Neo Geo MVS 4 slot problems - sound, capacitors, Chinese bootlegs etc

[Max...]

Further update, moving onto the 2 slot now - annoyingly could not get it on video as it is again random but this seems the general sequence when sound does fail.

So sequence is: boot up sound all good, coin in, switch from slot 1 (MPE) to slot 2 (PI2), start game = zero sound. Soft reset still zero sound. Power on/off - sound restored.

Just leaving the 2 boots running and cycling through attract sequences alternatively does not seem to cause sound loss. It's only when you coin up and switch slots it seems.

EDIT 5 minutes later - above is wrong, left them cycling (no coin up or button pressing) and sound has gone again.

AliX accepted the return free post so I'll order another but PI2 is not so easy to find so I may have to order from the same AliX supplier again...

 

[Retroman839]

TBH probing and all that is past my pay grade, I can do basic modding, consolizing, making leads and Jamma harnesses etc but once you delve deeper

Further update, moving onto the 2 slot now - annoyingly could not get it on video as it is again random but this seems the general sequence when sound does fail.

So sequence is: boot up sound all good, coin in, switch from slot 1 (MPE) to slot 2 (PI2), start game = zero sound. Soft reset still zero sound. Power on/off - sound restored.

Just leaving the 2 boots running and cycling through attract sequences alternatively does not seem to cause sound loss. It's only when you coin up and switch slots it seems.

EDIT 5 minutes later - above is wrong, left them cycling (no coin up or button pressing) and sound has gone again.

AliX accepted the return free post so I'll order another but PI2 is not so easy to find so I may have to order from the same AliX supplier again...

I’m confused
Your 4 slot - has sound issue regardless of carts ?


Just has sound loss on sigle bottom board using sound test ?…

If you burn a diag bios chip it will diagnose some sound faults and z80 ..
If no z80 error at least you know it is not your z80.

Check amp pinout
I’m sure it’s pin one to pin 2 will show a short on continuity with a multi meter if amps blown .

Your 2 slot is this fine with legit carts ? Then it’s fine

 

[Max...]

I’m confused
Your 4 slot - has sound issue regardless of carts ?
Amp & caps

Just has sound loss on sigle bottom board using sound test ?…

If you burn a diag bios chip it will diagnose some sound faults and z80 ..
If no z80 error at least you know it is not your z80.

Your 2 slot is this fine with legit carts ? Then it’s fine

Sorry - yes.

In short:

The bootleg PI2 is causing issues regardless of the hardware.

The 2 slot board sound seems fine regardless.

The 4 slot board sound is fooked independant of the bootlegs.

 

[Retroman839]

Sorry - yes.

In short:

The bootleg PI2 is causing issues regardless of the hardware.

The 2 slot board sound seems fine regardless.

The 4 slot board sound is fooked independant of the bootlegs.

At least it’s not corroded traces or corrotion in the cn conector by sounds of it ( excuse the pun !)

If your getting noise amp is ok
Crackly and hiss disapearimg reappearing - caps

 

[Max...]

Thanks for the help all - anyone got a link to a supplier for a full re-cap kit for these boards? It's the MV4 FT2 4 slot.

 

[Retroman839]

Thanks for the help all - anyone got a link to a supplier for a full re-cap kit for these boards? It's the MV4 FT2 4 slot.

Someone set one to a place on here to a little while but was fully repaired,

Can’t remeber name of Co.
But sure it can’t be hard to find the thread

 

[Max...]

I'll look around, guessing I'll have to do the lot.

 

[TheDaddy]

Looks to me like they may have been replaced before ?? Still could be a cap issue mind.

Dave.

 

[Retroman839]

 

[Retroman839]

View attachment 48919

His look to be original
All the small ones are flat on top

 

[Max...]

