[KD8EYY-Joe]

Hello everyone!
New to the forum and need some help.
Looking to bring back to life a 41-250 (X-Mas gift for the father in law).

Here's what I found:
Dead 84 rect.
Questionable Osc and 1st det tubes (both XXL)
questionable because my Hickok manual had an error in it
So I ended up checking them wrongly and I think they were hurt in the process
Don't use the consolidated Hickok manual settings for an XXL tube use the settings for a 7A4...Story for a different post

What I have done so far:
Replaced all paper caps
Replaced the 250uf items21&21A and the 370uf items24&25
new 84
two new XXL (7A4)
replaced a hand full of the rubber wires that were cracked bad.
cleaned all the contacts with deoxit
Temporarily bypassed the arching on/off switch until I can get the replacement installed

After power up I have nothing but occasional subtle static and a real slight hum
voltage across item 27A (16uf) is spot on 182V
voltage across item 62 (12uf) is spot on at 266V
voltage across item 27 (8uf) is way high at 183V
Reading at the plate of the osc is the same 183V

The 33Kohm and the 18kohm resistors at location 26 & 28 respectively check ok.
what is driving the high voltage?

HELP

Thanks
Joe

[Radioroslyn]

Hi Joe,
Welcome to the Phorum!!!!
Been a ham for a while?? Got my ticket back in '88. Thought we might be able to fix this old guy over the airwaves ( I don't touch type) but I see on qrz that that won't be possible.
I think I would just start with some basic tests. Turn it on let it warm up. Touch the wiper connection of the volume with your tip of your finger. If things from the volume to the speaker are working you will hear a loud buzz. Please don't do this if you don't know where the wiper is. I'm not trying to be condescending but I don't know how much you know about tube circuits and HV. I don't want you to get hurt fooling with this thing.

Next would be using a signal generator to generate a signal at the IF frequency. This will tell you if the detector and IF stages are OK
Then would tune the generator up to the BC band and see if I could get a signal though the front end.
Sometimes it's easier to try to isolate the stage that isn't working and then start looking at the voltage around that stage rather that looking at all the voltages to try and figure what isn't working that will cause the voltages to be off.
I'm going take alook and see if I can find another copy of the diagram. The online one is pretty hard to read.
Terry N3GTE

[KD8EYY-Joe]

Terry,
Thanks a bunch for the reply.
Although I am a newbie to the EE side of things (I know what the wiper is) .
Just don't tell my boss that his hydraulics engineer is fooling around with EE stuff

Been playing around on 2m coming up on 5 years now.
Seem to have most my fun making and trying out antennas
Looking to knock out the general class exam in January
Thought there is no better way than practical experience
when it comes to learning the fundementals of electronics
So about 2 years ago my Dad handed me an old Murdock Neutrodyne
three dial and said have at it....Several chassis later
And a couple nice ones sitting in the dining room and I think I'm hooked!!!

I think I've found the problem with this one
In swapping out tubes one of the new 7A4's to replace the XXL was very unreadable
That along with one of the other loctals being the same way it would appear that they got switched! A little warm breath on the tube shows me they were indeed backwards

Feel real stupid...kind of like working on a car for hours down under it trying to figure out why it wont run only to pop the hood up top and see the carb is on upside down...
Sometimes starting with the obvious is really a good idea!!!

It appears to be picking up something on all three bands, so now I think its on to peaking it up a bit with the generator.

By the way the online schematic was so unreadable I was told to use the 41-280 schematic. It's close enough and far more readable, especially for the alignment portion.

Again...
Thanks a bunch!
73's

[Radioroslyn]

Glad to hear the Philco on the road recovery. Sometimes these little things can throw off the track! Wish you the best on getting General class ticket. I had a lot of fun when I had my tech ticket working the local repeaters during the drive time but having the HF privileges is a whole other world. If you are fortunete to have a bit of ground and can put up a few longwire antennas the world will be at your finger tips. For me the most fun is to take a head full of parts and put them together and make a transmitter or receiver. Put it on the air and enjoy the performance of what you just made.
GL OM
Terry N3GTE

[gary rabbitt]

Hi Joe,
"Replaced the 250uf items21&21A and the 370uf items24&25"I hope you mean 250uuf (pf) and 370uuf.

[Texasrocker]

The front ends of the 41-250 & 41-280 sets using the XXL / 7A4 tubes can sometimes ( most times) be intermittent because of dirty loctal tube pins. Clean ( scrape) all the individual loctal tube pins shiny clean with a exacto knife blade. Do the same with the other loctal type tubes pins in the set. Work all them in and out of the sockets a few times for good sockets contacts. Lube all the tube pins with WD-40 from a Q-tip. Spray WD-40 in the old sockets as well. Let dry, remove excess lube. The old band switches in these sets are highly problematic also. Flush them several times with Deoxit, carefully work the switch back and forth using deoxit, then relube switch contacts and wafers with WD-40. Check the old candohm resistor going to ground from the filter caps also to make sure the resistors built in are still good.

[LASJayhawk]

What you didn't like watching the hickok drive the meter through the right hand side of the case???? I sent Stan an email he should have the consolidated chart fixed by now.

As I was doing the same think to a 41-250 in December (including making tube tester unhappy) I second the tube socket on the XXL tubes being dirty. Mine was DOA till I cleaned the sockets and the radio/phono button on the pushbutton switch board.

As for the power switch I recommend you read this:

http://www.philcoradio.com/notebook/41226.htm

same setup, same switch