Need help to fix quadra 800

imactheknife · Jun 18, 2022

The board had a small amount of battery leakage. I have ordered new pieces. Only one I couldn’t order was a custom vls1 chip. It needs to leg repairs. I pulled that chip off but it snagged a pad. In the attached picture you will see no traces or holes where the pad was. Just curious if this is a ground pad and how to fix it. Thank-you, mark

lobust · Jun 18, 2022

That pad is N/C.

You can safely ignore it.

imactheknife · Jun 18, 2022

Wow, made my morning

thank-you

lobust · Jun 19, 2022

imactheknife said:
Wow, made my morning thank-you

No problem!

No trace and no via means it's not connected to anything.

I did a bombed 650 board (same board as 800) recently and most of the N/C pads were gone, and a couple of the connected pads needed some repair. All worked fine when I soldered the IC back on (along with some other repairs in the same area).

imactheknife · Jun 26, 2022

Ok, just need to confirm if the copper around the postive is ok like this. I scraped around it to see why the little copper trace leading to one of the diodes wasnt connected. I want to put new battery holder on.

joshc · Jun 26, 2022

imactheknife said:
Ok, just need to confirm if the copper around the postive is ok like this. I scraped around it to see why the little copper trace leading to one of the diodes wasnt connected. I want to put new battery holder on.

Probably needs a bodge wire, check continuity between the pad and where the trace leads to.

imactheknife · Jul 2, 2022

ok all my traces are connected, and bodge wires done. I got the chime on first power but forgot to plug monitor in. powered off, plugged monitor in, no chime. now no chime. I also notice that my reset buttons are non functional. could this be the issue or an issue??

imactheknife · Jul 23, 2022

Ok, any one have any idea what to look for?? Ni video, no scsi activity. Chimes with no error, reset buttons work, soft power works but cant do pram reset. I get a little static in speaker shortly after the chime which I think is not ok. Power supply has good voltages.

jajan547 · Jul 23, 2022

Do you have a full view of the chips near video out connector? Leads me to believe a VDAC issue. As for the sound it happens, Color Classics tend to have that issue as well.

imactheknife · Jul 23, 2022

Im not getting scsi activity either. I am not sure the order of how things go once you hear the chime.

jajan547 · Jul 23, 2022

Question does soft power work?

lobust · Jul 23, 2022

I'd remove the ram and vram simms while testing. Wombat has both onboard.

After the chime, it does the memory test, then there should be a faint pop from the speaker, and then you should get video.

I am curious if the behaviour changes if you remove U63 altogether. I have a wombat board on hand that I'd be prepared to do such experiments on, but I have just moved house and all my soldering gear is packed away in temporary storage.

Edit: you should combine your/my posts about this from the other thread into this one, so that it's not confusing for other responders...

imactheknife · Jul 23, 2022

Soft power works, i get a small speaker noise but no video. I cant do a pram reset. Does u63 have anything to do with video?

lobust · Jul 23, 2022

imactheknife said:
Soft power works, i get a small speaker noise but no video. I cant do a pram reset. Does u63 have anything to do with video?

I don't think U63 has any direct connection to video, but it is presumably somehow instrumental in the early boot process as evidenced by my board with the same symptoms.

imactheknife · Jul 23, 2022

Well, it can be part of the problem still. U63 was affected by the battery acid leak, two feet were corroded off. I had to dremal the chip and use some wires to reconnect it all. It may still be part of the issue I guess. I really dont wont to pull it off as all the fine soldering i did lol.. i dont have a spare u63.

imactheknife · Jul 23, 2022

What is this slot for? I traced one pin of u63 to it. I dont have anything to go into it. One before memory slots

jajan547 · Jul 23, 2022

That's a ROM slot, typically on early boards you see them because Apple figured if the machine had ROM issues they could essentially install a jumper and the new or working ROMs on a simm. Thus if the Jumper was on and the ROM simm installed it disabled the onboard ROMs and used the ROMs found on the simm. I personally wouldn't see that as causing your issues though because on most boards that slot is removed entirely.

jajan547 · Jul 23, 2022

Can you provide a close images in and around the leaked area, make sure they are clear.

lobust · Jul 24, 2022

lobust said:
I don't think U63 has any direct connection to video, but it is presumably somehow instrumental in the early boot process as evidenced by my board with the same symptoms.

imactheknife said:
Well, it can be part of the problem still. U63 was affected by the battery acid leak, two feet were corroded off. I had to dremal the chip and use some wires to reconnect it all. It may still be part of the issue I guess. I really dont wont to pull it off as all the fine soldering i did lol.. i dont have a spare u63.

According to the Guide to Macintosh Family Hardware 2nd Edition, the RTC (at least on previous models) also contains the PRAM, so it makes sense that it would be accessed early in the boot process...

On the other hand, the volume of the chime is stored in PRAM, so it must be reading that...

imactheknife · Jul 24, 2022

Ok will take a few snaps today. I did find some of the diodes by battery were not making contact through vias on other side so had to put temp bodge wire on where needed. Didnt change anything unfortunately as far as booting etc. the pram makes sense because I can’t even do a pram reset, so something in u63 must not be making a connection, or u63 is part dead??

Need help to fix quadra 800

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