Amiga 4000 WOES...

[MaDDuck]

This post will sound simelar to, " A4000 - help greatly appreciated" But I assure you that it is unique!!
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This is an Amiga 4000(d) with 16 MB of RAM on the MLB
 Standard 3040 68040 stock CPU
 Standard 1.76MB HD floppy drive
 Standard KS & WB 3.0
 EMPLANT board (with working SW!!)
 A *REV B* MLB (the one with 5 SIMM sockets on it!)
  ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 

 Now..................
 I just inherated an Amiga 4000 from a friend who lightly used it (wrote a textbook and song lyrics, etc.)since new in fact I helped her pick it out, set it up and upgrade it a few times over the years!  

It gives an error upon bootup saying there is no FAST RAM. Knowing better (I had installed 16MB in there several years prior) I disconnected all cords and opened 'er up.

 What I saw was exactly what I was NOT hoping for. The battery had leaked and gotten [goo] on the lower SIMM socked and judging by the looks of the SIMM itself, had shorted it out.

 I then cut the battery off (very carfully!) and using some baking soda and cotten swabs cleaned the aera around the battery as best I could.

 The board looks great, but there was some (blue!?) crap on the socket itself, most of which I was able to clean off.
 
 I then replaced the 4MB SIMM and fired it up. It booted correctly and seemed to work. Even the EMPLANT ran correctly. It the most memory intensive SW that I have installed on here.
 
 But after a reboot- nothing.  
 
 I rotated *SEVERAL* known working 4MB SIMMS around various sockets, confirmed that the jumpers were set correctly (THX big book of Amiga hardware!).
 Still nothing.
 
 I then disconnected (one at a time)
 The EMPLANT board
 The HDD
 The FDD
 The RAM in 1 & 2 slot tries.
 
 And I even pushed down on the only socketed chip on that side of the board (SUPER BUSTER 11) and to no avail!
 
  I've been an Amiga owner/user since 1991 and have averted many problems over the years, but I must admit that I am truly baffled!!

 Any sugggestions?
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 ALSO:
 Would installing 8 or 16 MB SIMMS hurt the Amiga? I know the MLB would not see the full ammount- but will it cause any damage?
 
 During the troubleshooting that I have outlined above- I left the SIMM in the CHIP RAM SIMM slot the entire time
 
 The corrosion only seems to of gotten to the lower SIMM socket, all others seem clean.
 
 
 THANKS!!!
___________________________
Come the millennium, month 12,  
 In the home of greatest power,  
 The village idiot will come forth  
 To be acclaimed the leader.  
 -Nostradamus 1555 :-D

[Matt_H]

The lower SIMM socket? That could be trouble. My limited knowledge of the A4000 tells me that's the CHIP socket. Or do you mean the one closest to the edge of the board? I think that's a FAST socket.

If it is in fact a FAST socket, I *think* you could use 8MB SIMMs in sockets 2 and 4. Don't know for certain, though.

Hope this helps.

[MaDDuck]

good guess!!!
the CHIP socket is at the top, closest to the riser.
and on further examination, I've noticed a couple of things.

1. the floppy drives do NOT click so it seems to have its problem while still doing the power on (pre-boot) stuff

2. there was only VERY minor corrosion under the battery so I doubt that caused any problems afterall.

3. the SIMM socket with the burned out SIMM may be the culperat. It is burned out aprx. 3/4 of an inch in from the side, not on the edge closest to the battery.

4. the 68040 card is a model A3640 not an A3040 as I stated above. Musta been punch drunk from thinking 'bout this all bleeding day!

Thanks bunches!
Keep 'em coming!!!

___________________________
Come the millennium, month 12,  
 In the home of greatest power,  
 The village idiot will come forth  
 To be acclaimed the leader.  
 -Nostradamus 1555