Anyone up for some IIcx troubleshooting assistance? We have clocks but no activity...

Sideburn · Jul 15, 2023

GRudolf94 said:
Same section of the IIcx board as shown by recap-a-mac. Also 0230-B.

View attachment 59389

Anyway, this all is besides the point. Throwing random parts at it, especially ones taken from an equally defective board, is not the way to go.

Well it wasn’t exactly random. The soft power switch wasn’t working then I saw my original board of same Rev has the two diodes that are directly connected to the power circuit and the power circuit is working on the orig board with the diodes and it is not working on the new board without the diodes. So I figured it was worth a shot.

Sideburn · Jul 15, 2023

GRudolf94 said:
Same section of the IIcx board as shown by recap-a-mac. Also 0230-B.

View attachment 59389

Anyway, this all is besides the point. Throwing random parts at it, especially ones taken from an equally defective board, is not the way to go.

They aren’t equally defective.

The original boards power circuit works.
The original board does not have cpu activity and no power up chime (when powers from either the stock power supply or externally from my atx supply).

The new boards power circuit does not work.
The new board does have cpu activity and a power up chime (sad mac) when powered externally for my atx supply.

Sideburn · Jul 15, 2023

I hear ya though. I’ll put the diodes back on the original board.

Sideburn · Sep 3, 2023

Hey all,

Got back to the IICX repair project(s) today and I have some more parts, components, and new discoveries and could sure use some help if anyone is up for it.

So Since my las post I have acquired and repaired an AppleColor RGB monitor that I can use on the bench for troubleshooting the IICX boards.

I've also got a Powerbook 180 that I used to repair the monitor. The picture looks perfect now.

Next, I have two more IICX boards and I am focusing on the one in the best shape now.

Heres the rundown of the boards:

Board A - This is the one we have been troubleshooting and left off with it having a clock but no activity on the bus. No signals on the ROMS and had lifted the UC9 - 13 and UD 9-13 chips. I have set this board aside for now.

Board B - This one is in pretty good shape. It powers up and makes a sad mac chime. It has data and address signals all throughout the board but there is no activity on any of the NUBUS pins. I am focusing on repairing this board.

Board C - This one suffered unrepairable damage to the front right area around where the battery is located. I have never seen damage this bad before. So bad that the battery holder had corroded and fallen off the board along with a bunch of chips. both side have major damage in this area but the rest of the board looks good so I can use this as a donor board for parts.

So on with Board B...

The first thing I tried was hooking the two video cards I have up and no picture on the screen with either card so I began probing with the scope...

My findings so far are:

UH2 -
• No signals at A15 (pin 2&5).
• No signal at A16 (pin 10&13) except while the sad mac chime is playing, then i have some activity.
• No signal at A17 (pin 11&14).
• No signal at RAA7 or RBA7 (pin 9&12)
• There are signals on the rest of the pins except 8,15(GND) and 16.

UJ3 -
• No signals at A18 (pin 3&6).
• No signal at A19 (pin 2&5)
• No signal at RAA8 or RBA (pin 7&4)
• There are signals on the rest of the pins except 8,15(GND) and 16.

UC8 (FPU) -
• signals on D0-31 look good.

UG8 (NUCHIP)
• A0 - 31 - no signals except pin 81 & 4
• pin 50 = LOW
• pin 49 = HIGH
• pin 70 = HIGH
• pin 55 = LOW
• pin 48 = HIGH
• pin 57 = LOW
• pin 78 = HIGH
• pin 77 = HIGH
• pin 44 = HIGH
• pin 47 = HIGH
• pin 52 = Has a signal
• pin 45 = LOW
• pin 69 = LOW
• pin 79 = LOW
• pin 46 = HIGH
• pin 67, 66, 65, 64, 62, 61, 60, 59 = LOW
• BERR (pin 13) = HIGH
• HALT (pin 15) = HIGH
• BR (pin 16) = HIGH
• DSACK0 (pin 22) = Has a signal
• DSACK1 (pin 21) = Has a signal
• SIZ0 (pin 28) = Has a signal
•SIZ1 (pin 27?) = LOW
• AS (pin 29) = Has a signal
• R/W (pin 30) = HIGH
• DS (31) = Has a signal
• ARST (pin 32) = HIGH
• BG (pin 41) = HIGH
• CK (pin 68) = Has a signal
• BGACK (pin 75) = HIGH
• RMC (pin 80) = HIGH
• FC1 (pin 84) = Has a signal
• PAS (pin 10) = Has a signal

Thats about all I have checked at this point and kind don't know where to go next.
If anyones got some suggestions I would appreciate it a lot!
Hoping to get at least one of these boards running! lol

** I should expect to see some activity on the NuBus slots right?

Thanks!

