The battles we've fought at the bench

[Bill Hutchinson]

Let's tell a story or two about the tough fixes we've acomplished.

Before we get going...put a round on my tab, Ron.

One of the more challenging radios I've worked on was the 42-122 I did this past summer. The details were in the "Latest Philco Save" thread.

Another fun one with similar problems was a 37-84 cathedral I did a few years back. I was fortunate to come up with one where the photo finish was in pretty good shape. The chassis...we'll, let's just say that I learned a lot from it.

The IF transformer had an open primary - it was my introduction into rewinding coils! And then there was this twisted wire capacitor! What was up with that? After scratching my head for a bit, it was Mr. Schwark to the rescue! He explained that that's exactly what it was, a cheap twisted wire "capacitor" for this (very) inexpensive circuit. I especially love where the volume control is located in the circuit - right in front, between the antenna and the antenna coil!

It works pretty good for a 4 tube radio. Works best on the locals, of course.

Bill

[Ron Ramirez]

One of my worst bench experiences is now featured on Chuck's site:
http://www.philcorepairbench.com/tips/svctip42.htm

I first told the story here in the Phorum:
http://www.philcoradio.com/phorum/showthread.php?tid=6

I've had plenty others...a 42-350 comes to mind with an extremely dirty band switch...another 42-350 that I never did get SW to work on although AM did well...a 42-380 that I had to replace the entire pushbutton assembly (this includes bandswitch functions, guys) to get it to work...UGH.

(edited to add links)

[Bill Hutchinson]

Another one that was frustrating to get going, but came out pretty nice in the end was a battery farm radio we found in a far NE Minnesota antique shop. It's a Coronado 650 that has a very nice black airplane dial (almost Zenith-like), an art deco speaker cutout, and a couple of very nice dark wood (ebony?) inlays running down the top. It even has a 6 tube circuit - not bad for a battery unit!

It was pretty dirty and had no price tag on it - time for wheelin' and dealin'. The guy first said $30 and I almost choked. I said I'd offer him $10, so we agreed on $15.

Got it home, pulled the chassis out, and found a whole bunch of insulation stuffed underneath! Perhaps Mickey and Minnie lived there for a while?

The cabinet was the easy part. I stripped it, and the natural color looked so nice, I decided after cleaning it up, I'd just finish it without staining it. A good decision - it looks terrific. A new grill cloth, and it was done.

The chassis was somewhat of a beast. New caps and resistors weren't too bad, but for some reason, aligning it was a real uphill battle. It would work, but there was hardly any gain to it. I fought with it on and off for about a week until I got the IF tweaked to a point where it would finally pass a strong enough signal, but for whatever reason it wanted to wrestle with me.

I won.

Bill

[Big Dave]

Not a radio, but my Philco 50T1403 gave me H**l after the recap. I was having trouble getting the ion trap adjusted just right and getting the horizontal on freq was a nightmare. I replaced a true mica cap in the horizontal for the H**l of it. Finally got it working right. Details on my website. Turns out this set is a solid performer.

I have 2 RCA's (Sorry about the non-Philconess) that are driving me nuts. I'll put the details on my site and give an alert here since they aren't Philco.

[Robbie Roberts]

Well, I am in the middle of my first overhaul- a 37-650, which I found in a local antique store for $25.00... Being an analytical perfectionist, I have applied all I learned rebuilding antique cars- while taking apart, make lots of pics and notes. I still have access to my first car- a 1944 Willys Jeep. Started out as a 46 CJ2A, but through many years of parts scrounging(back before repros were available for most of the parts) I soon had one of the most authentic MB's going! So, anyway, I have this radio. And it does not work, so I am bound and determined to make her right again... I don't think this radio has ever been so completely disassembled! And not only have I decided to replace the caps, but to rebuild the bakelites, cans, and replace many of the resistors. I am also planning to replace the original wires- they're all disconnected currently anyway- being sure to cut to original lengths, to preserve resistance factors.

Anyway, I'm having fun, can't wait for the parts to arive, and looking forward to having a real neat radio to listen to! Then I can start on the Model 20, then the 41-220, and the 39-116RX and its "Mystery Control"(which is en route, as well!) Then, after all that, recapping a Grundig Majestic, and a pair of Z-word Transpuddlers.

Scott

[Ron Ramirez]

Well, for me, it's here we go again...

The latest patient on the bench is a Model 19B Code 126. As you probably know, the 19 is nearly identical to the Model 89; the main differences are an added shadowmeter and four-point tone control.

Anyway, the power transformer had a lot of wax seepage. Expecting the worst, I first powered it on with the 80 rectifier removed. All seemed well, so I turned it off, put the 80 back in and began bringing it up on the variac. When it hit 90 or so volts, the 80 began to put on an AWESOME fireworks display internally.

Fortunately, I found a power transformer from a junked 144 out in the garage. I'll have to fix the insulation on the wires - the cloth insulation has dry-rotted and cracked in several places - and then try it again.

I anticipated the usual oscillator trouble; I had a baked and lacquer-sealed coil form ready, rewound and installed it in place of the original oscillator coil. Once I get the transformer replaced, I expect it should do well.

[Ron Ramirez]

So I've set the 19B aside for awhile, as I just received a package from Heyboer Transformers. It's a custom-made power transformer for an Atwater Kent Model 82. I had recapped the set and set it aside while I waited for the new transformer.

Finished installing it this afternoon. As a precaution, I powered it up on the Variac; came right on with absolutely no problems. Makes me VERY happy when they come right on the first try.

