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[Repair Log] Sega Naomi

standard scsi cable,
any bios should work with a gdrom.
not sure about if your using CF cards though.
 
I'm not using CF cards ATM; thanks for your answer.
I had checked with BIOS list on Sega-Naomi and GD-ROM for Naomi 1 seems to be only supported for BIOSes higher than 21576E, but was wondering if a certain DIMM board firmware version required a particular BIOS version.
Anyways, I found I had some BIOS versions not listed there (21577G, 21578D, 21578G, 23608, 23608A, 23085). Is there interest in a dump of them?
Naomi-Bios.jpg
 
Got a new SCSI cable; old one wasn't the problem.
Any ideas on how I can test my Dimm board?
Any pics of where to find the buffer chip that causes the board timeout?
Thanks
 
@'chacal231077' 74LCX16245MTD-ND is the DigiKey part number, right? Seems like I got 'till Feb 2023 to hone my SMD soldering skills.
Any recommendations on the kind of soldering needles best suited to do that kind of work.
TIA
 
There is probably an alternate available
 
There are many matching replacements for the transceiver; just slightly different part numbers. Anything in particular to pay attention too?
 
Can’t catch a break on my initial d 3s..now this is happening
 

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Hi, can you remove the super CAP from sega Naomi and leave it without replacing it, I think it only saves settings 🤔
 
chacal231077 said:
maybe Bad bios ?
Click to expand...
So I just got this inside and I haven’t turned it on since that day. I just turned it on and it ran perfectly fine for 5-10 mins. Went into a race and then 5 seconds into the race the screen went black and the naomi restarted. Then the scrambled graphics came back like that again until it went to a white screen and froze there.

Can anyone tell if this just ram taking a dump after heating up?
 
@hrvat9 I see flashes of checker board there. That is usually bad ram. If you check your 3.3v while game is running is it over 3.3? (you can measure with multi meter probes on the filter board)

@Adrick yes you can leave the super cap off the board.
 
TylerDurden67 said:
After having repaired a lot of Naomi, I share with you the most frequent problems and how to repair it:

General:

N1 or N2
- Does not exceed 5.1V, the buffer chips do not support more, then even if it is less than $1, better to avoid changing by pure luck! Rams aren't supporting more voltage too.
- If a fan is not running (Naomi checked rotating using the 3rd wire), it does not boot for safety. otherwise that kind of stuff can append


- The super-condo 0.1f EECS0HD104H (known by the nickname "c'te bastard ") located in C29.Can be found on Mouser or other website of course.
If naomi does not boot, changing it can help (even a lot! 4 naomi failing, 3 have booted just by changing it!).
His nickname comes from the fact that it tends to be leaks.
On N2 is less problematic (but do not take the problem lightly has, leaks of electrolyzed wreak havoc) on N1, the stream that flows goes under BIOS EPROM and EEPROM as Altera, cutting tracks.
Risk of non boot in the end, and if it starts luckily, there may be a BAD test IC29 (it is not defaulting, you just do what I quoted).

So desoldering, cleaning, redo the tracks.

A small scheme if the tracks are down (or check them)

EEPROM (IC31) -> Altera (IC30)
Pine 1 -> pin 12
pin 2 -> 1 pin
3 pin -> pin 37
4 pin -> 4 pin
pin 5 -> GND
6 pin -> unused
pin 7 -> + 5V
pin 8 -> + 5V

Family Photo (left to right the C29 "c'te bastard")



Naomi 1:

Black screen

several solutions:
-Bios Corrupt or not present
-Fixed CPU had more particularly to the BGA (rare as on the N1)
-supercap (a change or which sank)
-GPU Fan not working


Black screen but with sound
- RAMDAC HS (IC41)


Naomi 2:

Black screen
-Bios Corrupt or not present
-Problems CPU had more particularly to the BGA (extremely rare.changing GPU rams can make itboot)
-supercap (to change or leaked.Less worries than N1, not too many components around)
-GPU Fans not working
- 1 or 2 Mains RAM (IC106 and IC107) is / are dead (s)



has the Common Naomi 1 and 2:

-error 03: the one, it is well
normally the IC31 contains the serial number of board.If it cant be read, error 03.
therefore check as before for the super cap.
Otherwise, another trick: reprogram the BIOS! (I had the case with on a pretty old export BIOS)

-This kind of graphical glitche


and when doing RAM Test,except somes others glitches you got all rams GOOD


Try Changing IC16 (Graphical RAM)

- This one
p1280110.jpg


Simply do a RAM test and the bad one will appears

- this glitch
Naomi_Repair_2.jpg


Just investigate the filter board,specialy the vga connector.


I / O Board
Not detected, malfunctionning, blah

-recurrent, it is ALWAYS the IC02 which is HS (the big black ugly stuff all over support).
So we find on the net, but must reprogram the ...
sells or otherwise gzipuk andy geezer

- somes buttons are pressed.

its just one or somes octoisolators PS2801.
change it by using this pinout.Check between pin depending of your error and all octoisolator.at a moment,it will "beep" and that's this one which have to be changed.

From Andy Geezer
Digital Inputs (60pin AMP RA connector)

01 (+5V)
02 (+5V)
03 (+5V)
04 (+5V)
05 (+5V)
06 (+5V)
07 (+5V)
08 (+5V)
09 (GND)
10 (GND)
11 (GND)
12 (GND)
13 (GND)
14 (GND)
15 (GND)
16 NC
17 (1P Start)
18 (2P Start)
19 (1P Right)
20 (2P Right)
21 (1P Left)
22 (2P Left)
23 (1P Up)
24 (2P Up)
25 (1P Down)
26 (2P Down)
27 (1P SW1)
28 (2P SW1)
29 (1P SW2)
30 (2P SW2)
31 (1P SW3)
32 (2P SW3)
33 (1P SW4)
34 (2P SW4)
35 (1P SW5)
36 (2P SW5)
37 (1P SW6)
38 (2P SW6)
39 (1P SW7)
40 (2P SW7)
41 (1P Service)
42 (2P Service)
43 (Test Sw)
44 (Tilt Sw)
45 (Coin SW1)
46 (Coin SW2)
47 NC
48 NC
49 (Coin Meter 1)
50 (Coin Meter 2)
51 (Output 1)
52 (Output 2)
53 (Output 3)
54 (Output 4)
55 (Output 5)
56 (Output 6)
57 (+12V)
58 (+12V)
59 (+12V)
60 (+12V)


That's all for now.
Click to expand...
Excellent!
 
MickyMac said:
@hrvat9 I see flashes of checker board there. That is usually bad ram. If you check your 3.3v while game is running is it over 3.3? (you can measure with multi meter probes on the filter board)

@Adrick yes you can leave the super cap off the board.
Click to expand...
Yeah I already made sure the voltages were good, they’re spot on
 
MickyMac said:
@hrvat9 I see flashes of checker board there. That is usually bad ram. If you check your 3.3v while game is running is it over 3.3? (you can measure with multi meter probes on the filter board)

@Adrick yes you can leave the super cap off the board.
Click to expand...
thank you very much, perfect removed from my Naomi 1/2 luckily it was not leaking yet.
 
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