Got an old school two button President Washington (upd858 PLL), with an old school 1306 driver and an old school 1307 final on the desk.
Issue:
Blows fuses once turned on.
Cause:
All caps, every single cap was shot.
Fix:
Recapped entire radio, even power supply and button board.
After fixing the above issue by recapping, the radio works beautifully. I'm just curious of something about this radio, the output power.
The owner wanted a variable power control. So I removed the factory carrier control VR, ran wires from that now empty VR spot over to a 5k ohm potentiometer in place of the RF Gain control.
The variable power works great, but with it turned all the way up the radio will deadkey 20w and swing to 50w PEP. Even at that high of a key, the radio still swings forward up to 30w in average mode. The radio does not run hot, final and driver stays cool/warm, passthrough stays cool/warm, power supply runs cool/warm. Everyone says it sounds great to them and swings forward on their S-meters. The limiting circuit is still working, because I can turn the carrier down and the swing comes down with the carrier.
Only upgrades I made, other than completely recapping the radio was:
1. Replaced passthrough (1419) to a 6487G.
2. Replaced power supply regulator (1419) to a 6487G.
3. Replaced the 3300uf 16v power supply capacitor to a 10,000uf 25v.
4. Broadbanded the xmit.
5. Set power supply voltage to 14.10v.
That's it...
Now, how in the world is this old antique President Washington doing 50w PEP max swing with no power supply drain whatsoever with just a 1306 kicking a 1307?
Did the 6487g regulator swaps contribute to this max output?
Did the 10,000uf cap contribute to this max output?
On my peak meter it's around 35w peak swing.
An old school President Washington doing 50w PEP, lol... I've seen it all now, lol...
And by the way, no swing mods or hacks, just the broadband xmit mod.
Issue:
Blows fuses once turned on.
Cause:
All caps, every single cap was shot.
Fix:
Recapped entire radio, even power supply and button board.
After fixing the above issue by recapping, the radio works beautifully. I'm just curious of something about this radio, the output power.
The owner wanted a variable power control. So I removed the factory carrier control VR, ran wires from that now empty VR spot over to a 5k ohm potentiometer in place of the RF Gain control.
The variable power works great, but with it turned all the way up the radio will deadkey 20w and swing to 50w PEP. Even at that high of a key, the radio still swings forward up to 30w in average mode. The radio does not run hot, final and driver stays cool/warm, passthrough stays cool/warm, power supply runs cool/warm. Everyone says it sounds great to them and swings forward on their S-meters. The limiting circuit is still working, because I can turn the carrier down and the swing comes down with the carrier.
Only upgrades I made, other than completely recapping the radio was:
1. Replaced passthrough (1419) to a 6487G.
2. Replaced power supply regulator (1419) to a 6487G.
3. Replaced the 3300uf 16v power supply capacitor to a 10,000uf 25v.
4. Broadbanded the xmit.
5. Set power supply voltage to 14.10v.
That's it...
Now, how in the world is this old antique President Washington doing 50w PEP max swing with no power supply drain whatsoever with just a 1306 kicking a 1307?
Did the 6487g regulator swaps contribute to this max output?
Did the 10,000uf cap contribute to this max output?
On my peak meter it's around 35w peak swing.
An old school President Washington doing 50w PEP, lol... I've seen it all now, lol...
And by the way, no swing mods or hacks, just the broadband xmit mod.
