[murf]

Hi guy's,
Have aquired a real nice model 42-1012 console with the beam of light record player,and am trying to get the radio chassis to power up.
Noticed the rectifier tube was bad and replaced it.
Still no power to tubes or lights.
Anyone out there know how to check and or replace trannie in one of these?
Looks like a real mess under there.
I guess I would need to know which wire goes where to replace trannie.
Would like to re-cap this,but would like to get it to power up first.
Any info would be helpful.
Thanks,
Murf

[Sean]

Do you have power to the primary of the transformer? If not, check the wiring between the transformer primary and the power plug. Also check that the power switch is making contact.

[gvel]

Hi,

schematic is here: http://www.nostalgiaair.org/PagesByModel...013494.pdf

The power transformer/rectifier in on the right, toward the bottom.

Pull the rectifier tube, if you plan on starting it up to check transformer voltages.
If the power transformer checks out OK, change electrolytics and line bypass caps then "fire" it up! The line bypass caps are part 101, 2 x .01 uF. The radio will work w/o the bypass caps, so if you don't have any, oh well.

[murf]

Hi,

schematic is here: http://www.nostalgiaair.org/PagesByModel...013494.pdf

The power transformer/rectifier in on the right, toward the bottom.

Pull the rectifier tube, if you plan on starting it up to check transformer voltages.
If the power transformer checks out OK, change electrolytics and line bypass caps then "fire" it up! The line bypass caps are part 101, 2 x .01 uF. The radio will work w/o the bypass caps, so if you don't have any, oh well.

I have power to the chassis block and nothing coming out of the trannie if I check on the rectifyer pins.
There are 2 yellow and 2 green wires coming from the tranny to the rectifyer.No juice on any of them.
I assume it is bad.
I can detect a color scheme on the tranny wires on some of the wires.Not real clear on others due to wax leakage from the tranny.
If I were to get a used transformer,what are the odds that I will be able to seee the wire colors?
Appreciate your help guy's
murf

[codefox1]

Determine that there is any voltage on the primary of the transformer with rectifier remove and dim bulb tester or not, and then start measuring the secondaries, which will be much lower than nominal if you have a bulb in the line. Put a 2 qmp fuse in the line either side of the primary and leave it there. No smoke, the filaments should start to get warm if you change to a 100 watt bulb. No go if the bulb looks as if it is as bright as it is in the kitchen.

[gvel]

Murf,

As long as you can determine the primary winding, colored wire won't matter. Connect primary to source, and measure voltages on secondary leads.

Filament windings will have very low resistance across it. The secondary will have three leads. The other "should" be the primary. The primary will have higher resistance across it, than the filament windings.

Measure resistance across each winding in your transformer. Based on what you're saying, it sounds like all of the secondary windings are open. That's not impossible - but it's not likely.

[murf]

Murf,

As long as you can determine the primary winding, colored wire won't matter. Connect primary to source, and measure voltages on secondary leads.

Filament windings will have very low resistance across it. The secondary will have three leads. The other "should" be the primary. The primary will have higher resistance across it, than the filament windings.

Measure resistance across each winding in your transformer. Based on what you're saying, it sounds like all of the secondary windings are open. That's not impossible - but it's not likely.

You lost me Greg,
Have not run any of those tests before.
I just check for voltage with my volt meter,and am not getting anything from the output side of the tranny.
Not sure if this could be due to a problem with the switches?
They seem to operating as they should mechanically?
Thanks again for you help.This is kind of new to me.Just a hobby at this point.
murf

[murf]

Murf,

As long as you can determine the primary winding, colored wire won't matter. Connect primary to source, and measure voltages on secondary leads.

Filament windings will have very low resistance across it. The secondary will have three leads. The other "should" be the primary. The primary will have higher resistance across it, than the filament windings.

Measure resistance across each winding in your transformer. Based on what you're saying, it sounds like all of the secondary windings are open. That's not impossible - but it's not likely.

You lost me Greg,
Have not run any of those tests before.
I just check for voltage with my volt meter,and am not getting anything from the output side of the tranny.
Not sure if this could be due to a problem with the switches?
They seem to operating as they should mechanically?
Thanks again for you help.This is kind of new to me.Just a hobby at this point.
murf

Would the primary be from the chassis strip wher the cord is connected to the wire that goes from the chassis strip to the tranny?
I am really new to this.Played around with old radios when I was a kid.Now I am 60 and have found it to be really enjoyable to bring these old radios back to life.
So excuse my ignorance,but I am willing to learn.
Have a great weekend
murf

[Ron Ramirez]

Reading this thread, I can't help but wonder...what about the off-on switch? Is it good? Have you checked it? It should be "on" when any of the buttons are pushed in except for the "off" button.

Make sure the radio is unplugged, connect an ohmmeter across the terminals of the switch and push any button other than the "off" button and make sure it is OK before suspecting the transformer.

Of course, the transformer could have an open primary, or as Greg said, all of the secondaries could be open. Highly unlikely, but not impossible.

But do check the simple thing first (the switch) before suspecting a transformer.

