TF536 + 68000 relocator and ROM board project.

[stephen_usher]

Well, three boards are on their way to @PhilC and should arrive tomorrow.

Given my lack of pins he may be able to build a board before I do.

[PhilC]

Wouldn't be the same without bodge wires.

[stephen_usher]

Well, a quick "dry fit" looks OK.

IMG_2047.jpg (86.31 KiB) Viewed 3017 times

[PhilC]

Looks good @stephen_usher , if I've got the parts I'll try and get it built up tomorrow afternoon if it arrives tomorrow as planned.

[stephen_usher]

Well, I've made up one of the boards, except for the pins.

Have I mentioned just how much I detest surface mount chips?

Either there's too much solder, too little solder, the solder goes in the wrong place or the chip moves JUST AT THE WRONG SECOND or a joint looks soldered but isn't or the other way around. Aaaargh!

IMG_2048.jpg (296.71 KiB) Viewed 2993 times

(Try to think calm thoughts...)

[stephen_usher]

First fitting after removing the original CPU.

IMG_2049.jpg (264.41 KiB) Viewed 2980 times

The large capacitor on the left has to have its forward connection de-soldered and moved to the hole already there to the left, otherwise everything fits nicely. Actually, I don't have to worry about being as low profile as I thought on the CPU socket as the MMU sits quite high, so I'll need the extra height to get over the top of it. This will mean, however that the top shield may not be able to fit at all, but it shouldn't impinge on the bottom of the keyboard, which is the most critical thing.

P.S. And after fitting the CPU socket the machine still boots! Phew! The Hakko made very light work of removing the CPU, it just fell out.

[PhilC]

Mine is assembled but I've got to find something to put it in as the motherboard i was going to use ive pinched the ram off of

20201010_172401.jpg (203.7 KiB) Viewed 2970 times

[stephen_usher]

Hehe. Oops!

By the way, you should just be able to solder a pin into J1 and it should fit directly into the ROM socket pin 20, if I've got the measurment correct! No bodge wires!

[PhilC]

@stephen_usher ah but not on an H4

So ivevhad some sucess, it will boot from either CPU slot just fine but the jumper key is the wrong way round

No luck do far with booting it from the on board rom socket with either tos1.04 or tos2.06, thats the roms I had to hand. To boot I have to put tos1.04 into the H4 socket which obviously means the TF536 won't boot but I call this a very good start, so well done Steve.

Not sure what time I'll have tonight but may try and delve into it a bit more.

@exxos is rom_ce on the H4 the right hand pin of JP13? I can't remember.

BTW, I didn't have 75hct157 but did have act157 which seem to work just fine.

[stephen_usher]

Well, the CPU switcher is Derkom's magic... the ROM decode is all my fault.