A4000 040 Dead jim?

[MadLensman]

Hi all
 
As most of you know from my intro thread, I am currently having a few challenges with my A4000. She's a 040 model with 2m Chip, 8m fast and no HD so to speak. here's the breakdown so far....
 
Originally had her running, would boot from WB Install disk (WB3) and would access the HD tools but never saw ANY hd (Inc. her original disk)
 
Now:
 
1) No boot screen - Just a dead black screen
2) On investigation, discovered that some clever soul has broken a couple of the SIMM retainer clips - The RAM still sits in the slots fine, and retains ok, but not perfect! - Been like that since I acquired the A4000 so don't suspect this as the problem
3) Checked for ACID damage at battery and caps, none apparent, so assume this is not one of the usual faults!
 
So.......
 
Any pointers? (please!) :biglaugh:

[MadLensman]

I shall follow those instructions an await a purple screen of happiness - Many thanks chap!

[MadLensman]

The A600 overheated and expired - Wasn't a simple cap problem, it just turned it's toes up and shuffled off this mortal coil..... :python:

[MadLensman]

Mine just fried one sunny afternoon whilst reinstalling her HD - I'm in the process of thinking maybe its time to rejuvenate the old girl! (Perhaps - Maybe just rape the FD for the 1200 I've got with a DF0 problem)....

[MadLensman]

You are most correct my friend..... I fail to accept that she is dead, and will no doubt return to repairing the A600 - Simply because she's the only Amiga I have with a decent Wing Commander install on..... Sad but very true!
 
I am in need of a piece of technical critical info though..... Jumpers on the A4000 board... what are the settings usually for the following Jumpers:
 
J501
J502
J500
 
J852
 
J213
J214
 
I can see the legends alongside the jumpers simply enough, J213,214 seem to be ram settings - Although I'm fairly sure that there was never a 4000 with 8mb Chip ram so 213 should be at 2m setting - and J212 must be set for PAL not NTSC so that ones fairly obvious - But the others I'm just ? :huh: don't fancy frying the old girl just because of user error! :crazy:

[MadLensman]

Figured that was the case with the RAM jumpers.
 
My worry is that some other "tech" has been inside the case prior to my acquisition of the 4000 and may have changed settings. A set of full schematics is downloading as we speak so I can check them.
 
Currently on my fourth 4mb SIMM, and have just had the bright idea of pre-testing this particular stick in the accelerator of my working 1200 prior to using in the 4000 so I know it's a known good stick.
 
I do have another worry mind, the keylock switch looks bu66ered - could this be having an effect? Is it supposed to be open or closed circuit for normal ops? - Clutching at straws, but simple things etc etc etc..... :laughing:

[MadLensman]

(Mine no longer has one now!!!! - But don't tell anyone!)
 
Still getting just black screen I'm afraid - It appears to be finished!
 
Tried 4 x 4mb RAM SIMMS - All known good units
Processor is now getting warm(ish) where it wasn't before
Get the black screen right after power up - it doesn't appear to reset the AGA set as mentioned
It does appear to be doing something as the "AVI" Message on the TV disappears after power on and the screen goes deathly black.
 
This has to be a simple component failure or voltage issue - Just before the black screen of doom I did notice that she lost all her fast RAM - then wouldn't boot again..... (If that helps!)
 
STRESS - The force generated when the mind over-rides the body's desire to get out a hammer...... :furious:

[MadLensman]

Caps all changed, although to be fair, the originals looked A-ok and there were no signs of leakage except around the barrel battery - (Which I also have changed just in case) - After cap replacement she still booted fine and dandy so no worries
 
What actually occured was a sudden loss of all Fast Ram - just 16m to nothing in milliseconds then when I rebooted to check the RAM she refused to boot up at all!
 
So - now got the board out of the case and bread boarded - Getting heat at Alice and CPU so assuming they're running but no output. Buster is colder than a cold thing in a freezer, and paula, she's a mean b1tch - hot one second cold the next boot so thinking I'm flogging the proverbial dead horse maybe?
 
It's a REV B board and I've got a A1200 accelerator with a removable 040 in it that looks compatible with the same slot on the A4000 CPU card - Presumably it's a simple(ish) matter of change the chip and as long as I'm not too heavy handed this'll tell me if the cpu is fubar? (A1200 should boot using the chip from the A4000 if no boot then dead cpu?)
 
Ta for the offer of the cpu board Spirantho - If I could be sure it wasn't something likely to fry someone else's gear I may have been happier to accept.... lol! :hat:

[MadLensman]

I think I may be making somke progress - Now have heat at Paula, Alice, The 030 but no heat from Buster at all.
 
On investigation, the RAM slots have obviously gotten warm at some point in their long lives as the plastic retaining clips are missing in some slots, broken in others and have migrated under the motherboard! - This no doubt explains the loss of FAST Ram I experienced before the machine swan dove into her grave.
 
No matter how gentle people seem to be, these damn clips appear to be more and more fragile - Most SIMMS are sitting in the slots fine, and seem to retain ok, but banks 2 & 3 are not clicking into their laid back position properly.
 
Even running with just Chip RAM is proving difficult as Bank 0 doesn't appear to lock properly either.
 
I may be about to give up and move this old girl on as a donor parts machine!

[MadLensman]

Well, no life whatsoever after leaving her all night with just the chip RAM in - Think the old girl may have been toasted good.
 
A fine inspection with a magnifyer still shows none of the usual capacitor damage and I've used a good PCB cleaner to clean the dust and debris off the board front and rear to make sure that it's not just a "cr4p-out" (Literally) - SIMM in chip ram slot is now a known good working 2mb 70ns chip as recommended, and will run overnight again to see if the dreaded black screen does go away at all, but I'm almost at the end of my rope now - Brace yourself Spirantho - I forsee an A4000 board in your near future my friend! :roflmao:

[MadLensman]

That's it - I give up!
 
(I don't want to, but have run out of time to spend on this particular machine)
 
Anyone who would like a crack at this A4000 is most welcome, free to a good home! - The following are the good bits:
 
Working PSU in apparently good order
Seems to get power to most of the motherboard - Although no output?
4 x 4mb SIMMS Ram + 2mb Chip RAM - all checked and good (Working)
Everything other than the motherboard seems good!
Case in OK condition
Genuine AMIGA branded keyboard etc etc.
 
Will throw in a switch dead commodore monitor which I haven't even had time to look at yet!
 
All free to good home - Collection from Devon UK advised! :roflmao:

[MadLensman]

PM replied to.... lol!