Admiral 14R12 Restoration - Page 14 - Videokarma.org TV - Video

Crist Rigott · #**196** 10-22-2016, 02:11 PM

The last 2 days were spent working on the cabinet. As you know, it was pretty faded and there was some water stains from a flower pot on the top and sides.

I decided to clear coat the cabinet.

What I did was first used some Prep-Sol to remove any wax, dirt, etc from the cabinet. I then used some 600 grit wet sand paper to sand down the entire cabinet. I then concentrated on some scratches on the top and also the water stain being very careful not to sand through the top layer. I sanded enough of the light scratches out along with most of the water stain. I then went over the cabinet with 800 grit wet. The water stain was still visible. I didn't want to refinish the cabinet and have a water stain on the top.

So when it came time to shoot the clear, I wiped down the cabinet with some rubbing alcohol and used a craft stick that was pointed off with my hobby knife to get into the corners and along the ridges. Once that was done I took a can of Mohawk Perfect Brown Toner and lightly went over the water stain. After a few very light coats, I put one light coat over the entire top, just to blend in the water stain area. After it dried in like 5 minutes, I could barely see the water stain but I could also see the markings of the Bakelite. Good enough.

Time for the clear coats. I used Mohawk Instrument Clear Gloss. I use a cheapie Harbour Freight HVLP Touch Up gun. I reduce the clear using Mohawk reducer by at least 50/50. I spray at 20 lbs and a swath of about 3 inches. I like the touch up gun because I can get close to the work and I feel I can control the paint better.

After tack ragging the cabinet, I shoot a coat of clear lacquer. I wait 5 minutes to see how it flowed out and then shoot another coat with the adjusted thinned lacquer. Usually I add more reducer. Then another coat is shot and so on without messing with the reducer/thinner ratio. Yesterday I shot about 8 coats. Now remember that when I shoot a coat, it is pretty thinned out. I really hate orange peel. When shooting, the lacquer looks like it will orange peel, but within a few minutes, it flows out nicely.

Last night I lightly sanded the lacquer with some 800 grit wet to "level" the lacquer and have a very smooth surface for the final coats.

Today I again wiped down the cabinet with rubbing alcohol, tacked and was ready for the final coats. These final coats are thinned even more and were thinned probably to about 30% lacquer and 70% thinner. The cabinet was shot like before till I ran out of the thinned lacquer with an extra coat on the top. BTW, painting conditions were about 70 degrees and below 50% humidity. The lacquer flowed out great.

I'll wait for at least 2 weeks and probably 3 till it gets wet sanded, rubbed out and waxed.

In the meantime I'll do some work on the knobs and the escutcheon, and the chassis. Getting close to finishing this project.

Here are a couple of pics of the cabinet. I hope they show up real well, but you'll get the "picture".

Crist Rigott · #**197** 10-23-2016, 06:31 PM

The video saga continues. I messed around with the response curve some last night and today. I got the double hump and the pips were at the correct frequencies per Sams and Riders. I then hooked up my D to A converter and I got audio, but no video. I tried my DVD player with my RF converter but got the same thing.

So I went back to my pictures that I took when I got the TV and placed the slugs about what they were in the picture. I hooked up my 360 and O'scope and I had just a single peak curve. Hmm......

I then hooked up my D to A converter and now I was getting video and audio! I then tweaked the slugs to get the best picture and the audio slugs to bet the best sound by ear.

I then went back to the 369 setup and tweaked the curve to the one in the picture below. The pip at the peak is at 20.3 and not at 24.3 but it is playing nicely.

I then hooked up my DVD player RF converter and sure enough I have a pretty decent picture.

Back to the DtoA converter and I took the picture below. I realize I need to adjust the focus coil, linearities, etc.

I checked my frequency counter by inserting the 10.7Mc crystal into the 369 marker slot and turned off the variable marker. The frequency counter read 10.690067 or something very close to that. So I'm pretty sure that the 369/frequency counter are good.

Any explanations as to why it works on 20.2 instead of 24.3?

Could there be anything that the tuner would cause this? I did replace the resistors and some caps in there. I did pay attention to lead dress, though they couldn't go any other way.

Kevin Kuehn · #**198** 10-23-2016, 07:56 PM

That seems really strange. I think someone mentioned earlier that most service grade sweep generators won't produce a pure sine wave, and also there's no way to get an accurate frequency reading if there's any frequency modulation(sweep) turned on. So it's very possible your counter is picking up on a false harmonic. Another thought is it's possible that your local oscillator is producing something other than the correct IF frequency. But if the IF slugs are back to their original positions that's not very likely, not unless someone else had that thing incorrectly aligned long before you got your hands on it. But at any rate the fact that you're getting the best video and sound with a single peaked frequency response is very strange.

