M4 - not working?

eto · 19:50, 17 September 24

I forgot that I have a M4 and after a few years (yeah... sorry) now I finally plugged it into my CPC to try it out. But I don't see any boot message.

I downloaded the latest firmware and it seems it installed it (red LED stayed on for quite some time, then reset) but sstill no boot message.

Am I missing something? Anything I have to do to make it work?

HAL6128 · 20:03, 17 September 24

Do you see anything on screen, stays it black?

eto · 20:08, 17 September 24

I get to the normal boot screen but without any M4 specific message. I can typie in BASIC and also tried to type some M4 commands but they are all unknown.

GUNHED · 20:42, 17 September 24

Quote from: eto on 20:08, 17 September 24I get to the normal boot screen but without any M4 specific message. I can typie in BASIC and also tried to type some M4 commands but they are all unknown.

Checks solder points at 50 pin IDE connector, maybe one needs resoldering.

Check if Jumper is there for power supply.

eto · 22:13, 17 September 24

thanks... not the solder points but checking them helped ;-) after close inspection I saw some tiny little fibers on the backside of the PCB and after cleaning it with some Isopropanol it started.

HAL6128 · 08:50, 18 September 24

So, it's always worth checking physical connection and conditioning of it, especially if the device hasn't been used after a while. Thanks for sharing this experience.

eto · 09:07, 18 September 24

Quote from: HAL6128 on 08:50, 18 September 24f it, especially if the device hasn't been used after a while. Thanks for sharing this experience.

Honestly I did that. It looked perfectly fine. It was more like dust with tiny little fibres that you don't even recognize if you don't look very closely. And everything else worked, so obviously no short. Anyway... maybe best practice to always use a bit of Isopropanol if it's dusty :-)

Shaun M. Neary · 09:45, 18 September 24

Everyone's going down the complicated route with this one.

Tried re-seating the SD card or trying a known working SD card in case the card got fried?

eto · 12:02, 18 September 24

Quote from: Shaun M. Neary on 09:45, 18 September 24Tried re-seating the SD card or trying a known working SD card in case the card got fried?

sure, I tried several cards several times

Shaun M. Neary · 12:31, 18 September 24

You got another Amstrad you can test it on in case it's the expansion port?
Or another expansion you can test the port on?

@Duke - Any ideas for this guy?

eto · 12:37, 18 September 24

Quote from: Shaun M. Neary on 12:31, 18 September 24You got another Amstrad you can test it on in case it's the expansion port?
Or another expansion you can test the port on?

Duke - Any ideas for this guy?

It's already resolved: https://www.cpcwiki.eu/forum/index.php?msg=242845

GUNHED · 12:45, 18 September 24

Quote from: eto on 22:13, 17 September 24thanks... not the solder points but checking them helped ;-) after close inspection I saw some tiny little fibers on the backside of the PCB and after cleaning it with some Isopropanol it started.

Glad to hear it works again!

Shaun M. Neary · 13:30, 18 September 24

Quote from: eto on 12:37, 18 September 24
Quote from: Shaun M. Neary on 12:31, 18 September 24You got another Amstrad you can test it on in case it's the expansion port?
Or another expansion you can test the port on?

Duke - Any ideas for this guy?

It's already resolved: https://www.cpcwiki.eu/forum/index.php?msg=242845

My apologies, I completely misread!
Happy gaming.

chinnyhill10 · 19:55, 19 September 24

Like the Div on the Speccy, the M4 seems to demand that your edge connector be very clean. I've never been clear if this is due to the demands of the devices or tiny differences when mating modern to old edge connectors. Either way DeOxit Gold is your friend.

Bryce · 20:05, 19 September 24

Quote from: chinnyhill10 on 19:55, 19 September 24Like the Div on the Speccy, the M4 seems to demand that your edge connector be very clean. I've never been clear if this is due to the demands of the devices or tiny differences when mating modern to old edge connectors. Either way DeOxit Gold is your friend.

It doesn't really have anything to do with any electrical "performance" requirements, the signals are simple, relatively slow, low current 5V connections. It's just because old computer connectors, especially ones that haven't been used for a while will be heavily oxidised, so the connections will be bad and the signals won't get through at all if the oxide layer is thick enough.

Bryce.

GUNHED · 20:50, 19 September 24

That's the cool thing about Centronics connectors (6128plus and German CPC6128), not problems at all. It's already golden.

However, in the case of the M4 we have IDE connectors, not problems with the usually. Now, in this case the edge connector to the PCB can be a problem.

chinnyhill10 · 21:31, 19 September 24

Quote from: Bryce on 20:05, 19 September 24
Quote from: chinnyhill10 on 19:55, 19 September 24Like the Div on the Speccy, the M4 seems to demand that your edge connector be very clean. I've never been clear if this is due to the demands of the devices or tiny differences when mating modern to old edge connectors. Either way DeOxit Gold is your friend.

It doesn't really have anything to do with any electrical "performance" requirements, the signals are simple, relatively slow, low current 5V connections. It's just because old computer connectors, especially ones that haven't been used for a while will be heavily oxidised, so the connections will be bad and the signals won't get through at all if the oxide layer is thick enough.

Bryce.

Trust me, I keep mine clean on the daily drivers. But unplug and replug and the CPC (or Speccy) edge connector needs another clean. Never seem to have the same issue on the drive connectors (again both on the CPC and +3).

Bryce · 11:39, 20 September 24

Quote from: chinnyhill10 on 21:31, 19 September 24
Quote from: Bryce on 20:05, 19 September 24
Quote from: chinnyhill10 on 19:55, 19 September 24Like the Div on the Speccy, the M4 seems to demand that your edge connector be very clean. I've never been clear if this is due to the demands of the devices or tiny differences when mating modern to old edge connectors. Either way DeOxit Gold is your friend.

It doesn't really have anything to do with any electrical "performance" requirements, the signals are simple, relatively slow, low current 5V connections. It's just because old computer connectors, especially ones that haven't been used for a while will be heavily oxidised, so the connections will be bad and the signals won't get through at all if the oxide layer is thick enough.

Bryce.

Trust me, I keep mine clean on the daily drivers. But unplug and replug and the CPC (or Speccy) edge connector needs another clean. Never seem to have the same issue on the drive connectors (again both on the CPC and +3).

The Centronics connector definitely gives a better connection because it keeps more pressure on the contacts compared to edge connectors. The edge connector to the floppy drive is slightly more reliable because it's shorter and puts slightly more pressure on the contacts because of this. This pressure also helps to "cut through" the oxidation when you connect it.
As far as the "gold" is concerned, it's obviously better than the solder covered connections that were used up to the 70's, but it's not really gold. Real gold doesn't oxidate, but the coating is far from that. It's called ENIG in the PCB industry and it's done with a very quick dip in a chemical solution of gold and nickel, but this doesn't 100% coat the surface and there is a lot of exposed copper in the gold that will still oxidise and cause problems. On modern connectors / PCB's a newer process is used called "ENEPIG" which uses Palladium and nickel instead of gold and is more robust.

Bryce.

GUNHED · 11:36, 30 September 24

Haha, nice to see that we agree in an hardware topic.

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M4 - not working?