My next set I chose to restore is a 1952 Bakelite Motorola 17" set. It has the optional UHF tuner in the middle of the set. It's a very unusual set in the way it's laid out. I put in what capacitors I have and will order the rest. The flyback is mounted underneath with a spring loaded access door on top to reach the 1G3 rectifier.

Here is the underside of the chassis. This uses a 17hp4, which is philco branded. Obviously changed at one point. I'll need to fabricate a yoke cover because the old one is dusentigrating.

Unusual, for sure! What jug does it use? It almost looks too flat-sided for a 17".

jr

It uses a 17HP4.

Here is the underside with the flyback cover removed.

Here is the odd spring loaded door to reach the hv rectifier from the top of the chassis.

Neat, I love Bakelite sets. There's one on eBay (http://www.ebay.com/itm/MOTOROLA-Television-TV-Table-Top-Bakelite-17-Console-1950s-17K10E-17T5E-Works-/272168615719?hash=item3f5e837f27:g:HWwAAOSwoBtW5ZU c)right now that I thought had the wrong knobs but apparently not.

Neat, I love Bakelite sets. There's one on eBay (http://www.ebay.com/itm/MOTOROLA-Television-TV-Table-Top-Bakelite-17-Console-1950s-17K10E-17T5E-Works-/272168615719?hash=item3f5e837f27:g:HWwAAOSwoBtW5ZU c)right now that I thought had the wrong knobs but apparently not.
I posted that one on ARF. It's pricey, but in real nice condition. That bakelite all polished-up, on a hairpin-legged table with a nice set of rabbit-ears on top -you have a real classic mid-century piece!

Here's a little better picture of the set. The UHF tuner is the gold knob in the center.

I still got one of these sets sitting in the trunk of my car in the garage.. :D

SR

I have one too (model 17T3) but the CRT is necked :(
https://farm8.staticflickr.com/7260/7564577598_d10f830cf7.jpg (https://flic.kr/p/cwsrnG)

That's a bummer on your crt. Hopefully you find a replacement for it. This set is built like a tank and uses a thick Bakelite cabinet. The UHF tuner assembly and flyback cover is made out of copper, which is different to see. St. Louis didn't get a UHF station until '65/66, so either this came from another city or there was a heck of a salesperson behind the counter that day. It's possible they bought the UHF tuner later, but I doubt it.

The parts are just copper plated like the chassis.
Motorola made that set, with minor variations for about four model years. They made that same set with a metal cabinet, painted all kinds of fancy, decorator colors. The UHF tuner is really a convertor. You had to set the set on channel 5 and flip the lever to the UHF position.
The set shown, is probably the last of the bakelite models. IIRC, the earlier chassis didn't have the trap door for the 1B3. The chassis had to be removed to replace the 6AF4 tube. In this area, UHF was used a lot, so you were lucky to get 6 months out of a 6AF4.
The UHF tuner was either factory installed or dealer installed.

St. Louis didn't get a UHF station until '65/66, so either this came from another city or there was a heck of a salesperson behind the counter that day. It's possible they bought the UHF tuner later, but I doubt it.

A list in the Jan '54 Radio Electronics shows KSTM ch 36 in St Louis and WTVI ch 54 Listed as St Louis-Belleville. Like many of the early UHF pioneers, I suspect that they did not survive long (or changed channels) after more VHF stations were put on the air in the area.

jr

A little history of "The Big Mo" here:

http://www.dougquick.com/stlouisTVghosts2.html
.

The cabinet is polished and the parts are in order.

Here is the chassis ready for new parts. You can see the copper UHF tuner in the center.

After recapping the chassis, I briefly had a bright horizontal line. I replaced a couple more remaining bumblebees, turned it back on and nothing on the CRT at all. I get sound, but that is it. My fusistor is good, I've swapped hv rectifier, horizontal oscillator and horizontal output tubes with no change.

I still can figure out why I have no high voltage. Would a bad yoke cause this? One lead goes from the flyback to the yoke.

Have you rechecked those last couple caps you replaced? If you had some HV before but none after possibly something got hooked up wrong, or maybe it threw the horizontal oscillator so far off it quit, try adjusting the Horiz Hold and see if you can hear it running.

I can hear the horizontal and vertical running. I thought I'd triple checked everything, but I'll check again.

The hv disappeared while it was on, before changing the last capacitors. So I'm not sure what failed?

Great website, very interesting reading.

I still can't figure out where my high voltage is lost. Capacitors and resistors in the horizontal oscillator and can't find anything wrong...any suggestions?

Have you compared voltages at the H out tube base to what the schematic calls for?

The horizontal output voltages are supposed to be -25v at pin 5 and 150v at pin 4. I have -770v at pin 5 and -225 at pin 4. So what is happening here?

Are you sure your meter isn't busted? I don't think that set could produce 770 volts in the low voltage supply under any conditions, not without something blowing up.

Yeah so my meters batteries must be getting low. I actually get 124v on pin 4 and -115v on pin 5.

Are you sure your meter isn't busted? I don't think that set could produce 770 volts in the low voltage supply under any conditions, not without something blowing up.

It doesn't take much to damage a digital meter, even a Fluke.
They pick up a spike and give all kinds of whacko readings. Check the fuse and the battery. :sigh:

I can't figure out what's wrong, everything seems to match the sams fir it. I do notice that the horizontal output tube played glow red, which usually means a bad electrolyric of miswire , but where?

The hv output tube no longer glows red, but high voltage is no where in sight. After spending the better part of the day checking and rechecking things, I can't figure it out. This might be one of those sets that gets put back together and move onto another set.

Sounds like your horizontal oscillator isn't running, recheck the components around V13 and make sure nothing was installed incorrectly, make sure C81 is a .0047 and not a .047, check the voltages and see if they're close.

The output tube may have stopped glowing red because it's gotten weak from the overload, but it'll probably still work.

Is that "Test Socket" supposed to be normally open or normally shorted? Someone may have removed the plug at some point.

Ok will do. Not sure about the test socket, but I assume it stays open; but I don't know. Thanks for the help.

I've replaced s couple of out of tolerance resistors and a couple mica caps around v9 and v13, but still no hv. The horizontal oscillator is definitely not running as the horizontal hold control makes no audible change when changing that control. The .0047 is correct around the horizontal oscillator. I'm about out of ideas on what could be wrong. Any other thoughts?

Check voltages on the osc. tube next.

I found that the 150v supply to the horizontal output tube had a poor solder joint. I found this out by accident. As I was trying to use my vom and get a reading, the wire just broke off. I resoldered it and finally got a raster! Now I have to figure out where my audio is.

Ok the sound was due to an open resistor near the audio output tube. I am now calling this one restored!