Uploaded August 2025 | Updated September 2026, 2 weeks ago

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I'm back on the dead Zenith ZT-1 and it's time to go through my list of faults and try to figure out what is broken. (Again!)

Part 1: youtube.com/watch?v=5VLS-vUDV1I
Part 2: youtu.be/5Cdh13hjNf0
Part 3: This part!
Part 4: youtu.be/-OYCf5ll7_s

0:00 Intro
1:46 RGB2HDMI and glitching video
17:30 Analyzing how the 8275 actually works
40:28 Time to break out the logic analyzer (again)


-- Links

Dumps of the ROMs and other info on Github:
github.com/misterblack1/zenith_zt1/tree/main

Additional photos:
terminals-wiki.org/wiki/index.php/Category:Zenith

Intel 80xx MCU datasheet:
keil.com/dd/docs/datashts/intel/80xxah_ds.pdf

Intel 8275 Datasheet:
jameco.com/Jameco/Products/ProdDS/52821.pdf

Adrian's Digital Basement ][ (Second Channel)
youtube.com/channel/UCbtwi4wK1YXd9AyV_4UcE6g

Support the channel on Patreon:
patreon.com/adriansdigitalbasement

My GitHub repository:
github.com/misterblack1?tab=repositories

--- Instructional videos

My video on chip removal without damage:
youtube.com/watch?v=XQVjwPsVFd8

--- Music

Intro music and other tracks by:
Nathan Divino
@itsnathandivino