Amstrad CPC 464 + DDI6 problem

[Nigel]

Hello everyone! 

I'm asking for help from the community. I have a CPC 464 (Spanish keyboard, shortened board) and I purchased a DDI6. From the first moment I used 464+DDI6, I found that about 30% of relatively new games do not run via DDI6 - after the run"disc command, the computer immediately reboots. I run without problems - "Babaliba", "The Dark Knight", "Orion Prime", "Revenge of Trasmoz". Unable to run - "The Key", "Gates to Heaven", "Phantomas 2.0", "Package Engine Demo", "Croco Folie &28", "Dr.Roland". I think this list is much longer. 

In addition, I have encountered unstable operation of my 464 with DDI6 connected. Periodically, a situation arises when the 464 stops displaying a picture on the screen with the DDI6 connected, although the DDI6 itself is functioning. Assuming that there might be a problem with the contacts on the CPC connector, I made an adapter on the cable for the DDI6 (so as not to bend the connector on the board), but this did not solve the problem.

Then I decided to run several utilities to check the memory, and for example, "Amstrad Diagnostics 1.3" (and several other utilites) finds errors when checking the upper memory. I don't know if this is normal because one of the other memory test utilites didn't see any errors when checking. But the strangest thing is that after finishing the memory test, the "Amstrad Diagnostics" program freezes, I reboot the 464 and again my screen doesn't show anything until I physically turn off the DDI6.   After that, I turn on the 464 without DDI6 and the computer works well. I plug in the DDI6 again, and the black screen appears again. Only after a prolonged shutdown of 464+DDI6 do they work together again.

I tried using two different 3 amp and 4 amp power supplies - the result is the same. Without DDI6, my 464 loads almost all CDT images well via TZXDuino and internal tape recorder. So far, I see the problem only paired with DDI6.

I may have described the problem a little haphazardly, but is it possible to draw a conclusion about the source of the problem based on the above description? If anyone with a 464 and a DDI6 is reading this message, please share your experience using these devices together. The DDI6 is a new device on the market. I didn't even find a review on it, and to my shame, I don't know all its functionality. For example, the purpose of the upper-left switch and the LED next to it is unknown for me. So many questions)

I would be grateful for any help!

[Shaun M. Neary]

From the description of the DDI6, it's most likely an ABBA Switch

More info here: https://www.cpcwiki.eu/index.php/ABBA_switch

If it's switched the wrong way, It may screw up loading some games as they traditionally load from the A: drive, and not the B: drive.
This may be your issue as you're on a 464 and you've no second drive, but it would most likely say "Drive A: Read fail" if you were trying to load, so probably not.

Looks like some of the RAM in the expansion could be fried though!

[Nigel]

The switch ABBA is located below (to the left of the flash drive) and of course it is turned on correctly, otherwise I would not have been able to download anything at all.

[Shaun M. Neary]

What about the OS? I've a DDI device (can't remember the exact model) and there's a switch that changes from AMSDOS to ParaDOS. It should tell you on the main screen after a restart?

[dodogildo]

Did you contact zaxon (the creator) ?
Assuming you bought it on SellMyRetro website from his store.. https://www.sellmyretro.com/offer/details/ddi-6-amstrad-cpc-464-64558?lang=en_GB

[McArti0]

I tried using two different 3 amp and 4 amp power supplies -

Never connect large power supplies to the CPC. The power supply in the monitor has an OCP of 1.7A and protects the CPC by turning off the power supply at any short circuit.
If you connect a powerful power supply you no longer have this protection.

[Nigel]

What about the OS? I've a DDI device (can't remember the exact model) and there's a switch that changes from AMSDOS to ParaDOS. It should tell you on the main screen after a restart?

Yes, I can switch between AMSDOS and ParaDOS when I can run CPC and DDI6 at the same time. I've tried running games in both OS variants.

[Nigel]

Did you contact zaxon (the creator) ?
Assuming you bought it on SellMyRetro website from his store.. https://www.sellmyretro.com/offer/details/ddi-6-amstrad-cpc-464-64558?lang=en_GB

Yes, I wrote to the author of DDI6. Apparently, he doesn't have the opportunity to check the device at home and give me an answer yet.

[Nigel]

I tried using two different 3 amp and 4 amp power supplies -

Never connect large power supplies to the CPC. The power supply in the monitor has an OCP of 1.7A and protects the CPC by turning off the power supply at any short circuit.
If you connect a powerful power supply you no longer have this protection.

I don't have an Amstrad monitor - I use a Sony Trinitron CRT and connect via SCART. Which power supply should I use - 2 amps?

[eto]

The screen which can be seen in Amstrad diagnostics can happen if the addressing logic that enables the RAM expansion is not properly working. I had that with my own expansion when the addressing logic was not fully working yet. 

