A4000 + A3660 Fast Ram Issue

Hoping that someone out there can help me from pulling out what remains of my hair
Sorry for the long Post!
Some brief background on my setup:
- A4000/030 CPU
- 2MB Chip Ram, 16MB Fast Ram
- Picasso IV
- BigRamPlus 256MB
- X-Surf-100 for Ethernet
- Workbench 3.1.4 and have Genuine 3.1.4 ROMS
- I recapped the motherboard and replaced the RTC/cleaned up the whole area from a battery leak. At the time I checked all the traces and found everything was working fine and passed all checks in SysTest. I've taken pictures of the area.
All works absolutely fine and all memory (including BigRamPlus board) detected. I've been fancying a speed boost so I purchased an A3660 Rev 1.1 with Rev5 68060 CPU.
To setup the A3660 I copied over the 68060.library file to by Workbench 3.1.4 LIBS: folder. I then replaced my 3.1.4 ROMS with the patched ones the A3660 came with. Changed J100 & J104 to External, slotted in the A3660 and....flashing yellow screen. I tried removing things and found that if I removed all the cards and only left in 2MB Chip Ram +16MB Fast Ram, the screen would flash yellow a few time, but then booted into Workbench. However...….only 500k of Chip ram was available and 0 Other Ram. So the Fast Ram was not being detected at all. ARGH!
Troubleshooting things I've tried & Some interesting (and confusing) findings:
- Removing and re-seating everything
- The first thing I tried was removing and re-seating the A3660 - No Change
- I tried re-inserting the BigRamPlus card only - Got a Board Error message (v. odd as the BigRamPlus card is brand new)
- I read on forums that the 3.1.4 ROMS would work with the A3660, so I removed the patched roms and replaced them with my original 3.1.4 ROMS - same thing happened
- I inserted my DiagRom BIOS chips and it hang. Seems like it was showing a problem with the Memory being detected. I tried this with all my banks of 4MB SIMM's, and had the same issue.
- I removed all FastRam and it booted to Workbench with no Yellow screen
- Concerned at this I swapped out the A3660 for the original CPU and everything ran and tested fine.
- I then put everything back to its original state (CPU, Jumpers, Memory, Cards etc) and everything worked absolutely fine and workbench detected all my Ram.
- I also checked the Diag. info for the cards and all were shown as Working.

So, I need some help here.
- Has anyone had this kind of issue or could advise that I'm missing something obvious?
- Could the Yellow screen mean anything else?
I'm confused why everything works find with the original 68030 CPU card but when I put in the A3660 card everything shows as having an issue. It's driving me crazy so if anyone can help it would be very much appreciated!!

On some early A4000 the Clock Buffer Chip U103 (74FCT244) was exchanged with an 74FCT240 to bypass the old A3640 Rev 3.0 issues.
Motherboard 030 CPU work flawless with this Hack jast as many but not all A3640 Rev. 3.1/3.2.
If the A3606 has the Speedup Patch in the GAL Chips then it will surely never work with the wrong Buffer Chip and in some A4000 the Motherboard Timing is so critical that the Buffer Chip has to replaced with 6 wire jumpers.

Hi, thanks for the quick response. I've made a correction to the CPU information. My original CPU is a 68030 not 68040.
I've checked the chip at U103 and it is a 74FCT244TP.

So something strane and more fun and games....I started to check the traces around j100/J104 and all seemed ok, apart from on the bottom of the PCB J100 Pin 2 was connected to U102 Pin 4(T2) on the EP8700. I've checked on Amiga PCB Explorer and the A4000 Rev. B schematics and I cant see this in place. I've attached a picture showing the wire bridge.

I tried removing this, setting J100 and J104 to External and then booting with the A3660. This time I got a completely black screen.

I then put the bridge back to check against original setup (cautious me) and now I'm getting a bloody Blue screen when I boot with the original A3630 CPU. I'm giving up for today, but if anyone has any ideas I'm open to listening.

Some additional info:

U103 is a 74FCT244TP

Since the blue screen seems very recent, have you tried using the onboard 030 CPU again?

If it doesn't work with that combo, check that U975 & U976 are generating clock signals as this caused a blue screen for me.

Pin4 of U102 is an 5ns Delay for CLK90, i thing someone tried to do some heavy OC with this board, but there must also some other mods otherwise J102 set to INTERNAL results in a short circuit of J102 Pin4 and Pin 10 which sooner or later kills the Delayline.
With a A3660 and the Jumpers set to EXT and this Mod removed the Delayline is completely out of use so a defective delayline could not produce a Black screen.
Best double check all Traces and solder points around J100/J104 and U103 with a good magnifying glass there may be a crack in some trace or another Jumper around

Which 68060.library did you copy?

I used the ones from MMULibs from aminet.

awmosoft said:

Which 68060.library did you copy?

Click to expand...

Just to close this off, the chap I sent it too found that when he took out the super buster chip there was corrosion on the chip and socket pins. He tested the SB and it was dead, so after replacing the socket and a new SB it was now working fully!

There were some other issues causing it to act strangely so the ROM sockets were replaced and the ram sockets and a few of the chips around the battery were reflowed. It's being shipped back to me today!

I thought 3.1.4 ROMS supported the 3660 and didnt need the patched 3.1 ROMS.

That’s correct, but you still need the 68060 library file in LIBS