STFM 4MB SIMM ADAPTER KIT INSTALL BLOG

[PeteW]

Follow up on my last post. Until anyone tells me otherwise, I've connected the capacitor between the earth pad and the lower pad of the inductor (Because there's a hole for a component half way along the inductor and it looks like that may be where it was connected in the how to guide.

20180729_155241.jpg

Please correct me should that be wrong. I won't be powering it on today as I have a couple of other questions:

1. My mmu is surface mounted. Do I still need to connect the jumper wire between the ram board and pin 64 of the mmu? If so I will use where the track connects to resistor r63 to do it.

20180729_155412.jpg

2. The ram kit itself came with 3 surface mount capacitors and space for 2 on the board (c2 and c10 as far as I can tell). Was the third one just a spare?

20180729_155533.jpg

Think that's all!
Thanks
Pete

[exxos]

Follow up on my last post. Until anyone tells me otherwise, I've connected the capacitor between the earth pad and the lower pad of the inductor (Because there's a hole for a component half way along the inductor and it looks like that may be where it was connected in the how to guide.

As long as its on 5V and 0V line it will be OK.. but you probably don't need that cap anymore.. I would re-route the floppy power cable to the front of the PSU connector though..

1. My mmu is surface mounted. Do I still need to connect the jumper wire between the ram board and pin 64 of the mmu? If so I will use where the track connects to resistor r63 to do it.

SMT has different pinout... you want MAD9
See pinout here...
https://www.exxosforum.co.uk/forum/viewt ... f=31&t=149
.. it won't have anything connected to it (maybe small track which doesn't go anywhere).

2. The ram kit itself came with 3 surface mount capacitors and space for 2 on the board (c2 and c10 as far as I can tell). Was the third one just a spare?

Have you look on top of the PCB ? Theres been a few revisions of that board, think there was 1 on top and 2 on bottom.

[PeteW]

Nearly done. Took a long time (Nearly all day with a few short breaks to do other stuff)

The board isn't yet soldered to the motherboard, but is otherwise complete.

20180729_203030.jpg

The capacitor C49 has been relocated even though I probably didn't need to refit it (both ends of inductor L51 seem to be 5v, so I just connected to the end that was easiest)

Resistors r71-73 have been fitted (47 ohm as I had some available)

All I need to do is solder the Ram board to the motherboard, attach the MMU jumper and trim the psu metal to fit around the board.

The ram board won't be quite as high as it needs to be to allow for the simm to be removed (headers not long enough for that), but the chances of me ever needing to remove it are slim to non existent.

[exxos]

:bravo:

Make sure you have no broken tracks on the motherboard where the pins will solder to, hard to find such faults when its all soldered in place!

[PeteW]

:bravo:

Make sure you have no broken tracks on the motherboard where the pins will solder to, hard to find such faults when its all soldered in place!

I will double check - I did find one that I had to repair. I still need to check that any plated through holes still connect to tracks that may be on the other side. Maybe I'll refill them all with solder to be sure?!

[exxos]

Maybe I'll refill them all with solder to be sure?!

No real point soldering any holes which are not used by the board.

[PeteW]

Ok it's fitted. Powered it on to boot the flashfloppy loader and I get 3 bombs on the screen:

20180731_192756.jpg

Any ideas? It's hardwired to be in 4mb mode - maybe needs to use 1mb?

It boots to TOS if I unplug the gotek

Ideas from those more brainy than me much appreciated :)

[exxos]

You need to try this to test RAM..

https://www.exxosforum.co.uk/forum/viewt ... ?f=25&t=28

[PeteW]

Thanks but without a working drive I can't access it. Will double check everything and see what I can find

[PeteW]

Solved with good old fashioned looking! Was a small solder bridge between pins 66 and 65 of the smt mmu (the legs are very close together)

Sorted that out and it boots as normal :)