Need help with Robotron Horiz width

Waterborn

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I just picked up a Robtron cab and the horiz width needs to be brought in a bit. I know that I need to use the coil to make this adjustment, by cannot figure out how to do so. It appears that they is a space for a hex key to adjust the tightness of the coil, but none of my key (both standard and metric) will work. Any suggestions?


Thanks,
Dane
 
I just picked up a Robtron cab and the horiz width needs to be brought in a bit. I know that I need to use the coil to make this adjustment, by cannot figure out how to do so. It appears that they is a space for a hex key to adjust the tightness of the coil, but none of my key (both standard and metric) will work. Any suggestions?


Thanks,
Dane

stop what your doing there, do not use allan keys to adjust a width coil , they sell tv adjusting sets at most crap shacks for under 5 bucks , proper tool for the job. metal keys will heat up quickly due to inductance, you also stand a huge chance of shattering the ferite core
 
Use the plastic dittle adjustment tools to adjust the width coil. Your hex metal will bust up your ferite core and your picture will probably be bigger. Spray a non conductive spray inside to lubricate the core as over time they can seize up inside.
Hopefully you do not have a mylar cap going out of value as usually screens dont get bigger on their own.
 
Thanks for the help guys. As you can probably tell, I am new to the cab hobby. So if I understand you both correctly, I can pick up the proper tool to adjust the coil at radio shack? Is it actually called a "dittle" or should I ask for a "tv adjusting set"?

Thanks again for your help.

Dane
 
yes you can get an alignment tool set at most radio shacks, usually under 5 bucks and no waiting for shipping. you will not need to discharge the monitor to adjust the width coil either , only removing the chassis will necessitate discharging the tube , and you wont do that to adjust the coil, i do it with the power to it and pic on the screen. just be very careful around the back of a powered monitor cus they will give a nasty 25 kv bite to you. usually work one handed with the other hand in your pocket so you dont complete a circuit if you are hit
 
Got a set of tools today at Radio Shack (on sale for .99 BTW). If I understand the process correctly, I need to insert the coil tool into the center of the coil and rotate clockwise (to decrease the width of the picture). Is this correct. How much torque and turning should this take? I tried a few times and could not see any change in the HzW of the screen. The tool does not turn very easily. Is something wrong?
 
That center hex piece may be stuck or something. I usually turn it both ways until I see it definitely moving in the direction I want it to move. The adjustment will be very minute at first, so you may have to turn it a bunch to get a noticeable change.

If that doesn't work, you can change a cap on the chassis to decrease the size of the image a little...
 
So far it won't budge. Any suggestions for lubricant, or is that a bad idea? I also tried to warm up the coil by leaving the machine on for an hour, but no luck.
 
Please forgive my ignorance, but should I use an oil, or graphite or something else? I am completely new to this stuff. Thank you for all of your help, everyone.
 
Going to put it to rest for tonight. The tool that I bought actually began to torque a bit and slip within the coil. I will leave the game on overnight in hopes that the coil will warm and loosen up and pick up another tuning tool tomorrow.

As suggested here and on the NEAC forums, I looked into checking the B+ voltage but cannot located the coil to make that adjustment. Some folks suggested that I have a G07 chassis, but the B+ coil is not in the front left of the board as indicated on Bob Roberts' site. The chassis I have has "ECC 20380" written on it. The HzW coil is black and not white as indicated on BR. I will try again tomorrow. Thanks to everyone for your attempts to help me with this.
 
Maybe. First, you need to verify your chassis type. Check the pictures here, and see if anything looks familiar:

What's my monitor?

As I mentioned earlier, there is a cap on your chassis that determine the width of your picture. If you can't adjust it in enough with your width coil, then the next step is to change the value of that cap...
 
If you look at the pots on the edge of the board, you'll notice that two are set a little behind the others and facing up. The one on the left is the B+ adjust.

Make sure - before you mess with it - that you know where to test for your B+ voltage, and what reading you should have...
 
Well I recapped the entire monitor board but am still having the horiz width issues. I have not tried to adjust the B+, which does not seem to be in the location indicated by moddessit (the horizontal hold is in that area, but no B+). My next step I guess is to try and replace the ferrous coil, which still won't budge. Any additional suggestions would be greatly appreciated.

Thanks,

Dane
 
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