Secret Agent PALs

Stoog

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Hey all

Hope Caius chimes in :)

Doing a repair to a Serect Agent (Sly Spy) which hopefully someone can help me

Basiclly the cpu is stuck all address lines data lines no activity reset pin has vaild reset clock correct freq

I have gone over this PCB checked boot ram roms all good buffers all good and connections between cpu ram roms and buffers but still yet to find whats causing it not to run

The only thing left is the CPU and these 3 PALs near the first 2 boot roms seems the WR and a few other inportant pins run into these

i may have either a faulty one or all 3 faulty and i would like to replace these to rule that out but i am not 100% sure if the ones dumped in the mame set are correct and are vaild dumps

Im yet to find a faulty 68k cpu but anything is possible
Can anyone help?
 
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Already been there there is some dumped but says untested but in mame seems the whole sets been dumped i really hate these kind of faults as i have a couple of pcbs now that still yet to understand why they refuse to boot :( they been in the too hard pile for a long time
 
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'Untested' means they have not been yet tried but they can work so it's worth a try.Board will not blow up if they will not work :) If you will get same behaviour, it will mean PALs are not the cause of your issue.
Don't forget on JAMMArcade there is also the Sly Spy PAL set, hardware is the same so you should try them too but they need first to be converted to GAL since they are in native PAL fuse map.
 
Cheers :) yes i know it won't blow up hehe but hey can't make it any worse then it is but like i said thats all thats left that i can think of besides the CPU after that i really have no idea whats causing it to just not run. Seems these PALs control the CE WR on rams and boot roms

Isn't there a program to convert PAL to GAL fuse map i think i had it awhile back but can't remember what it was called :(
 
Just download from jammarcade the sly spy ones there all in JED format already or are you talking about the Secret Agent ones?
 
Sly Spy ones are in yes in JED format but they are for PAL devices and not GAL, if you open the .JED you will notice it.So, you have to convert them to GAL.The Sly Spy archive contains also the dump of the 'TA-2' (which is missing from the Secret Agent one) which is obtained from an unsecure registered device (PAL16R4).This must be adapted in GAL fuse map too if you want to try it
Anyway, try first the Secret Agent ones, they are ready to be burned onto GAL16V8

P.S.
I think dumps from both sets are the same since hardware is the same (the two games are only different region) but need to check equations.
 
ok great thanks yes i did notice that would you be able to convert these for me please?

ill give the ones already to go a try tomorrow but if nothing changes ill rule out those being faulty and if its not the cpu then its going in the too hard pile i did put a known working cpu over the top of it but no changes so i highy think its not the cpu

i did change out the buffers just to rule them out but no change i do get video displaying but its just random garbage changes on each power up
 
Is the CPU putting itself into HALT mode?

Just in case check for continuity on data and address buses from CPU to the ROMs. I had a NeoGeo a few weeks back with a 'dead' CPU (no activity, halt pin low). I found 3 data bus lines shorted together far away from the CPU at one of the customs. Of course this means the 68K will try to boot, get a very corrupt stack ptr and reset vector, and immediately be so horrified it goes into HALT.

Just for fun - burn a pair of boot roms filled with all zeros, and see if the CPU does anything. The 68K can execute all zeros without ever hitting illegal instruction, bad irq vectors, etc, which limits ways it can go into HALT.

And yes, a PAL controls /OE on the ROMs so a bad PAL won't help things.

(Trivia fact - Secret Agent has a dynamic memory map for protection - a PAL 'moves' the tilemap addresses around in 68K address space so they are in different places on different levels)
 
No not going into halt mode and ive meter all of that back from cpu to buffers to rams/roms all connected correctly but could be further along hmmm shame no schematics for this

ill try that eprom idea might help me a bit hopefully but other then thats its strange what ever i do just wont show any acivity what so ever on the cpu
 
Obviously the CPU commands the whole system, so all troubleshooting must start from it.This is something people still have troules to understand.
 
yes i know that but as i stated ive had issue before with 68k cpus pcb games doing this i couldnt figure out the excat same problem give me a z80 based pcb anyday i do try thats the main thing sorry if i dont explain things correctly have a hard time doing that
 
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So /HALT and /RESET are both high, there's a clock and still not activity? Does sound like bad CPU at that point. Check/replace the capacitor near the CPU (that's involved with reset) anyway.
 
IIRC this board uses the typical power-ON delay circuit to generate the /RESET signal : a voltage monitor (a PST518 used most of times or a simple BC547 or a 1N4148 diode), a capacitor and a resistor.You should check if /RESET signal is correctly generated, 68000 requires on pin 18 a signal of 2ms at least to branch into the /RESET vector and initialize the core.So, check if signal is briefly LOW on start-up
 
So /HALT and /RESET are both high, there's a clock and still not activity? Does sound like bad CPU at that point. Check/replace the capacitor near the CPU (that's involved with reset) anyway.

Thats correct ill check out the reset section again but couldn't fault any issues
 
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