Palomar 300a

[my2995dx]

I heard years back if you have a radio with MOSFET don't run it in a tube amp is that a bunch of bull.This was about 20 years ago

 

[linearone]

I heard years back if you have a radio with MOSFET don't run it in a tube amp is that a bunch of bull.This was about 20 years ago

I've had a couple weird issues with leakage in various tube amps . Nomad has spoken about this in radios but essentially you can get a tingle from certain amps if they are plugged in, on and not keyed from the RF jacks. This tingle could mean nothing or it can damage some sensitive stuff if it's connected.

 

[nomadradio]

If you have a solid-state radio, don't run it with a 300A that has worn-out relays.

We learned the hard way to ask this when a typical Uniden base radio would arrive with a blown final and no other faults.

The "hard way" means that after repairing the Cobra2000/Washington/Madison it would come right back a day or a few later with the exact same problem. No transmit. The customer naturally expected us to repeat the repair, but this time for free.

Learned to point out that blowing up the radio with a worn-out relay in your 300A was NOT covered by any warranty. Pointing it out in advance seemed to work better.

Same rule applies to any radio with a MOSFET final, but it applies to other radios as well.

73

 

[1iwilly]

while on the subject of 300A is there a difference between the chrome cover and the black cover and the ones with 3 relays on board

 

[my2995dx]

If you have a solid-state radio, don't run it with a 300A that has worn-out relays.

We learned the hard way to ask this when a typical Uniden base radio would arrive with a blown final and no other faults.

The "hard way" means that after repairing the Cobra2000/Washington/Madison it would come right back a day or a few later with the exact same problem. No transmit. The customer naturally expected us to repeat the repair, but this time for free.

Learned to point out that blowing up the radio with a worn-out relay in your 300A was NOT covered by any warranty. Pointing it out in advance seemed to work better.

Same rule applies to any radio with a MOSFET final, but it applies to other radios as well.

73

Got it this 300a going to need some work was given to me both high voltage caps leak one end cracked open and someone ran a jumper wire off the high voltage cap 1 and attached it to the board

 

[my2995dx]

If you have a solid-state radio, don't run it with a 300A that has worn-out relays.

We learned the hard way to ask this when a typical Uniden base radio would arrive with a blown final and no other faults.

The "hard way" means that after repairing the Cobra2000/Washington/Madison it would come right back a day or a few later with the exact same problem. No transmit. The customer naturally expected us to repeat the repair, but this time for free.

Learned to point out that blowing up the radio with a worn-out relay in your 300A was NOT covered by any warranty. Pointing it out in advance seemed to work better.

Same rule applies to any radio with a MOSFET final, but it applies to other radios as well.

73

Looks like they ran a jumper on the negative side of the high voltage cap to ground on the 4 tube board take it they lost ground that's why they did that have to pull board out and check it