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 Post subject: Predicta Debutante Restoration
PostPosted: Aug Thu 09, 2018 11:42 pm 
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Joined: Jan Sun 18, 2015 5:01 am
Posts: 1131
Location: Waxahachie Texas
I got this TV last fall and now that other people's projects are nearly all done, I'm starting on my own project. I messed with this TV just a little in February. Then the other people's projects for the nearly the last 5 months.

On with the show!

Here is the TV as I got it. The 17" CRT tested very good!

The chassis is a 11L43.


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File comment: Here is what the chassis looked like when I pulled it from the cabinet.
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File comment: And an after shot after taking it to the car wash.
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 Post subject: Re: Predicta Debutante Restoration
PostPosted: Aug Thu 09, 2018 11:44 pm 
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Joined: Jan Sun 18, 2015 5:01 am
Posts: 1131
Location: Waxahachie Texas
I decided to make up all new networks like I did on my Seventeener II project.
I used my CAD program DeltaCad. I used the Seventeener II drawings a "seed" to come up with the ones I needed for this project.
I etched my boards, then populated them. Then they were coated with 15 minute epoxy on both sides.
Once cured, they were spray painted to approximate the original colors.


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 Post subject: Re: Predicta Debutante Restoration
PostPosted: Aug Thu 09, 2018 11:47 pm 
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Joined: Jan Sun 18, 2015 5:01 am
Posts: 1131
Location: Waxahachie Texas
I decided not to re-stuff the electrolytic caps. Instead I used the method that Bob Andersen describes in his videos on his restoration of a Princess/Debutante. I still have to pull the main board, and when I do, I'll place the 3 electrolytic's from the small E-Cap.

First up were the 2 200uf 160V caps. I used some 220uf 250V 105 degrees Nichicon caps. They were placed on the terminal strip that is next to the Fusistor. One was a direct replacement on the terminal strip while the other came "from" the large 4 section E-Cap. While I was messing around with the terminal strip I replaced the 2 original diodes with 2 1N5408 diodes.

The other 3 that came "from" the large E-Cap was attached to the terminal strip located between the main board and the IF board.

I then removed several wires that were not needed and the "jumpered" the wires where they would have connected to each E-Cap terminal.


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 Post subject: Re: Predicta Debutante Restoration
PostPosted: Aug Thu 09, 2018 11:49 pm 
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Joined: Jan Sun 18, 2015 5:01 am
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Location: Waxahachie Texas
I then did the IF board. It was simple to remove. After a good cleaning, all the resistors were replaced with 1W. I then added solder to each ground stud to beef them up. I also checked each coil. All was good.
After the board was installed, I wrapped each wire around its stud 1 or 2 turns. Then cut off the excess wire leaving a small 3/32 end sticking out. This is to aid in removing the wire in the future. Then each one was soldered.


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 Post subject: Re: Predicta Debutante Restoration
PostPosted: Aug Sat 11, 2018 12:28 am 
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Location: Durham, NC
Those boards haven't looked that good since they were made!

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 Post subject: Re: Predicta Debutante Restoration
PostPosted: Aug Sat 11, 2018 1:19 am 
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Joined: Jan Sun 18, 2015 5:01 am
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Location: Waxahachie Texas
Today I worked on getting the main board removed. I labeled each wire with the "L" designation and then unwound the wire wrap. Then unsoldered the ground links. Once removed I cleaned up the excess solder on the ground studs and cleaned off the board real good.
On to recapping.


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 Post subject: Re: Predicta Debutante Restoration
PostPosted: Aug Sat 11, 2018 2:05 am 
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Joined: Jan Thu 01, 1970 1:00 am
Posts: 1118
Location: Jackson, TN
Holy moly Crist that's a beautiful job.

What is the car wash step you mentioned above?

Thanks for taking the time to document this project.

Tim


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 Post subject: Re: Predicta Debutante Restoration
PostPosted: Aug Sat 11, 2018 2:07 am 
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Joined: Mar Sun 01, 2009 10:27 pm
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Location: Ann Arbor, MI
I wonder what percentage of the resistors are out of tolerance. Are you ever curious enough to check the old ones after replacement and find out? If you do, what did you find?

