[Trog1058]

Bought from a citizen

[Radioroslyn]

Yup S-38 alright. It's missing it's back cover which may be kinda important. The chassis and cabinet are insulated from each other because the chassis poses a shock hazard. When servicing it do use an isolation transformer between it and the wall socket. I've worked on a few of them and their old siblings the Echophone EC-1 and the Hailcrafters S-41.

[David]

I like the S-38 series the E has 7 pin miniature  tubes the others no. The first model in the series did not have the gimmick wire.  Hailcrafters resistors and caps do not age well. Please let us know which one in the series. David

[Jimradio]

I put one of these in the radio.
https://www.mouser.com/datasheet/3/236/1/N_68X.pdf
Mouser has them.

[Trog1058]

Here's a better pic

[David]

A link for info. David     https://www.nostalgiaair.org/models/Hall...c-S-38.htm

[Joe Rossi]

Looks to be in clean shape. Great catch!

[David]

Great info at this site. David    http://www.stanwatkins.com/hals38.htm

[MrFixr55]

Seems from the schematic that te S38 suffers from the same issues that most "AA5s" suffer from, namely the "warm" chassis (Chassis connected to power through a cap or cap / resistor combo, and the fact that the switch is in the "B-, base of heater string junction", making the chassis warm no matter the polarization of the power cord, depending on the position of the power switch. For example, if B- is at "neutral" potential, the chassis will be cold with the power switch on, but "warm" (or hot if the cap shorts) with the switch off, due to the very low resistance of cold tube heaters. If the polarity of the power cord is reversed, then the chassis will be cold with the switch open but warm (or hot) with the switch closed.

I don't know why manufacturers always chose to switch the cold side of the line (They continued this all the way to the demise of the AA5 radio and replacement with solid state devices, including doing this with clock radios). Was it for hum reduction? I don't know, but I modify all of my hot chassis and warm chassis sets to place the switch on the hot side and use a polarized power cord. Of course, I ensure that all safety devices in existence at time of manufacture are in place. However, for example, my Emerson FG330 is a warm chassis set. The chassis screws protrude to the bottom of the cabinet, are metal and at chassis potential. While not common for someone to want to touch the bottom of the radio while plugged in (except the 5 year old version of MrFixr), I see this as a problem.

While installing an isolation transformer is an excellent option for adding safety, adding a polarized plug and putting the switch on the "high side" (rectifier plate and heater), connecting B- and heater low side (usually detector / 1st AF tube to the wide blade of a polarized plug will add safety without much expense. In addition, ensure that all chassis to cabinet isolation is in place and in excellent condition.

IMHO, this should be done on all transformerless sets unless not possible. For example, sets with a "Cordohm" (curtain burner) power cord with the built in filament dropping resistor and many battery / line power portable tube sets are very difficult to perform this mod without replacing the filament dropping resistor portion of the power cord.

[David]

The problem is hum in the sets do not understand but it happens. Using a polarized plugs can make the hum a bigger problem.  Old houses with poor or no ground system and no ground wire big trouble. One old wiring standard from 1930 to 1970 a house was wired for 110 volts only the fuse box had 2 sets of fuses one for each leg. If you took a voltage reading from each leg to ground 55 volts. Have a army signal corp generator from 1952 that does 60 volts to ground on each leg the army finally got rid of them in 1977. Have worked on a few habit houses the electrical system were different some had no ground rod.

[Arran]

I have two versions of the S-38, an S-38, and an S-38B, the latter only has five tubes, and does not have a pitch control for the BFO, called "C.W Pitch" on the S-38. I fixed up the latter, but never did anything with the S-38, they both had the same problem, missing knobs, and missing control shafts for the main tuning, and the bandspread, the latter had both missing.
As for house wiring it seems like it was all over the place as far as standards go, in Canada we had a national electrical code pretty early on, but there was still a lot of regional variants. Like where I am they were already using circuit breaker panels by the late 1930s, but in Ontario they were still using fuse boxes in the late 60s or early 70s. Older houses used to use the water pipes for a ground, which would be fine until someone did some plumbing and broke the circuit. Neutral should not be confused with earth ground, it's the center tap of the secondary at the power pole, so it's ZERO volts with reference to each leg, which is nominally 120 volts each, but may be well above earth ground.
Regards
Arran

[Trog1058]

Chassis pics