I got started with TRS-80s back in about 1979 at high school. First one I owned was a Model III 4K L1. Still have it, though it got upgraded over the years and became a Model 4.
Today I got a Model I with an expansion interface and monitor. Checked +12 and +5 and they were good, so was -5. No video on monitor (can't believe the monitor even had a raster). Started troubleshooting with the SAMS material and I see a strong waveform on Z41 pin 6 but nothing but noise on pin 5.
The pulses on pin 6 grow in length as I type a few characters, so I think the computer is alive inside. I ordered a new Z41 and it should arrive in a few days.
Question: could a defective Z41 be caused by plugging in the power supply to the video output DIN connector? I bought this computer at an estate sale and it is in remarkable condition, but the original sale photo showed connectors plugged in. Not certain what was plugged in where, but I suspect it could have been wrong.
Thanks for your help (and sure wish I could make it to Tandy Assembly this year),
Paul
Today I got a Model I with an expansion interface and monitor. Checked +12 and +5 and they were good, so was -5. No video on monitor (can't believe the monitor even had a raster). Started troubleshooting with the SAMS material and I see a strong waveform on Z41 pin 6 but nothing but noise on pin 5.
The pulses on pin 6 grow in length as I type a few characters, so I think the computer is alive inside. I ordered a new Z41 and it should arrive in a few days.
Question: could a defective Z41 be caused by plugging in the power supply to the video output DIN connector? I bought this computer at an estate sale and it is in remarkable condition, but the original sale photo showed connectors plugged in. Not certain what was plugged in where, but I suspect it could have been wrong.
Thanks for your help (and sure wish I could make it to Tandy Assembly this year),
Paul