A1200 scart to tv problem

[alphagemini]

My A1200 has been recapped and a math coprocessor and accelerator installed.
It worked well with a bog standard TV for over a year. It developed an intermittent fault, sometimes failing to access the screen but showing all the usual lights. One day it quit completely and did not function with another TV. It still had the lights as usual.

I bought a new Alba TV small screen but no use. I sent the 1200 to Amigakit who cleaned some contacts and it worked and tested well. Got it back and it worked, albeit after some display adjustments. It worked all day number crunching as usual. Turned it off and on a few times, all working. Next day it would not work,
in spite of fiddling with the scart plug etc.. The TV gets a signal, i.e the 'no signal' message goes out but nothing more.

If anyone has any suggestions or insights I would be very grateful!

[Daedalus]

Have you tried using the composite connection instead? The quality will be quite poor, but it will work on almost everything, and helps to narrow down the fault.

[alphagemini]

Originally Posted by Daedalus

Have you tried using the composite connection instead? The quality will be quite poor, but it will work on almost everything, and helps to narrow down the fault.

Thanks for the quick reply. I will get a composite connection and see if it works.
I hope I haven't destroyed anything!

[lesta_smsc]

It would seem strange to damage it by mere turning off/on particularly if it had new capacitors. What exactly did Amigakit do? If it was purely cleaning the contacts, there may be a fault that lies elsewhere and I wonder if it could be due to a poor connection on the PCB.

One other option would be to take out all peripherals and see if it boots without anything attached. If so, may be worth looking at PSU?

[alphagemini]

Originally Posted by lesta_smsc

It would seem strange to damage it by mere turning off/on particularly if it had new capacitors. What exactly did Amigakit do? If it was purely cleaning the contacts, there may be a fault that lies elsewhere and I wonder if it could be due to a poor connection on the PCB.

One other option would be to take out all peripherals and see if it boots without anything attached. If so, may be worth looking at PSU?

Thanks for your response. Amigakit checked everything and cleaned some contacts on the accelerator board. It worked for one day after that. This all started with an occasional fault, failing to output video, which then failed completely. I have examined the board and its plumbing and it all looks clean with the exception of the accelerator board. The plumbing looks rough, I could do a much cleaner job myself. The problem with all this stuff is sending it away to be looked at by the professionals. It wastes time and money. I will get a back up machine. My 4000 ran from new with no probs until it burnt its CPU card.

The machine boots OK it seems, all the lights flash, if that means anything!

[FOL]

There is absolutely nothing wrong with the machine. It works 100% perfect as it should. There is nothing wrong with the soldering or accelerator card.
I think there is some confusion. The key is that the Power led and HDD Led are working as they should meaning the machine is booting fine.


Lets just wait and see what happens when using Composite.

[Daedalus]

Steve Clifford (AmigaPassion) is in Kent and offers a repair service. That may at least help with the hassle and risk of sending it away again, if it can be personally delivered.

[alphagemini]

Originally Posted by FOL

There is absolutely nothing wrong with the machine. It works 100% perfect as it should. There is nothing wrong with the soldering or accelerator card.
I think there is some confusion. The key is that the Power led and HDD Led are working as they should meaning the machine is booting fine.


Lets just wait and see what happens when using Composite.

Hi Chris, thanks for your response. I have a suspicion that the hard drive has a fault. It worked ok for a whole day and then quit. I tried it with another TV but had the same result. So? Intermittent faults are the worst, OK then not OK. When you worked on it you were using your own HD, so no faults shown. I bet mine has a prob

[FOL]

Originally Posted by alphagemini

Hi Chris, thanks for your response. I have a suspicion that the hard drive has a fault. It worked ok for a whole day and then quit. I tried it with another TV but had the same result. So? Intermittent faults are the worst, OK then not OK. When you worked on it you were using your own HD, so no faults shown. I bet mine has a prob

If you suspect HDD, boot a floppy disk, i.e. workbench.


