I say go at it! Don't modify your color classic at all, though. Just hack up the board and sit it in there. Try to get it to fit inside the caseback, get everything hooked up electrically, and see if it *works*. If it does work, then consider modifying your plastic frame to actually fit it inside permanently.

I'm going to have to open my Takky up sometime in the next couple of weeks to install a new PRAM battery. When I do, I'll try to take some better pictures. Smile

Once again, I say try it. Hack up a 575 board, but don't modify your color classic until AFTER the 575 board is doin' its mojo thing.

And... please excuse my spelling. I've had a little bit of champagne tonight.

AG-Wolf's picture
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ha, no it's quite alright...

ha, no it's quite alright... you've given me a bit more confidence in tackling this project a second time Tongue Thanks much for now, and I certainly await additional pictures with enthusiasm. =^.^=

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» Main Mac: PowerMac 6500 inside Color Classic/G3 500Mhz 1MB L2/128Mb Ram/40Gb HD/OS 9.1/ATI Rage 128/OrangeLink USB-FireWire/CSII E-net/TV-FM Tuner

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sat down to do prelim work...

sat down to do prelim work... I took out the old CC board, and had a look at my handiwork from 3 years ago, and I have absolutely no idea what's going on... I numbered the three modifications for ease of referring to them here.

This is my CC's A/B:

1) This was the sense wire mod, correct? 20 and 24 were linked, and 25 was left open, right? A lot of people choose to modify the S1 connector and link pins 19 & 20, leaving 21 open.... (I found all my old notes, but im still kind of in the dark ;_; )
---does this need to be done on the lc 575 a/b? Did you do the modification to your S1 connecter, thus negating the need to do any physical trace modifications to the a/b?

2) This is the -10/-5 v mod you outlined in your page, but when I look back on the VGA mod I did ( http://colourclassicfaq.com/general/vga.html ), it doesn't say anything about this step. When I read through the standard main PCC walkthrough (http://www.stuartbell.dsl.pipex.com/PowerCC/PCC2.html), it shows a picture of it, and I obviously DID this modification, but I don't remember what it was for... Does a trace need to be cut anywhere else? Is there a page anywhere that actually specifies what this does?

3) god only knows... I THOUGHT I recalled opting to do the VGA mod (68.4v or whatever) to put as little strain on the CC a/b as possible, but there are TWO soldered wires there... and I don't know why. One of them is for the horizontal deflecting voltage and the other is a mystery... it could be just some patch for a botched job or something, but I have no idea. Point is, I DONT have to do THIS on the 575, right? the whole point of using the 575 a/b is so that you're using an a/b that is actually capable of what you're asking of it.

----------------
EDIT:
To make matters absurdly more frustrating, it seems as though i NOT ONLY modified the CC a/b, but I did the S1 trace mod AS WELL:

maybe I did that preemptively? Maybe when I did it, I was aware that they were both the same thing? To reitterate a prior question, does this now mean I don't have to worry about any potential trace wire problems if I ever finally get the 575 a/b prepped?

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» Main Mac: PowerMac 6500 inside Color Classic/G3 500Mhz 1MB L2/128Mb Ram/40Gb HD/OS 9.1/ATI Rage 128/OrangeLink USB-FireWire/CSII E-net/TV-FM Tuner

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I'm really sorry to keep prat

I'm really sorry to keep prattling on and on about all this... I tried to figure out more information about what I circled and labeled "2", the yellow wire... is that something that has to do with cutting jumper "J19"?

OHHHHHH!!! J19 IS ON THE -TOP- SIDE OF THE A/B!!! AND THERE IT IS ON THE 575's A/B AS WELL!! I just figured this out (again?) Tongue *laughs* it's all slowly beginning to make sense :3

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Main PC: Sempron 2Ghz 256k L2/768MB Ram/40,60,120Gb HD's/CDRW/DVD+-RW/WinXP SP2
» Main Mac: PowerMac 6500 inside Color Classic/G3 500Mhz 1MB L2/128Mb Ram/40Gb HD/OS 9.1/ATI Rage 128/OrangeLink USB-FireWire/CSII E-net/TV-FM Tuner

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I took those pictures I promi

I took those pictures I promised. Smile I've got 'em on a terrible looking webpage:

http://www.fenestrated.net/~macman/details/

You're right about everything. #1 on your CC A/B is a modification for sense-line coding. Since it seems that you've done it to your wiring loom, too, you won't need to do any mods to the 575 board for that purpose.

#2 on your A/B is the 5V/10V mod for Takky operation. It wasn't obvious at first, but the directions are identical to the CC A/B directions in this regard. Cut J19 and solder in this wire. The purpose is to allow the 6500 board to work--unlike the CC board that expects to see +5v on this pin, the PCI boards expect +12v. This mod supplies it, and is required for the 575 board (see my black wire).

#3 looks to me like exactly what you guess--a VGA or HiRes mod plus a fix for an aborted attempt. I haven't done anything like that to my 575 boards and they even give a tiny picture at 1024x768!

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I took those pictures I promi

I took those pictures I promised. Smile I've got 'em on a terrible looking webpage:

http://www.fenestrated.net/~macman/details/

You're right about everything. #1 on your CC A/B is a modification for sense-line coding. Since it seems that you've done it to your wiring loom, too, you won't need to do any mods to the 575 board for that purpose.

#2 on your A/B is the 5V/10V mod for Takky operation. It wasn't obvious at first, but the directions are identical to the CC A/B directions in this regard. Cut J19 and solder in this wire. The purpose is to allow the 6500 board to work--unlike the CC board that expects to see +5v on this pin, the PCI boards expect +12v. This mod supplies it, and is required for the 575 board (see my black wire).

#3 looks to me like exactly what you guess--a VGA or HiRes mod plus a fix for an aborted attempt. I haven't done anything like that to my 575 boards and they even give a tiny picture at 1024x768!