| Author |
Message |
    
W4mwk
New member
Username: W4mwk
Post Number: 1
Registered: 4-2004
| | Posted on Sunday, April 18, 2004 - 10:08 pm: | 
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Hi Everyone,
I have a JB-12 Power Modulator, I am in need of a copy of the schematics, does anyone have a set? or does anyone know where I might find a copy? all help would be appreciated.
73s
W4MWK - Mike |
2600
Advanced Member
Username: 2600
Post Number: 528
Registered: 7-2002
| | Posted on Wednesday, March 30, 2005 - 12:54 am: |
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You'll need both the "jb_12_rec_amp" diagram, and the "jb_12-150_power_supply" files.
That model was made over a period of years. Some improvements were made that those two diagrams don't contain.
Biggest of all, is the keying circuit/relay.
The original version had a 6AQ5 (skinnier) tube that would sense the radio's driver power and engage (key) the relay when you key the mike. This one uses a 110-Volt DC coil on the relay. Can't use a 120-Volt AC in its place. Just not the same.
The later version used a 12-Volt DC relay. In place of the smaller tube socket is a small circuit board with a transistor keying circuit.
Never have seen a diagram posted on the net for the newer versions.
73
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Jp1116
Member
Username: Jp1116
Post Number: 95
Registered: 5-2002
| | Posted on Sunday, April 03, 2005 - 11:05 am: |
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I posted the newer diagram but not sure if the link will work. You can try this and see if it works.
http://home.kc.rr.com/amprepair/JB12.JPG |
