I have no logic!

[The MAC MANIAC!]

OK if you have seen my post about my CRT issue you know that it has a strange problem. But when i was messing around it seems i broke a rom chip and now my logic board is mostly inactive! After putting in a disk it spun up for about 2 seconds and then cut off. I decided to check my rom chips and see if had put them in wrong. But when i switched them it just made a loud sound as if i made a remix of the Macintosh pluses startup sound. 3rd times the charm right? Well no, its not, in fact i found that a leg broke off of the LO rom.

So i think that getting a new logic board will fix this?  Also it makes no startup bong when i switch it on.

Things that work is the-

CRT

power supply

floppy drive

analog board

 

[The MAC MANIAC!]

Screens gray also it shows tightly spaced horizontal lines. And now some diagonal  lines after the roms leg broke off. Also Does the order of the simms matter?

 

[techknight]

When I saw the topic of this thread, I thought of something entirely different. 

You break legs off the ROM, you certainly need to replace it. 

 

[CharlieFrown]

you could go with a Rominator instead of regular ROM chips. 

 

[Johnnya101]

.. Rominator II is for Mac II or SE/30. Unless you're talking about something else.

 

[just.in.time]

.. Rominator II is for Mac II or SE/30. Unless you're talking about something else.

There is the Rominator (no II) for the 128/512/Plus.  It is awesome and amazing.  However, BMOW no longer sells the kit to build it (some soldering was required).  However, they open-sourced it so you can order all the parts yourself, download the initial ROM data, and if you have the tool to do so, then burn the initial ROM to the new rom chips.  Or get lucky and find someone selling one.

@The MAC MANIAC! I've never tried reversing the order of the ROMs, but I'm going to take a stab in the dark and say that yes, both order and orientation matter for the ROM simms.  I recommend google image search a Plus logic board to see what the order is.

 

[Johnnya101]

Wow, never knew that! Thanks for letting me know.

 

[chu-oh]

I've got a spare Plus rom with the 3rd revision spare if you need? I got the last batch of the original Rominator's so I no longer need it. 

 

[The MAC MANIAC!]

Thanks but i still think a new board should fix. Because it would be a waist to get something and then have it turn out not to fix it. Does the board model need to be the same or can i just get an older version of one that has different chips for a cheaper price?

But the good thing is It was not working correctly to start with. So any damage i did wont matter because its broken to start with. 

 

[The MAC MANIAC!]

Before i broke the leg off it was still no beep and it showed a blank grey screen.

The programmers switch did nothing when i pressed them. 

 

[The MAC MANIAC!]

Here is what is happening. When i power it on theres no beep sound. The screen is all grey with nothing on it. Putting a disk in makes the disk drive turn for a little under a second.  And the programmers with does nothing. 

When i switch the Hi and LO roms i hear screeching sounds that sound like boot sounds and they dont stop. The screen is still grey. 

 

[chu-oh]

Here's a photo I took for my own reference of the correct placement of the Hi/Lo bios chips. Notice the different numbers on the chips:

342-0341-C for Hi
342-0342-B for Lo

Once you know the bios chips are in the right order you'll be in a better place to troubleshoot what's happening. 

 

[The MAC MANIAC!]

You have another board i have a 820-0174-c but i see a scratch between the ROMs and the connector and because the board is green and not really flat i cant tell if the scratch has broken the trace.

If it was not as tight i would use pencil lead to try to give the trace more conductivity but that would just make it worse.

I only do that for corrosion on old games. Would the ROMs cause the blank grey screen and no boot sound?

 

[The MAC MANIAC!]

the computer has not even been discharged but after a week or two i think its discharged. But is it safe? The HI ROM if you hold it where you can read it, it has its lower most right leg broken off.

 

[Johnnya101]

Plus's don't have bleeders, you're probably fine, but I'd still discharge it just in case .

If you post a photo of the entire board as it is it may help us out to see what's going on. You NEED the ROM.

 

[The MAC MANIAC!]

I cant yet without the equipment its my last priority to mess with the crt right now. 

Can i stick a Led light leg in the hole where the roms leg went and stick the rom in it? 

Will that work for a way to test the board?

 

[The MAC MANIAC!]

​

 

[The MAC MANIAC!]

i have no put in the simms in the picture but i have them.

 

[AwkwardPotato]

Can i stick a Led light leg in the hole where the roms leg went and stick the rom in it? 

This will probably work, but only as a temporary solution.