Groppo91 wrote: Wed Mar 30, 2022 2:39 pm
Based on the schematics provided sporniket I am finding the Address pins wrong on my board:
Pin 2 says it should be going to A16 on the CPU (pin 47) but mine seems to be going to pin 48 which is A17.
I then tested pin 3 on ROM that should be going to A15 on the CPU (Pin 46) but mine seems too be going to pin 47 which is A16.
If we are talking about p4 of my schematics ("U102 U103 - EPROMS"), the pin 2 of the eproms is named "A16", and is wired to "A16_SELECT" that goes to W104 and then connected either to GND or A17 of the address bus. So in fact all is normal on your board
Groppo91 wrote: Wed Mar 30, 2022 2:39 pm
Based on the schematics provided sporniket I am finding the Address pins wrong on my board:
Pin 2 says it should be going to A16 on the CPU (pin 47) but mine seems to be going to pin 48 which is A17.
I then tested pin 3 on ROM that should be going to A15 on the CPU (Pin 46) but mine seems too be going to pin 47 which is A16.
If we are talking about p4 of my schematics ("U102 U103 - EPROMS"), the pin 2 of the eproms is named "A16", and is wired to "A16_SELECT" that goes to W104 and then connected either to GND or A17 of the address bus. So in fact all is normal on your board
Ah many thanks for the clarification. I am now puzzled to what is causing my issues as everything is testing fine. Has anyone got any ideas of what I could try next?
You could always just swap the new ROMs over and see what happens. Wouldn't hurt anything... Just in case they were marked up incorrectly.
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.
stephen_usher wrote: Wed Mar 30, 2022 3:15 pm
You could always just swap the new ROMs over and see what happens. Wouldn't hurt anything... Just in case they were marked up incorrectly.
+1 for this.
Collector of many retro things!
800XL and 65XE both with Ultimate1MB,VBXL/XE & PokeyMax, SIDE3, SDrive Max, 2x 1010 cassette, 2x 1050 one with Happy mod, 3x 2600 Jr, 7800 and Lynx II
Approx 20 STs, including a 520 STM, 520 STFMs, 3x Mega ST, MSTE & 2x 32 Mhz boosted STEs
Plus the rest, totalling around 50 machines including a QL, 3x BBC Model B, Electron, Spectrums, ZX81 etc...
stephen_usher wrote: Wed Mar 30, 2022 3:15 pm
You could always just swap the new ROMs over and see what happens. Wouldn't hurt anything... Just in case they were marked up incorrectly.
