Zenith D-513-F radio

[electra225]

This thing was in my parts set box. There was a tag on the power cord that said it had SMD. I played it two days, played perfectly. I fired it up this morning. It ran about 15 minutes, then displayed the lightning crashing noise in the speaker. I think it does have SMD. I have been working on the cabinet as well. I have never attempted an SMD repair. This is a Zenith, so it is not high on my list of sets to save. I figure I have nothing to lose. I'll run some voltage checks, then go from there.

[TC Chris]

Keep us updated. I've got various Zeniths and may benefit from your experience.

Chris Campbell

[electra225]

"Obscure problems go in when the name goes on" is my motto for Zenith radios. Pre-war Zeniths are infested with wimpy power transformers and green crud in the coils. Post-war Zeniths are infested with SMD and have almost-always-bad selenium rectifiers. I haven't attempted to repair SMD in the past due to the fact my hands aren't as steady as they once were and my eyesight is not as good as it once was. I would really like to make a successful SMD repair on this set so I can save a more worthy set sometime in the future. In its defense, this set is a good performer when it is working right. And I have already done considerable work to the cabinet. Maybe I can find a good IF transformer in a parts chassis, another option. I'm really not optimistic that I can drill out the rivet then effect a successful repair in light of the tiny wire used in IF transformers. But, we'll see. I've been watching YouTube videos trying to get some ideas of how best to proceed. I like Zenith TV's. Their radios and I have yet to come to a "meeting of the minds"......

[electra225]

I ran this radio again today for several hours. There was one episode of lightning crashing in the speaker, but it ran well the rest of the time. I need to get the schematic out and refer to it so I can get the caps right. I worked on the cabinet as well. I think I'll paint this one Allis-Chalmers orange and off-white. I think I can still get the paint at Tractor Supply.

[electra225]

Boy, did I step in it with this thing. I removed the speaker so I could prep the front panel for paint. The whole corner of the front panel, on the opposite side if where the main cabinet was damaged, that whole corner fell off in my hand when I took the speaker out! About a two inch square chunk. It was a good, clean break, if that is a good thing. I glued it back, now we'll let that dry and proceed from there. I ran the chassis again all day, never skipped a beat. I had a VTVM measuring grid voltages all day, nothing found out of line. I watched a YouTube video that showed how to check for SMD with the "Noise" setting on a signal tracer. I tried that and found nothing out of the ordinary. I don't know what to think now. One would think SMD wouldn't get "better", the condition does not "heal itself". Could this little Zenith be suffering from a case of green crud somewhere that a good heating baked out of the chassis? I hate to say anything good about a Zenith radio, but this thing is a dandy performer, hot as firecracker with good audio. The thing is all speaker, with a 6X9 speaker. My luck it will refuse to work at all once I get the cabinet done and get the guts back into the cabinet.

[TC Chris]

I don't know what to think now. One would think SMD wouldn't get "better", the condition does not "heal itself". Could this little Zenith be suffering from a case of green crud somewhere that a good heating baked out of the chassis?

Could it have been something as simple as poor contact on a tube pin?

Chris Campbell

[electra225]

I now have the cabinet and front panel in primer. It took two hours to mask off the front panel. The idea is to paint that gold rim around the speaker grille Allis-Chalmers orange like the body. Then leave the tan grille and outer surround like it is. I used Simichrome to polish that area up a bit. If my masking is good, this should work. Plan B is to paint the speaker grille orange if the masking isn't good. It was real tough to mask that front panel. ACE hardware has Allis-Chalmers orange paint in Rustoleum, so that's what I'll use, since I have Rustoleum primer.

[William]

That would be a pain to mask off. I hope it turns out ok.

Bill

[electra225]

I have the cabinet and front panel in primer. They will get another coat of primer, then color probably next week.

[electra225]

I like using the aluminum HVAC tape on broken cabinets. Not only does it provide a platform to hold the Bondo in a hole, it will reinforce the area that was so badly broken. The parts didn't want to come back together. I figured if an impact broke it, perhaps another impact, judiciously placed, would put it back. I put a book under the broken part, then smacked it with a tack hammer. It worked! If I don't want the tape to show, I primer and paint it.

[electra225]

The masking worked out well. I learned why the blue Frog Tape is cheaper than the green. The green gives sharper paint lines. The blue won't peel fresh paint.

[William]

Sharp looking, Greg, you do nice work with the painting.

Bill

[electra225]

Thanks, Bill! The Allis-Chalmers paint I used is ACE branded. It is very thin stuff. You put on a mist coat, wait five minutes, add another mist coat, wait five minutes, put on a thin coat, wait five minutes, go a little heavier, and so on. If you even THINK of going heavy, the stuff runs like crazy. I got one small run, but re-positioned the cabinet and it flowed back out. The guy at the ACE hardware gave me a heads up, or I could have messed up and had to start over. It looks nice and dries really fast, ready to work with in an hour. I'll let it dry all night before I try to work with it. I need to put the Zenith emblem back on and make the red mark for the dial pointer.

[electra225]

Zenith radio done.....

[William]

That looks great, how does it sound?

Bill

[TC Chris]

Visually, at least, it's a complete success.

Chris Campbell

[electra225]

Though it is a lowly AA5 with 50C5 output, it sounds pretty good. It has a large antenna and a 6X9 speaker. This was the radio that was in the worst condition of all the ones I redid. The big RCA was pretty busted, but it worked good. This radio got dropped and damaged on the corner where the volume control is located. I'm really surprised it works at all, considering the way it was damaged. I got lucky, being able to get the broken pieces of the cabinet back into place. Allis-Chalmers orange is a milky color, really elegant considering it is farm implement paint.