OT Philco 41-285

YahoooooOOOOOOOOOO!!!!!

I have it working again. I found it on my front porch Christmas day.

First thing I did was replace the filter caps and one audio cap.

The hard part was replacing the audio transformer as it was riveted in
and I had to drill it out...not really a major big deal.

I found a "close enough" equivalent in my junk box.

It was actually a 115/230 to 12v control transformer
but the impedance was close enough.

I robbed a 7B7 out of another Philco I had handy
and I could hear audio, but no stations were tunable until I connected
the antenna...and now it sounds good.

I went up to the attic and brought down my small box of loctals
and did not have another 7B7


Now I pulled out my 1963 Radio Amateur's Handbook and found another ...a
7A7 with the same base diagram...put that in and it works fine.




The dial string is ok
but there is a 2nd one for the band indicator I'll have to sort out...
but basically I've got it!!!!

philo wrote:
YahoooooOOOOOOOOOO!!!!!

I have it working again. I found it on my front porch Christmas day.

LOL. Nice.

First thing I did was replace the filter caps and one audio cap.

Were they actually shot, or was this more of an insurance policy? (Did you
even turn it on first, I mean)

The hard part was replacing the audio transformer as it was riveted in
and I had to drill it out...not really a major big deal.

I found a "close enough" equivalent in my junk box.

It was actually a 115/230 to 12v control transformer
but the impedance was close enough.

Control transformer, or filament transformer? But I'm not sure what a
"control" transformer is.

You could probably get a real audio transformer if you looked for one, but
as you say, it works fine anyways.

I robbed a 7B7 out of another Philco I had handy
and I could hear audio, but no stations were tunable until I connected
the antenna...and now it sounds good.

I take it has no loop antenna on the back, then?

I went up to the attic and brought down my small box of loctals
and did not have another 7B7


Now I pulled out my 1963 Radio Amateur's Handbook and found another ...a
7A7 with the same base diagram...put that in and it works fine.

I was an amateur radio operator since the 1960's, too, but I let my license
expire (Advanced Class). One reason I didn't renew it is that amateur
radio seems to be inhabited nowadays by a bunch of "appliance operators",
who know nothing about, or care nothing about, radio and electronics. It
wasn't always that way. :-( I take it that doesn't bother you! :-)

On 01/02/2012 03:55 PM, Bill in Co wrote:

portions snipped for brevity


LOL. Nice.

First thing I did was replace the filter caps and one audio cap.

Were they actually shot, or was this more of an insurance policy? (Did you
even turn it on first, I mean)

I did turn the machine one and there was just a very fain hum.
I replaced the caps more as an insurance policy. I do have a capacitor
checker and the values were *very* low.
It also gave me a chance to check my "junk box" capacitors and weed out
a few bad ones.


The hard part was replacing the audio transformer as it was riveted in
and I had to drill it out...not really a major big deal.

I found a "close enough" equivalent in my junk box.

It was actually a 115/230 to 12v control transformer
but the impedance was close enough.

Control transformer, or filament transformer? But I'm not sure what a
"control" transformer is.

The transformer I used was from a control circuit of an industrial
battery charger. (I repair industrial battery chargers for a living and
get plenty of spare parts from obsolete units) It was actually a
step-down transformer 460/230/115 to 12v. I "ohmed" it out and found it
very close to what the specs called for and best of all it was an exact
fit. Same size and same mounting! Hey, it works fine.

You could probably get a real audio transformer if you looked for one, but
as you say, it works fine anyways.

Though I did not want to spend any money...I really wanted to get the
xmfr replaced asap to see what else may have been wrong.

I robbed a 7B7 out of another Philco I had handy
and I could hear audio, but no stations were tunable until I connected
the antenna...and now it sounds good.

I take it has no loop antenna on the back, then?

Correct. I took the radio out of the case and the loop antenna stayed in
the case. Figured I'd pick up at least something. but my workshop is in
the basement.

I went up to the attic and brought down my small box of loctals
and did not have another 7B7


Now I pulled out my 1963 Radio Amateur's Handbook and found another ...a
7A7 with the same base diagram...put that in and it works fine.

I was an amateur radio operator since the 1960's, too, but I let my license
expire (Advanced Class). One reason I didn't renew it is that amateur
radio seems to be inhabited nowadays by a bunch of "appliance operators",
who know nothing about, or care nothing about, radio and electronics. It
wasn't always that way. :-( I take it that doesn't bother you! :-)


Actually it does bother me.
I am also an Advanced class operator and though I did renew my license
have not been on the air in years for the same reason you have quit .

philo wrote in :

loctals

?

Nice save. I got that feeling when I repaired an older Fenix P3D LED
flashlight. I like its light colour so much that it was worth it even after I
bought two new lights. Finding it after throwing it aside during a night-time
run past some woodland was even better. Best of all is making my own driver
circuits, simple but unusual methods that make very interesting results.
Dimmable, strobable high power floodlights are fun, I kid you not. It was a
laser driver when I started it last month, but it mutates nicely, I find.

On 01/02/2012 05:20 PM, Lostgallifreyan wrote:
wrote in :

loctals

?

Nice save. I got that feeling when I repaired an older Fenix P3D LED
flashlight. I like its light colour so much that it was worth it even after I
bought two new lights. Finding it after throwing it aside during a night-time
run past some woodland was even better. Best of all is making my own driver
circuits, simple but unusual methods that make very interesting results.
Dimmable, strobable high power floodlights are fun, I kid you not. It was a
laser driver when I started it last month, but it mutates nicely, I find.



