Mega ST and TOS 2.06 decoder board
- stephen_usher
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Re: Mega ST and TOS 2.06 decoder board
You have installed pull-ups on the 1772 data lines haven't you?
Intro retro computers since before they were retro...
ZX81->Spectrum->Memotech MTX->Sinclair QL->520STM->BBC Micro->TT030->PCs & Sun Workstations.
Added code to the MiNT kernel (still there the last time I checked) + put together MiNTOS.
Collection now with added Macs, Amigas, Suns and Acorns.
ZX81->Spectrum->Memotech MTX->Sinclair QL->520STM->BBC Micro->TT030->PCs & Sun Workstations.
Added code to the MiNT kernel (still there the last time I checked) + put together MiNTOS.
Collection now with added Macs, Amigas, Suns and Acorns.
Re: Mega ST and TOS 2.06 decoder board
No I haven't because of the description of the fix:
The 1772 Has a set of inverters on its output which connect the floppy drive. The original Atari drives had internal pull-up resistors however, other compatible drives such as the MPF920 (and possibly others) do not have the resistors and should be fitted to the Atari directly.
I am only using an original Atari drive or a Gotek, which I understand both already have internal pull-up resistors.
If this is a potential issue, I'm 100% on board for trying it, just seemed like a recipe for trouble doubling up on the resistors if not needed.
The 1772 Has a set of inverters on its output which connect the floppy drive. The original Atari drives had internal pull-up resistors however, other compatible drives such as the MPF920 (and possibly others) do not have the resistors and should be fitted to the Atari directly.
I am only using an original Atari drive or a Gotek, which I understand both already have internal pull-up resistors.
If this is a potential issue, I'm 100% on board for trying it, just seemed like a recipe for trouble doubling up on the resistors if not needed.
Re: Mega ST and TOS 2.06 decoder board
Ok, so try this, use the /ce line from the right hand socket, when I connected mine to the left socket /ce like you have it wouldn't work for some odd reason.
Just another thought, when you remove the blitter patch you do reconnect the cut track under the cpu right?
Am away from home tonight, so not able to give a more complete answer
Just another thought, when you remove the blitter patch you do reconnect the cut track under the cpu right?
Am away from home tonight, so not able to give a more complete answer
If it ain't broke, test it to Destruction.
Re: Mega ST and TOS 2.06 decoder board
hmmm @coonsgm When you soldered the decoder wire to the ROM PCB.. did you remove the CE pin which is plugged into the socket ? As that pin needs to be removed when driving from a external decoder... It probably wont matter for TOS206, but it may screw up TOS104..
https://www.exxosforum.co.uk/atari/ All my hardware guides - mods - games - STOS
https://www.exxosforum.co.uk/atari/store2/ - All my hardware mods for sale - Please help support by making a purchase.
viewtopic.php?f=17&t=1585 Have you done the Mandatory Fixes ?
Just because a lot of people agree on something, doesn't make it a fact. ~exxos ~
People should find solutions to problems, not find problems with solutions.
https://www.exxosforum.co.uk/atari/store2/ - All my hardware mods for sale - Please help support by making a purchase.
viewtopic.php?f=17&t=1585 Have you done the Mandatory Fixes ?
Just because a lot of people agree on something, doesn't make it a fact. ~exxos ~
People should find solutions to problems, not find problems with solutions.
Re: Mega ST and TOS 2.06 decoder board
@exxos ive not removed the pin on any of mine but I have to use the other socket /ce
If it ain't broke, test it to Destruction.
Re: Mega ST and TOS 2.06 decoder board
It shouldn't really be done that way, as GLUE and the TOS206 decoder would both be driving the CE pin.. and they won't be driving at exactly the same time they would short each other out for maybe 100ns or something.
For example, the decoder board would drive CE low pretty much within 10ns... But GLUE could still be driving it HI for some time, I've can't remember how fast GLUE decode, but for the sake of Argument, GLUE could be still driving HI up to 100ns...
https://www.exxosforum.co.uk/atari/ All my hardware guides - mods - games - STOS
https://www.exxosforum.co.uk/atari/store2/ - All my hardware mods for sale - Please help support by making a purchase.
viewtopic.php?f=17&t=1585 Have you done the Mandatory Fixes ?
Just because a lot of people agree on something, doesn't make it a fact. ~exxos ~
People should find solutions to problems, not find problems with solutions.
https://www.exxosforum.co.uk/atari/store2/ - All my hardware mods for sale - Please help support by making a purchase.
viewtopic.php?f=17&t=1585 Have you done the Mandatory Fixes ?
Just because a lot of people agree on something, doesn't make it a fact. ~exxos ~
People should find solutions to problems, not find problems with solutions.
Re: Mega ST and TOS 2.06 decoder board
Sweet, I'll try the other CE/ pad.
Yes I did connect the trace cut when the blitter patch was removed with a bodge wire under the board.
Your thoughts on the 1772 floppy failure fix? Do you think that could have an impact on this if I'm using either an original Atari drive or Gotek?
Yes I did connect the trace cut when the blitter patch was removed with a bodge wire under the board.
Your thoughts on the 1772 floppy failure fix? Do you think that could have an impact on this if I'm using either an original Atari drive or Gotek?
Re: Mega ST and TOS 2.06 decoder board
@coonsgm try the 1772 pullup fix as it's simple to do and may cure it.
If it ain't broke, test it to Destruction.
Re: Mega ST and TOS 2.06 decoder board
Well, I'm calling a full retreat here. I'll live with the Mega as it is.
Super big thanks to everyone with ideas and suggestions. I fully understand when working with these computers these are the risks we take
- I've added the 1772 pull ups and results are neither better nor worse.
I've swapped to the "other" CE/ pad with the decoder input with both CE pins in the socket.
I've swapped to the "other CE/pad with the decoder input with the CE pin attached to removed
I've swapped to the "other CE/pad with the decoder input with both CE pins removed
I've tried the original CE/pad with the decoder input with both CE pins removed
I've tried the original CE/pad with the decoder input with the CE pin attached to removed
Super big thanks to everyone with ideas and suggestions. I fully understand when working with these computers these are the risks we take
Re: Mega ST and TOS 2.06 decoder board
@coonsgm can't fault you for your efforts. After all, I've still got one Mega that won't run with a TF536 and another that does but hates floppy drives.
Sometimes it's knowing when to quit is the wisest decision to make.
Sometimes it's knowing when to quit is the wisest decision to make.
If it ain't broke, test it to Destruction.