The famous grey screen black frame issue.

[JupiterJones]

Hi,

Regarding icompplus , I've just ordered a couple of chips and some capacitors form them. I'm based in Barcelona, they are located in Madrid, so I expect to have these goods early next week. I don't exepct to have any issues, they look dependable.
If you are interested I'll post my experience.

[WacKEDmaN]

i grabbed some 40007 gate arrays from icompplus... they arrived within 2 weeks to australia... and the chips are genuine new old stock..

[oyshals]

Received my Dandanator Mini Dual today, but sadly it won't boot either, same grey screen, so I'm not able to test the ram Banks.

Any ideas?

Edit: Still no reaction (beeps) while using keyboard.

[Rabs]

I have never used a Dandanator so can't help much but user manual says

The CPC Dandanator! Mini has three buttons.

• Right button : Performs a CPC reset.

• Central button : With the button pressed during boot or reset, the cartridge is deactivated and the CPC Basic starts.

• Left button : With the button pressed during the boot or reset, an alternative software is started, by default a test rom.

[Rabs]

Received my Dandanator Mini Dual today, but sadly it won't boot either, same grey screen, so I'm not able to test the ram Banks.

Any ideas?

Edit: Still no reaction (beeps) while using keyboard.

The CPC beeps? So it is alive? Just the display is an issue?

[oyshals]

Received my Dandanator Mini Dual today, but sadly it won't boot either, same grey screen, so I'm not able to test the ram Banks.

Any ideas?

Edit: Still no reaction (beeps) while using keyboard.

The CPC beeps? So it is alive? Just the display is an issue?

Sadly, no beeps.

[eto]

is Amstrad diagnostics installed as lower ROM and do you press the button to boot into lower ROM when you turn on the Dandanator?

[oyshals]

is Amstrad diagnostics installed as lower ROM and do you press the button to boot into lower ROM when you turn on the Dandanator?

According to the description of the Dandanator it should be installed. When I press the button while turning the computer on, the whole screen actually turns dark gray, almost black (no frame), but nothing else happens.

[Rabs]

Is the edge connector clean?

[oyshals]

Is the edge connector clean?

I've cleaned it with contact cleaner and a paper towel, so it looks clean, but I'll give it another try tomorrow. Watched a video with Noel's retrolab, and he used an eraser. Will try that tomorrow.

[Rabs]

Yes, I use an old ink eraser. I often have problems with the top of the edge connector and even when I think it is clean, I clean it again.

[oyshals]

Cleaned the connector again with a pen eraser, but no change.

Started checking voltages again and noticed that the voltage is unstable, it varies between 4,6v and 4,9v. I guess this would give me boot problems.
Replaced the power on switch with a jumper, with no change. I suspect there might be a problem with the mother board 5v female socket, as there are some visual corrosion, and some noise from the speaker and flickering on the screen, when moving the power supply plug.
I find it very hard to clean it properly, so I searched for a new one online. I only found it on "serve-retro.co.uk", but they don't ship to Norway. Anywhere else I can get my hands on one?

[Rabs]

Cleaned the connector again with a pen eraser, but no change.

Started checking voltages again and noticed that the voltage is unstable, it varies between 4,6v and 4,9v. I guess this would give me boot problems.
Replaced the power on switch with a jumper, with no change. I suspect there might be a problem with the mother board 5v female socket, as there are some visual corrosion, and some noise from the speaker and flickering on the screen, when moving the power supply plug.
I find it very hard to clean it properly, so I searched for a new one online. I only found it on "serve-retro.co.uk", but they don't ship to Norway. Anywhere else I can get my hands on one?

Indeed I have had power connection problems which manifest as a grey screen, but this was on the internal header posts. Similarly, if I touched the header, I saw an impact. If you struggle to get a power socket message me. I have one sat in my draw unused.

[JupiterJones]

Cleaned the connector again with a pen eraser, but no change.

Started checking voltages again and noticed that the voltage is unstable, it varies between 4,6v and 4,9v. I guess this would give me boot problems.
Replaced the power on switch with a jumper, with no change. I suspect there might be a problem with the mother board 5v female socket, as there are some visual corrosion, and some noise from the speaker and flickering on the screen, when moving the power supply plug.
I find it very hard to clean it properly, so I searched for a new one online. I only found it on "serve-retro.co.uk", but they don't ship to Norway. Anywhere else I can get my hands on one?

