 Previous Messages |
Posted By
pepax
on 2008-07-22
15:41:19
|  Re: American Plus 4
So I have swapped the crystals and Kernal and this is the outcome: http://www.flickr.com/photos/93402213@N00/2692888479/
It's not exactly the Black Screen of Death, rather a weird pattern. The CPU and TED are OK and so is the C64 power supply.
If you have any suggestion, please lay it on me, thanks!
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Posted By
pepax
on 2008-07-08
09:44:33
| Re: American Plus 4
Thanks!
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Posted By
IstvanV
on 2008-07-08
07:47:42
| Re: American Plus 4
Yes. The TED documentation actually says 17734475 +/- 70 ppm, so it can differ by at most about one kHz.
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Posted By
pepax
on 2008-07-08
03:22:12
| Re: American Plus 4
I guess I'll find out very soon if swapping the oscillator and ROM is enough. 
However, the only crystal I can get easily is a 17.734475 Mhz one and the specs say a 17.734472 MHz one is used in the PAL Plus/4. Is the difference negligible?
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Posted By
pepax
on 2008-07-07
13:37:21
| Re: American Plus 4
Hi!
Do you guys know of any NTSC-to-PAL conversion HOWTO? I think I once saw one but I don't remember where anymore. 
Is the crystal easy to find?
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Posted By
Marky
on 2005-11-19
13:18:29
| Re: American Plus 4
I've decided to sell it on ebay as is, listed under american plus 4. The PLA is soldered in and so would be a little work to desolder and if its the ROM we would need an NTSC one.
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Posted By
Plus4Vampyre
on 2005-11-13
15:38:32
 | Re: American Plus 4
yeah Crown is right, PLA or ROM could also be dead - however - at least one chip or he board is dead - to continue Marky has to check all chips to find out which one is faulty.
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Posted By
Crown
on 2005-11-13
14:53:41
| Re: American Plus 4
I would say its either the ROM or the PLA which is dead here.
While you are keeping the RESET button pressed the CPU is stopped and the TED is working normally in the State it was when you pressed the button. Because you are getting a proper screen while the RESET is being pressed and because only parts of the initial text is on the screen, it is possible that the ROM has a failure.
Also the first screen happens when the TED is taking character character set data from unconnected ROM area (anything below $8000 or when a non existent ROM is banked in, also point towards ROM or PLA failure)...
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Posted By
Plus4Vampyre
on 2005-11-13
14:03:07
| Re: American Plus 4
Marky the pictures show no regual behaviour it looks like you "grilled" the TED or the CPU - maybe with you selfmade output? Please take a PAL c16 or Plus/4 and check the chips especially the TED and the CPU if they are still working correctly - make sure that no chip is broken before you continue. if you use a c16 be careful with the direction of the chips.
.
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Posted By
Marky
on 2005-11-13
12:25:31
| Re: American Plus 4
That wire is the composite video out, going into the composite input of the TV.
The latest developments are that it had a duff processor so we replaced it but found we only got a "sensible" picture when the reset button was being held down!!!
Normal condition:-
Reset being held:-
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Posted By
JamesC
on 2005-11-11
20:48:04
| Re: American Plus 4
What in the WORLD is that wire coming from the monitor port?
If you want to attach to an NTSC television, please use the RF port on the left side of the computer. I suspect that your wire may be feeding signals from the monitor port to the television tuner, which doesn't know how to decode them.
The RF port is intended to feed a television with a tuner (channel selector). The monitor port is meant to feed a monitor through RCA jacks (dedicated picture).
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Posted By
Marky
on 2005-11-11
04:43:02
| Re: American Plus 4
We took the composite signal, and there were syncs but no picture. This was into an NTSC capable TV. Wonder if the processor has died?
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Posted By
MMS
on 2005-11-08
17:24:37
 | Re: American Plus 4
Hi Vampyre,
Not in the opposite way? USA uses 110V and 60Hz, and Europe uses 230V and 50Hz (2 times the 25 half-picture, or what).
There are cheap converters may provide 110V and 60Hz to the Plus/4 even in Europe.
Example for 10Ł: http://www.cybermarket.co.uk/ishop/923/shopscr1577.html
Then the RF output will be surely according to that good old "normal NTSC" signal.
So then this is the only problem "we" still have. )
Dear Marky,
The best is really to get such a TV prepared for NTSC reception, but surely not the cheapest solution.