The SRAM itself seems to be fine.

Afaik the DDI-6 now also supports the C3 RAM banking mode. Maybe the switch enables/disables it. If you change the switch and run diagnostics again does it then show 448KB of expanded RAM?


Btw: why is there no proper documentation for the device? I costs a whopping £130 and it doesn't even come with an explanation of the buttons and switches?

[McArti0]

I don't have an Amstrad monitor - I use a Sony Trinitron CRT and connect via SCART. Which power supply should I use - 2 amps?

yes and with short circuit safeguard.

[Nigel]

The screen which can be seen in Amstrad diagnostics can happen if the addressing logic that enables the RAM expansion is not properly working. I had that with my own expansion when the addressing logic was not fully working yet.

The SRAM itself seems to be fine.

Afaik the DDI-6 now also supports the C3 RAM banking mode. Maybe the switch enables/disables it. If you change the switch and run diagnostics again does it then show 448KB of expanded RAM?


Btw: why is there no proper documentation for the device? I costs a whopping £130 and it doesn't even come with an explanation of the buttons and switches?

Unfortunately, I can't check this switch right now, because my CPC is still at work, maybe tomorrow or later I'll get to it again. Secondly, it shows a black screen again when turned on along with DDI6. I can't understand at all what this problem is about. When I manage to get CPC+DDI6 to work together, it can last 10-20 minutes, in different ways. Then Amstrad freezes and after restarting it, I get a black screen. Without DDI6 its work fine. I examined the board and did not find any problems externally. I cleaned the drive connector and even slightly soldered it additionally to improve the contact layer. Could there be a problem with loose contacts or a microcrack at the connector?.. Or maybe the electrolytic capacitor next to the power connector needs to be replaced?

I have a MC0044D Z70375 board. Like this

[Nigel]

The screen which can be seen in Amstrad diagnostics can happen if the addressing logic that enables the RAM expansion is not properly working. I had that with my own expansion when the addressing logic was not fully working yet.

The SRAM itself seems to be fine.

Afaik the DDI-6 now also supports the C3 RAM banking mode. Maybe the switch enables/disables it. If you change the switch and run diagnostics again does it then show 448KB of expanded RAM?


Btw: why is there no proper documentation for the device? I costs a whopping £130 and it doesn't even come with an explanation of the buttons and switches?

Yes, there are no manual for DDI6 yet. Unfortunately, it was not ready at the time of purchase.

[Nigel]

I don't have an Amstrad monitor - I use a Sony Trinitron CRT and connect via SCART. Which power supply should I use - 2 amps?

yes and with short circuit safeguard.

can I ask for a link to one of these power supplies for an example?

[McArti0]

will not guarantee you the quality of a specific model.

The option is called OCP in laboratory power supplies.

I use the original monitor and the monitor has already turned off 5V a few times because I touched the ground with the probe somewhere, causing a short circuit.

[Nigel]

The problem with running games has been solved!

Zaxon wrote to me today that I need to remove ROM "Booster" (ROM position 02 from the Amstrad Diagnostics report). With the |ROMAN command, I went to the ROM manager, but it absolutely did not want to be deleted, despite the absence of errors during the deletion. And then I turned on the upper-left switch (now we know that this is write protection), and then I was able to delete this ROM. And bingo! All the games that previously didn't want to run started working for me. I have no idea why this "Booster" was needed, but it was the reason.

It remains to deal with the second problem. I continue to struggle with glitches and a black screen when connecting DDI6 to my CPC. No matter with or without a cable adapter, it is very difficult to catch the angle of connection of the connector to the computer board at which they would work together. I suspect that it's a matter of poor contact between the slot on the board and the DDI6 slot, but I can't figure out exactly where yet. There is an idea to make another adapter by soldering wires to the contacts near the edge of the motherboard to bypass the EDGE connector section. Has anyone encountered a similar problem?

[eto]

Many problems I had with expansions not properly working were related to corrosion. Did you clean the expansion port on the CPC? If it looks even a bit like the port of the motherboard in the picture you posted I would not be surprised that it doesn't work properly. 

[Nigel]

Many problems I had with expansions not properly working were related to corrosion. Did you clean the expansion port on the CPC? If it looks even a bit like the port of the motherboard in the picture you posted I would not be surprised that it doesn't work properly.

Yes. Many times and without sparing isopropyl alcohol. And I rang the contacts of the connector with the connected extension cord and there was a good contact. Sometimes Amstrad stops working at the slightest touch to DDI6. At the same time, on DDI6 all functionality continues to work - I can control the device using buttons since DDI6 continues to receive power from my CPC.