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Thread: I need some opinions...

  1. #1
    Join Date
    May 2006
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    Hamilton, Ontario, Canada
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    Default I need some opinions...

    Hi,

    I got tired of seeing all the Commodore 64s, 64Cs, 128s, Vic-20s and Amigas, with their monitors sitting around the warehouse, so I had them trucked over to my house and I am making fixing them a pet (no pun intended) project.

    Most of all the C64 PSUs tested bad on a load test-jig I set up, so, I had some new hybrid transformer/switching supplies manufactured and they are testing under monitoring. I had them made with 5VDC@3A and 14VAC@2A which is powerful enough to drive a C128. I am having a slip-on adapter with the C128 square 5-pin DIN connector on the end (yes, I found a bunch of them) to test them on the C128s. The 14VAC is fused and the supply can be opened to replace a blown fuse.

    I had some very nice serial cables made up, but, now I am turning my attention to the AV cables that I'll have manufactured.

    That's what I need the opinions on. Which cables should I have made, what length should they be, would the original ones be best (5-pin DIN to dual RCA, 8-pin DIN to triple RCA), s-video, scart, what?

    I would appreciate your comments as they will be the basis for my decision. What I'm having a little trouble finding is some of the wiring diagrams for the cables (which connector pins to which colour RCA plugs, etc) so my manufacturer can fabricate them, so, if you have or know where I can find them I'd appreciate that information as well.

    Thanks.
    Legacy Computers and Parts

    Sales of, parts for, and repairs to, Vintage and Legacy computers.

  2. #2

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    Quote Originally Posted by Druid6900 View Post
    Hi,


    Most of all the C64 PSUs tested bad on a load test-jig I set up, so, I had some new hybrid transformer/switching supplies manufactured and they are testing under monitoring. I had them made with 5VDC@3A and 14VAC@2A which is powerful enough to drive a C128. I am having a slip-on adapter with the C128 square 5-pin DIN connector on the end (yes, I found a bunch of them) to test them on the C128s. The 14VAC is fused and the supply can be opened to replace a blown fuse.

    Thanks.
    I wonder why 14V AC. The original C64/C128 PSUs have 9VAC output, usually it's around 10-11V max. All the C64 "breadbin" boards have an additional LM7805 linear voltage regulator, feed by the 9VAC rectified and smoothed. That regulator feeds the Vdd (+5V) rail to the VIC-II and SID chips and it already runs seriously hot at 9VAC rectified input. IMHO giving 14VAC input to the old breadbins is looking for this regulator to fail.
    Newer C64-C boards and the C128 don't have this regulator anymore, but why feeding a 50% higher voltage anyway?

    Frank IZ8DWF

  3. #3
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    Default

    Quote Originally Posted by iz8dwf View Post
    I wonder why 14V AC. The original C64/C128 PSUs have 9VAC output, usually it's around 10-11V max. All the C64 "breadbin" boards have an additional LM7805 linear voltage regulator, feed by the 9VAC rectified and smoothed. That regulator feeds the Vdd (+5V) rail to the VIC-II and SID chips and it already runs seriously hot at 9VAC rectified input. IMHO giving 14VAC input to the old breadbins is looking for this regulator to fail.
    Newer C64-C boards and the C128 don't have this regulator anymore, but why feeding a 50% higher voltage anyway?

    Frank IZ8DWF
    You are, of course, correct and it is, indeed, 9VAC.
    The 14VAC was for the TRS-80 Model I power supplies we had manufactured.
    Getting old, ya know.....
    Legacy Computers and Parts

    Sales of, parts for, and repairs to, Vintage and Legacy computers.

  4. #4

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    Quote Originally Posted by Druid6900 View Post
    You are, of course, correct and it is, indeed, 9VAC.
    The 14VAC was for the TRS-80 Model I power supplies we had manufactured.
    Getting old, ya know.....
    Thanks I was feeling so bad for those C64 @ 14V
    Frank

  5. #5
    Join Date
    Apr 2018
    Location
    Los Angeles, CA
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    Default

    So the only way I can answer this is that when I needed the cables, i made 8 pin DIN to S-Video/Composite. In my opinion, the only way to go with stock video on a C64 would be direct to a Commodore CRT or via S-Video, and most new people getting into this (and having a need for a cable), will probably not be going the route of the Commodore CRT so S-Video/Composite is probably the most common needed cable.

