A630 issues - Help needed

[DDNI]

Hi all,

Hopefully someone with more A600experience can help me.
I think I need a Tech to fault check and repair my A630.
The board is an Apollo A630. 68030 clocked at 40mhz 68882 rated at 33mhz.

I have two A600s ( REV 1.0 and REV 1.5). Each demonstrate the same issues when the A630 is connected.

Simple issue is that it is very very very tempermental.
Very rarely it will boot WB. On opening a shell, CPU reports a 68030 and 68882. AVAIL shows 32MB FAST RAM.

Sometimes if it boots to WB there is NO FAST RAM seen.

More often than not it either hangs with a black screen or a Yellow then Green screen. I have also seen an occasional Red or Purple screen.

Physically the board looks to be A1 condition.
On power up the 030 882 and mach chips get warm.
I use a fan to cool them (powered from Floppy cable).

Steps that I have taken include.
- Running A630 with no RAM (RAM and WAIT Jumpers open).
- Running A630 with RAM with WAIT Jumper closed.
- Bare MOBO with nothing connected except floppy drive and A630
- Cleaning contacts on 68000 and A630 connector.
- Cleaning SIMM socket connectors.
- Straightening pins on A630 connector.
- Trying different RAM (15 different SIMMs 4mb/8mb/16mb/32mb).
- Different Known good PSUs - an A500 one an A600 Heavy one and a modified ATX PSU with extra oomph.
- Connecting ATX PSU to Floppy connector on MOBO to give extra power.
- Different Floppy and cable.

None of these steps have really made any difference.

Hopefully someone can offer some help?

[rkauer]

Did you notice the place for power connector on the leftmost side of the board?

Solder a 470uF capacitor in the place.

Still no go? Solder wires from the power connector on the pads.

Still no go? Time for an expert.

[Zetr0]

hmmmm the only thing I can think of at the moment is if you have an FPU try disabling it?

[chiark]

Can you clock the 030 down a little - perhaps to 25MHz?

It sounds like either power (which you've tried) or connection (which you've tried)...

[DDNI]

Hi all thanks for the guidance.

@ rkauer, what will the resistor suggestion do?
Also, to add power to the pads, is it simply +5v and GND from somewhere like the floppy connector?

@ Zetro, I will pull the FPU later and report back.

@ Chiark, sadly the xtal is SMD so it isnt easy to underclock the board.

[rkauer]

No resistor, mate.

A 470 micro-farads on the accelerator's power rail will do wonders for stability. Your best chance to confirm if the problem is power-related is checking the point with a multimeter. The voltage must be in the 4.85 to 5.25V range and rock steady.

The problem in those accelerators are they are directly powered from a pressure contact from the underneath SMD 68000 and the whole board takes more than 2.5A from that poor contact. Hence the need for the capacitor or routing power wires into it.

I'll download a picture and edit it accordingly to show what you need to do if you need more details.

[EDIT]

Picked the photo from AHDB: do you notice the blank place near the 68000 socket? That's where you will solder the capacitor, measure the +5V rail voltage or even route the +5V wire to. Prefer to solder it directly from the power supply connector instead from the overloaded floppy connector.

http://amiga.resource.cx/photos/photo2.pl?id=apollo630&pg=3&res=med〈=en

[Damion]

I have an M-Tec '030 that exhibited similar issues with *3* different A600 boards (also random freezes). Replaced the caps on one of the motherboards, and it's been 100% stable ever since.

[DDNI]

Thanks rkauer.

Can you edit the pic to show what needs done please. I work better at the visual end of autism

@Damion, shoot I hope that is not the case here..... Did your caps look bad? Mine all look A1 and the A600 works perfectly without the A630 - No sound issues / crashes etc.

[rkauer]

As requested:

[DDNI]

Thanks Rkauer. So I need to solder a +5v wire to the top pad (one marked +) and a GND wire to the lower pad? OR a 470uF Capacitor between the two pads.

[rkauer]

Exactly.

[Zetr0]

@DDNI

make sure you use a electrolytic capacitor and that the + symbol is on + of the cap.

