UNIDEN MADISON FINAL REPLACED. problematic

[Stellasarat]

The final in my Madison took a dump. I had it replaced, but the new final is not A 1959. It's an aftermarket final that apparently comes from the UK., at least that's what I was told. The Madison is definitely not what it used to be. The output is low compared to the final that originally came in the radio. There are other things I just can't put my finger on. I'm not sure if it's the audio, but I do know the only thing that was done to the rig was the replacement of the final. I do have an old Cobra 139 23 channel single sideband am rig. I'm not sure if it has the same final as the Madison, and I'd rather not install a used final, but if I can't get a new old stock I will consider using the final from that 139 as a replacement. Can I get a new old stock 1959 or the original final that came in the Madison (is it a 1059?). Does anybody know where I can get one, end has anyone else had this problem with replacement non-original finals? Thanks

 

[Robb]

The final found in this radio is a 2sc1969.
The English company named 'Eleflow' make xlnt replacement transistors (power output equal to/or greater than the mitsubishi it replaces), so I doubt very much that that is the problem.

 

[loosecannon]

well there are a LOT of fake 2SC1969's out there. way more of those than the real ones.
there are even fake Eleflow parts out there now.

the thing is, even the good eleflow part might need a component value tweak or two in order to be completely compatible with the radio. yes, they call it a drop in replacement, and it is, as it will put out power without making any other changes to the radio, but it still may need some optimizing depending on your particular radio.

SAR, i would start the search for a good used 2SC1969. buy it from someone you know or at least trust.
you must get over the mindset that a used transistor is somehow substandard, and not as good as a new one. unless the part is bad, it will work just as well as the day it was made.

after replacing the final with a real 2SC1969, you must re-adjust the driver and final bias pots, and the transmitter section should also be realigned.

after this, you should be all good to go.

here is a link to a real 1969 that you can trust. yes, it's expensive, and they have a 25 dollar minimum order, but it will be the real deal.
https://www.rfparts.com/2sc1969.html

LC

 

[Stellasarat]

well there are a LOT of fake 2SC1969's out there. way more of those than the real ones.
there are even fake Eleflow parts out there now.

the thing is, even the good eleflow part might need a component value tweak or two in order to be completely compatible with the radio. yes, they call it a drop in replacement, and it is, as it will put out power without making any other changes to the radio, but it still may need some optimizing depending on your particular radio.

SAR, i would start the search for a good used 2SC1969. buy it from someone you know or at least trust.
you must get over the mindset that a used transistor is somehow substandard, and not as good as a new one. unless the part is bad, it will work just as well as the day it was made.

after replacing the final with a real 2SC1969, you must re-adjust the driver and final bias pots, and the transmitter section should also be realigned.

after this, you should be all good to go.

here is a link to a real 1969 that you can trust. yes, it's expensive, and they have a 25 dollar minimum order, but it will be the real deal.
https://www.rfparts.com/2sc1969.html

LC

Thanks. Much appreciated for the replies. I'm just going to adjust the output via the two VR output pots and everything should be fine.

 

[Stellasarat]

well there are a LOT of fake 2SC1969's out there. way more of those than the real ones.
there are even fake Eleflow parts out there now.

the thing is, even the good eleflow part might need a component value tweak or two in order to be completely compatible with the radio. yes, they call it a drop in replacement, and it is, as it will put out power without making any other changes to the radio, but it still may need some optimizing depending on your particular radio.

SAR, i would start the search for a good used 2SC1969. buy it from someone you know or at least trust.
you must get over the mindset that a used transistor is somehow substandard, and not as good as a new one. unless the part is bad, it will work just as well as the day it was made.

after replacing the final with a real 2SC1969, you must re-adjust the driver and final bias pots, and the transmitter section should also be realigned.

after this, you should be all good to go.

here is a link to a real 1969 that you can trust. yes, it's expensive, and they have a 25 dollar minimum order, but it will be the real deal.
https://www.rfparts.com/2sc1969.html

LC

Great video. Thanks loose cannon.

 

[Klondike Mike]

There's enough room in that Madison to fit something like this in there, DIY KITS 45W ssb linear power amplifier for transceiver HF radio;

http://rover.ebay.com/rover/1/711-5...0001&campid=5336136228&icep_item=171858503075

 

[Stellasarat]

There's enough room in that Madison to fit something like this in there, DIY KITS 45W ssb linear power amplifier for transceiver HF radio;

http://rover.ebay.com/rover/1/711-5...0001&campid=5336136228&icep_item=171858503075

There's plenty of room,, and that an excellent item, but I have quite a few amp and enjoy using them.. For someone who feels 45 watts is fine that looks like a great way to go. I saved that link and if anyone seems interested in an in rig 45 watt amp I'll pass it on. Thanks.

 

[Stellasarat]

The final found in this radio is a 2sc1969.
The English company named 'Eleflow' make xlnt replacement transistors (power output equal to/or greater than the mitsubishi it replaces), so I doubt very much that that is the problem.

I confirmed it's an Eleflow. Should it have shown 4 watts on AM and 12-15 ssb (upon install) without having to adjust the output for those numbers using the VR pot's? If no adjustments should be necessary, maybe I should install another Eleflow. Maybe I got a bad one.. I'll wait for your reply to decided what to do. Thanks very much Robb.

