A friend of mine got one and got from yard sale for $40.00 and surprises me had orgnail stock microphone plus plug to and got tech check out and turn out in excellent shape for 40 channels only! But tech said put new POWER cord , open Clairfier to and the orgnail 6 pin to Cobra 4 pin pig tail to for him! Watts are 7 watts Am also 20 watts SSB plus modulation turn up too ! Tech said Clairfier was so easy to in to do 5 mins too and big clean up too!
Great tips Mike! And very cool radio! I never had this radio, however I had a JC Penny's back in the day that looked similar to this rig! The earliest newspaper ad I can find on this rig was April 1977, with a price tag of $259.95US, that equates to $1,033.96US in 2016 money.
My theory about the splitting film capacitors is that the aluminum layers inside are absorbing moisture from the environment. Aluminum oxide is less dense than the original metal layer on the plastic layers. Less dense also means larger. I really think that these caps swell from inside, as oxidized aluminum pushes outwards from inside as the oxide slowly forms. Sure wish someone with an electron microscope would tackle this issue. Don't think Santa will be bringing me one of those this year. Great work as always!
I bought a monster 25 channel CB once, as is. Years later, all it took to bring it to life was an alignment once I had a service manual.Had channels 1 through 23 and "A" and "B" which turned out to be what is now 24 and 25. And even though it was tubes, it was a base-mobile and would run on either 12-14Vdc or 120Vac. It was a massive box with elecroluminescent strip across the front. Needless to say, as a mobile, it sucked far too much power just idling. My first try in the car resulted in the wiring bursting into flames while I was driving.
Gee Mike for a minute there I thought you'd discovered a new electronics phenomenon - the "de-amplifier" driver stage! BTW, my "Bench Cookies" arrived yesterday, great addition to the bench as I'm always reaching for something to prop a piece of gear up on the bench invariably with it ending up slipping off...not anymore!
A deamplifier stage, the name for a solid state attenuator. :) I love my bench cookies. I have 4 tubes of them here at the bench and some like 10 set of them out in the woodworking shop. One of those make it simple stupid tools.
I have one but somebody painted the entire face Black so no letters are still Silver.It works but was in a junk pile at the 2017 Orlando Hamcation & I rescued it for $5.The AM light or S meter light does not work & the frequency is crazy towards the top of the band.It was only doing 4 watts PEP on SSB but I tuned it to 12 watts like it should be.AM power is 3 watts & swings to about 12.It's not pretty but for $5 it's a keeper for my personal collection & I may even attempt painting the letters so I can see them.I have no idea what putting it back like it was would even cost but I'm not spending $50 on it for sure.It can sit on my shelf like it is for FREE.Really getting to be a difficult find that works at all.
I use the same type, just a better quality name brand one. Marine radios, I couldn't honestly say. I have only worked on a few of them. To far away from the coast to really see many come across my bench.
How did you clean old messy paint? Without making more harm :) I find mess someone made holds better than nice paint someone painstakingly put on something.
I have an old Sears Roadtalker 40 AM/SSb mobile. It was handed down to me by a cousin. I would like to see if you can get it 10-8 Plus if possible De KC6ZTM. I'm good on QST.
Why yuck. There have been double sided pcb's pretty much since there have been pcb's. Makes for a more efficient compact design. Modern boards can have several layers.
Another great American Made radio almost ruined for good by Good Buddies "adding channels" and twirling screwdrivers and splattering solder blobs inside and leaving critical parts missing. . People shouldn't just indiscriminately replace all of the electrolytic caps "just because" in older radios, either; particularly in low voltage solid state units that aren't exhibiting any problems.
You must hold the world’s record for cap replacement.
A friend of mine got one and got from yard sale for $40.00 and surprises me had orgnail stock microphone plus plug to and got tech check out and turn out in excellent shape for 40 channels only! But tech said put new POWER cord , open Clairfier to and the orgnail 6 pin to Cobra 4 pin pig tail to for him! Watts are 7 watts Am also 20 watts SSB plus modulation turn up too ! Tech said Clairfier was so easy to in to do 5 mins too and big clean up too!
About 45 yrs ago I paid 900 nz$ for a highly modified one of these, lent it out once and didn't get it back. PS they are really a great unit.
Excellent video. Nice explanations. Like your work.
I am so glad I found your channel. Awesome!
Great tips Mike! And very cool radio! I never had this radio, however I had a JC Penny's back in the day that looked similar to this rig! The earliest newspaper ad I can find on this rig was April 1977, with a price tag of $259.95US, that equates to $1,033.96US in 2016 money.
People seem to forget how much radios cost back then. Some of the ultra premium radios got over $1,000.