If you are using an SMD component



the Black part is the negative lead

[Loedown]

Originally Posted by Zetr0

@DDNI

make sure you use a electrolytic capacitor and that the + symbol is on + of the cap.

If you are using an SMD component



the Black part is the negative lead

Zetr0 is exactly right, but for some inexplicable reason, Tantalum SMD caps have the stripe on them being POSITIVE

http://www.ami.ac.uk/courses/topics/...m_gtrp_phi.jpg

They also make fine tantalum bullets when plugged into 240V AC.

[DDNI]

Ta guys.

Should I go for the wires first or the Cap?

If the Cap doesn't work, do I remove it and add the wires? Or do I leave it and have both Cap and wires?

[Loedown]

Originally Posted by DDNI

Ta guys.

Should I go for the wires first or the Cap?

If the Cap doesn't work, do I remove it and add the wires? Or do I leave it and have both Cap and wires?

In this case, think of the capacitor as a type of very fast battery, or accumulator of charge, if the board drags as much current as is being claimed, then the capacitor is being used to help the power supply keep a nice constant current flow, even when the board is first switched on, dispels any transient current flows. Much like the triphammer devices in a water line, they smooth out water flow when a solenoid is rapidly turned on, or shut off in your washing machine or dishwasher.

[Zetr0]

@DDNI

try the cap first m8.... then remove the FPU, still have no luck put the FPU back in and wire up a sensible source of +5 and ground

@loedown,

O/T time ...... my ol'electronics (and physics) teacher once taught....

Electricity is like water, were capacitors (condensers) are the resevoir's, the resistors being pipe gauges and the circuit a cascading collection of waterfalls..

As with water you have a current flow, you have mass (voltage) ... he did go on a bit and in all truth It took me a while to understand how he ment all that. but its one of those things you will never forget when it all falls into place....

.... like cascading waterfalls..... i am sure if he was alive today he would be smurking at me for paying attention in class, even if I pretended not too... lol...

perhaps I already gave the game away when he got the radoactives out and I coudln't contain my interest in them LOL

(after all, we all know from comic books that radioactives give you super powers )

then there was the time I set my chemistry teachers arm on fire using lithum.... ... yeah.... that one will stay with you....

[DDNI]

Hi again, before I had off and buy a Capacitor.... What voltage rating should I go for?

[rkauer]

Anything over 6.3V is OK. 16V as a common sense precaution. Just remember: the bigger the voltage, the bigger the piece will be (for the same capacitance).

[DDNI]

OK, time to update things.

I attached a 470uF 16V capacitor to the discussed solder points. - No improvement.
I didn't have one like above, so used one of these.



I then attached +5v power to the points. - No improvement.
I pulled the FPU - Nada.
I pulled, cleaned and reseated MACH chips - Nada.
I reseated FPU - Nada.

In my temper/desperation I pressed down on the back of the board with a pen tip which slipped and scratched the board! I hope I didn't cut any tracks.... How deep are they in the board?

To quote rkauer, I now "need an expert". Anyone here fancy taking a look-see?

[Loedown]

Originally Posted by Zetr0

@DDNI

try the cap first m8.... then remove the FPU, still have no luck put the FPU back in and wire up a sensible source of +5 and ground

@loedown,

O/T time ...... my ol'electronics (and physics) teacher once taught....

Electricity is like water, were capacitors (condensers) are the resevoir's, the resistors being pipe gauges and the circuit a cascading collection of waterfalls..

As with water you have a current flow, you have mass (voltage) ... he did go on a bit and in all truth It took me a while to understand how he ment all that. but its one of those things you will never forget when it all falls into place....

.... like cascading waterfalls..... i am sure if he was alive today he would be smurking at me for paying attention in class, even if I pretended not too... lol...

perhaps I already gave the game away when he got the radoactives out and I coudln't contain my interest in them LOL

(after all, we all know from comic books that radioactives give you super powers )

then there was the time I set my chemistry teachers arm on fire using lithum.... ... yeah.... that one will stay with you....

I even went looking for a water animation for this exact scenario