Problem with an A4000

[Xanxi]

Hello.

I am experiencing problems with my A4000 and could use some advices.

So, i have an A4000D RevB, ROM 3.1, which has recently gone through caps replacement by Cosmos and coin cell battery hack. It aslo have a modified ATX PSU instead of the original PSU, but with the fan mounted outside the PSU case, just behind the drive bays.

Here is the expansion list of this computer:
- WarpEngine 40/40
- CyberVision64/3D
- Commodore A2386 with 486SLC2/50 CPU
- Deneb in Z3 PIO mode (Buster 11)
- STB Nitro64 2MB ISA VGA card and SounBlaster 16 ISA card for the A2386
- Internal FZ357A HD drive for the amiga part
- Internal floppy/memory card reader combo with floppy part connected to the A2386 and card part to the Deneb
- Internal power USB hub in the 5.25 bay
- Internal 3.5' IDE 160GB Maxtor drive connected to the native IDE
- External scandoubler as i have not yet received my Indivision 4000.
- External ethernet and audio USB dongles to the Deneb

Everything was working great for a month.
Last tuesday, i made some "upgrades":
- added the A4000 spacers to hold the warpengine in place
- replaced passive cooling by a chipset heatsing and fan (i had to use a bit of superglue on it as the adhesiv thermal past was not enough)
- removed a useless Catweasel Z2 card
- replaced the old ISA board by the new STB Nitro
Then everything worked fine until yeasterday.
The A4000 has crashed after some hours using it. The case was quite hot, it happened from time to time when the weather is hot, so i turned it off.
Today, the computer was nt booting with only black screen from the AGA output, whith the HD not even spining.
I opened the case, and removed everyboard until there is only the CPU card left. Still no boot. Replaced teh warpengine by a Blizzard 4030 i have in stock.
The 4000 booted fine to the kickstart screen. Replaced teh warpengine, booted ok, so refitted everything and still ok.
After about 20 minutes using it, it freezed again.
I have again opened the case and removed everything. I got 1 boot from 10 attempts from both the 030 and 040 cpu boards, but now nothing.

I suspect either:
- bad contacts with the CPU slots (may be solved by the use of 4 spacers instead of the only 2 i have?)
- flacky PSU: indeed the PSU is often quite hot and the external fan may not be good enough to refresh it, as the 040 and the 486 CPU inside the A4000 are ultra hot after some use.

I would apreciate any advice on the matter, and help to get either 2 more A4000 spacers or a new PSU.

Thanks.

 

[jvdbossc]

I would recommend to fit a strong matx psu, it can made to be fit with two screws as default and to make it strong you should make a piece of metal to support it a bit.

A cable adapter can be bought at amigamaniac web store.

You will have a large opening in the back then for extra large fans

Fol also pointed to me that the socketed buster is a real problem, I refitted that a few times and cleaned the contacts with IPA and it gave more stable amiga

 

[Xanxi]

So you think about the PSU too? Can a PSU die at once after a month of good function?

What would be the error from bad contacts on the CPU slot? Red screen maybe?

The buster seems fine, i have pushed it in this socket several times.

 

[merlinkv]

Hi my friend

- bad contacts with the CPU slots (may be solved by the use of 4 spacers instead of the only 2 i have?)

Yes, best is to use 4 spacers.

- flacky PSU: indeed the PSU is often quite hot and the external fan may not be good enough to refresh it, as the 040 and the 486 CPU inside the A4000 are ultra hot after some use.

As others saids, I recommend to use one good mATX PSU.

The airflow inside the A4000D is very bad and you have a lot of hot-components inside.

Time a go I used the A4000D case in one full loaded A4000.... Problem: Airflow.

My solutions maybe is not the best but I nstalled some slim/quiet 8cm fans inside the case:

- First fan: I drilled a hole on the left side (up to the mouse-KB connectors, near the back of the case) and I installed the fan here.

- Other fan installed near the Zorro guides (the front of the case)

- PSU (mATX inside the original PSU case): I installed a new fan and changed the direction for the airflow to go outside. Also I opened with a screwdriver the air vents of the PSU case.

- HDD: One double fan plate down of the HDD

Of course you need to use very quiet & slim fans to reduce noise.

As I said, maybe is not the best solution (you need to drill a hole in the case) but, in the past, my A4000D run for days without issues.

Now, I have all my A4KD's towerised......

Best wishes

 

[Xanxi]

Hello.

Now i have a new PSU and all 4 spacers. I also have received my new indivision 4000.

However, this does not solve the problem. I still have a black screen on boot with nothing happening even with all cards, daughterboard and harddrive removed.

I have also pushed on every socketed component, and replaced the mobo SIMM.

This morning, it has booted once with my reserve CPU board (Blizz 4030) to the KS screen, but not anymore.

Any idea?

I suspect now a problem with the mobo, although it has been refitted lately by Cosmos with new caps.

 

[jvdbossc]

I really would feel better if you removed any socketed chip and at least cleaned all contacts with some ipa or alcohol.:roll: