SEC REV SEC1_F3_2019 BETA FITTING INSTRUCTIONS

[exxos]

This installation assumes a 70789 style motherboard.

Firstly the bus pullups (address & data) on the motherboard need replacing for 2.2K ones.

A track needs cutting above the GLUE. This is pin 53 SND CS...

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Then I soldered a header pin into the VIA.. This wire goes to the SEC board (left pad).

(And yes I missed a pull-up resistor off the board )

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The rightmost pad on the SEC board goes to the new DUALTOS boards.. The Solder link is between the middle and right pad ( as looking at the image below )... When the wire connects to the DUALTOS board to the SEC booster.

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It should be possible to retrofit any previous of my DUALTOS boards (I have not actually tried this) if the LS11 is removed.. Then the ROM wire solders into pin 8 location where the LS11 was.

The SEC will run with TOS104 or TOS206, with or without blitter installed.

If all goes well, you should see 309% on ROM and 505% on int-div.

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The SEC is running 50MHz. It may run at 55MHz, but I think the SEC was unstable at around 56MHz (it will be documented in the main SEC thread somewhere) though I don't really recommend trying to overclock it anymore anyway. It should also work with slower OSCS, such as 40MHz, 16MHz etc. But its geared up for 50MHz anyway.

[PhilC]

Can this be run without the Rom board but with slower Rom speeds? I need to get a rom board for my test STFM by the looks of things Will add that for the next time I feed Harry

[exxos]

Can this be run without the Rom board but with slower Rom speeds?

Nope. ROM is decoded internally and run at high speed all the time, so the ROM board has to keep up.

[PhilC]

Fair enough then