 

[Robb]

Should it have shown 4 watts on AM and 12-15 ssb (upon install) without having to adjust the output for those numbers using the VR pot's?

Nope; it was already installed in that radio when you got it and it was adjusted by the previous owner IIRC. It will read whatever dead key watts he adjusted it to.

Or; did you replace the original final with the eleflow recently?

 

[Robb]

Q:
What are you getting in AM mode for output on your meter?

 

[Stellasarat]

I've a variable output knob on the Madison. Before the replacement final was installed I was saying for walks on AM Ende 20 Watts on single side band with the gain knob turned all the way up. With the new

Q:
What are you getting in AM mode for output on your meter?

Nope; it was already installed in that radio when you got it and it was adjusted by the previous owner IIRC. It will read whatever dead key watts he adjusted it to.

Or; did you replace the original final with the eleflow recently?

no, I did not install it myself. Last week the final went, and I gave it to a local who has owned several Madison's and not only knows them very well but has worked on mine in the past and did a great job. I brought it to him and he installed the eleflow. When he was finished I asked him what the output was. He told me and I did mention it was low as compared with the old final, but I assumed it had something to do with different meter antenna / SWR excetera excetera that he who installed it uses.. When I got it home and hooked it up it was basically the same as he stated. Approximately two watts on AM and will only hit 12 Watts on SSB when speaking loud and close to the mic. This was deffenetly not the case with the original 1969 that was replaced. The 1969 final that was replaced showed 4 dead key watts on AM and 20 Watts on SSB with the variable output knob turned all the way up speaking 6 inches away from the mic in a soft voice. Should I have him adjust the VR pots to match the original output of the 1969 with the variable output knob turned all the way up, or should I just install another eleflow? I can also get a new old stock 1969, but from the test video you added above the eleflow seems to be an excellent replacement. If the eleflow should have shown what the 1969 showed with the variable all the way up and no adjustment having to be done on the VR pots, is it possible I got a faulty Eleflow?. If you don't think the VR pots should have to be adjusted to match the 4 am and 20 single side band watts that the original 1969 showed (variable output knob all the way up) should I have him install another eleflow? Sorry for being so verbose but should it be necessary to adjust the VR pots after installing a replacement final or is this not common practice,. What you say my friend?

 

[Robb]

Replacing a final also requires adjusting the bias pot to ensure that it is saturated with enough current to operate properly. Too much current can cause it to fail prematurely by overheating. This is also true of the driver as well.

Besides the bias adjustments, the radio may need to have the TX coils re-peaked. All of these adjustments are done in SSB mode. Hope your friend has some equipment and enough experience to do it right.

A variable output control still should allow no more than 4 watts wide open in AM mode with the modulation turned all of the way down. These final/driver devices are spec'd to work fine so long as you don't try to make them do more than what they were designed to do . . .

 

[Stellasarat]

Replacing a final also requires adjusting the bias pot to ensure that it is saturated with enough current to operate properly. Too much current can cause it to fail prematurely by overheating. This is also true of the driver as well.

Besides the bias adjustments, the radio may need to have the TX coils re-peaked. All of these adjustments are done in SSB mode. Hope your friend has some equipment and enough experience to do it right.

A variable output control still should allow no more than 4 watts wide open in AM mode with the modulation turned all of the way down. These final/driver devices are spec'd to work fine so long as you don't try to make them do more than what they were designed to do . . .

Thanks Robb. I'll update how everything works out. I should get around to dropping it off sometime next week.

 

[Stellasarat]

Replacing a final also requires adjusting the bias pot to ensure that it is saturated with enough current to operate properly. Too much current can cause it to fail prematurely by overheating. This is also true of the driver as well.

Besides the bias adjustments, the radio may need to have the TX coils re-peaked. All of these adjustments are done in SSB mode. Hope your friend has some equipment and enough experience to do it right.

A variable output control still should allow no more than 4 watts wide open in AM mode with the modulation turned all of the way down. These final/driver devices are spec'd to work fine so long as you don't try to make them do more than what they were designed to do . . .

Robb. He does have an oscilloscope and other test equipment and I'm sure he's capable of bring the output up to where it should be. I would like to ask him beforehand what he plans on doing to get the output where it should be, but I don't know the questions because I don't have the knowledge. Would you please tell me what i should hear when I ask him what his process is going to be to bring the output back to where it was with the original 1969 with the variable output knob turned all the way up which was 4 Watts on AM and 20 Watts on single side band. I would like to ask him the proper questions because if I'm uncomfortable with his answers I will unfortunately have to send it out to my tech and lessons learned. I am fairly positive he does know what he's doing and will bring it back up to where it should be properly. On the other hand I would hate to have something happen to this Madison which is a terrific radio. I get great reports on and would like to continue to get those same reports. The worst thing that can happen is a mistake or improperly doing what he needs to bring the output back up to where it should be, and then nightmare city. I definitely don't want that. If I knew what to ask him about the process he will use to perform this job, and got the correct answers from him I would feel so much more comfortable. Can you help Robb? Thank you my friend

 

[Robb]

He will probably attempt to peak and align the the radio until he finds an area that won't come into adjustment - after a close visual inspection for bad parts and poor solder joints and replace/resolder as necessary first. From that point he will probably troubleshoot/isolate whatever problem area(s) he may find and replace part(s) as needed. Then he will give it a final adjustment(s) and test before he gives it a clean bill of health.