454 Fireworks -- almost fixed! Low horizontal gain

Sean Turner

Hey folks,

Quick question. I almost have "ol sparkey" fixed thanks to Walter from Sphere and the VintageTek museum. Many thanks to both for finding me the transistors I needed to fix the vertical amplifier. That is working great now!

However, there is a problem with the horizontal amplifier. The gain is too low, and the 1X gain adjustment doesn't have enough range (to express another way: markers from my 184 are too close together).

(1) all the semiconductors in the horizontal amplifier seem fine.
(2) I probed the horizontal amplifier with the signal conditions specified in the manual and found no discrepancies.

Has anyone seen this? I thinking it could be a leaky cap or something now, but just figured someone else might have seen a similar issue in these scopes.



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