MegaSTe CPU PCB wire modification?

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Fujiyama
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MegaSTe CPU PCB wire modification?

Post by Fujiyama »

I'm in the midst of replacing the PLCC socket for my MegaSTe CPU as I'm having trouble getting my MonSTer board to work flawlessly with it (and suspect bent pins/bad contact of the previous socket).

I bought the computer second-hand, and I notice there's a wire soldered from the underneath of the motherboard between the CPU (U7) and a PAL20L8 chip (UA2) which I wonder is standard and correct or some sort of modification, or it could be because of an error when designing the PCB.
megaste_cpu_wire.jpg
The wire connects between pin 32 (A1) of the U7 (68000 CPU) and pin 19 (I04) of UA2 (PAL20L8).

Here are the relevant parts from the MegaSTe schematics (click for larger images):
U7cpu_pin32.png
UA2_pin19.png
Is it supposed to be like that?
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czietz
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Re: MegaSTe CPU PCB wire modification?

Post by czietz »

Fujiyama wrote: Mon Oct 26, 2020 12:59 pm Is it supposed to be like that?
If you want a HD floppy to work, yes.
mste.PNG
From: https://docs.dev-docs.org/htm/search.php?find=C302953
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Fujiyama
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Re: MegaSTe CPU PCB wire modification?

Post by Fujiyama »

Ah!!!!
Thanks for pointing that out.

On second thought, I probably did that modification myself when I upgraded my floppy drive :D
Mega STe | MonSTer (Mega STe) with dual IDE-CF memory card adapter | STe | SM-144 |NEC Multisync 1990SXi | IDE doubler | ST_ESCC | RSVE | ICD Link II | Link '97 | HD floppy drive/AJAX | HD floppy module | Minolta PCMCIA card-drive | Realtime Clock module | Discovery cartridge | Unitor-2 | Export | Combiner | Steady Eye | Human Touch | Unicorn USB

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