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Forums > Vintage Apple > Lisa & Macintosh XL
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Elemenoh Active Tinkerer Bay Area -------- Joined: Oct 18, 2021 Posts: 428 Likes: 415 |
Apr 15, 2025 - #1
This Lisa had horizontal video smearing that didn't improve after recap of the video board or power supply.
The culprit ended up being Q2, a D40N2 transistor in the contrast circuit. Fortunately I had a parts Lisa I was able to get another from which resolved the problem. Unfortunately, D40N2 is no longer made and its pinout is E-B-C which modern parts don't use. I'm still hunting for an ideal permanent replacement. Please LMK if you know of one. Before swapping Q2: After swapping Q2:
Liked by _nec6678 |
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Stephen BetterBit San Francisco -------- Joined: Sep 5, 2021 Posts: 215 Likes: 264 |
Apr 15, 2025 - #2
Have you ever used alltransistors.com? You may be able to find alternatives which are either still made (unlikely) or has NOS. Perhaps a modern transistor could be used with an adapter board.
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Elemenoh Active Tinkerer Bay Area -------- Joined: Oct 18, 2021 Posts: 428 Likes: 415 |
Apr 15, 2025 - #3
Not that specific site but I've been researching substitutes. My plan is to get a more modern part with a B-C-E pinout and just jumper and insulate the emitter.
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