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Texas Instruments Interface RVB PHA 2037 Repair

Texas Instruments Interface RVB PHA 2037 Repair

We begin to explain what is this PHA-2037. This interface/Converter for the Home Computer Texas Instruments TI-99/4a is used to convert the video signals from Component (Y/Pb/Pr) to RGB (Scart Standard).

The defect of the PHA-2037 that i have received for repairing is to display images without the “BLUE” color in this case of the Video Component “Pb”.

The problem was in one of the three LM 318 (Op Amp). Just replaced, the PHA-2037 has begun to work properly.

PS: How you can see from a photo a pin of a transistor has not been cut. Maybe it was better to do it. :D

Gallery of the repair:

  1. Jueggi
    June 9th, 2017 at 23:02 | #1

    I got a PHA 2037 from eBay but unfortunately it didn’t work. The screen remains black, only sound can be heard. Do you have a circuit diagram of the device or another hint how to repair such a defect?
    Best regards

  2. Alessandro Garoli
    June 13th, 2018 at 16:07 | #2

    da irriducibile “texano”, ho acquistato su eBay un PHA2037 per usare la scart (Peritel in origine). Sembra a posto ma ho notato che la prima colonna del video non è visibile. Sembra che il video sia shiftato a sinistra di 8 pixels, percui comincio a vedere i caratteri dalla colonna 2.

    E’ possibile regolare nel PHA2037 (magari con trimmer) la pos. X ?

    Esistono schemi del PHA2037?

    Grazie e complimenti per il Vs. lavoro,
    Alessandro Garoli

  3. June 14th, 2018 at 08:44 | #3

    @Alessandro Garoli

    Ciao Alessandro, non ci sono regolazioni all’interno del PHA2037 , questo e’ un classico problema causato dal monitor/tv LCD o CRT , se hai occasione di provare con un’altro monitor magari CRT probabilmente sparisce.