-Tavis

Sideburn · Sep 3, 2023

I also checked all of the data lines on UD9,10,12,and 13 and there is activity..

I'm having a hard time reading the schematic on page 9 and 10 though, the NUBUS section. I cant tell what the rows of 22222 33333 4444 are supposed to be representing and which pins are going to the NUBUS connector.

And wether or not I should expect to see activity there. I think this board is very close to running though.

Also the chips UH and UJ chips have some slight corrosion, not too bad but wondering if this is the area to be focusing on.

UH1 and UJ1 all have activity on the RA and RB address lines but UH2 and UJ3 have some dead lines as mentioned above. That can't be good.

Sideburn · Sep 3, 2023

*** Did some more digging and continuity checked UH2 and UJ3 and they trace all the way to the UA5 ROM and no activity directly off the ROMs on those particular pins. Plenty of activity everywhere else on the ROM data and address lines so I assume this is normal.. I do get some activity on some of those non active lines while it's playing the sad mac on a reset. SO assuming this section is ok.

Phipli · Sep 3, 2023

Sideburn said:
Hey all,

Got back to the IICX repair project(s) today and I have some more parts, components, and new discoveries and could sure use some help if anyone is up for it.

So Since my las post I have acquired and repaired an AppleColor RGB monitor that I can use on the bench for troubleshooting the IICX boards.

I've also got a Powerbook 180 that I used to repair the monitor. The picture looks perfect now.

Next, I have two more IICX boards and I am focusing on the one in the best shape now.

Heres the rundown of the boards:

Board A - This is the one we have been troubleshooting and left off with it having a clock but no activity on the bus. No signals on the ROMS and had lifted the UC9 - 13 and UD 9-13 chips. I have set this board aside for now.

Board B - This one is in pretty good shape. It powers up and makes a sad mac chime. It has data and address signals all throughout the board but there is no activity on any of the NUBUS pins. I am focusing on repairing this board.

Board C - This one suffered unrepairable damage to the front right area around where the battery is located. I have never seen damage this bad before. So bad that the battery holder had corroded and fallen off the board along with a bunch of chips. both side have major damage in this area but the rest of the board looks good so I can use this as a donor board for parts.

So on with Board B...

The first thing I tried was hooking the two video cards I have up and no picture on the screen with either card so I began probing with the scope...

My findings so far are:

UH2 -
• No signals at A15 (pin 2&5).
• No signal at A16 (pin 10&13) except while the sad mac chime is playing, then i have some activity.
• No signal at A17 (pin 11&14).
• No signal at RAA7 or RBA7 (pin 9&12)
• There are signals on the rest of the pins except 8,15(GND) and 16.

UJ3 -
• No signals at A18 (pin 3&6).
• No signal at A19 (pin 2&5)
• No signal at RAA8 or RBA (pin 7&4)
• There are signals on the rest of the pins except 8,15(GND) and 16.

UC8 (FPU) -
• signals on D0-31 look good.

