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My GQ4x4 programmer decided today to fail every damn eprom writing for wathever reason... so was not able to make this M1. Decided to use extermination approch and started socketing & replacing several IC. Op AMP : innocent Y3016 : Innocent TA820: Innocent Capacitors : innocent (lol for the...

Do i need to burn both new M1 and Sp1, or the new M1 works just fine with regular sp1?

UPDATE Checking out continuity, found that PINs 10 & 11 of NEOBuf in GA8 where shorted. Tracked it back to Resistor pack in CR6. Comparing to other pack, pin 3 & 5 are not supposed to be connected. Seems it suffered a damage or current load. Anyways, swapped it, and Start/Select are...

One mor Another thing g to keep in mind, found out that BuF @ GA8 and GA9 have also to controllet input. So if you have trouble in some buttons behaviour, than i am quite sure is one of them.

I am currently fixing an MV1A slot for different problems, but during diagnose i was swapping almost all bufs, and i got 2 time z80-<>68k communication error in Diag, one time removing buf in GA9, and anoyher time in GA8. When removing the HC273, i got the following error: Hope this helps also.

Update Half probleme solved. I am really enjoying what i am learning through repairs and truly appreciate your advices. Didn't pay attention to the diag screen in the bottom, which start/select seem to be active, even i unplugged the controller. So this led me (a blind shot to be honest) to...

Hi again, Now that i am progressing (hope so) in my novice knowledge of MVS repair, i grabbed an old MV1A slot that considered as scrap. First watchdog’ fixed that with broken trace on bios pins. But still only boots on diag bios. Stock and unibios still watchdog. Second the diag screen is...

Great pinning layout. Do th pinning you traced from 68k and z80 is the same if it was to a NeoC1, instead of BuF+273? If yes , you are right it might be one of both. Even The BUF seems to be failing regulary.

Absolutely! Before, image with composite was so bad that i was considering recapping the set. Difference is very noticeable. And the 240p test suite cart i made few months ago was extreamly helpful to fine tune the geometry.

Well it seems every road lead to the oscilloscope. Damn i am just learning to use a probe. Now an oscilloscope..

Not a very clever guy on CRTs, but there might be V.HOLD and a H.OLD pot on the chassis that could fix the video jiggeling. Have seen many on several CRTs before, and very small turns fixed the issue. On other cases, pots were damaged themselves and needed replacement. Hope this helps.

Now to finish the setup of the slot i repaired, it sadly came without the plastic cartridge holder, which if i recall consists of 2 parts, held togzther with some screws. Any open source availabke 3D file for this exact slot so i can try to print it at a friends office, which has a 3D printer...

A quick recap on the whole repair done, ot might be useful for others. Black screen: NEO-D0 (swap) Traces repair near it (battery leak) Watchdog: NEO-E0 (corroded pads/getting hot/swap) NEO-F0 (corroded pads/getting hot/swap) NEO-C1 (corroded pads/getting hot/swap) BIOS SOCKET (Weak contact...

Ahh the sweet sound of the Diag cart test pass... "prrrrrrrrrt". Bull's eye @ack It was defenetly two vias connecting SD1 & SD2 from NeoC1 to RAM6116 to Z80. Connection was actually to the ram, but 2 vias were not making it to z80, knowing that i repaired the whole corroded area before...

UPDATE Thanks to the Ram location templates on ack's github, i could focus cheking traces on the lower wram. Finding them all fine, i went straight to swapp it, and finally i could see the sweet "test pass" from diag. Now the slot is able to play games on Unibios, but without sound. Diag...

Checked all the traces and patched the few suspected.. Anyways, now just by flexing a little the board i Managed to get the following error with diag bios:

Hello, This is to share my first experience of modding a CRT into RGB. This one is a Sony Kv-1499X. Having only RF and 2 Composite inputs (typical for sony CRTs in north africa) i started by reading it's manuals. Found out in the manual that the jungle chip had actually a second RGB inout...

Great saving! I have a PVM 20m2e which i struggle to fix since mor than 2 years.. I searched and post threads everywhere but without succes. I don't know how good you are at PVMs, but i'll try to ask anyway, becausr i am still a novice. Do you mind if you hekp me out figure out whats wrong...

@ack any idea how to proceed for this update? Thanks in advance.

A potential stupid question: dif you try another game besides kof99? Just asking because i had a game with corrupt M1 that was working fine just days before the issue occure. Besides that i jsut remembered i had a sound issue were NeoGeo jingle would play at charachter selection screen whatever...