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Old 13 July 2018, 04:34   #1
Retrofan
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My "new" Commodore 128.

Hi:

This is a long story, but I bought this cheap C=128 I believe that near the end of 2017, when it was intended as my birthday's gift for the beginning of march of 2018.

Because of my lack of time and room I've left it awaiting... till now

I bought it very cheap, 50€ including... ahem... some italian games and a very ugly datassette unit. The C= was missing a key and a PSU... Ahem.

So I first bought a used PSU and later, with time I finally found the missing "No Scroll" key that it was missing.

So as I was saying, finally yesterday I found the time and ... energy (sorry for getting old) to open my birthday's boxed gift...

So yesterday I was very happy to undust the huge box and later I was so happy to find a nice looking C=128 in all of it's glory

As I've said I had the missing key to replace it and after ... 45 minutes? I was finally able to take out the remainings of the original key from the keyboard using a couple of screwdrivers and some small pliers. Then I only had to install the new key with the spring under it. Easy peasy.

Then it comes the time, Ten minutes ago when you have to connect the PSU, the video cable, cross your fingers and say that known phrase about "now the smoke test"

Well... Better to show pictures I believe









Now I will change caps. I'm a bit/very worried after seing Jan Beta making the same:

[ Show youtube player ]

That's a very recommended channel that I'm following as a subscriptor and also as a small patreon .

What I'm wondering just after booting this C=128 is about those stripes, those vertical lines all along the screen...... Come on, isn't there a way to get rid of them in the C=128?

Any input is highly appreciated

Last edited by Retrofan; 13 July 2018 at 05:07.
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Old 13 July 2018, 05:06   #2
TjLaZer
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Radial caps don't need to be changed as urgently as SMD caps, so as long as it works you are good for a while. They don't leak and destroy like SMD.

Last edited by TjLaZer; 27 July 2018 at 03:23.
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Old 13 July 2018, 05:15   #3
Retrofan
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Quote:
Originally Posted by TjLaZer View Post
Radial caps don't need to be changed as urgently as SMD caps, so as long as it works you are good for a while. They don't leal and destroy like SMD.
Thanks. This is the first time I hear that (sorry as I'm a newbie). I'll change my radial ones in any case.

BUT what I'm mostly wondering now is about those so ugly stripes. Do you know about any solution for that in the C128?
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Old 13 July 2018, 05:28   #4
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Quote:
Originally Posted by Retrofan View Post
(sorry as I'm a newbie)


Sure...........
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Old 13 July 2018, 05:44   #5
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Originally Posted by Retrofan View Post
BUT what I'm mostly wondering now is about those so ugly stripes. Do you know about any solution for that in the C128?
If you have any CRT TV try it first, it could be your LCD Monitor.
I have similar lines on my Monitor with my Amigas.
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Old 13 July 2018, 05:59   #6
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Originally Posted by Retrofan View Post
BUT what I'm mostly wondering now is about those so ugly stripes. Do you know about any solution for that in the C128?
I owned many 64's & 128's in the early days.... the ONLY way I got rid of those (intrinsic) vertical lines was to use a 1902 or 2002 CRT monitor. Maybe there's a Jens' type of hardware mod for the symptom these days but I don't know....

BTW, I always root for your success Retrofan!!!

Last edited by Amiga4000; 13 July 2018 at 06:05.
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Old 13 July 2018, 11:47   #7
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BUT what I'm mostly wondering now is about those so ugly stripes. Do you know about any solution for that in the C128?
These are a common problem with C64/C128's. Most of mine have it to some extend. As I understand it, the two most common fixes (other than lucking out with a monitor that doesn't display them) are to either use a C64 reloaded motherboard, which won't help you much as it's not C128 or to use a LumaFix64.

I haven't actually tried the LumaFix64 myself yet, but I'm considering it for sure.

It's not that expensive either and should work with all VIC-II's (but best ask them to be sure!). See: https://www.protovision.games/shop/p...roducts_id=197
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Old 13 July 2018, 11:49   #8
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Quote:
Originally Posted by Retrofan View Post
Thanks. This is the first time I hear that (sorry as I'm a newbie). I'll change my radial ones in any case.

BUT what I'm mostly wondering now is about those so ugly stripes. Do you know about any solution for that in the C128?
Haven't looked into that (it's on my list) but have assumed one could use the same solution as on the C64: take the leaked signal (AEC?) and inject an inverted version.

My C128 have extremely irritating lines I've never seen on any C64 so there may be some differences in the video circuit between them.
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Old 13 July 2018, 12:17   #9
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Quote:
Originally Posted by TjLaZer View Post
Radial caps don't need to be changed as urgently as SMD caps, so as long as it works you are good for a while. They don't leal and destroy like SMD.
C64 are very old machines, and the capacitors need to be changed on them.

on the C64 they dry up. And you better be well equiped, because the C64/128 boards are very fragile, it's very easy to rip a trace like Jan Beta did in his video.
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Old 13 July 2018, 21:25   #10
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Ah, then he was meaning that the ceramic caps don't need to be changed so often (I know), not smd ones.