My theory about the splitting film capacitors is that the aluminum layers inside are absorbing moisture from the environment. Aluminum oxide is less dense than the original metal layer on the plastic layers. Less dense also means larger. I really think that these caps swell from inside, as oxidized aluminum pushes outwards from inside as the oxide slowly forms.
Sure wish someone with an electron microscope would tackle this issue.
Don't think Santa will be bringing me one of those this year.
Great work as always!
Very possible that could be what's happening. And don't feel bad, Santa has forgotten to bring my scanning electron microscope several years running.
what a great find. and a rare one at that. thanks for sharing
Too bad several hackers have been through this radio already and nearly ruined it.
These radios were perfect right out of the box and LEFT ALONE.
I bought a monster 25 channel CB once, as is. Years later, all it took to bring it to life was an alignment once I had a service manual.Had channels 1 through 23 and "A" and "B" which turned out to be what is now 24 and 25. And even though it was tubes, it was a base-mobile and would run on either 12-14Vdc or 120Vac. It was a massive box with elecroluminescent strip across the front. Needless to say, as a mobile, it sucked far too much power just idling. My first try in the car resulted in the wiring bursting into flames while I was driving.
Some great tips here Mike, It's amazing how important it is not to go flicking solder everywhere :)
Cheers
John
I bought one of these, and it has at least nine split poly dip caps in it. Time to find some replacements.
I'd like to get one of those someday, neat rig.
They show up regularly on ebay. Just have to keep a look out for them.
Nice work Mike!
I've got that radio's older, AM only brother with less features. Johnson Messenger 4140, I think. Looks very similar.
That's a big 10-4 Good buddy, Am is all about shouting as loud a possible
Gee Mike for a minute there I thought you'd discovered a new electronics phenomenon - the "de-amplifier" driver stage! BTW, my "Bench Cookies" arrived yesterday, great addition to the bench as I'm always reaching for something to prop a piece of gear up on the bench invariably with it ending up slipping off...not anymore!
A deamplifier stage, the name for a solid state attenuator. :)
I love my bench cookies. I have 4 tubes of them here at the bench and some like 10 set of them out in the woodworking shop. One of those make it simple stupid tools.
I like those Bench Cookies as well, just ordered me a set of 4!
I have that exact radio I just need a mode know for mine. great video
A mode know? What is that in English?
I have one but somebody painted the entire face Black so no letters are still Silver.It works but was in a junk pile at the 2017 Orlando Hamcation & I rescued it for $5.The AM light or S meter light does not work & the frequency is crazy towards the top of the band.It was only doing 4 watts PEP on SSB but I tuned it to 12 watts like it should be.AM power is 3 watts & swings to about 12.It's not pretty but for $5 it's a keeper for my personal collection & I may even attempt painting the letters so I can see them.I have no idea what putting it back like it was would even cost but I'm not spending $50 on it for sure.It can sit on my shelf like it is for FREE.Really getting to be a difficult find that works at all.
What about using Metal foil polypropylene capacitors designed for 250v
When replacing the green poly capacitors, do you use the same type of capacitor? Also, what is the best made brand of marine radio, in your opinion?
I use the same type, just a better quality name brand one.
Marine radios, I couldn't honestly say. I have only worked on a few of them. To far away from the coast to really see many come across my bench.
How did you clean old messy paint? Without making more harm :) I find mess someone made holds better than nice paint someone painstakingly put on something.
Testors model paint "dope thinner & brush cleaner".
Come on Mike, everyone knows that removing the shields makes the radio lighter and faster..... Sheeesshh.... :-)
Didn't even consider that it may be a race radio. :)
+MikesRadioRepair what s the cost to get a lineament and tuning on a 4740,4230,4120,4145 Johnson's
Excellent work . Are you still accepting radios to work on.?
+lwoodt1
Yes I am. Just add @gmail.com to my youtube user ID to email me.
So basically replace caps and everything will be fine.
I have an old Sears Roadtalker 40 AM/SSb mobile.
It was handed down to me by a cousin.
I would like to see if you can get it 10-8 Plus if possible
De KC6ZTM. I'm good on QST.
Just add @gmail.com to my youtube user ID.
YES-QRZ! Ooop's
Double sided board radio. YUCK!!
Why yuck. There have been double sided pcb's pretty much since there have been pcb's. Makes for a more efficient compact design. Modern boards can have several layers.
Another great American Made radio almost ruined for good by Good Buddies "adding channels" and twirling screwdrivers and splattering solder blobs inside and leaving critical parts missing. . People shouldn't just indiscriminately replace all of the electrolytic caps "just because" in older radios, either; particularly in low voltage solid state units that aren't exhibiting any problems.
I own this model, I like to run in my Kenworth one day.