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| Classic II - Logicboard Rev. B troubleshooting |
Posted by: macintosh2002 on 2022-07-06 13:12:57
Hello, I recapped a rev. B Classic II LB (820-0326-B) some time ago, not my best recap job because this was one of my first board I‘ve done (solderpad C5 + is broken, made a line to R21).
No battery leackage, board looks great, but it won‘t work. No chime, no screen, nothing. The Classic II works with my Rev. A board, so analogboard (recapped) works.
I already have the schematic, and found out that the -12V line on Molex pin 9 is not there. Checked some traces from EGRET - EAGLE but I can’t found any mistake. Unfortunately I don't have any replacement ROMs to swap, what else could I do, any ideas? |
Posted by: jajan547 on 2022-07-06 15:55:08
Hello I looked at your board, capacitors shouldn’t be hanging like that (I get it for testing purposes). I made two examples of where the positive and negative should go but I think your issue is EGRET related. I’d recommend alcohol and a tooth brush at the least and then try reflowing the pins. Can you provide any photos of the EGRET area? And yes my board has seen better days but hey she works. |
Posted by: joshc on 2022-07-07 00:03:14
A Classic II board will start up without any capacitors, so the problem is unlikely to be there. I'd look at the Egret and ASC (Apple sound chip/DFAC) first. |
Posted by: macintosh2002 on 2022-07-07 01:43:16
@jajan547
Thank you. The hanging capacitor was just for testing purposes (positiv pad broken, goes to R21, correct, negativ pad is loose but ok).
Later today I`ll come back with better pictures of EGRET area. Whole board is pretty clean, I already cleaned it with 99,9% Isop. I noticed that the EAGLE chip gets pretty warm...
@joshc
thank you, I`ll do that |
Posted by: macintosh2002 on 2022-07-07 13:09:32
Now I‘ve resoldered the EGRET pins and used solder wick to clean the pads and put some new solder on there, I got a very strange screen. I didn’t pull the EGRET of the board, but I could if I should. What do you think? |
Posted by: jajan547 on 2022-07-07 15:19:05
Now I‘ve resoldered the EGRET pins and used solder wick to clean the pads and put some new solder on there, I got a very strange screen. I didn’t pull the EGRET of the board, but I could if I should. What do you think? Go ahead and pull it and check for gunk under it. |
Posted by: WillJac on 2022-07-07 20:11:22
Not sure anyone can help with this on my classic II. Also recapped. I get this on the screen. Feedback I gotten is ROM is bad so I have blanks on way to program and try. |
Posted by: macintosh2002 on 2022-07-08 11:32:04
I pulled the EGRET, but it was very clean underneath. I also checked the traces - now I have the same screen again... Could maybe a bad ROM cause that issue or the EAGLE? |
Posted by: jajan547 on 2022-07-08 11:36:50
Put EGRET back, this is good news! Try removing one or two ROMs and see what it does. |
Posted by: macintosh2002 on 2022-07-08 12:14:54
It does nothing, both ROMs sit great and correct in place. I also put some flux on EAGLE and heated the pins and flooded the board with Isopropanol. Will try later, but I slowly losing patience with this board. |
Posted by: jajan547 on 2022-07-08 12:19:24
Don’t sweat it I can make you some ROMs |
Posted by: imactheknife on 2022-07-09 09:23:15
How much for a set of rom Jajan? I am at my end with rev a board lol |
Posted by: WillJac on 2022-07-13 18:41:05
This not my thread but as I posted a message in here I want to add that my issue is resolved. Turned out to be 2 traces. First one is the reset from pin 15 egret eagle. See pics. Then the second is on this copied post I did in TinkerDifferent. pics also included.
Today I spend the day checking traces again using the schematic and going chip by chip. I had a feeling it was scsi related to I started there on the scsi/scc/via chip going to the others. I came to pin 64 that goes to 125 on the eagle chip. This trace is for the CE1 that is needed to enable the even numbered address bytes. Without this, system was acting very strange and preventing drive access and other systems to install properly. I was getting other errors that also made me go check rom traces and pins in the sockets. By checking them with the meter and probe, I accidentally pushed some of the metal springs inside to be bigger. I had to remove the plastic cover after a little heat and bend the springs back and returned to plastic covers. Put the rom chips back and all was good. With the trace fixed, rom sockets good, I got my chime back and system booted with no issue to any image I gave it from blueSCSI. To test floppy, I have. 7.0.1 on floppy so installed it that way. All worked very well. I had great support from @jajan547. In these pics, the board is dirty and has UV mask in various places. The best part, I learned a lot here and a classic II is now saved. The adventure continues……. Oh I want to add this trace is in the bottom edge of a capacitor battlefield so no wonder it went. I had 2 broken traces total on this board. Not so bad. I want to add I am a noob to this and I took long to find the issues but it is possible and just need to do the testing. Schematics help and research. |
Posted by: MacMoofer on 2022-11-15 15:48:25
@macintosh2002, did you ever get your Classic II rev. B logic board working? I’m having similar problems with that same board, and just now found your thread. Looking at your pix, I wondered if your ROMs have been installed correctly? On mine (see attachment) and in the few images of this board I can find online, 341-0261 is in the slot nearest the edge. Can anyone verify the correct placement? |
Posted by: jajan547 on 2022-11-15 21:44:23
@macintosh2002, did you ever get your Classic II rev. B logic board working? I’m having similar problems with that same board, and just now found your thread. Looking at your pix, I wondered if your ROMs have been installed correctly? On mine (see attachment) and in the few images of this board I can find online, 341-0261 is in the slot nearest the edge. Can anyone verify the correct placement? I actually see what you mean and think you are right, the LL and ML ROMs are swapped in the wrong places. |
Posted by: MacMoofer on 2022-11-16 07:33:54
I actually see what you mean and think you are right, the LL and ML ROMs are swapped in the wrong places. Interesting that you agree. I can’t find any authoritative source for which goes where. If swapping them solves the problem, or not, I hope you’ll let us know. |
Posted by: jajan547 on 2022-11-16 07:39:21
Interesting that you agree. I can’t find any authoritative source for which goes where. If swapping them solves the problem, or not, I hope you’ll let us know. My apologies I was wrong was looking at it going right to left but if one were to go from left to right (which is the way it’s supposed to beit would be the following:
LL-341-0864
ML-341-0865
MH-341-0866
HH-341-0867
hence ROMs are in proper order |
Posted by: marcelv on 2022-11-16 08:04:50
ROMS are not correct in the original post ?
341-0257
341-2061 has to be nearest to the edge |
Posted by: jajan547 on 2022-11-16 08:06:32
ROMS are not correct in the original post ?
341-0257
341-2061 has to be nearest to the edge And once again I completely missed the fact this was a two ROM board I thought it was a four and overlooked it, @marcelv youre correct. |
Posted by: MacMoofer on 2022-11-17 09:59:23
@marcelv, thanks for confirming. |
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