Strange card on a mac plus

[plb007]

Hi, 

I have a mac plus with an extra db9 cable going through the security hole and don't know what is it.



The computer was heavier than the others. As I have a sad mac icon at startup, I decide to open the computer to have a look inside. The computer is very full of extra component.



It looks that there's an extra power supply just under the screen, an extra card at the back of the computer, an extra card packed at the logic board and a extra fan (or a relocation) to cool everything.

Does someone have information on this setup ? The back's card has "Micrographic mega screen written) I assume the db9 port is VGA or component (RGB) ? 

It looks very complicated to remove those cards, lot of extra screws and extra wiring to deal with. 

Have a look at the pictures

 

[Trash80toHP_Mini]

[SIZE=17.92px]Now THAT is some strange setup![/SIZE]



http://www.digibarn.com/friends/janek-kaliczak/index.html

This one (and that cutoff "P" in your pic) makes me think you have the Plus version, possibly with accelerator? HDD? That is one big PCB running from front to back over the Logic Board!

Link found here: http://myoldmac.net/SELL/MacSE-MegaScreenCard.htm

 

[plb007]

This might be an Megascreen I as there's a cooling fan in the setup. I'll try to take it apart. I can't remove the logic board as it seems to hold a cable to another board. I need to figure out the disassembly order first. I'm impressed how they packed all that stuff inside this small case. 

I guess there's no hard drive inside. 

What's the sad mac 02FFFF meaning ?

 

[BadGoldEagle]

02 usually means bad RAM but I'd be willing to bet the add on card is the cause of this issue. I'd say the additional PSU has failed (recap in order?) and can't drive the Megascreen card properly, which in turn causes issues with the Mac's logic board in the RAM department.

The analog board still seems to have enough juice left to power the display and the logic board. If you can get it further apart, I would recommend trying to disconnect the add on card from the logic board. You can still leave the additional PSU connected to the Analog board as it seems to be fine with that. 

 

[plb007]

Thanks for your answer, I tried to dismantle everything today with no luck. I mean I think I can take it apart but with no idea how to reassemble it later. Some bolt and/or nuts will fall inside the computer and I have no idea how to put them together. For now it's on hold as I need some place in my desktop. There's no need to rush as nothing seems to leak everywhere in the main board. I'll try first to power it as if it is from stock and then add elements one by one. 

 

[Trash80toHP_Mini]

MegaScreen "1" and MegaScreen Plus appear to be the same



Your MegaScreen Plus(?) appears to have some interesting features.



That circuit board bolted up to the Logic board has some interesting possibilities. The Macintosh Plus wouldn't need the internal HDD option where the 512k would.

edit: all(?) compacts with expansion boards require spreading the chassis tracks for installation/removal. Maybe someone can post linkage to a good howto vid, page or manual for you.

 

[BadGoldEagle]

edit: all(?) compacts with expansion boards require spreading the chassis tracks for installation/removal. Maybe someone can post linkage to a good howto vid, page or manual for yo

Yep, that's how you're supposed to remove the board when you have accelerators etc on early macs. It's a different story for compacts SE onwards.

Start by positioning the Mac on its face and look at the bottom (logic board), grab the left side of the chassis (if needed, rotate yourself to the left so that you can see the floppy drive), put your thumb inside the Mac where the red arrow is and carefully bend the chassis (and the tracks) outward to 'release' the board.

 

[Trash80toHP_Mini]

It's a different story for compacts SE onwards.

Not all that different sometimes. The slot for Radius FPD and TPD cards at the rear of their Accelerator boards required the Killy Klipped card method as it blocked slotted track removal. Was it much the same story with the socketed PowerCache board in the SE/30?

 

[BadGoldEagle]

I can remove the Powercache and the logicboard as one unit without bending the chassis at all (thanks to the tracks in the chassis being different and better IMO). Same thing with the Micromac 030 in my Classic although I do have to slide it all the way up. I don't have a FPD yet so I don't really know about those. I thought the accelerator or the Magicbus card could stay on the board and be removed the same way.

Now that I think of it, probably all cards that have the same width as the logic board need to have the chassis bent a bit to be removed. So that's almost all early mac boards, plus some (most?) of the SE cards. My bad. 

 

[JRL]

Reviving this thread to say that I picked up a Plus with this set of upgrades recently as well (MegaMath + MegaScreen). Mine was disassembled at some point (I have the MegaScreen and board with the MegaMath installed) but I'm putting it back together now.

EDIT: Mine boots up with Sad Mac code 0f002 right when the floppy disk icon appears.

 

[plb007]

Hi,

It looks like we have the same board. I finally took the time to disassemble everything.
Here are the pictures.



This is the extra PSU, the power is taking directly from the main AC so it doesn't stress the analog board.


At the back of the computer, we found this extra card, there is a Db9 cable going through the security hole connected to the J2 connector



On top of the logic board, we found this card. One connector is attached to the previous card, the other attached to the logic board.

This is the plus logic board with some chip wiring and the link to the previous board.


There's a glued board on top of the processor that I'm not able to remove without applying to much force.
Unfortunatly, the Plus doesn't boot (sad mac and checkerboard). 5V, 12V and -12V are good.

 

[plb007]

Reviving this thread to say that I picked up a Plus with this set of upgrades recently as well (MegaMath + MegaScreen). Mine was disassembled at some point (I have the MegaScreen and board with the MegaMath installed) but I'm putting it back together now.

EDIT: Mine boots up with Sad Mac code 0f002 right when the floppy disk icon appears.

My additional PSU is not working. Do you know what voltage is it supposed to provide ? I guess there are 2 different voltage, one is 12V for the fan, but the other ... ?

 

[Phipli]

My additional PSU is not working. Do you know what voltage is it supposed to provide ? I guess there are 2 different voltage, one is 12V for the fan, but the other ... ?

Logic in old macs is 5V, so it is probably 5V. Check by continuity testing to a logic chip ("74LSxxx" or similar), then look up the check the chip is 5v... it almost certainly will be.

If there is continuity to a chip like that, you probably are on a 5v power rail.

 

[plb007]

The PSU is working now (easy fix). But the mac still show a checkerboard pattern.

 

[Phipli]

The PSU is working now (easy fix). But the mac still show a checkerboard pattern. View attachment 59576

Probably start by using contact cleaner where it clips onto the logic board.

 

[joshc]

I've also had weird patterns (although maybe not that one) on Pluses caused by unseated/badly seated RAM chips. Worth cleaning the SIMMs and the slots with contact cleaner.