UG8 (NUCHIP)
• A0 - 31 - no signals except pin 81 & 4
• pin 50 = LOW
• pin 49 = HIGH
• pin 70 = HIGH
• pin 55 = LOW
• pin 48 = HIGH
• pin 57 = LOW
• pin 78 = HIGH
• pin 77 = HIGH
• pin 44 = HIGH
• pin 47 = HIGH
• pin 52 = Has a signal
• pin 45 = LOW
• pin 69 = LOW
• pin 79 = LOW
• pin 46 = HIGH
• pin 67, 66, 65, 64, 62, 61, 60, 59 = LOW
• BERR (pin 13) = HIGH
• HALT (pin 15) = HIGH
• BR (pin 16) = HIGH
• DSACK0 (pin 22) = Has a signal
• DSACK1 (pin 21) = Has a signal
• SIZ0 (pin 28) = Has a signal
•SIZ1 (pin 27?) = LOW
• AS (pin 29) = Has a signal
• R/W (pin 30) = HIGH
• DS (31) = Has a signal
• ARST (pin 32) = HIGH
• BG (pin 41) = HIGH
• CK (pin 68) = Has a signal
• BGACK (pin 75) = HIGH
• RMC (pin 80) = HIGH
• FC1 (pin 84) = Has a signal
• PAS (pin 10) = Has a signal

Thats about all I have checked at this point and kind don't know where to go next.
If anyones got some suggestions I would appreciate it a lot!
Hoping to get at least one of these boards running! lol

** I should expect to see some activity on the NuBus slots right?

Thanks!

-Tavis

I feel like... You're complicating things a little. I haven't ever had a scope to help repair a board, what I do is look with my eyes in good light, with a magnifying glass or zoomed in on photos and search for damage. Find it, repair it.

Mentally divide the board into a grid and look at every square in detail. Most damage is visible. Even if a break under a chip isn't visible, a load of corrosion around a chip says it is worth checking that bit of circuit with a continuity tester against the schematic.

Logic analyser wouldn't be the first tool I reached for. It's too much data.

Sideburn · Sep 3, 2023

Phipli said:
I feel like... You're complicating things a little. I haven't ever had a scope to help repair a board, what I do is look with my eyes in good light, with a magnifying glass or zoomed in on photos and search for damage. Find it, repair it.

Mentally divide the board into a grid and look at every square in detail. Most damage is visible. Even if a break under a chip isn't visible, a load of corrosion around a chip says it is worth checking that bit of circuit with a continuity tester against the schematic.

Logic analyser wouldn't be the first tool I reached for. It's too much data.

I’ve been through that phase though. I’ve re-capped it and fixed all the broken traces I could find so far and now I’ve got a sad Mac chime. Good news but still not there yet so now I am resorting to the scope…chances are it is a broken trace I haven’t found yet but I’ve been looking!

I will take your advice though and go back over it today in fine detail.

Phipli · Sep 3, 2023

Sideburn said:
I’ve been through that phase though. I’ve re-capped it and fixed all the broken traces I could find so far and now I’ve got a sad Mac chime. Good news but still not there yet so now I am resorting to the scope…chances are it is a broken trace I haven’t found yet but I’ve been looking!

So use logic.

1. It sad macs. This means... The reset works. The CPI works. The ROM works well enough that it can execte some code. The sound works.

2. Sad mac means the hardware test fails. So what does that test? Where in the test is it failing?

3. Are you usng a stock ROM? The ROM does a RAM test, lets consider that. Time how long from power on the sadmac happens. What happens if you press reset? Remove the RAM, contact clean it and the slots. Take care of the clips (are any broken already? This is an important question). Compare how long it takes to sadmac with 4MB RAM and 8MB RAM - is it different?

Phipli · Sep 3, 2023

This whole process following is successful:

Possibly step 6. asside.

Sideburn · Sep 3, 2023

Phipli said:
So use logic.

1. It sad macs. This means... The reset works. The CPI works. The ROM works well enough that it can execte some code. The sound works.

2. Sad mac means the hardware test fails. So what does that test? Where in the test is it failing?

3. Are you usng a stock ROM? The ROM does a RAM test, lets consider that. Time how long from power on the sadmac happens. What happens if you press reset? Remove the RAM, contact clean it and the slots. Take care of the clips (are any broken already? This is an important question). Compare how long it takes to sadmac with 4MB RAM and 8MB RAM - is it different?

I’m using the stock soldered on ROMs. I’ve got a lot of RAM to work with and I’ve tried different sets in different not the 4 A bank slots as well as both banks full but I have not conspired the timing. I will do that.

All sim slots are in great shape. No corrosion and no broken plastic.

One thing ive found is if I use an OEM supply it doesn’t chime and it shuts off immediately. So something isn’t right with the power circuit.