My 464 power connector had to be fixed twice (once in the late 80's and another time recently). Those power sockets seem to receive quite stress. Try to reflow socket's solderings. In my case I needed to do a bridge using wire as the pads were ripped off from the PCB. Hope that could help!
I had my 464 fixed d

[oyshals]

Cleaned the connector again with a pen eraser, but no change.

Started checking voltages again and noticed that the voltage is unstable, it varies between 4,6v and 4,9v. I guess this would give me boot problems.
Replaced the power on switch with a jumper, with no change. I suspect there might be a problem with the mother board 5v female socket, as there are some visual corrosion, and some noise from the speaker and flickering on the screen, when moving the power supply plug.
I find it very hard to clean it properly, so I searched for a new one online. I only found it on "serve-retro.co.uk", but they don't ship to Norway. Anywhere else I can get my hands on one?

Indeed I have had power connection problems which manifest as a grey screen, but this was on the internal header posts. Similarly, if I touched the header, I saw an impact. If you struggle to get a power socket message me. I have one sat in my draw unused.

I'm sorry, my English isn't great, could you explain the "internal header posts" please?

[oyshals]

Cleaned the connector again with a pen eraser, but no change.

Started checking voltages again and noticed that the voltage is unstable, it varies between 4,6v and 4,9v. I guess this would give me boot problems.
Replaced the power on switch with a jumper, with no change. I suspect there might be a problem with the mother board 5v female socket, as there are some visual corrosion, and some noise from the speaker and flickering on the screen, when moving the power supply plug.
I find it very hard to clean it properly, so I searched for a new one online. I only found it on "serve-retro.co.uk", but they don't ship to Norway. Anywhere else I can get my hands on one?

My 464 power connector had to be fixed twice (once in the late 80's and another time recently). Those power sockets seem to receive quite stress. Try to reflow socket's solderings. In my case I needed to do a bridge using wire as the pads were ripped off from the PCB. Hope that could help!
I had my 464 fixed d

Thanks, I did that earlier today, sadly didn't help. It looks like there's corrosion inside the socket, but it's a bit difficult to reach inside to clean. Will try again later before sending a message to @Rabs

[oyshals]

Just a little update; I was playing around with the Dandanator and the CPC, just to see what happened, since i couldn't get it to work.

What happened was that every time I connected the Dandanator, the voltage went from 4,9-4,8V to 4,5-4,6V. This made me a bit hopeful that my issue is as simple as my bad 5V socket (which I've known for a while). I'm expecting the new socket this week, so keeping my fingers crossed!

I've also been studying more posts on this forum, and I see that my symptoms very often are related to bad ram. If so, I think I have bad chips on both banks. I accidentally ordered chips and sockets twice, so I guess 32 of each should be enough 😅

I also have a new Z80, CRTC, FAL, 40010, 40015 and 40025, so I should have most of what I need.

I know, why didn't I just put this money in a tested CPC from eBay? This one is MINE, probably the best Christmas gift ever! Another one just wouldn't be the same.
Also, I'd like to learn.
When i finally make it, I'll probably try to get my hands on a 464 or 664 on eBay 😊

So now I'm just waiting for the socket to arrive, I'll start with that as it is the only issue I've confirmed so far.

Thank you all for your patience and answering all my questions so far, I guess more will come!

@Rabs Thank you for offering a socket, but since I found new sockets on eBay, I didn't want to violate your private stock as you may need it on a later occasion 😊

[oyshals]

So I received my new power supply socket. Unfortunately, it didn't resolve the main issue. However I now have stable voltage.

I've eliminated the Z80, the fal chip and the gate array.

So, two questions: If all my ram chips on both banks have died of old age, could this prevent loading the diagnostic tool on my dandanator?

I will now order an oscilloscope. Would one with a range of 5hz be sufficient?

[JupiterJones]

So I received my new power supply socket. Unfortunately, it didn't resolve the main issue. However I now have stable voltage.

I've eliminated the Z80, the fal chip and the gate array.