Crist Rigott · #**199** 10-23-2016, 08:56 PM

Quote:

Originally Posted by Kevin Kuehn

That seems really strange. I think someone mentioned earlier that most service grade sweep generators won't produce a pure sine wave, and also there's no way to get an accurate frequency reading if there's any frequency modulation(sweep) turned on. So it's very possible your counter is picking up on a false harmonic. Another thought is it's possible that your local oscillator is producing something other than the correct IF frequency. But if the IF slugs are back to their original positions that's not very likely, not unless someone else had that thing incorrectly aligned long before you got your hands on it. But at any rate the fact that you're getting the best video and sound with a single peaked frequency response is very strange.

Kevin,

The frequency I'm measuring is the maker frequency, not the sweep frequency. My Freq. Counter is "tapped" off the Marker Osc. tube. It is rock steady when varying the sweep frequency. It should be because they use different oscillators.

Is there a way to measure the local osc freq? It does look like it is half of the 6J6 tube. If so what would I expect from channel 3. That's what my D to A converter and my RF modulator are set to.

Kevin Kuehn · #**200** 10-23-2016, 10:25 PM

There's a lot of variables involved in simply connecting your counter into that circuit. Same reasons you don't hook your scope prob into a high frequency oscillator circuit without expecting it to de-tune the circuit.

Does your 369's marker dial track your counter's reading at various locations on the dial?

Crist Rigott · #**201** 10-23-2016, 10:42 PM

Quote:

Originally Posted by Kevin Kuehn

There's a lot of variables involved in simply connecting your counter into that circuit. Same reasons you don't hook your scope prob into a high frequency oscillator circuit without expecting it to de-tune the circuit.

Does your 360's marker dial track your counter's reading at various locations on the dial?

OK.

Yes, the marker dial does track the counters readings across the dial on all bands.

Kevin Kuehn · #**202** 10-23-2016, 11:05 PM

When you had the IF aligned to 24.3MC, did you try adjusting the oscillator slug for channel 3 (Sams reference A19) while you had your DVD player playing through the rf modulator? Also A8 is the master oscillator adjustment that will offset all channels equally. If you look at the schematic you will see A8 is a trimmer cap in parallel with the fine tuning control. A9-A20 are the individual slugs for each channels oscillator coil. Those adjustments combined are what sets the correct oscillator frequency that in turn is mixed with the input rf, and is sent into the video IF. Another possibility is that if someone had the tuner coils out they may have gotten them mixed up and not installed back in the correct order, in which case channel 3 may not really be creating the correct oscillator freq for channel 3.

Crist Rigott · #**203** 10-23-2016, 11:18 PM

Quote:

Originally Posted by Kevin Kuehn

When you had the IF aligned to 24.3MC, did you try adjusting the oscillator slug for channel 3 (A19) while you had your DVD player playing through the rf modulator?

No. Maybe I should try that?

Kevin Kuehn · #**204** 10-23-2016, 11:37 PM

I think so. Also see what I just added to my last post. If the tuner is goofed up there's no way it can send out the correct IF frequency for the channel you think you're receiving.

Crist Rigott · #**205** 10-24-2016, 12:14 AM

Does this turret tuner look right to you? I would think the inserts would go numerically in order.

Crist Rigott · #**206** 10-24-2016, 12:23 AM

I looked at some other pictures of turret tuners and their inserts are all numerically in order.

Looks like I have to redo the order?

Kevin Kuehn · #**207** 10-24-2016, 12:35 AM

A few are definitely out of order. Are 2,3, and 4 in correct consecutive order? Is one section missing? At any rate they should be in the same order as the channel knob on the front. And since someone was in there messing with them it's even possible they're not all working correct.

Crist Rigott · #**208** 10-24-2016, 01:13 AM

Quote:

Originally Posted by Kevin Kuehn

A few are definitely out of order. Are 2,3, and 4 in correct consecutive order? Is one section missing? At any rate they should be in the same order as the channel knob on the front. And since someone was in there messing with them it's even possible they're not all working correct.

Right.

I got them in order. Channel 10 is missing the forward insert. Also there are a few that are not numbered but they went with the ones in that channel number. After reassembling the tuner, I have a decent picture on channel 3 and my bar generator works on channel 6 as it is supposed to. Tomorrow I'll work at getting the double hump curve with the proper freq where they belong. I'm not sure the tuner inserts are the problem because Sams says I can use any channel.

We'll see what happens.

Kevin Kuehn · #**209** 10-24-2016, 01:25 AM

So were the channel 3 coil modules already in the correct location? I'm not even sure if that A8 adjustment can cause the tuner IF to be out by 4MC. Something sure seems to be throwing your tuner IF output off.

Crist Rigott · #**210** 10-24-2016, 11:36 AM

Quote:

Originally Posted by Kevin Kuehn

So were the channel 3 coil modules already in the correct location? I'm not even sure if that A8 adjustment can cause the tuner IF to be out by 4MC. Something sure seems to be throwing your tuner IF output off.

I'm not really sure if they were in the correct position on the turret. I lost the metal insert that goes into the plastic channel dial so I can't use the correct dial. I'm using another dial just to be able to turn the channel selector. I looked into the tuner and when the channel 3 inserts were making contact with the wipers, then I used some masking tape to mark the dial. I know it's a bit hokie, but my friend has a metal piece I just haven't gotten to go over his house.