    While I have a SCART box, I don't use it with the C64. It doesn't really support s-video so kinda leaves you with composite which isn't the best option. Of course, I'm not living in a SCART country, so I could be wrong on it's requirement in this particular case.
    -- Brian

    Systems: Amstad PCW 8256, Apple IIe/II+/Mac+/Mac 512k, Atari 800/520STFM, Commodore 64/Amiga 3000/PET 4032/SX-64, IBM PS/1 2121-B82, Kaypro II, Osborne 1, Tandy 1000 SX, TI-99/4A, TRS-80 Model 4 GA

  6. #6

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    Regarding the video cable: so far I only used a "5-pins DIN plug to two cinch plugs" cable for the C64. It can be used for the VIC-20 as well. For the C128 I have one where the cable from the 5-pins DIN plug first go to a 9-pins D-connector plus case. A little switch has been fitted in the case. It switches between the video signal coming from the DIN plug and the video signal from the D-connector. I have an original IBM CGA monitor standing around that I can use if I need to see the RGB of the D-connector.
    Why those cinch plugs? All my displays have them, even my one year old 40 inch smart TV.
    With kind regards / met vriendelijke groet, Ruud Baltissen

    www.baltissen.org

  7. #7
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    Quote Originally Posted by iz8dwf View Post
    Thanks I was feeling so bad for those C64 @ 14V
    Frank
    Frank,
    I would NEVER hurt a C64...It would be bad for business
    Legacy Computers and Parts

    Sales of, parts for, and repairs to, Vintage and Legacy computers.

  8. #8
    Join Date
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    Quote Originally Posted by ngtwolf View Post
    So the only way I can answer this is that when I needed the cables, i made 8 pin DIN to S-Video/Composite. In my opinion, the only way to go with stock video on a C64 would be direct to a Commodore CRT or via S-Video, and most new people getting into this (and having a need for a cable), will probably not be going the route of the Commodore CRT so S-Video/Composite is probably the most common needed cable.

    While I have a SCART box, I don't use it with the C64. It doesn't really support s-video so kinda leaves you with composite which isn't the best option. Of course, I'm not living in a SCART country, so I could be wrong on it's requirement in this particular case.
    I agree with you on this and, while we do have a number of 1702, 1802, 1084 (not the S) and 2002 monitors, not nearly enough for all the 64, 128 and Amiga units we have. Most people don't want to pay the shipping costs for a CRT because, using the "box in a box" method we use, the size (and cost) gets up there quickly.
    I know there are some mods to the SCART that are supposed correct some of its deficiencies, and, although a little sloppy, it may be worth considering.
    Legacy Computers and Parts

    Sales of, parts for, and repairs to, Vintage and Legacy computers.

  9. #9
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    Quote Originally Posted by Ruud View Post
    Regarding the video cable: so far I only used a "5-pins DIN plug to two cinch plugs" cable for the C64. It can be used for the VIC-20 as well. For the C128 I have one where the cable from the 5-pins DIN plug first go to a 9-pins D-connector plus case. A little switch has been fitted in the case. It switches between the video signal coming from the DIN plug and the video signal from the D-connector. I have an original IBM CGA monitor standing around that I can use if I need to see the RGB of the D-connector.
    Why those cinch plugs? All my displays have them, even my one year old 40 inch smart TV.
    I agree that the basic system seems to work and it's simple. Your modified cable sounds interesting, but, I didn't want us to get into having the person doing mods to the computer. That's how we designed the power supply, simple. 2/3rd the size of the original, a quarter of the weight, easy to change the fuse and NO EPOXY!!!
    I didn't want an expensive "this supply does everything Commodore every made" supply, just a nice simple safe PSU that you can use with the 64 series and the 128 series (perhaps the A500 and A600, but that remains to be seen).
    Can the 5-pin 2/3 RCA cable be used on both the 5-pin sockets and the 8-pin sockets?
    I want to get this right on the first run.
    The only 5-pin to RCA cable I have is in a complete, boxed Atari XEGS and I don't want to be unpacking in any more than I have to. 30 year old cardboard ain't what it used to be....
    Last edited by Druid6900; June 28th, 2019 at 05:55 PM.
    Legacy Computers and Parts

    Sales of, parts for, and repairs to, Vintage and Legacy computers.

  10. #10
    Join Date
    Apr 2018
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    Default

    Quote Originally Posted by Druid6900 View Post
    I know there are some mods to the SCART that are supposed correct some of its deficiencies, and, although a little sloppy, it may be worth considering.
    Meh. I have the scart box specifically for using modern lcd with my Atari ST. For composite or svideo systems, I have a Retrotink.

    Quote Originally Posted by Druid6900 View Post
    Can the 5-pin 2/3 RCA cable be used on both the 5-pin sockets and the 8-pin sockets?
    I want to get this right on the first run..
    The first 5 pins on the 8 pin connector are the same, and a five pin connector works on an 8 pin computer. Unfortunately the 5 pin cable doesn't support svideo.
    -- Brian

    Systems: Amstad PCW 8256, Apple IIe/II+/Mac+/Mac 512k, Atari 800/520STFM, Commodore 64/Amiga 3000/PET 4032/SX-64, IBM PS/1 2121-B82, Kaypro II, Osborne 1, Tandy 1000 SX, TI-99/4A, TRS-80 Model 4 GA

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