Did find some lists for caps on these baords if it helps anyone in the future and I have cross referenced both of these and now double checked against my board (MV4 FT2) so the definitive list, at least for this 4 slot FT2 revision is:

Value Quantity
100uF 16v 4
10uF 16v 2
1uF 50v 2
220uF 16v 2
22uF 16v 4
4.7uF 25v 8
470uF 16v 7 (including 2 for the top board)
47uF 16v 1

Neo Geo MVS - TechWiki

wiki.console5.com

and: https://www.neo-geo.com/forums/inde...ed-cap-kit-for-mvs-mv4ft.262742/#post-4276055
MV4F / MV4FT2
Value Quantity
100uF 16v 4
10uF 16v 2
1uF 50v 2
220uF 16v 2
22uF 16v 4
4.7uF 25v 8
470uF 16v 7
47uF 16v 1

NEO-MVH It seems this is possibly a later revision, with a more compact design?
and second link for an MV4-FT3 gives:

bottom board
4.7uf 25v qty. 8
470uf 16v qty. 6
100uf 16v qty. 4
22uf 16v qty. 4
1uf 50v qty. 2
220uf 16v qty. 2
10uf 16v qty. 2

top board
470uf 16v qty. 2

 

[Retroman839]

Was it retroclinic ?
That a guy sent his mvs to for sound recap?

 

[Max...]

I'l be happy to have a go at the re-cap myself.

But...f@@@king buggering MVS! One thing after another - 2 slot now playing up. Got a Z80 error that I've never had before, then graphics have started to glitch on all games (slots are cleaned and cleaned again) then I managed to let the metal cover lean across the back of the PCB while checking things - cue burning smells from the loom but miraculously doesn't seem to have caused any more issues - for the moment...

For 20 odd years I've had no issues with my 2 slot and 4 slot then it all screws up.

Wish I'd stockpiled a ton of boards when they were super cheap!

 

[TheDaddy]

I would not bother getting a lottery ticket any time soon , You seem to be out of luck

Z80 errors can be anything , 80% of the time it happens on single boards when battery leakes and it takes out the tracks. This does not normally happen on 2 slots as the battery is over the other side near the customs. Past that it could be a ram , CPU or TTL issue. I suppose you need to do some proper diagnostics by not using the Ali Express boards to see if thats causing issues. I personally (And just my opinion) dont think the dodgy bootlegs are destroying you boards.

Dave.

 

[Max...]

No, I agree Dave - it's all just time I think playing it's dirty tricks. Been watching loads of MVS repair videos and what I take away is even for real nerds with all the tech and probing and know how it's an utter PITA when MVS boards start and continue to fail.

As I say though any thoughts of diagnosing all the issues is really beyond me...

I think I've just been lucky for a long while despite my bad run this weekend!

 

[Retroman839]

Hope your 2 slot is ok mate

I have had slots like that work better when cart is pushed in then slightly lift it up and the slot contact pins make a tighter contact on the uplift of the cart and the gfx issue is resolved.

Put it down to the slot pins loosing some tension over thr years.
Like some carts have thicker plastics than others ..
I hate putting a bootleg cart in Thats tight as it will make great contact on all pins for that cart but put tension in the whole slot.

Do you use deoxit gold ?

 

[Max...]

Not got deoxit but did the usual credit card wrapped in kitchen paper with contact cleaner a few times and the slots similar but also very gently first with a 2000 abrasive.

I've checked the cap list and have updated the post earlier.

 

[Max...]

Ordered a H13001 and Z80a as so cheap I may as well have them on hand. Will get the caps ordered and done and update.

Any ideas on buzzing on my 2 slot now (!)? Normally I'd think this was earthing etc but if I touch the SCART plug earth to MVS ground then no change, wiggling plugs etc makes no difference. Leads are away from power supply. Adjusting line level slider on MVS makes no difference to buzz volume.

 

[Retroman839]

Oxidisation

Ordered a H13001 and Z80a as so cheap I may as well have them on hand. Will get the caps ordered and done and update.

Any ideas on buzzing on my 2 slot now (!)? Normally I'd think this was earthing etc but if I touch the SCART plug earth to MVS ground then no change, wiggling plugs etc makes no difference. Leads are away from power supply. Adjusting line level slider on MVS makes no difference to buzz volume.

got a vid of fault ?

 

[Max...]

Not really - it's just a constant tone loud buzz/hum