[ARC5] WWII German Torn. E.B. Receiver Revived.

[arc5 at ix.netcom.com]

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On Sun Mar 24 03:27:47 CDT 2024 Hubert Miller wrote:

You sure there are manufacturing errors in this? 1937 would have had rigorous inspection, plus 2 years of use in field maneuvers before

the war started...

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Morning, Hue.

The set was introduced in 1937, but this particular radio was built in 1943. Whether or not the swapped wires on the power plug are definite wiring errors could be debated, because there are schematics that show them wired differently from one set to another. First glance I thought the error was more complicated, but it was the A+/A- leads swapped.

Also, there are quality control issues. Changing out the coil sets, I discovered that the guide pins and screw holes could be different diameters from one coil set to another. Some guide holes had to be slightly enlarged in order to get the replacement coil set to fit flush.

One coil is missing a screw because the screw hole was slightly offset. The coil sets must fit all the way down flush or one can damage the band switching mechanism. Then there was the strange issue of the 1st RF's Plate and Screen leads being oddly unsoldered.

I have seen these sort of issues before- a depot-refurbished RBC with a band switch reinstalled 180 degrees out, a ZM-11 with the wires to a voltage divider circuit swapped etc., which would have prevented function. From personal experience in such repair shops, when one has a pile of such to get done, there are occasional '"dogs" which end up getting shoved under the bench because you have so many more that you can fix quickly.

These "dogs" move from one hiding place to another over time, but they rarely end up getting fixed- there are too many ”quick-fixes” waiting and you can't afford to spend half a day (or days) digging into that one. The time comes to surplus things and they go out the door- end of problem.

These sets end-up in the surplus market and still don't work, even though they are "new/refurb" except for the bumps scratches and dents they get from being shoved around from hidey-hole to hidey-hole over the years.

Of course, there's no way to tell for sure about this set other than there were errors.

Perhaps they were introduced by the previous owner. He certainly did other odd things.

Here's another weirdness:

I replaced several leaking capacitors.

Every one of them, tested at the operational 90 volts, was leaking about the same amount- 2 to 3 mA. I don't know if that's a testament to the quality control of German components or what. The components in this and other German radios are quite impressive in their quality. I have a Russian radio here and they obviously copied the manufacturing techniques of the Germans, because they look very much like German components, lol.

Two or three milliamps may not sound like a significant amount of linkage, but it's cumulative. The set is only supposed to draw like 20 milliamps from the A+ buss in operation. The leakage in those bypass caps would have more than doubled the load on the A+ buss.

If you think this one was weird, wait until I write to you about the FuG X EK receiver. Now that one is a trip.

https://photos.app.goo.gl/DmKJtKSr7dZJW3wf7

73 OM DE Dave AB5S

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