Motorola vt-71 restoration

[josephdaniel]

I am finally starting the restoration of a Motorola vt-71 that I got from Sean when I was in Missouri. It has the late ts-47 chassis and a replacement mask already (thanks Sean). I just ordered the caps and resistors I need. Does anyone know where i can get new paper labels for the back or replacements?

[josephdaniel]

I have the knobs sitting on my desk

[josephdaniel]

So far I have replaced mOst if the caps in the set except for the filter caps and there are no hv caps installed at all and there are 5 papers eating on just radios.
Would it be ok to test it for a short amount of time? I plugged it in a little while agao and got good clear audio but only a white dot on the screen ( don't worry I turned down the brightness do it would not burn in) I would like to show it to my parents do they can see the progress

[compucat]

Originally Posted by josephdaniel

So far I have replaced mOst if the caps in the set except for the filter caps and there are no hv caps installed at all and there are 5 papers eating on just radios.
Would it be ok to test it for a short amount of time? I plugged it in a little while agao and got good clear audio but only a white dot on the screen ( don't worry I turned down the brightness do it would not burn in) I would like to show it to my parents do they can see the progress

With no HV caps installed you will get no vertical or horizontal deflection which is why you got just a white dot on the screen. I would not test it like this as you can very quickly burn a dot onto the picture tube phosphors. Wait until you get the high voltage caps replaced in the deflection circuits and the high voltage power supply then test it. After that, you will probably have a useable picture with which you can continue the restoration. Don't expect it to work reliably until all paper caps and electrolytics have been replaced.

[josephdaniel]

With the brightness and contrast turned all the way down there is no dot would it be ok to run it for a few minutes like this or would it damage the high voltage transformer?

[Phototone]

I noticed an empty tube socket on the back. That is where a ballast tube goes, and unless it has been replaced with resistors under the chassis, there is no way the whole set will work without it.

[josephdaniel]

I used the schematic I found on here to rebuld the old one with capacitors and resistors. Those pictures are from when I first got it.
I would post some pictures but my iPhone wolnt let me upload them for some reason.

[Einar72]

Be careful using plain wirewound resistors to replace the legs of the ballast that the CRT is on. I did just that, and now, every time I turn it on, the CRT lights up bright white until the other tubes in series get warmed up. Must be a few with "controlled heater warm-up time" in the string (of which the CRT is NOT). I'm still looking for a toaster-wire-type ballast substitute for mine as well.

[josephdaniel]

I used the schematic in this thread
http://www.videokarma.org/showthread.php?t=249434

If you are looking for a ballest I have heard good things about the amperite ballests sold apparently they last allot longer than the orgionals and provide some sort of current regulation.

[compucat]

Originally Posted by josephdaniel

I used the schematic in this thread
http://www.videokarma.org/showthread.php?t=249434

If you are looking for a ballest I have heard good things about the amperite ballests sold apparently they last allot longer than the orgionals and provide some sort of current regulation.

I currently have an Amperite ballast tube in my Motorola replacing the original metal one that burned out and it works great.

[josephdaniel]

Got the hv caps and all but 4 paper caps and I am rewarded with this! At first it wouldn't come in at all but then I realized the set wasn't plugged in:p
Any ideas miswired socked or misplaced hv caps?

[josephdaniel]

y It's a very crisp cross hatch pattern in person

I know the CRT needs to be turned.

[bandersen]

Looks promising Does adjusting the horizontal and vertical controls on the back help any ?

[josephdaniel]

Yes it did help some could a weak or gassy 6sl7 cause this?

[josephdaniel]

The lines move side to side but those vertical lines are not there in person