When I use the bench ATX supply then it’s powering up and chiming.

Another thing I’ve noticed is when I put a card on the NuBus (I have 4 of them) all but one cause the board to only make a clicking sound and no chime the boards not coming up. One card has an LED on it that flashes on for a split second and back off. And none of the cards are moving data. Only a clock signal. The card that does let the chime happen is my 2nd video card. So some clues there.

I have no address or data activity on NuBus wjen it has no cards installed but maybe this is normal behavior?

Phipli · Sep 3, 2023

Following the reference in step 6... we find this :

Where you are falling over in step 1 or 2.

This begs two questions.
1. Hows your RAM?
2. Do you have a video card installed?

Sideburn · Sep 3, 2023

Phipli said:
This whole process following is successful:

Possibly step 6. asside.

Good info. Thanks!

Phipli · Sep 3, 2023

Sideburn said:
All sim slots are in great shape. No corrosion and no broken plastic.

Corrosion isn't what I'm talking about, a small amount of dirt, dust or grease, even just from age, is enough to need cleaning.

Sideburn · Sep 3, 2023

Phipli said:
Following the reference in step 6... we find this :

View attachment 61590

Where you are falling over in step 1 or 2.

This begs two questions.
1. Hows your RAM?
2. Do you have a video card installed?

See above

Phipli said:
Corrosion isn't what I'm talking about, a small amount of dirt, dust or grease, even just from age, is enough to need cleaning.

I cleaned the board with toothbrush and alchohol after re-capping. It looks good to me. But I’ll give it another once over.

To answer your video card question see my post above. When I put the card in with the Apple Macintosh ii video card (or any other non video card) I get no chime. When I put the Radius video card in I get a chime but no video and probing it with the scope I see no activity other than a clock.

Sideburn · Sep 3, 2023

As far as the ram goes, I have no way to test it but I have a lot of them. Probably at least 24 or 32 SIMMs.

Phipli · Sep 3, 2023

Sideburn said:
One thing ive found is if I use an OEM supply it doesn’t chime and it shuts off immediately. So something isn’t right with the power circuit.

Well, that means it isn't latching. That's a broken trace or dry joint in the power circuit. It might be a dead chip, but it almost never is.

Sideburn said:
Another thing I’ve noticed is when I put a card on the NuBus (I have 4 of them) all but one cause the board to only make a clicking sound and no chime the boards not coming up.

This is worrying.

Sideburn said:
I have no address or data activity on NuBus wjen it has no cards installed but maybe this is normal behavior?

I'm not in the habit of running my machines with no cards while connected to a logic analyser.

Sideburn said:
See above

No... you haven't said you cleaned the contacts "look ok" isn't enough

Sideburn said:
I cleaned the board with toothbrush and alchohol after re-capping. It looks good to me. But I’ll give it another once over.

I was talking about contact cleaner on the RAM and slots. Specifically contact cleaner.

Phipli · Sep 3, 2023

I'd put my effort into working out why it won't chime with a NuBus card installed first. I suspect it might sadmac with no video card anyway, so that doesn't tell us anything.

Sideburn · Sep 3, 2023

Phipli said:
Well, that means it isn't latching. That's a broken trace or dry joint in the power circuit. It might be a dead chip, but it almost never is.

This is worrying.

I'm not in the habit of running my machines with no cards while connected to a logic analyser.

No logic analyzers. All I’ve been doing is touching pins with my oscilloscope probe to see if there’s any activity.

Phipli said:
No... you haven't said you cleaned the contacts "look ok" isn't enough

Phipli said:
I was talking about contact cleaner on the RAM and slots. Specifically contact cleaner.

Haha well I scrubbed the board down and cleaned it a while ago. I will deoxit them today!

Phipli · Sep 3, 2023

Sideburn said:
No logic analyzers. All I’ve been doing is touching pins with my oscilloscope probe to see if there’s any activity.

Haha well I scrubbed the board down and cleaned it a while ago. I will deoxit them today!

Again, the RAM contacts and RAM slots, not the board.

Anyone up for some IIcx troubleshooting assistance? We have clocks but no activity...

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