Yep, I'll change the radial electrolytic ones and I'll see if I see any difference in the stripes.
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Old 13 July 2018, 22:24   #11
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I've found what seems a very nice Lumafix128 version. The guy will make a new batch if there is interest enough:

[ Show youtube player ]

Last edited by Retrofan; 14 July 2018 at 03:12.
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Old 13 July 2018, 22:43   #12
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the commodore 64 or 128 usually don't need any recap
there are about 3 or 4 electrolytic caps in those motherboards, generally are done by Nitchicon or Elna , (both good brands)

Those caps remain good always in 99% of the motherboars


yet I have a Commodore C64C which work like new, I never changed anything


The vertical lines is a different problem, nothing related to bad caps
is a bad component inside the modulator which affect certain types of monitors or TVs a greater degree than others


The C128 have RGB connection so this problem can be solved connecting a RGB monitor
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Old 13 July 2018, 22:51   #13
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Thanks, you are true. I will try with the RGB cable.
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Old 13 July 2018, 22:58   #14
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The C128 have RGB connection so this problem can be solved connecting a RGB monitor
That's what I said.....
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Old 13 July 2018, 23:11   #15
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Will it be better, sure?. I was watching now some video using a RGB cable and the stripes were there.
I mean that maybe you get a better image not because of the RGB cable but because of the monitor. Edit: Yes, I see that that's what you mean, sorry my bad. The thing is that if I don't have the room for my C128 I have less for a RGB monitor.

BTW I've tried now with a video converter and my PC monitor using a s-video cable, but the stripes are visible there too.



So I'll try to get one of those new Lumafix128 boards http://eab.abime.net/showpost.php?p=...3&postcount=11

To tell the truth I'm not sure if changing the caps. It isn't at all that I could be scared, as I've changed a ton of them. It's just that the image is crystal clear (yep, with all of those so ugly vertical stripes). @Mrz has a good point about those few caps, the same that I've listened from Ray Carlsen even. Also there is the well known advice about "if it ain't wroken, don't fix it". It isn't the same with the C64; I mean at least about the 5V DC-DC converter that I've changed recently in a couple of C64's. You see, I don't like seing things running very hot, and that's the main thing in the C64. About the C128 I will like to open it and -my idea, just thinking- at least clean the existing thermal paste and put some Artic five over the chips that connect to the metal shielding plate and later to put with some heatsink plaster some dedicated heatsinks over each one (over the metal shielding). That's my idea after I saw that the metal shielding doesn't reduce ANY heating: [ Show youtube player ] .

I was just wondering now if Jens from Individual Computers couldn't take the idea about developing such a nice solution as it seems to be the one that I've posted above; a new product like a Lumafix128. I believe that it's a nice suggestion.

Last edited by Retrofan; 27 July 2018 at 01:17.
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Old 15 July 2018, 16:25   #16
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I owned a C128 in the past

The most cool thing about it is that it's 3 computers in one
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Old 16 July 2018, 00:30   #17
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Quote:
Originally Posted by Retrofan View Post
Thanks. This is the first time I hear that (sorry as I'm a newbie). I'll change my radial ones in any case.

BUT what I'm mostly wondering now is about those so ugly stripes. Do you know about any solution for that in the C128?
Those stripes are caused by signal crosstalk on the motherboard; ALL (no exceptions!) of the C64/C128 machines suffer from it. Back in the day, it wasn't very noticeable because of the analog nature of the CRT receivers, but now that we have very fast (i.e. high bandwidth), precision digital sampling and output of the signals, its very noticeable.

Lumafix attempts to fix this by adding in an opposing signal. Due to the way these signals operate (with respect to delays), it cannot 100% cancel out the effects of the crosstalk.

In my experience, the only way to kill off these stripes (technically it doesn't remove them, but the circuit operation makes it almost unseeable) is to use an old 1702 or 1084 monitor (i.e. a monitor with the bandwidth limited displays of that era). I farted around for weeks with every kind of scan rate converter I could find, and if the converter produced a stable display, it also had the lines in it. I finally bit the bullet and accepted that I wasn't ever going to get rid of the lines and use a modern LCD; even the one ancient LCD that I found which somewhat masked them, had color phase shifting on the horizontal edges of color changes, and no amount of fiddling with the controls would remove it. I recall reading somewhere that the phase shift is in fact a design flaw in the VIC-II chip, and that when Commodore had their monitors built, there was built-in correction for the chroma/luma delay.

Also, the RGB output of the Commodore 128 only outputs from the 80-column graphics chip; it will not help with the vertical lines on the 40-column VIC-II chip.

Changing the capacitors will not improve the display; the stripes are caused by mainboard traces being routed adjacent to each other, without shielding or clearances to reduce crosstalk, so you'll be disappointed to find out that the image hasn't changed after you've replaced every capacitor in the machine.

A proper fix would be a replacement VIC-II daughterboard, with an FPGA implementation of the digital and analog parts of the VIC-II, routed out to a DAC, built on a quality board by someone who knows their shit. Also, they would need to be able to manage the Chip Select signal, since it tends to glitch a lot (due to the asynchronous logic that generates it), and modern FPGA's would pick up on that in a heartbeat. Hard combination of skills to come by in the hobbyist space. Hard to come by in the professional space, too.

Last edited by Shadowfire; 16 July 2018 at 00:57.
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Old 16 July 2018, 00:49   #18
Retrofan
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Thanks for your answer. I really would love to get a 1084 monitor for example. Maybe someday I'll do.

What do you think about this solution that I've commented? [ Show youtube player ]
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Old 16 July 2018, 01:03   #19
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If you're happy with the image quality of the Lumafix, then use it. It does look better than the stock video output.

Looking better than the stock image isn't exactly a high bar to overcome.
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Old 16 July 2018, 03:15   #20
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the vertical lines issue also affect some sinclair spectrums
ie I have a spectrum 48k which have this issue but also I have a spectrum 128k which doesn't have this issue


both connected through RF to the same TV , the spectrum 128lk display perfect image but the spectrum 48k display vertical lines



I think is a problem in the modulator or some other buggy component in the motherboard

for ex some commodores 64 were assembled with different modulators, and the RF quality and composite video varies from one commodore 64 to the other


I've had several C64s and I'm left with the best one which display a crystal clear image in composite video or RF


is a C64c , in the back side says"made in germany" but there are "made in UK" , "made in filipines" , "made in singapur" etc
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