Re: MTX 512 (debugging thread)
Posted: 10 Jun 2019 08:56
First of all, sorry for late reply and thank you for your answers.
1.) Regarding EEPROMs it sounds like a good idea but the friend does not have an EEPROM burner yet. So this suggestion will have to wait, I'm also reluctant in modding the machine before i get it to a working order. (However i saw somewhere that there is a diag cartidge, that i can connect externally, would this also boot, if the CPU is ok?) i prefere the external option if that is even possible.
2.) I'll focuse on the video memory first. Thank you for the suggestion.
3.) Can you please elaborate on GAL solution? If i understand correctly, I should firstly restore the machine to MTX500 state and than go from there? Is this trivial or it needs some work? What is the bill of material and is there any reference on how to do it? I see that i should "putting the PAL back in without the extra board and changing LK7 from the '4' position to the '2' position and LK6 from 4-C to C-H (as he has the 'H' specification OKI RAM chips) would do that" - Where can i find the original PAL-A chip specifications? And can someone please elaborate what a LK7 and LK6 are? Or please reference me to the appropriate documentation.
4.) I also noticed the traces, will need to check for continiuity. Thank you.
5.) I've checked the Operator’s manual, for starters i was hoping for something like MTX Technical Specification, 1st page just in high resolution, as i need to learn what is what firstly. Does something like that exists?
6.) Not shure to what i'm refering in the PCB location, is there any reference, which will help me understand the layout? Or is it just a column/row kind of thing? From left to right based on chip order?
7.) If I understand correctly, i shoud also hook up the Hi-Fi (sound output) if boot sequence is started i should hear a tone? And test with <Control><G> for output. This is really trivial and i'll try it. Thank you.
8.) Can you please elaborate what a VDP is? Is it a video chip? Are ROMs prone to failure, can "originals"(non EEPROMS) be easily sourced? To test this, could i get away with the diagnostic cartidge?
9.) "The replacement chip in 9D is a CMOS (HC) device, rather than the original high speed TTL (S) chip." - I presume this refers to the soldering/replacing IC marks and is related to point 10?
10.) Will try to make a sence of the mod from page 47 of the manual and post additional pictures to confirm this.
Thank you all for all of your suggestions, I'll go through them and post the updates, but I can't guaratee that they will be regular or often, as RL gets in the way.
1.) Regarding EEPROMs it sounds like a good idea but the friend does not have an EEPROM burner yet. So this suggestion will have to wait, I'm also reluctant in modding the machine before i get it to a working order. (However i saw somewhere that there is a diag cartidge, that i can connect externally, would this also boot, if the CPU is ok?) i prefere the external option if that is even possible.
2.) I'll focuse on the video memory first. Thank you for the suggestion.
3.) Can you please elaborate on GAL solution? If i understand correctly, I should firstly restore the machine to MTX500 state and than go from there? Is this trivial or it needs some work? What is the bill of material and is there any reference on how to do it? I see that i should "putting the PAL back in without the extra board and changing LK7 from the '4' position to the '2' position and LK6 from 4-C to C-H (as he has the 'H' specification OKI RAM chips) would do that" - Where can i find the original PAL-A chip specifications? And can someone please elaborate what a LK7 and LK6 are? Or please reference me to the appropriate documentation.
4.) I also noticed the traces, will need to check for continiuity. Thank you.
5.) I've checked the Operator’s manual, for starters i was hoping for something like MTX Technical Specification, 1st page just in high resolution, as i need to learn what is what firstly. Does something like that exists?
6.) Not shure to what i'm refering in the PCB location, is there any reference, which will help me understand the layout? Or is it just a column/row kind of thing? From left to right based on chip order?
7.) If I understand correctly, i shoud also hook up the Hi-Fi (sound output) if boot sequence is started i should hear a tone? And test with <Control><G> for output. This is really trivial and i'll try it. Thank you.
8.) Can you please elaborate what a VDP is? Is it a video chip? Are ROMs prone to failure, can "originals"(non EEPROMS) be easily sourced? To test this, could i get away with the diagnostic cartidge?
9.) "The replacement chip in 9D is a CMOS (HC) device, rather than the original high speed TTL (S) chip." - I presume this refers to the soldering/replacing IC marks and is related to point 10?
10.) Will try to make a sence of the mod from page 47 of the manual and post additional pictures to confirm this.
Thank you all for all of your suggestions, I'll go through them and post the updates, but I can't guaratee that they will be regular or often, as RL gets in the way.