So, two questions: If all my ram chips on both banks have died of old age, could this prevent loading the diagnostic tool on my dandanator?

I will now order an oscilloscope. Would one with a range of 5hz be sufficient?

First question: I think so. CRT builds image from memory using some multiplexers in between. However I think it is unlikely all chips failing at once unless some really bad power supply has been connected.

Second question: Any two-channel o'scope from 40MHz and 250MSamples should do to check lines. Crystal in CPC is 16MHz, CPU clock 4MHz so going to more than 50MHz will make you pay more (but wel, I've got a cheapo Hantek at 200MHz, but for price it was a bargain).

[oyshals]

So I received my new power supply socket. Unfortunately, it didn't resolve the main issue. However I now have stable voltage.

I've eliminated the Z80, the fal chip and the gate array.

So, two questions: If all my ram chips on both banks have died of old age, could this prevent loading the diagnostic tool on my dandanator?

I will now order an oscilloscope. Would one with a range of 5hz be sufficient?

First question: I think so. CRT builds image from memory using some multiplexers in between. However I think it is unlikely all chips failing at once unless some really bad power supply has been connected.

Second question: Any two-channel o'scope from 40MHz and 250MSamples should do to check lines. Crystal in CPC is 16MHz, CPU clock 4MHz so going to more than 50MHz will make you pay more (but wel, I've got a cheapo Hantek at 200MHz, but for price it was a bargain).

Thanks!

[JupiterJones]

I'm sorry that I'm a bit messy, just trying to check everything.

When studying the back side of the mother board, i noticed that the color of the solderings for IC112 is a bit yellow-ish. It looks more like heat than corrosion. From the schematics, the IC112 seems to be connected to the 16MhZ clock signal, and this signal is good. Is this something to look into?

As pointed by Rabs it may be some flux residue. clean it with isopropilic alcohol, or common alcohol if you don't have IPA at hand.
IC112 is an OR gate used to drive reads and writes to PIO (8255). If I'm not wrong it should not have influence in booting the system (at least to get the blue welcome screen).

[Rabs]

In the case of the Diagnostics ROM, which you should be booting the Dandator up as, then you don't need working RAM as it is providing diagnostics on the RAM. But you will need a working z80, GateArray and CRTC, and any supporting logic. Oh and a good expansion port connection. @Bryce would be able to confirm.

What are you seeing now with and without the Dandanator, I have lost track.

[oyshals]

In the case of the Diagnostics ROM, which you should be booting the Dandator up as, then you don't need working RAM as it is providing diagnostics on the RAM. But you will need a working z80, GateArray and CRTC, and any supporting logic. Oh and a good expansion port connection. @Bryce would be able to confirm.

What are you seeing now with and without the Dandanator, I have lost track.

I still have the grey screen and black frame, with and without the Dandanator connected. With the Dandanator connected, the grey "square" moves rapidly from top to bottom. When I adjust the knob on the back of the monitor, it centers on my screen.
When I push the left button (the one for diagnostics) on the Dandanator while turning the computer on, the whole screen turns dark Grey (no frame). No reaction while pressing "del" on keyboard.

[Bryce]

I don't have a Dandator or know about its inner workings, so I can't comment on that. Regarding the RAM, it's not as some may assume, ie: 8 chips with 8k bytes per chip. Each chip stores just 1bit of each of the 64k of bytes. So if just one RAM chip fails, the entire 64k bank has failed.

Regarding scopes: 5MHz is completely pointless for most things other than analogue audio work. The bandwidth should ideally be around 5x the highest frequency you intend to measure. So for the CPC 5x16 = 80MHz, but you can get away with a 50Mhz scope for most retro related work.

Bryce.

[JupiterJones]

In the case of the Diagnostics ROM, which you should be booting the Dandator up as, then you don't need working RAM as it is providing diagnostics on the RAM. But you will need a working z80, GateArray and CRTC, and any supporting logic. Oh and a good expansion port connection. @Bryce would be able to confirm.

What are you seeing now with and without the Dandanator, I have lost track.

Hi @Rabs, you are right. If no RAM chip is healthy Noel's test will show a red pattern and numbers in screen. If this doesn't even show, then either Z80, the VDU or/and the gate array are faulty, or even the glue logic (IC110 and IC112 at least).