g07-my experience with the curl mod-nothing that special

[tron guy]

g07-my experience with the curl mod-nothing that special

So over the last 7 or 8 years I have rebuilt quite a few g07's. Some were easy, some were hard, some I couldn't fix.

I fixed a tough one today-nicely rewarding.

but to the point of this thread....

For the curl mod, bob roberts suggests using a 10uf to 22uf cap in position (c301 or 303 I forget) anyway, he always sends a 10uf cap for that position.

I went ahead and put in a 22uf cap today. It was the first time the curl completely went away in a matter of a second or two of adjusting the H-freq.

So who knows it they will all do that or not, but next time you are on a g07 look through your spare caps and toss a 22uf in there instead of the 10uf.

late

 

[WindDrake]

Huh! Will have to try this. Thanks for the heads-up.

 

[djsolzs]

I recently did the same - worked great for me. I was typically skipping over it if it wasnt a problem but I think I will start doing it on all my repairs

 

[KenLayton]

I've never thought about using a 22 uf there, but I think I will try it out myself soon.

 

[Tighe]

Wow great post!

 

[bold69]

Awesome info! I will keep this mod in mind.

 

[Slackmoe]

I will remember that thanks Dylan

Andrew

 

[incrediblegamez]

i did this mod last night and the curl is not as big as it was prior to but i also havent adjusted it yet so ill do that in the next few days and report my results.

 

[JamBurglar]

I have a slight curl on mine but it's a positive sync. I've always heard the curl mod only works for negative sync. Anybody know what's up with that? If the game uses positive sync you just have to deal with it, no?

 

[JamBurglar]

I have a slight curl on mine but it's a positive sync. I've always heard the curl mod only works for negative sync. Anybody know what's up with that? If the game uses positive sync you just have to deal with it, no?

Bump just in case somebody knows but missed this.

 

[schwaggs]

Moving C305 to C501 changes the coupling capacitor between the amp/buffer section and the HA11244 synchronous processor from .001uf to .1uf. This change will impact both positive and negative sync setups. To what extent, I don't know.

Adding the 10-22uf cap in C305 changes the coupling between the negative sync input and the positive sync input. X305 inverts the negative sync signals to a positive sync signal and feed it through C305 to the positive sync amp/buffer section. X306 does the same for the vertical sync signal.

The larger C305 could reduce influence of the inverter on the positive input amp/buffer by eliminating additional DC from the inputs of the amp/buffer... but I am not sure without testing the circuit.

So net is that the the mod *could* help both types of sync signal.

 

[JamBurglar]

Moving C305 to C501 changes the coupling capacitor between the amp/buffer section and the HA11244 synchronous processor from .001uf to .1uf. This change will impact both positive and negative sync setups. To what extent, I don't know.

Adding the 10-22uf cap in C305 changes the coupling between the negative sync input and the positive sync input. X305 inverts the negative sync signals to a positive sync signal and feed it through C305 to the positive sync amp/buffer section. X306 does the same for the vertical sync signal.

The larger C305 could reduce influence of the inverter on the positive input amp/buffer by eliminating additional DC from the inputs of the amp/buffer... but I am not sure without testing the circuit.

So net is that the the mod *could* help both types of sync signal.

I really appreciate the thorough response. I may try curl mod with the 22uf cap just to see what the results are. The only reason I know the curl is there is because I was running a laserdisc with a test pattern but it would be cool to eliminate it if possible.