President Jackson without final

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cb4ever104
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Re: President Jackson without final

Post by cb4ever104 » 06 Jan 2020, 20:06

rocketry23 wrote:
06 Jan 2020, 19:21
It is hard to find even a 2SC1969 in Hungary.... :( Maybe if you can link me a trusted seller on ebay?
2SC1969 here

https://www.ebay.co.uk/itm/272488057198

An MRF477 might be a bit harder . There's a couple of originals on Ebay , but they're £40+ , which is too expensive . If I were you I'd just repair the driver and final stage and stick in a Eleflow CB-20 .

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Handle "Fortune Hunter" back in "the day"
Radios ....? Anything that says "TAIWAN R.O.C" on the back.

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Re: President Jackson without final

Post by rocketry23 » 06 Jan 2020, 20:11

cb4ever104 wrote:
06 Jan 2020, 20:06

2SC1969 here

https://www.ebay.co.uk/itm/272488057198

An MRF477 might be a bit harder . There's a couple of originals on Ebay , but they're £40+ , which is too expensive . If I were you I'd just repair the driver and final stage and stick in a Eleflow CB-20 .

Sammy
Thanks for link but they do not ship to my country.. {bnghd}

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Re: President Jackson without final

Post by cb4ever104 » 06 Jan 2020, 20:52

They ship to Europe, and Hungary is in Europe. Send them an email and ask them.

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Paul aka "Sammy". (108) PY60 Old Paisley DX Group (RIP Rab Markie)
Ex GM0 , now EA5 .
Handle "Fortune Hunter" back in "the day"
Radios ....? Anything that says "TAIWAN R.O.C" on the back.

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Re: President Jackson without final

Post by rocketry23 » 06 Jan 2020, 21:11

I'll give it a try! Thanks! :)

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Re: President Jackson without final

Post by Edd200sx » 07 Jan 2020, 10:30


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Re: President Jackson without final

Post by 4a0026aleks » 07 Jan 2020, 13:26

in Hungary it is easier to find a Soviet transistor kt 920 V

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Re: President Jackson without final

Post by 4a0026aleks » 07 Jan 2020, 13:33

please read the service manual for the device.... what transistors are in presidents ....2sc1969 or 2sc2166 ARE not SUITABLE !! by gain and mode....when installing KT920V mechanical alteration! when you install the other transistors...- designers put 2sc1969 (2sc2166) in parallel - not just like that

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ch25
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Re: President Jackson without final

Post by ch25 » 07 Jan 2020, 15:24

If you want use mrf455 or similar just mount transistor on back and connect it with wires. Put 1n4148 as bias diode.
Set bias with PR and job done.
Chris
You can't have too many antennas...

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Re: President Jackson without final

Post by rocketry23 » 13 Jan 2020, 21:00

ch25 wrote:
07 Jan 2020, 15:24
If you want use mrf455 or similar just mount transistor on back and connect it with wires. Put 1n4148 as bias diode.
Set bias with PR and job done.
Chris
Ok I wired in my SD1487. I had to replace VR9 because it was faulty.
It is interesting, there is 7mA bias current even the radio is switched off!
I set 150mA bias on TX.

There is 10W AM/FM output, but i cannot set SSB power above 20W. I even tried to adjust the related coils L43 42 41 33 30 as written in manual.


Thank you all for your help!
82443370_931477770581185_7564317339680768000_n.jpg
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ch25
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Re: President Jackson without final

Post by ch25 » 13 Jan 2020, 21:58

rocketry23 wrote:
13 Jan 2020, 21:00
It is interesting, there is 7mA bias current even the radio is switched off!
So there is something really weird with your radio :)
You can't have too many antennas...

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Re: President Jackson without final

Post by rocketry23 » 13 Jan 2020, 22:15

ch25 wrote:
13 Jan 2020, 21:58
So there is something really weird with your radio :)

Haha, yeah its a weird radio :lol:
Or maybe I'm doing something wrong.

But at least I learnd lot of things thanks to you!

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Re: President Jackson without final

Post by cb4ever104 » 14 Jan 2020, 15:12

Is the base on your SD1487 connected to the chassis ?
30TM060
Paul aka "Sammy". (108) PY60 Old Paisley DX Group (RIP Rab Markie)
Ex GM0 , now EA5 .
Handle "Fortune Hunter" back in "the day"
Radios ....? Anything that says "TAIWAN R.O.C" on the back.

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Re: President Jackson without final

Post by rocketry23 » 15 Jan 2020, 07:38

cb4ever104 wrote:
14 Jan 2020, 15:12
Is the base on your SD1487 connected to the chassis ?
No it is not connected to chassis.

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Re: President Jackson without final

Post by cb4ever104 » 15 Jan 2020, 08:51

rocketry23 wrote:
15 Jan 2020, 07:38
cb4ever104 wrote:
14 Jan 2020, 15:12
Is the base on your SD1487 connected to the chassis ?
No it is not connected to chassis.
OK . It was difficult to see in the photo .
30TM060
Paul aka "Sammy". (108) PY60 Old Paisley DX Group (RIP Rab Markie)
Ex GM0 , now EA5 .
Handle "Fortune Hunter" back in "the day"
Radios ....? Anything that says "TAIWAN R.O.C" on the back.

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Re: President Jackson without final

Post by 13EL121 » 15 Jan 2020, 21:47

I did a Mosfet conversion at two President Jackson with very good results. Easyly 8-10 watts AM/FM and over 20w SSB PEP clean audio with two Fqp13n10 for driver and final. You will need to swap some more parts, but they are cheap. But it's not a job for starters.

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