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 Post subject: Re: Predicta Debutante Restoration
PostPosted: Aug Sat 11, 2018 3:15 am 
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Posts: 1131
Location: Waxahachie Texas
Tom Schulz wrote:
I wonder what percentage of the resistors are out of tolerance. Are you ever curious enough to check the old ones after replacement and find out? If you do, what did you find?

Tom, good question. Yes I check every resistor and log its value. I also log its replacements value. So I know exactly how many were out of tolerance, how many were very close, and how many were "well" within tolerance.

On the IF board, there were 13 resistors I replaced. 5 were out of tolerance, 2 were very close of being out of tolerance, and 6 were "well" within tolerance. On these Predicta boards, seeing what a job it is to remove the boards, I don't know why other people don't replace them all.

Now my usual practice is to replace them all anyway, especially on Predicta boards. I'll let you know what the tally is on the main board.

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 Post subject: Re: Predicta Debutante Restoration
PostPosted: Aug Sat 11, 2018 3:22 am 
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Joined: Jan Sun 18, 2015 5:01 am
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Location: Waxahachie Texas
Tkilboy wrote:
Holy moly Crist that's a beautiful job.

What is the car wash step you mentioned above?

Thanks for taking the time to document this project.

Tim

I take the very dirty chassis to the "Quarter" car wash. I tape off all the labels and areas I don't want to get wet the best I can. I then use the "Presoak" setting to initially spray off the dirt. Don't get too close and use common sense. One cleaned, I use the "Spot Free" rinse to completely rinse off the chassis. Then I let it drip dry before putting back into the car. Once home I either put it in the oven and the lowest temp for an hour or set it outside in the hot Texas sun to dry it. Then I spray each pot with WD-40. Then on to the bench.

More on the "Final" cleaning on the next post.

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Last edited by Crist Rigotti on Aug Sat 11, 2018 3:23 am, edited 1 time in total.

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 Post subject: Re: Predicta Debutante Restoration
PostPosted: Aug Sat 11, 2018 3:22 am 
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Location: Waxahachie Texas
The car wash gets the initial cleaning done. For the "final" cleaning as to what you see here, this is what I do.

After the board was removed from the chassis, a good look see inspection was done to determine the condition of the board. Both boards were in great shape. Then I head over to the sink and turn on lukewarm water. Then I spray the board with "Scrubbing Bubbles" bathroom cleaner. I let it foam for a few seconds, then I use a 1" chip brush I get from Harbor Freight, to gently, but completely, brush the entire board. Getting in between the components. You'll be amazed at how brown the foam will get. Probably from smoking all those years. Then it is completely rinsed off and the process is repeated. Once rinsed off, I shoot contact cleaner into the pots, tube sockets, adjustable coils, and elsewhere I think it needs it. Then into the oven again for about an hour or out in the Texas hot sun.

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 Post subject: Re: Predicta Debutante Restoration
PostPosted: Aug Sat 11, 2018 3:30 am 
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Posts: 1131
Location: Waxahachie Texas
The first thing I did was to add the 3 E-Caps to the board. A big thanks to Bob Andersen for this method.

For the 100uf 50V cap I'm using a 100uf 160V cap. There are 2 area that are already "cleared off" and tinned for the cap! All you have to do is drill 2 holes. I used a 1/32 PCB drill bit. The holes are drilled in the pad just south of the "Vert Lin" screening.

For the 10uf 450V cap I used a 10uf 450V cap. There is a small square where the "+" lead will go and you have to drill a hole next to the square for the "-" lead. Again, I used a 1/32 drill bit. On the next one I do, I'll drill the hole a little be further away from the ground link. Once the ground "-" hole is drilled, I scrapped off the solder mask and cleaned an area around the hole of the copper trace so I could solder. This is the only time you need to do this. The last cap goes into existing holes. More on that next.

For the last cap a 20uf 350V cap I used a 22uf 450V cap. This cap will be placed into the lower 2 boxes labeled "WR1". See the above picture for their location. The left hand hole is ground so the "-" lead goes there. The "+" lead goes in the right hand hole. This hole is connected to the box just north of it. I then took a white/green wire I previously removed when I removed the old E-Cap and wrapped it around the stud labeled "Audio B+", then soldered it into the that last box. Thus connecting the "+" lead to the stud. As a matter of fact, when I was removing the wires from the old E-Cap, if I just left the white/green wire on that stud and cut it about a couple of inches long, I could have used it to jumper to the last "+" box.