Yes...those LED flashlights are great

I love them because they give a lot of light and are very easy on
batteries. I can yet a year or two's worth of use on one set of batteries!

"Bill in Co" wrote in
m:

I was an amateur radio operator since the 1960's, too, but I let my
license expire (Advanced Class). One reason I didn't renew it is that
amateur radio seems to be inhabited nowadays by a bunch of "appliance
operators", who know nothing about, or care nothing about, radio and
electronics. It wasn't always that way. :-( I take it that doesn't
bother you! :-)


Apparently it got really easy to get a license now. I'm thinking about
getting one because the LM317 regulator has some extremely interesting
habits, one of which is multi-Mhz cabilities including self-oscillation in a
tuned circuit. (Harry Lythal, in Sweden, documented that). As an LM317 does
so many cool things, I want to explore that myself. If I could do it all the
way to testing transmissions, legally, it could be worth the trouble of
licensing.

On 01/02/2012 05:25 PM, Lostgallifreyan wrote:
"Bill in wrote in
m:

I was an amateur radio operator since the 1960's, too, but I let my
license expire (Advanced Class). One reason I didn't renew it is that
amateur radio seems to be inhabited nowadays by a bunch of "appliance
operators", who know nothing about, or care nothing about, radio and
electronics. It wasn't always that way. :-( I take it that doesn't
bother you! :-)


Apparently it got really easy to get a license now. I'm thinking about
getting one because the LM317 regulator has some extremely interesting
habits, one of which is multi-Mhz cabilities including self-oscillation in a
tuned circuit. (Harry Lythal, in Sweden, documented that). As an LM317 does
so many cool things, I want to explore that myself. If I could do it all the
way to testing transmissions, legally, it could be worth the trouble of
licensing.



Morse code is no longer required...just a bit of theory however.

Those good old days are long gone
but that's fine, I enjoyed them while they were here

philo wrote in :

On 01/02/2012 05:20 PM, Lostgallifreyan wrote:
wrote in :

loctals

?

Nice save. I got that feeling when I repaired an older Fenix P3D LED
flashlight. I like its light colour so much that it was worth it even
after I bought two new lights. Finding it after throwing it aside
during a night-time run past some woodland was even better. Best of all
is making my own driver circuits, simple but unusual methods that make
very interesting results. Dimmable, strobable high power floodlights
are fun, I kid you not. It was a laser driver when I started it last
month, but it mutates nicely, I find.



Yes...those LED flashlights are great

I love them because they give a lot of light and are very easy on
batteries. I can yet a year or two's worth of use on one set of
batteries!


Absolutely. Take care though, I recently read a few web pages. There are
documented cases where a good LED flashlight differs VERY little from a pipe
bomb if running on dodgy or mismatched Li-ion cells. I imagine this is easy
to avoid with care, but I will be very cautious about Li-ion cells in
confined spaces, or during unattended charge or discharge. One guy apparently
managed to blast a hole in an oak cupboard door (by accident), and showed the
mortal remains in detailed photos.

I recently got a TK35. Now that is a LOT of light for such a small lamp.. And
there's a Chinese seller who makes LED's and floodlamps. SOme extremely
impressive stuff. I'm using it on my PV setup. He made an LED for an unusual
colour temperature for me. I never knew that ANYONE would ever manufacture a
high power LED like a bespoke suit! I'm hoping he'll do it again, with 10%
more green, 5% more red. If I can find the ideal colour light for indor
use, I'll buy several to run on a 320W PV installation, as I'm aiming to see
how far I can take that idea. I intend to sign up to some forum and do a
writeup of some of this stuff. I think a lot of other people have already
done that too.

philo wrote in :

The transformer I used was from a control circuit of an industrial
battery charger. (I repair industrial battery chargers for a living and
get plenty of spare parts from obsolete units) It was actually a
step-down transformer 460/230/115 to 12v. I "ohmed" it out and found it
very close to what the specs called for and best of all it was an exact
fit. Same size and same mounting! Hey, it works fine.


Any multi-cell chargers for Li-ion 18650 cells? If so and the case and
mechanical parts are all good, I'm after one so I can design my own
electronics for it. I don't know how heavy they are but I'd consider the cost
of transatlantic flight for it if it's what I want. (This is a long shot, but
I don't come across repairers of battery chargers every day!)

On 01/02/2012 05:36 PM, Lostgallifreyan wrote:
wrote in :

The transformer I used was from a control circuit of an industrial
battery charger. (I repair industrial battery chargers for a living and
get plenty of spare parts from obsolete units) It was actually a
step-down transformer 460/230/115 to 12v. I "ohmed" it out and found it
very close to what the specs called for and best of all it was an exact
fit. Same size and same mounting! Hey, it works fine.


Any multi-cell chargers for Li-ion 18650 cells? If so and the case and
mechanical parts are all good, I'm after one so I can design my own
electronics for it. I don't know how heavy they are but I'd consider the cost
of transatlantic flight for it if it's what I want. (This is a long shot, but
I don't come across repairers of battery chargers every day!)


Sorry, but the chargers I repair are for industrial lead-acid batteries

like this

http://www.enersysmp.com/enforcer_HF_ch.asp


The chargers weigh about 400 pounds and the batteries typically weigh
2000 - 4000 pounds. Big ones!