Another thing you can do is, hold both mouse buttons on switch on. In menu, select boot with no startup-sequence. Then in CLI after boot, type SET ECHO ON and press return. Then type execute s:startup-sequence and press return. It will then show you whats its doing on boot.

Did Composite lead work?

[alphagemini]

Originally Posted by FOL

If you suspect HDD, boot a floppy disk, i.e. workbench.


Another thing you can do is, hold both mouse buttons on switch on. In menu, select boot with no startup-sequence. Then in CLI after boot, type SET ECHO ON and press return. Then type execute s:startup-sequence and press return. It will then show you whats its doing on boot.

Did Composite lead work?

It won't boot from my old workbench floppy, it might be dead. I tried to do the mouse hold down but nothing came up on screen.

Haven't had the composite lead yet. Tomorrow prob.

[alphagemini]

Originally Posted by FOL

If you suspect HDD, boot a floppy disk, i.e. workbench.


Another thing you can do is, hold both mouse buttons on switch on. In menu, select boot with no startup-sequence. Then in CLI after boot, type SET ECHO ON and press return. Then type execute s:startup-sequence and press return. It will then show you whats its doing on boot.

Did Composite lead work?

I have tried the new lead but still no response, just a blank screen. What to do?

[alphagemini]

Originally Posted by alphagemini

I have tried the new lead but still no response, just a blank screen. What to do?

What chip controls the output to screen? Any way of testing this? Do you want it back to have another go?

[FOL]

Originally Posted by alphagemini

I have tried the new lead but still no response, just a blank screen. What to do?

Im guessing all Power and HDD leds are going as normal. It would need to come back, this time with everything you use, including HDD and PSU.
We can test your whole setup.

[alphagemini]

Originally Posted by FOL

Im guessing all Power and HDD leds are going as normal. It would need to come back, this time with everything you use, including HDD and PSU.
We can test your whole setup.

What is the PSU? As far as I can see the only difference between what I am doing and what you did was the HD. If I instal a new HD and there is no solution, then you can have it back. I don't need games so just need partitioning etc.. Can't let the present HD out of my control.

When this is all over I will buy another 1200 as a standby, you can recap and test it for me.

[FOL]

Originally Posted by alphagemini

What is the PSU? As far as I can see the only difference between what I am doing and what you did was the HD. If I instal a new HD and there is no solution, then you can have it back. I don't need games so just need partitioning etc.. Can't let the present HD out of my control.

When this is all over I will buy another 1200 as a standby, you can recap and test it for me.

The problem is, when you say no output. Is screen illuminated. This is what makes it hard to diagnose (without being there). PSU = Power Supply.

[alphagemini]

Originally Posted by FOL

The problem is, when you say no output. Is screen illuminated. This is what makes it hard to diagnose (without being there). PSU = Power Supply.

How could the PSU affect things? It supplies current ok

The screen is not illuminated. It says SCART cvps pal, then that goes off and nothing. The TV is obviously recognizing something. If there was no signal of any kind then that would show on the screen, as it does when the computer is turned off.

[FOL]

Originally Posted by alphagemini

How could the PSU affect things? It supplies current ok

The screen is not illuminated. It says SCART cvps pal, then that goes off and nothing. The TV is obviously recognizing something. If there was no signal of any kind then that would show on the screen, as it does when the computer is turned off.

CVPS PAL is crutial information. Does it say that for both scart leads?

[alphagemini]

Originally Posted by FOL

CVPS PAL is crutial information. Does it say that for both scart leads?

That is what it says for the combo lead. For the other one it says RGB/

Hope this helps. The floppy disk clicks as normal too

[FOL]

Originally Posted by alphagemini

That is what it says for the combo lead. For the other one it says RGB/

Hope this helps. The floppy disk clicks as normal too

Really think you should try another TV. What about trying your old one again with both leads.

[alphagemini]

Originally Posted by FOL

Really think you should try another TV. What about trying your old one again with both leads.

I've done that. Used a neighbours TV as well. My current TV worked at first
don't forget, for a whole day. The only problem I had was that after choosing the right aspect ratio the numbers and letters appeared correctly but the backgound blue has verticle stripes.