| Posted By
westsider_gw
on 2009-10-09
18:34:56
|  No Video Output?
On the negative side to my new Plus/4
I still have yet to get video output working...
Im using the RF output to an old style switchbox.. I've verified both switchboxes I've tried are functional, and the cable is fine. The ebay auction I got the Plus/4 from said the computer worked fine in testing..
I've also tried with a direct composite to coaxial adapter.. same problem.
No matter H or L setting, channel 3 and 4 just show a black or grey screen with heavy scanlines.. no sound, but not white noise either.
Its like theres a signal going through, but its not showing up right.
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Posted By
SVS
on 2009-10-10
05:24:57
 | Re: No Video Output?
Channel should be 36 if I'm not wrong (PAL).
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Posted By
Chicken
on 2009-10-10
05:55:03
 | Re: No Video Output?
SVS,
westsider_gw is in NTSC land  That's why I can't really help with the TV connection.
Though, a black/grey screen is a bit suspicious...
You could try typing this in:
COLOR4,2 (and press RETURN)
This switches the border color to white and maybe you can notice a change in the signal?!
Additionally, you could try this:
VOL8:SOUND1,100,1000 (and press RETURN)
This will play a tone and maybe that gets through.
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Posted By
westsider_gw
on 2009-10-11
00:40:50
| Re: No Video Output?
Nothing happens when I do either of those.. absolutely nothing.
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Posted By
westsider_gw
on 2009-10-11
18:20:39
| Re: No Video Output?
Anyone? I get no audio or video, but there is a signal coming through.. albeit only grey and white noise. (Now big vertical lines.)
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Posted By
MMS
on 2009-10-12
16:58:04
 | Re: No Video Output?
BTW: are you sure, that the computer you have is really NTSC, like yout TV?
(really sorry to ask).
Because typically this is the way how the different raster-freuqncy may appear.
And certainly the color carrier is on a different place, so you see "something", but picture is not in sync, and there should not be color. On the sound carrier I am not sure, but based on Wiki in NTSC the sound carrier is 4.5MHZ higher than th epicture, while in PAL the sound is at 6MHz shift.
So if you have no sound, and no color, and also the sync has troubels, then I suppose it is a PAL set, connected to an NTSC TV (or opposite).
How to be sure? I do not know, maybe the production place on the bottom may help. (I checked one american Plus/4 bottom side photo, there was not marking of origin)
A possible solution is a DVD-Recorder, as on their input (at least on SVideo) they could manage multi-standard signals, if I remember well.
Pioneer and Philips surely, Panasonic maybe. Then you just have to pass it to the screen. Read this thread, I hope it works:
http://www.mausoleumclubforum.org.uk/xmb/viewthread.php?fid=35&tid=9583
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Posted By
TLC
on 2009-10-12
19:28:42
| Re: No Video Output?
Hmmm... You say you can see some signs that there's at least some signal... but not what you'd expect?...
Judging from the fact that you _could_ switch between the L and H settings (at all) I'd presume it's an NTSC machine (European ones have a different RF modulator that do not have this switch). This must be an NTSC machine, no doubt.
I do remember seeing effects like you described... The computer emits plenty of EMI, especially on VHF... this can be noticed like that, sometimes even when there's valid signal (TV transmission) on those channels (if the antenna is within reach, so that it can pick up the computers EMI noise...).
It might be that you could have not tuned-in the TV to the signal... so you're only receiving the EMI noise from the Plus/4 directly (that is especially noticeable on the low TV channels).
I'd do the following: connect the computer and the TV together, turn the computer on, and let the TV search for new available programs automatically (let it sweep through all TV channels it's physically able to tune-in). You might be lucky. I'd also try that using a TV that I know well from that side.
Do I understand right that you used a box (for the other attempt) that converts composite to RF? ...Did you make a cross-test (ie. try if the box works with the same cabling, same setup, with a diffferent computer)? It would be good to know whether the TV failed to tune-in to the RF output of the box, or if the box received no, or no valid composite signal from the Plus/4.
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Posted By
westsider_gw
on 2009-10-14
02:47:12
| Re: No Video Output?
I am positive that all three switchboxes are working, one of them is original from the computer, one is for an atari 2600, and one is just a 3rd-party box.
I have tested them all to be working on other computers and consoles.
I also tried converting the RF cable directly into coax, which works instead of those switchboxes for higher quality here. Same problem.