I specified a 130 volt primary, as a hedge against future power line increases. The entire transformer is of conservative design (slightly lower B+ than original, higher current capability on all secondaries than original), and should last at least as long as the original did, as long as electrolytics are changed at the first sign of failure.

If you need a power transformer, especially one with 2.5 volt filaments or even the older style with 1.5 and 2.5 volt filaments and/or an extra 5V winding for 71A output tubes, I highly recommend Heyboer. They will design and build to your specifications, and their turnaround is very fast.

http://www.heyboertransformers.com/

[Poston Drake]

Ron,
Heyboer Transformer has been recommended to me by others, but I have never used them. What kind of turn-around time did they give you on your order? And what about cost? Of course I am not asking the actual cost of this specific transformer, what I mean is how does their cost to remanufacture a transformer compare to an equivalent new transformer from Hammond, assuming one was available?

Poston

[Ron Ramirez]

Poston

On this one they said to allow 10 days for assembly and delivery, and it took a few days longer than that (fourteen). But considering this is a custom made, one-off transformer, I can't complain.

As to cost - If the transformer you need to replace uses 6.3 volt tubes, you're usually better off looking at a Hammond unit. But if it uses 2.5 and/or 1.5 volt tubes, with or without an extra 5V winding for 71A output tubes, then Heyboer becomes an attractive option. Sure, AES has their P-T143 transformer for 2.5 volt tubes, but if it is for an application using more than seven tubes, then the AES replacement won't cut it - you're looking at either a transformer rewind, or a new custom made unit from Heyboer.

I like the Heyboer units because they are brand new - not rebuilt. Plus, since they are custom made to your specifications, you can specify a 130 volt primary, for example, instead of getting the usual 115 or 117 volt primary which is really too low for today's higher line voltages.

They are rather expensive. But so, I hear, is a transformer rewind. If the set is old and valuable (at least valuable to you and/or your customer), then it's well worth the investment.

[Ron Ramirez]

The 19B lives! It received a power transformer transplant from a junked 144 chassis.

[Chuck Schwark]

Thanks to Dr. Frankenstein (or is that Frahnken-steen??)

[Ron Ramirez]

Well, it wasn't quite as easy as replacing a power transformer on that 19B - after the set played for awhile, the shadowmeter died (coil went open). After some searching, I finally came up with a working replacement. Most of the ones I have are also bad. Another project for next year - to get the bad ones rewound. That's going to be a huge job!

I also had a Model 84 that was mysteriously cutting out. Finally traced it down to a small solder blob that had become lodged on the side of the tuning condenser frame, next to - and intermittently touching - the stator terminal that goes to the oscillator circuit. Gotta be more careful with that solder.

[Bill Hutchinson]

May latest battle won - and it involves the "Z" word. (But that's OK).

It's my ongoing fight for over 3 years with another $25 bargain (or should I say "bargain"?), a Zenith 6V27 farm radio that has an interesting story. Found it in a shop along the shore of Lake Superior in NE Minnesota. Had all the typical Zenith attributes - the black dial, the big tombstone case, the usual stuff. But this beast had it's share of problems. For starters, a vibrator powered battery radio (more on that later), and the fact that a mouse took up residence in the speaker for a while made it quite the project. It's taken this long to work on it (still not done, either) for the usual reason - not enough time.

Anyway, my goal with this one was to get it back to original operating condition, by building a solid state vibrator replacement and run it from a 6V power supply. Good intentions, right?

After searching for months to come up with a suitable circuit (could only find circuits for 3 and 4 pin vibrators, and this one has a 6 pin synchronous type), I found one that could be suitably modified to do the job. Fortunately, I had a usable OEM vibrator I could test with. When it first powered up, it was a good feeling, but when I measured the current draw, it was...shall we say... !!! This thing draws almost 3A!

So after doing some tinkering around with the SS vibrator, I'm happy to say that I came up with a suitable 1:1 replacement for the vibrator that puts out enough voltage to run the radio. If need be, I can pull out the SS unit and put in the original with no noticeable change in performance, aside from the hum of the original. It's nicer to have it operate so quietly with the SS part in place.

Which brings up a point - I could very well have built an AC replacement power supply and ditch the vibrator supply altogether, and done it that way. But I decided to go the "authentic" route to power it. I'm now calling this radio 1/2 done with the completion of the chassis. The cabinet still needs some grill work done where Mickey did his deeds, and the 6V supply still runs a little warm, but I need to get the right regulator for that.

Anyway, this was a battle royal at the bench, and I'm over the hump.

Bill

[Ron Ramirez]

I hate to admit this, but I've always thought the "Big Z" 6-V-27 was a nice-looking radio. And, yes, considering the huge interest in anything with a big black dial and the Z-word on it, I'd say $25 was definitely a bargain. I'd even buy one if I found one for $25.

I have worked on one before. Quite interesting. I'd like to know more about your synchronous vibrator replacement. The one I repaired still had a good vibrator; the set owner wanted me to convert it to AC, and I did so by installing a 125 volt to 6 volt transformer under the chassis and a solid-state rectifier circuit so that the radio was, in essence, being powered by 6 volts DC. That's just what the owner wanted...

[Bill Hutchinson]

Sure thing, Ron. I'm going to be out of town this weekend, but upon my return, I'll post more details on the SS vibrator circuit. Look for it in the Electronic Restoration column. See you when I get back.

Bill