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Thread: Videobrain help needed

  1. #1

    Default Videobrain help needed

    Hello all!

    So I recently obtained a nice looking videobrain in a box with some carts.

    When I power it up I get a black screen, cart or no cart installed.
    I checked the voltage of the brick and I think its 15v from 1-2 and 17v from 3-4. Thought that might be high and I think I seen somewhere that it should be 10/15 so I put it on my solder station output and dialed the voltage down. either way still a black screen.

    I then checked the internal power supply output to the main board and it seems to be 12v, 5v and 5v. with the power on. so I think the power board is doing its job.

    I was thinking about sending it off to get repaired by someone (a lot) more knowledgeable than myself. Does anyone have any suggestions?

    I'd assume all the carts I have are already dumped. I'll add a couple of pics once I figure out how to!

  2. #2

  3. #3

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    Many of the parts used in the VB are no longer available. Still the most likely failure item is the RAM. These are generally available. The most common technique is to piggy back the RAM on the board. It is not assured to make the computer work if this is done. It really depends on the failure method of the RAM.
    Do not run it long without the heat sinks. They were there for a purpose. The best source of parts is a donor machine if it is something like the video chip. I do not know anyone that repairs VB but is it worth repairing.
    I don't guarantee it is the RAM but that is your best bet on getting a working machine without more knowledge and the right tools.
    Dwight

  4. #4

    Default

    Would you be able to point out where the RAM is laid out or what part number it is?

  5. #5

    Default

    Quote Originally Posted by Stormbringer View Post
    Would you be able to point out where the RAM is laid out or what part number it is?
    First picture, upper left, as two columns of 2102s. These are generic parts so manufacture is not too important.
    Dwight

  6. #6

    Default

    Quote Originally Posted by Dwight Elvey View Post
    First picture, upper left, as two columns of 2102s. These are generic parts so manufacture is not too important.
    Dwight
    I should note that piggybacking is not a 100% valid test. A RAM could still fail in such a way that piggybacking doesn't work. It would be best to pull the RAMs and install sockets.
    Still, this really depends on your soldering and rework skills. If you damage the board while doing this, instead of one problem, you now have two or more problems. Reworking is always an added danger for these old systems.
    Dwight

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