Motorola 21CT2B restoration

[Electronic M]

With a lot more bench time than I've had in a while due to covid19 lockdowns I finally got back to this.

So far I have replaced some off tolerance resistors in the IF and color stages and managed to coax a decent color picture out of it.... however it don't want to stay good. The color osc is drifty and looses lock occasionally....more frustrating is the tendency of the osc to jump between being locked on the correct phase of color burst and the inverse phase...I can sometimes get it to jump between the two by adjusting horizontal hold... Which is not wonderfully stable either.

[Charlie]

Originally Posted by Electronic M

.... however it don't want to stay good. The color osc is drifty and looses lock occasionally....more frustrating is the tendency of the osc to jump between being locked on the correct phase of color burst and the inverse phase...I can sometimes get it to jump between the two by adjusting horizontal hold... Which is not wonderfully stable either.

Perhaps infected with covid-19? Make sure you're wearing a mask when you power it up!

[Electronic M]

Originally Posted by Charlie

Perhaps infected with covid-19? Make sure you're wearing a mask when you power it up!

Lol...It's been under quarantine for a year so it's more likely to have polio or mumps... Pretty sure it hasn't been vaccinated.

Yesterday one of my habbits specifically tuning to cartoon Network for test signal with saturated color bit me in the butt...the amazing world of gumball was on and with the chroma osc phase sync issue the orange character and the blue character were taking turns being each others color... Glad I had the sound muted or it would have been a confusing episode.