[Sean]

Murf,

The wires on the transformer are colored as follows:

Primary: White, White
B+ Secondary: Yellow, Yellow-Red, Yellow
Filament: Black, Black
Rectifier Filament: Blue, Blue

I have attached a photo of the underside of a 42-1015 I recently restored. It should be similar to your 42-1012. I have marked 3 points that pertain to the power cord, power switch, and transformer primary connections. With the power off and the set unplugged push any of the push buttons other than the OFF button (left most button). Set your meter to read resistance.

Put one lead of your meter on the point marked "POWER CORD & POWER SWITCH". Put the other lead of your meter on the point marked "POWER SWITCH & TRANSFORMER PRIMARY (WHITE)". You should get a resistance reading of nearly 0 ohms. If you get a reading that is higher than a couple of ohms then you have a problem with the power switch.

If this checks out OK then move the lead of your meter from the "POWER CORD & POWER SWITCH" connection and place it on the "POWER CORD & TRANSFORMER PRIMARY (WHITE)" connection. Keep the other lead on the "POWER SWITCH & TRANSFORMER PRIMARY (WHITE)" connection. You should get a reading of a few ohms (around 3 to 5 ohms). If you get a much higher resistance reading here then the primary of your transformer is most likely open.

[murf]

Murf,

The wires on the transformer are colored as follows:

Primary: White, White
B+ Secondary: Yellow, Yellow-Red, Yellow
Filament: Black, Black
Rectifier Filament: Blue, Blue

I have attached a photo of the underside of a 42-1015 I recently restored. It should be similar to your 42-1012. I have marked 3 points that pertain to the power cord, power switch, and transformer primary connections. With the power off and the set unplugged push any of the push buttons other than the OFF button (left most button). Set your meter to read resistance.

Put one lead of your meter on the point marked "POWER CORD & POWER SWITCH". Put the other lead of your meter on the point marked "POWER SWITCH & TRANSFORMER PRIMARY (WHITE)". You should get a resistance reading of nearly 0 ohms. If you get a reading that is higher than a couple of ohms then you have a problem with the power switch.

If this checks out OK then move the lead of your meter from the "POWER CORD & POWER SWITCH" connection and place it on the "POWER CORD & TRANSFORMER PRIMARY (WHITE)" connection. Keep the other lead on the "POWER SWITCH & TRANSFORMER PRIMARY (WHITE)" connection. You should get a reading of a few ohms (around 3 to 5 ohms). If you get a much higher resistance reading here then the primary of your transformer is most likely open.

Thanks everyone for all the good info.
Should be able to figure it out from all this good info.
Will keep you posted.
murf

[murf]

Murf,

The wires on the transformer are colored as follows:

Primary: White, White
B+ Secondary: Yellow, Yellow-Red, Yellow
Filament: Black, Black
Rectifier Filament: Blue, Blue

I have attached a photo of the underside of a 42-1015 I recently restored. It should be similar to your 42-1012. I have marked 3 points that pertain to the power cord, power switch, and transformer primary connections. With the power off and the set unplugged push any of the push buttons other than the OFF button (left most button). Set your meter to read resistance.

Put one lead of your meter on the point marked "POWER CORD & POWER SWITCH". Put the other lead of your meter on the point marked "POWER SWITCH & TRANSFORMER PRIMARY (WHITE)". You should get a resistance reading of nearly 0 ohms. If you get a reading that is higher than a couple of ohms then you have a problem with the power switch.

If this checks out OK then move the lead of your meter from the "POWER CORD & POWER SWITCH" connection and place it on the "POWER CORD & TRANSFORMER PRIMARY (WHITE)" connection. Keep the other lead on the "POWER SWITCH & TRANSFORMER PRIMARY (WHITE)" connection. You should get a reading of a few ohms (around 3 to 5 ohms). If you get a much higher resistance reading here then the primary of your transformer is most likely open.

Thanks everyone for all the good info.
Should be able to figure it out from all this good info.
Will keep you posted.
murf

Did the first check and got a high reading.Values kept climbing the longer I held the leads on the terminals.
Is it a big job to replace the switch on this one?
Looks like the pushbutton assembly would have to come out?
Thanks again for the help.
murf

[Sean]

You might be able to spray some contact cleaner into the switch and work the switch on and off a few times. That may be all the switch would need. I know I had cleaned the power switch on my 1015. I think I may have been able to remove the switch from the push button board to get access to the contacts. There are probably 2 or 4 metal tabs that are bent over to hold the switch casing onto the board. If you carefully straighten the tabs you can remove the switch.

[Ron Ramirez]

Murf, if you're still here, I see you are advertising for another chassis now.

Before you give up...did you try cleaning the power switch as Sean suggested?

[murf]

Murf, if you're still here, I see you are advertising for another chassis now.

Before you give up...did you try cleaning the power switch as Sean suggested?

Sure did.Used radio shack
cleaner.
Re-built the bakelight block cap tonight just for grins.No change.
Got to be the tranny.
Chassis available from one of our guy's for $25 plus shipping,but it is untested other than the tranny works.
If he tried it using a variac,that would be safe wouldn't it?
Thanks Ron,this is a very helpful website.Keep up the good work.
murf