Motorola roundie

[timmy]

At the 2 330pf caps sams shows 12v on each I’m getting 10v and 13v

[Yamamaya42]

Originally Posted by timmy

I don’t know what to believe at this point what to change or what not to change.

As we have been saying, first and foremost, you must do the Color AFC Alignment procedure, you must be precise and meticulous,doing every step as stated in the SAMS.

Then, and only THEN AFTER, if there is still color problems , do you move on to debugging any faults.

[timmy]

I understand I should go with the color alignment but I don’t have a scope to check waveforms and at this point I don’t want to mess this color circuit up anymore then it is by turning a17 and a18 and besides I was not able to free up the slug I mentioned earlier and the color works then it don’t so for now I’m just going to look for anything within v 21-22-23 and hope I can come up with something.

[Electronic M]

Originally Posted by timmy

I understand I should go with the color alignment but I don’t have a scope to check waveforms and at this point I don’t want to mess this color circuit up anymore then it is by turning a17 and a18 and besides I was not able to free up the slug I mentioned earlier and the color works then it don’t so for now I’m just going to look for anything within v 21-22-23 and hope I can come up with something.

Usually the chroma osc/chroma AFC alignment doesn't require a scope in Sam's procedure. IIRC it's chroma bandpass that needs a scope and I believe you don't need to do bandpass.
Your osc wasn't holding sync so just do the chroma osc adjustment.

[Yamamaya42]

Originally Posted by Electronic M

Usually the chroma osc/chroma AFC alignment doesn't require a scope in Sam's procedure. IIRC it's chroma bandpass that needs a scope and I believe you don't need to do bandpass.
Your osc wasn't holding sync so just do the chroma osc adjustment.

the Sam's procedure does say to hook up a scope and to check for correct waveform at point H with a color bar generator, and to check the G-Y B-Y output waves as well, how critical this is to the over all color AFC alignment , who can say.

the bigger issue is the stuck coil

[timmy]

I don’t believe there is anything wrong with the coils because the color was fine and slowly went out and it still sounds like a resistor or maybe a cap. A lot of people think micas don’t go bad but they do for all I know the 2 330pf caps may be the problem for me it’s a big crap shoot guess at this point.

[old_tv_nut]

Originally Posted by timmy

At the 2 330pf caps sams shows 12v on each I’m getting 10v and 13v

Exactly the kind of thing you would expect if the AFC alignment needs to be done.

[Electronic M]

If an adjustable coil can't be adjusted it's bad and must be fixed or replaced.... Especially when it's an adjustment for a stage that's acting up...If a stage is acting up the first thing to do is correctly adjust it, and you only conclude it's a circuit fault when you can't adjust the problem away....Often if you can't achieve an alignment instruction it clues you in to where the fault is.

If one of the adjustable colis on your convergence board was physically damaged and the part of the screen it effects was the only messed up part would you change the coil or troubleshoot the rest of the convergence board?
If the vertical linearity pot was rust ceased and the vertical sweep looked wrong would you fix/change the pot or change every resistor and cap?
If an adjustment that often exists to compensate for tube aging is stuck trying to make the rest of the circuit compensate and do the adjustment is about as much of a rube Goldberg waste of time as you can possibly achieve.

[timmy]

There is a slug in the back of the chassis that sams says it’s for the 3.58 xtal should this be touched at all I don’t think sams mentions this coil for the AFC.

[Yamamaya42]

Originally Posted by timmy

There is a slug in the back of the chassis that sams says it’s for the 3.58 xtal should this be touched at all I don’t think sams mentions this coil for the AFC.

Do you mean the 3.58 mhz trap, next to the circuit breaker? this is part of the demod area, and not the oscillator.

[Yamamaya42]

you really have no option, you have to get that coil unstuck, or find a replacement.

[timmy]

Originally Posted by Yamamaya42

Do you mean the 3.58 mhz trap, next to the circuit breaker? this is part of the demod area, and not the oscillator.

Yes the one next to the breaker so I’ll leave that alone. The coils are the a17 a18 that won’t move and there has to be a better way to get them to move and there is no steel Allen wrench that would fit that I would only use the plastic. When I heated one of them it started to move but was really tight.

[Yamamaya42]

Originally Posted by timmy

Yes the one next to the breaker so I’ll leave that alone. The coils are the a17 a18 that won’t move and there has to be a better way to get them to move and there is no steel Allen wrench that would fit that I would only use the plastic. When I heated one of them it started to move but was really tight.

There is one that will fit, if you have a full set of sizes metric and standard, I have more than one of the correct size.

but unless they can be freed, you won't be able to set the color sync correctly.

[Yamamaya42]

https://www.amazon.com/HORUSDY-Wrenc...0590499&sr=8-5

the correct size is sure to be in this set.

[old_tv_nut]

Ok, I'm blind - where is A20 on the schematic?