TF536 in Mega ST / Error 33

[macsonny]

I've now completed a complete recap of the ain board and then installed the TF536. If anything things got worse as I went from an Error 33 being displayed on the screen to now just a blank grey screen.

I plan on using TOS 2.06 in place of EmuTOS and replacing the resistor networks over the next week. Hopefully that will help make some progress.

[macsonny]

...
Secondly, the Bliutter fix seems to apply only when the 68000 CPU is actually installed. As I need to remove the chip for the TF536, is there any other way to do the Blitter fix or is it not required when using the TF536?

I removed the blitter chip from the board as well as removed the blitter patch. According to the PAK manual the blitter is slower then <33MHz 68030 anyway. So it doesn't make much sense to keep it. Cool to have but hardly anything uses it. Same with FPU.

Some more info regarding blitter needed or not.

Thred when PhilC got his TF536 working in a Mega.

In the tread where PhilC is trying to get things going there is lots of reference to a capacitor between CLK and GND. Does anyone know exactly where that should be installed on the board?

[PhilC]

@macsonny I never needed the cap on my TF536 in the end.

You don't need to do a blister patch and the blister can stay installed. You need to use maprom and blitfix to get it to run properly.

My Mega ST has had the bus resistors changed and the main oscillator replaced with a 32.08 mhz version, instead of the 32.04 that's standard. I use it to test the new ST536 when required by exxos.

FYI ST ram speed may also effect reliability of any 030 boosters on a Mega ST.

[macsonny]

@macsonny I never needed the cap on my TF536 in the end.

You don't need to do a blister patch and the blister can stay installed. You need to use maprom and blitfix to get it to run properly.

My Mega ST has had the bus resistors changed and the main oscillator replaced with a 32.08 mhz version, instead of the 32.04 that's standard. I use it to test the new ST536 when required by exxos.

FYI ST ram speed may also effect reliability of any 030 boosters on a Mega ST.

Thanks for the tip. I've downloaded the software as suggested and will dump in my AUTO folder tonight to test.

On a side note, how do you arrive at needing the 32.08 vs 32.04 MHz oscillator? Is that specific to just your setup, or will it be required for everyone using a TF536?

[rubber_jonnie]

I've now completed a complete recap of the ain board and then installed the TF536. If anything things got worse as I went from an Error 33 being displayed on the screen to now just a blank grey screen.

I plan on using TOS 2.06 in place of EmuTOS and replacing the resistor networks over the next week. Hopefully that will help make some progress.

So my question here is, are you getting a grey screen with the TF536 installed?

If so I'd suggest you go back to the base config and make sure your machine works as a standard Mega ST once you've completed any other work before you try to work with the accelerator again, otherwise you may be fighting multiple issues.

[PhilC]

@macsonny the oscillator was just something I decided to try and it helps with my setup but may not work in other machines.

As @rubber_jonnie has said, just verify that everything is reliable with emutos v1.4 256k, using your basic setup but with the tos decoder and a 68000 fitted. Then move on to the TF536.

[macsonny]

@macsonny the oscillator was just something I decided to try and it helps with my setup but may not work in other machines.

As @rubber_jonnie has said, just verify that everything is reliable with emutos v1.4 256k, using your basic setup but with the tos decoder and a 68000 fitted. Then move on to the TF536.

Good advice. I have removed the TF and gone back to stock 68000 CPU. When I got my MEGA 4 it had an odd mod and I didn't know what it did at the time. I removed it but have since worked out it was a home made Blitter patch. The machine seems to run just fine without the patch but I'm wondering if the previous owner also cut a trace when installing the Blitter patch that I now need to reverse?

I'm waiting on a ROM emulator to arrive that will let me run TOS 2.06 and I'll also replace the resistor arrays.

I ended up purchasing a new clock crystal too. At this point in the process I'm trying to keep all options open.

Will report back once I've slowly added each mod then see how the TF acts from there.

[PhilC]

@macsonny when the blitter patch was installed, there was a track that needed cutting on the bottom of the PCB between the motherboard pins, you'll need to remake this connection regardless of whether you use a blitter or not.

[macsonny]

This is the patch I need to make I assume (see attached pic)?

[Steve]

I don't know if this helps or not, but when I put a TF536 in my small STm I had to change the motherboard latches to the slower variants, as per the PAK30 instruction manual. It was unstable otherwise. (Sorry I don't remember specifics, you'd need to track down the manual to find out)