Search found 57 matches

by a4000bear
Fri Dec 22, 2023 6:53 pm
Forum: Collecting and History
Topic: De-yellowing your VIC-20 case
Replies: 47
Views: 17733

Re: De-yellowing your VIC-20 case

I have outlined my experiences and techniques for removing yellowing here: https://a4000bear.neocities.org/overclock/Retrobrite
There are also pictures of the process being done on a VIC-20 case.
by a4000bear
Fri Dec 22, 2023 6:46 pm
Forum: Collecting and History
Topic: De-yellowing your VIC-20 case
Replies: 47
Views: 17733

Re: De-yellowing your VIC-20 case

Yes they call it burn marks from the old cable touching it over the years and there's a chemical reaction between the two plastics :roll: Al little bit late here, but some time ago, I found a way to at least partially remove 'cable burns' simply by cleaning the affected area with mineral turpentine...
by a4000bear
Wed Jun 28, 2023 8:21 am
Forum: Hardware and Tech
Topic: VIC20 Jailbar removal & improved S-video modification.
Replies: 2
Views: 1916

VIC20 Jailbar removal & improved S-video modification.

I have just completed an improved version of the Vic-20 S-video modification, which now incorporates jailbar removal. Here are a couple of examples of the results. VIC20CR-ALL-TP.png VIC20CR-ALL.png And here is the same machine before modification: VIC20CR-UNMOD-TP.png VIC20CR-UNMOD.png The S-video ...
by a4000bear
Sat Apr 15, 2023 7:57 am
Forum: Hardware and Tech
Topic: FPGA 6561 - PAL Questions
Replies: 25
Views: 4627

Re: FPGA 6561 - PAL Questions

As already mentioned the PAL 6561 does not support interlace. I have always wondered why Commodore removed it from the PAL 6561. I wonder what would the consequences of including it in an FPGA version would be. I think it would be fun to have it available, assuming it doesn't break anything. PAL doe...
by a4000bear
Fri Jun 25, 2021 7:26 am
Forum: Hardware and Tech
Topic: Why not better composite video like C64?
Replies: 25
Views: 2308

Re: Why not better composite video like C64?

Just saw your video, and I posted some suggestions there, which I have also pasted below so that the people here can see it: I'm the guy who developed the S-video mod as described in the Denial wiki. While I never made any attempts to improve the composite output, I can give some explanations and su...
by a4000bear
Wed Jul 18, 2018 11:54 pm
Forum: Hardware and Tech
Topic: VIC-20 JetPack [split from: VICE Build and Mods]
Replies: 26
Views: 12029

Re: VIC-20 JetPack [split from: VICE Build and Mods]

Looks like a great project.

Just a few quick questions. Is it PAL or NTSC or switchable?
Does it support S-video output?

I'd love to get one, assuming it will work with PAL.
by a4000bear
Mon Jul 16, 2018 8:10 am
Forum: Collecting and History
Topic: VIC-1010
Replies: 2
Views: 5424

Re: VIC-1010

It's local pickup only, from Brighton, Australia. I'm only 100km from there, but I think I'll pass on that one!
by a4000bear
Fri May 25, 2018 7:25 am
Forum: Collecting and History
Topic: Holy cow
Replies: 12
Views: 11771

Re: Holy cow

Strange that the seller said "It is not compatible with NTSC TV". Japan used NTSC, and the pic of the PCB shows a 6560 VIC chip, which is the NTSC version. It could be faulty, which is why he could not get it to work on his NTSC TV.
by a4000bear
Wed Jan 31, 2018 8:16 pm
Forum: Hardware and Tech
Topic: Best display for Vic20?
Replies: 11
Views: 7784

Re: Best display for Vic20?

I use an LCD monitor intended for security applications. It has a 4:3 screen, so the display isn't distorted and it has an S-video input. My VIC is modified for S-video and the video levels carefully adjusted with an oscilloscope. I think the results are very good, considering how we struggled with ...
by a4000bear
Tue Jan 09, 2018 6:52 am
Forum: Hardware and Tech
Topic: Display issue
Replies: 34
Views: 4081

Re: Display issue

I concur with Radical Brad. Your colour subcarrier is off frequency. In NTSC this would result in incorrect colour, but in PAL, the colour phase is reversed 180 degrees on each line, cancelling out the incorrect colour on each pair of lines. In extreme cases you will get 'Hannover bars' due to the l...
by a4000bear
Thu Oct 26, 2017 4:42 pm
Forum: Hardware and Tech
Topic: VIC-2000 Expander. Modern Power Using Retro Parts!
Replies: 168
Views: 59725

Re: VIC-2000 Expander. Modern Power Using Retro Parts!

Looks like a fascinating project. May even like to build one for myself one day.

Would it be possible for those of us with a PAL VIC-20?
by a4000bear
Sun Oct 16, 2016 5:58 am
Forum: Hardware and Tech
Topic: Need advice on Oscilloscope probes
Replies: 51
Views: 5729

Re: Need advice on Oscilloscope probes

@Gyro Gearloose That's an important caveat. My own scope is a digital storage scope. How does a scope offer storage function with no digital technology ? Analog storage scopes use a special storage CRT. http://ecomputernotes.com/computer-graphics/graphics-device/write-short-note-on-direct-view-stor...
by a4000bear
Tue Jul 12, 2016 6:34 am
Forum: Hardware and Tech
Topic: 6560/6561 related oscilloscope and vectorscope images
Replies: 85
Views: 28216

Re: 6560/6561 related oscilloscope and vectorscope images

To clarify, the complete composite video signal should be 1V and is made up of two components. The sync signal which is 300mV and the white portions of the video signal which is 700mV. Adding them gives a total of 1V, which is what you see coming out of the VIC-20 (or any other video source). Note t...
by a4000bear
Mon Jul 11, 2016 7:13 am
Forum: Hardware and Tech
Topic: 6560/6561 related oscilloscope and vectorscope images
Replies: 85
Views: 28216

Re: 6560/6561 related oscilloscope and vectorscope images

I notice that you have 928 mV for the value between black/blanking and white. I've also noticed that the s-video mod instructions say this: The variable resistor, R10 will still function, allowing you to adjust the luminance level as before. If you have an oscilloscope, adjust this resistor to give...
by a4000bear
Sun Mar 03, 2013 1:20 am
Forum: Hardware and Tech
Topic: VIC 20 s-video mod problem
Replies: 1
Views: 1019

It looks like you are only getting the Y (luminance) signal into your monitor. The weak and erratic colour indicates there is nothing coming in on your C (chroma) input, and it is picking up noise. It's quite likely your scart cable is not wired to support S-video, or the monitor does not support it...