Oh, and the TV I have doesn't search for signals like that. Its from 1784 (like the computer), and its just got two big dials on the front to select the channels. ALTHOUGH I do understand what you me, I have done the same thing in a sense by testing every single channel on the TV in both H and L modes.. nothing 
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Posted By
TLC
on 2009-10-14
03:34:50
| Re: No Video Output?
I didn't mean the switch boxes, I meant "converting the RF cable into coax", that I had probably mis-understood earlier to be some other clever method (you wrote something like "direct composite to coaxial adapter" by which I understood you gave a try to something that converts composite signal to RF... it's obviously not the case, you just tried connecting the RF output of the computer to the TV directly with no switch-boxes).
It's pretty strange, anyway. I'd say unless the computer has some really nasty problem, your chances are high that you just couldn't tune to the computer's signal somehow. I'd suggest that because even if there's something wrong in the Plus/4, the RF part literally never breaks... so you should get a black screen even if the computer has some problems.
Hmmm. As I think that over, I may be wrong about that.
The TED defaults to PAL mode (upon power-up). PAL machines generate a valid videosignal regardless to most other components' validity. From the other hand, NTSC machines would not generate a valid videosignal, unless the computer is able to boot (ie. until the processor switches the TED to NTSC mode).
Then there are only two possibilities -- 1.) try if the computer works on a modern TV (by automatic program search), 2.) try if you can see something by connecting the computer to a composite monitor (if someone around you has one).
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Posted By
MMS
on 2009-10-14
15:25:57
| Re: No Video Output?
Or just connect to a modern TV's SVido input if no dinosaur monitor is arund 
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Posted By
TLC
on 2009-10-14
16:50:56
| Re: No Video Output?
I suggested using the monitor because most modern TVs (...better said, those with digital controls) most probably disable the screen if they're fed by some nonstandard videosignal... so he won't see practically anything but the TV's message about no valid videosignal... "old" monsters usually don't do that . It should somehow be determined if the computer produces absolutely nothing, or if it produces "something"... For PAL machines that's usually way easier... In a PAL machine, if you have a working oscillator and an at least partially working TED, that's already sufficient to get a black screen on a perfectly valid videosignal. As it seems it's not the case with NTSC machines (a bad coincidence of the TED defaulting to PAL mode and the machine providing an NTSC crystal... I hadn't remembered that first), so at this moment we don't know exactly "where" the problem is... not being in tune with the RF-modulator's channel, absolutely no RF signal provided by the computer, or all these are O.K., but the computer is "dead" in a digital meaning, with varying reasons but usually from a processor failure.
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Posted By
MMS
on 2009-10-17
17:26:26
| Re: No Video Output?
Hi Westsider!
Any success, till we made some theoretical discussion with TLC?
How it looks in the practice?
(most of the cases the practice is the death of nice theories, hehe)
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Posted By
westsider_gw
on 2009-10-21
00:31:01
| Re: No Video Output?
As far as I can tell though, nothing other than a useless black screen with lots of scanlines appears when I hook it up properly even with a switchbox. I tried it on a modern TV as well.. I still get the same problem.
I'd ship it to one of you to help debug this problem, but most of you (if not all) are in EU.. which would make shipping OUTRAGEOUS, not to mention your lack of NTSC standard there.
I'll keep trying to figure this out..
and I'll see if I can get some pictures up soon of all the problem(s)
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Posted By
TLC
on 2009-10-21
03:05:58
| Re: No Video Output?
Actually, a large proportion of TVs sold here are multistandard units (and if not, another large percent would still display the NTSC signal in black and white), but yeah, shipping the machine overseas just for the sake of some debugging looks overkill.
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Posted By
MikeZ
on 2009-10-21
10:28:21
 | Re: No Video Output?
Westsider: I'm in Florida. I have 5 plus4s and a test setup. If you want to ship it to me, I'll check it out and also try chip swapping to isolate the problem.
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Posted By
egr
on 2009-10-21
16:06:00
| Re: No Video Output?
I have the exact same problem here. Very interested to here what you find out!
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Posted By
westsider_gw
on 2009-10-28
02:02:10
| Re: No Video Output?
Well Mike, I'd ship it to you, but I'm in a court situation and have $0 to my name. When I get the money and you're still up for the offer, I'd even pay you to have a look at it.
Thanks
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