Welcome Guest! Be sure you know and follow the Phorum Rules before posting. Thank you and Enjoy! (January 12) x

Thread Closed
Thread Rating:
  • 0 Vote(s) - 0 Average
  • 1
  • 2
  • 3
  • 4
  • 5

Model 41-250 Bandswitch
#1

I'm up to the bandswitch in my restoration of my 41-250. Before I go ahead, are there any suggestions from those of you who performed this surgery on the best way to attack it. The top wires are easy, the real issue is how to get to the wires on the bottom of the switch. Thanks.

Harv
#2

The best way? Disassembly. Icon_twisted

But seriously...I have found that disassembly is the only way I can get to all of those d**ned rubber-covered wires without taking a chance on breaking a terminal. (Yes, I have broken a couple band switch wafers on 41-250 et al. chassis.)

It also makes it slightly easier to replace that double silver mica cap with three legs, I think it is 370 pF? Anyway, I replace this double unit with two individual mica caps. The old one is almost always bad...it's only covered in wax, and this is ineffective in keeping moisture and other nasties out, as we all know.

--
Ron Ramirez
Ferdinand IN
#3

I guess my question Ron is how much dis-assembly is needed. Since the wires on the switch are short, it seems that you can not move the band switch assembly around too much. It looks to me, that if I removed the station selector switch panel, I can get to the contacts that are closer to the chassis. I may try to disconnect one end of a wire, that is more accessible, and slip some shrink tubing over it. I can certainly understand why people say these are tough radios to restore.

Harv
#4

The entire assembly is held together by two long screws, two nuts, and two lockwashers. Along with spacers between the band switch wafers.

The nuts are easily accessible from the back of the switch. Remove these, the lockwashers, and then carefully begin to pull the wafers apart. The first two spacers can be removed when you do this; the others should stay on the screws. The switch, still being bolted to the chassis, will prevent the screws from falling out.

Reassembly is the reverse of disassembly.

It isn't that difficult to do, once you overcome your apprehension of doing the operation, and will be a great aid in getting to all of those rubber-covered wires on the terminals of the bandswitch.

--
Ron Ramirez
Ferdinand IN
#5

Good idea Ron. I did not think of taking that approach and it is easy enough to do.

Harv
#6

mandh, hi. I actually removed the sub-chassis from my 37-650 and then removed and disassembled the switch. Having done it that way let me spare you the agony I went through when I attempted to reassembly. I had not taken pictures or drawn same as to the orientation of the switch itself (having only two mounting screws it can go in two ways, one the right way and the other 180 degrees out). The second problem is the same, the wafers have a elongated opening like a rectangle but with rounded ends in the center rotor part and that's the same with the shaft and again could go in 180 degrees out. Fortunately, and I think this was done for proper production line assembly (not anticipating a clutz like me) the switch mounting plate had a tab on it that would only fit into a hole in the chassis when properly orientated.
Next, if you look carefully at the switch shaft rear end you will see a small bump/dimple/protrusion on only one of the long sides of the shaft and a corresponding groove/notch on the wafer rotors so, unless you force the wafers back on, the line up of the bump to groove will correctly orient the switches. Before I discovered these orienting points I thought I had lost the radio. Can you imagine the havoc having the switches disorient would cause! Been there, done that. PL
#7

The 41-250 has no subassembly, so everything is chassis mounted. The station selector switch is directly behind the bandswitch, so it makes for a tight area to work in. Part of the fun.

Harv




Users browsing this thread: 5 Guest(s)
[-]
Recent Posts
6TPZ and 5TPO Radio Help
Thanks, will do.R3Sons — 01:25 PM
1930s Stewart-Warner Tombstone Radio need help identifying model number
UPDATE: I was able to pick up a signal generator on the cheap (amazingly enough) on feebay and I did an IF alignment fol...captainclock1988 — 09:53 AM
Philco 91 Schematic
Hi Rod, The resistor connects to pin 4 and the ungrounded side of block 9. From pin 9 of the RF tube to one side of ...dconant — 09:34 AM
Just got a 49-1613 need to know...everything!
I just found your post. I have this exact same model, and have had it since 1985 when I was 15 years old! I performed a ...MuzzcoVW — 09:11 AM
B&K 1077B no video
Hello Tim, I would if it's a leaky Capacitor So are all 3 of those B- voltages low then ? Sincerely Richardradiorich — 01:55 AM
B&K 1077B no video
I found a schematic and think I have the problem traced down to the minus power supply. I have very low voltages that go...TV MAN — 12:41 AM
RCA 15X
I'd try replacing the bulb first and if that doesn't do it, then change the 35Z5 and see if the problem goes away.NostalgiaRadioTime — 12:28 AM
B&K 1077B no video
Hello Tim, I have that exact unit in my shop too plus a Sencore unit there are times I like one or other !!. Sincerely...radiorich — 11:07 PM
RCA 15X
Everthing goes at once, maybe it's the cold weather, I have had 2 dial strings break and no my little RCA is having dial...Paul Philco322 — 10:26 PM
Philco 91 Schematic
Hi Dan, I can't explain this specific resistor but I have seen the use of a switch to apply B+ voltage to screen gri...RodB — 09:36 PM

[-]
Who's Online
There are currently 11406 online users. [Complete List]
» 2 Member(s) | 11404 Guest(s)
AvatarAvatar

>