The last picture is an overall picture of the 3 E-Caps installed on the main board.


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 Post subject: Re: Predicta Debutante Restoration
PostPosted: Aug Sat 11, 2018 8:00 am 
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Very nice. I'm glad you were able to use the technique I came up with. It's almost like the old Philco engineers predicted electrolytics would get much smaller in the future and left pads for us :)


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 Post subject: Re: Predicta Debutante Restoration
PostPosted: Aug Sat 11, 2018 8:49 pm 
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Joined: May Thu 14, 2015 4:15 pm
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Location: Dallas, TX
Crist Rigotti wrote:
Then I spray the board with "Scrubbing Bubbles" bathroom cleaner. I let it foam for a few seconds, then I use a 1" chip brush I get from Harbor Freight, to gently, but completely, brush the entire board.

This is the first time I've seen someone else mention "Scrubbing Bubbles" for cleaning. I used it on part of a juke box when nothing else would touch the deposit. I don't regularly use it. I brought it up in a discussion at a radio club meeting and it kind of got a doubtful reaction. I don't think I described it well enough.
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 Post subject: Re: Predicta Debutante Restoration
PostPosted: Aug Sat 11, 2018 10:47 pm 
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Posts: 1131
Location: Waxahachie Texas
I recapped and changed out all the resistors too on the main board today. I left the high wattage wire wound resistors because the checked good and also looked good too.
I used 1W resistors to replace the 1/2W, 2W resistors to replace the 1W resistors, and 3W to replace 2W resistors.
I used a 1.6KV .0015uf Panasonic cap located in the upper right hand corner of the board.
I cut some standoffs from 1/2 dowel and used some #2 sheet metal screws to hold them to the board. Time well spent. I'll keep them in my jigs and fixtures drawer for later use.
All pretty routine with no problems. I re-flowed the solder joints on each tube socket and gave the board a very close inspection.
Before I did the recapping, I ohmed out each coil. All was good. I didn't bother with any of the ceramic disc capacitors either. I did check each slug on the transformers and coils to be sure they could be turned.


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 Post subject: Re: Predicta Debutante Restoration
PostPosted: Aug Sat 11, 2018 10:49 pm 
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Location: Waxahachie Texas
Tim,
The thing with Scrubbing Bubbles is that you have to completely rinse it all off. I love they way it really cleans.

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 Post subject: Re: Predicta Debutante Restoration
PostPosted: Aug Sun 12, 2018 4:43 am 
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Location: Waxahachie Texas
The main board is back into the chassis. Whew!
The tube sockets look like the better ones with the wider metal strip between the the terminal and pin socket. All checked good.


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 Post subject: Re: Predicta Debutante Restoration
PostPosted: Aug Sun 12, 2018 4:45 am 
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A member on this Forum asked if I checked the resistors that I replaced to see if they were out-of-tolerance.
On every restoration, I replace all the resistors 99% of the time. I log each resistor that was removed and each one that goes in. Just as a matter of record so to speak.

On this restoration with the IF and Main boards done, here is the tally.

IF Board:
14 resistors replaced.
6 were out-of-tolerance 43%
2 were close to being out-of-tolerance 14%
6 were within tolerance 43%

Main Board:
45 resistors were replaced.
31 were out-of-tolerance 69%
6 were close to being out-of-tolerance 13%
8 were within tolerance 18%

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 Post subject: Re: Predicta Debutante Restoration
PostPosted: Aug Tue 14, 2018 3:15 am 
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Location: Waxahachie Texas
Now that the main board is done I moved on to the HV cage. I cleaned it, replaced the 2 resistors (1 was out-of-tolerance, the other was ok), ohmed out the flyback (all checked good), and sealed the flyback with black Super Corona Dope.


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 Post subject: Re: Predicta Debutante Restoration
PostPosted: Aug Tue 14, 2018 3:16 am 
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Location: Waxahachie Texas
I then moved on to the input power plug. I replaced the 470K out-of-tolerance resistor, replaced the film cap with a .022uf X2 safety cap, and added a fuse holder.

Then I cleaned and lubed all the pots and cleaned the tube sockets.

This pretty much wraps up the chassis work.


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