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Type: Posts; User: Hugo Holden

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  1. Bytesaver, block move program & BASIC-5

    The 2708 UV EPROMS finally arrived in the post from Germany. I got the Bytesaver up and running with Processor Technology's BASIC/5 in PROMS.

    The BASIC/5 program was broken up and placed in seven...
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    I found an interesting anomaly on Ebay with the...

    I found an interesting anomaly on Ebay with the GSP.

    I was wanting to buy a five IC's from a fellow in the USA. He had specified in his auction the shipping cost to AU as $18 for one IC and the...
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    I have attached a block diagram which might help...

    I have attached a block diagram which might help make sense of my post on the topic.

    In the early days of TV's and video monitors, the phase comparator was simply made from two diodes and it acted...
  4. I think you would have to be careful with the...

    I think you would have to be careful with the material, especially not run it for too long if it was paper based.

    For example, polishing metal, once you have got to about 2000 or 3000 grade paper...
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    I agree with Dwight. What is happening when...

    I agree with Dwight.

    What is happening when you adjust the H hold is that the picture can be made to appear normally, but it is drifting left or right and falling out of lock because it is not...
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    It says 17W power consumption on 12V, so the...

    It says 17W power consumption on 12V, so the adapter would have to be capable of a minimum of 17/12 Amps. So a 1.5A rated adapter would just do it, but if you used a 2A capable one it (the adapter)...
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    Yes, if its is rolling vertically on both...

    Yes, if its is rolling vertically on both monitors, and won't come into vertical lock, it suggests something has happened to the vertical sync pulse circuit on the motherboard.

    If you could post...
  8. Thread: Dummy Load

    by Hugo Holden
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    It might or it might not stay on. With the...

    It might or it might not stay on.

    With the current drain from the dummy load, this tends to store some energy in the the filter inductors and cause a small voltage drop from the smps transformer...
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    Apple II vdu's as far as I recall have a very...

    Apple II vdu's as far as I recall have a very conventional H & V scan system (much like a standard video VDU). Which means they have separate vertical and horizontal scan oscillators and the set...
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    I have made some progress. I have replicated the...

    I have made some progress. I have replicated the top and bottom track layout of the adapter board. I have attached an image of the overlaid tracks & components. It took some hours to do it.

    I have...
  11. Most of the time with a CRT monitor, it is...

    Most of the time with a CRT monitor, it is usually fairly fairly easy to deduce where the problem is looking at the screen (though there are a few exceptions). Generally speaking if there is a change...
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    Dwight, Yest that is the one. I think it is...

    Dwight,

    Yest that is the one.

    I think it is a very impressive card. I have been reading about its functions & options.

    Rockwell made it so it would serve the RM-65 platform, but in addition,...
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    Dwight, I decided to use the Euro connector...

    Dwight,

    I decided to use the Euro connector version on both the adapter and the the video board.

    The reason being that the adapter board would also be able to be used with the RM-65 RAM...
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    I like to replicate vintage pcb's as closely as...

    I like to replicate vintage pcb's as closely as possible, it seems to increase the probability of it working out.

    I have been looking into the DIN Eurocard connectors. They are actually a 3 row...
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    Thanks for that link to the book ! The...

    Thanks for that link to the book !

    The schematic matches another photo of the card (attached that has two LS240 and a LS640). So from this I can replicate it. Though the tracks on the lower...
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    Thanks Dave, that is very helpful to see the...

    Thanks Dave, that is very helpful to see the exact document. I can make the interface from that.

    One of the problems I have quickly discovered for vintage computer interfacing is that there are...
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    Mike, When I read this I had no idea what...

    Mike,

    When I read this I had no idea what AH5050 meant. So I searched and found the attached information.

    If I was going to be able to set this up myself as an option you suggested and had any...
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    Yes that sounds like a good option, but I want to...

    Yes that sounds like a good option, but I want to run just the video card and composite video monitor with my AIM-65 so as to keep using the AIM's keyboard etc rather than farming the function out to...
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    There was a remark on Han's website about this...

    There was a remark on Han's website about this book:

    Datasheets of all available RM 65 modules are described in Chapter 9 of the 1984 Synertek Databook.

    Does anyone have a copy of this book or...
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    Most of the time with these sorts of supplies,...

    Most of the time with these sorts of supplies, you can repair them without the schematics.

    The first move is to re-cap them replacing every electrolytic cap. Also test the power devices including...
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    I found this attractive sketch on the back cover...

    I found this attractive sketch on the back cover of a vintage 1981 Rockwell IC manual.

    Rockwell probably made a lot of electronics gear for the space program. It is very cool. Makes me very proud...
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    It is interesting the liberties some designers...

    It is interesting the liberties some designers took with the power supply to the MC1488. In the Votrax TNT for example, they powered it from +12V and -5.6V. When I saw this I wasn't 100% happy with...
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    Thank you so much.

    Thank you so much.
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    Hi Dave, Thank you. I sent a PM with my email...

    Hi Dave,

    Thank you. I sent a PM with my email on it.

    From what I can see so far it looks like it has a custom Character generator. Matrox did this with their ALTR-2480 video card, rather than...
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    Also, I think the same adapter would be required...

    Also, I think the same adapter would be required to use something like the add on 8k RAM board (which I want to make a clone of too) so it will be very good to find information on the adapter. The 8k...
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