Yu are right, I think the video out is a possible (and I think better) solution, also not so cheap, but maybe cheaper than a brand new TV:
We have the Plus/4 Video output (the same aas C=64)
http://www.zock.com/8-Bit/D_C64io.HTML
http://personalpages.tds.net/~rcarlsen/cbm/pinouts.txt
Here are I see two signals similar to SVideo (Chrominance/luminance), but also have the composite video out signal (CVBS we call here, it is easier to handle).
Please check this one.
http://dfarq.homeip.net/article/20050104084808610
For SVideo:
http://sta.c64.org/cbmsvideoc.html
http://sta.c64.org/cbmsvideo.jpg
http://sta.c64.org/cbmsvideo.html
So you have a basic CVBS signal, which still 60Hz, but you are free from UHF/VHF and all other antenne issues.
The PAL <-->NTSC converters also expensive, but a 99$ I could find
http://www.bizrate.com/buy/products__cat_id--11510900,keyword--Pal%20Ntsc%20Converter.html
Or you can find such an equipment(VCR, TV, DVD-recorder), which is able to get via the Front AV an NTSC CVBS signal.
As an idea: some DVD-Recorders are able to receive and record both signals (like Philips DVDR985, it is an old model now), and may show their input signal in monitor mode via Scart the right picture. But I am not sure, if it really works.
Anyone may try out?
Bye: MMS
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Posted By
Plus4Vampyre
on 2005-11-08
10:48:37
| Re: American Plus 4
I am afraid what you like to do will not work - the reason is : the NTSC TV uses 110V 50 Hz - A PAL TV 220(or 230V) and 60 Hz - you can power down the 220V to 110V but you will have 60Hz so thats the reason why you get the vertical scan (because the NTSC TV need 50Hz but you put in 60Hz). What you need is a converter which can power down to 110V and can also change 60Hz to 50Hz and as far as I know such a converter is not cheap. If you use a TV which can switch internal to NTSC you will not have the problem, because the TV will use everytime the same voltage 220V and 60Hz.
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Posted By
Marky
on 2005-11-07
17:38:36
| Re: American Plus 4
I think I will go the video route, I don't have a commodore monitor or a cable so I will have to look into it. I had a few tribulations the TV route.
What I did was firstly as the output was VHF we had a minature TV with VHF capabilities and we could see it had found the plus 4 but we couldn't even get as good as a rolling picture. The next thing we tried was my neighbour had an NTSC TV so we powered it up but because it is old the capacitors had dried out an the vertical scan had collapsed - dooh!!!
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Posted By
Plus4Vampyre
on 2005-11-07
07:31:13
| Re: American Plus 4
The American and also Canadian Plus/4are heavier cause of the keyboard. It is difficult to get a picutre via UHF on your TV. It only works if your TV can switch to NTSC. My Panasonic TV and also all newer Sony TV's can do it. Try to use a 1084 Commodore - some of them (not all I think the scart Versions) shows a black and white screen. If you want to use a TV make sure that your TV can switch for PAL to NTSC. It's easier use a SCART cable to plug the Plus/4 to your TV. You can find the SCART <-> C64 / Plus4 cables on ebay.
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Posted By
JamesC
on 2005-11-06
13:42:50
| Re: American Plus 4
That POKE for NTSC/PAL does exist. However it doesn't change the supporting hardware on the motherboard..... the tuner that determines what signal is ultimately displayed is still NTSC or PAL.
One may be able to POKE TED to PAL and then output the signal through the video connector on the back of the Plus/4 to get a PAL signal out of an NTSC machine. The success of this will depend on the crystal installed. True (proper) conversion requires changing the crystal as well as the Kernal.
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Posted By
Mosh
on 2005-11-05
23:31:28
| Re: American Plus 4
I remember reading something about a poke that would change the TED output from NTSC to PAL... or is my mind playing tricks on me? Maybe I misread something....
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Posted By
Ulysses777
on 2005-11-05
12:36:24
| Re: American Plus 4
Unless you have an NTSC TV, there's no way you'll get a picture on the RF output, and you'll only get black & white on the AV output.
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Posted By
Marky
on 2005-11-05
12:09:46
| Re: American Plus 4
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Posted By
Marky
on 2005-11-05
12:06:07
| American Plus 4
Hello again,
My neighbour just gave me an American Plus/4. Its about 300g heavier than the usual, with some extra shielding (see pic). I got it powered up with an adapter but haven't been able to get any output on the UHF yet!
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