Search results

Whats the 5V rail actually delivering? If it there is a short, voltage should collapse, the IC would heat. The YM2610 always gets warm, you can ignore that.

The blue screen on the AES is the equivalent of the cross hatch screen on the MVS, usually caused by interrupted P Rom traces. I'd start checking the traces for the P ROM. @ack made a testing PCB for that, works in conjunction with the (new) DIAG BIOS...

R63 is 150 Ohm, confirmed by measurement

Multicarts pull more power than normal carts, did you measure if the 5V are actually 5V? Measure that on the power rail, but also on the ICs. At 4.7V things go weird.

If the Diag BIOS can't find problems but there is obvious problems with the graphics, its a hint that the problem is in parts that aren't tested by the DIAG BIOS. Check the connection of WE1-WE4 from the LSPC-A2 to the B1. https://wiki.neogeodev.org/index.php?title=LSPC2-A2...

have a look at this excelltent documentation by ack: https://github.com/jwestfall69/neogeo-diag-bios/blob/master/docs/ram_locations/neo-aes3.md I think you should focus on the 32k VRAM, the SRAM next to B1 is the Work RAM. here is a pic of the traces from the Work/Backup RAM, the Address lane...

its the P Bus, not the P ROM sorry see the port pinout for the AES: https://wiki.neogeodev.org/index.php?title=AES_cartridge_pinout there is a row for odd numbers: P1 to P23 then another one for the even number: P0 to P22 these go to the NEO-B1 and LSPC2-A2, by the looks of it, I'd test...

Yeah thats typical corroded traces, they might even work until you look too hard at them.. It was damaged already. I think your reasoning is right, rather paying someone who has done this before :)

Well if the RAM traces have continuity, I'd check them for shorts between them, its easy to create them. it looks like lines are doubled, can you see how many repetitions there are? https://wiki.neogeodev.org/index.php?title=Graphic_glitches#C_ROM So I'd check the C Rom address traces, see...

Good job with the pics! Now I can spot that the BIOS was socketed, the 68k as well, then a RAM IC (top right of the board) was either reflowed or replaced.. Trace repair was done on the BIOS as well. Those jumper wires for the SRAM ICs next to the reset button are way to big and dodgy...

You can disable the calendar test and all other HW tests with the Unibios (HW tests are disabled by default i the UniBios). FWIW, the area for the calendar clock is in your pic and I can spot rotten traces there: TBH, I don't think you need someone to pick up the whole arcade machine, much...

Hey Jamie, good to see you're looking for someone in the UK to take care of that PCB. I can see corroded traces in that area, but fixing that needs kind of experience IMO, I'd suggest not to practise on a 6 slot. There is a learning curve when aquiring new skills, that means you'll break more...

Take a close up of the jumper cables at the RAM ICs next to the B1/Reset switch, someone made a mess there. Can you burn an EPROM? If so, I'd suggest the DIAG BIOS: https://github.com/jwestfall69/neogeo-diag-bios Edit: good pics of this area would help IMO but then again, good pics of all...

The CRT switching is probably due to the switching voltage being present, it is expected since you've verified the voltages. So no sync at all at the OSSC, not even a fast changing one? I agree that it looks reworked from the pics, the white spots are delamination caused by excessive heat, at...

-- oops - misread the first post

The cheap replacement lasers often are not properly adjusted, but even if so, you still need to make adjustments to some potis: https://www.neo-geo.com/forums/index.php?threads/neo-geo-cd-repair-problems-laser-unit.264535/ TBH I'd recommend a NeoSD Loader anytime over a "new laser", the drive...

Yeah I use an OSSC with a 55 inch monitor attached to spot this kind of noise. On my consumer CRT there is no way to see the noise, these have an LPF or around 9-10MHz. Hehe sounds like you also have a small collection of MVS PCBs at home ;)

missing PC caps on the bottom usually means that they been ripped off by force, check for damaged traces there first, bent pins that are shorted etc. if that looks good I'd move on to check that each BIOS pin has connection to the 68k PC = power conditioning, they re not required, them missing...

I remember you mentioning that, even tried it with both frequencies using a dual frequency oscillator, 24MHz or 24.168..MHz did not make a difference on the same board. I did notice some boards (MVS and also AES) are just nosier than others (in the case of the AES it was even the same...

To conclude this in case someone else stumbles on it: - the NEO-244 at position C2 ( Buffer for P Bus) had half of it buffers shot - this caused the graphics problems - the NEO-244 at position E2 (Buffers for ADPCM) had 4 input/8 output shot, this caused missing sound and probably instability...