Paloamr 350Z preamp..

[Zman]

It blocks the receive when turned on. What do i need to look for?

 

[reddog45]

Possibly a stuck relay or a bad transistor closest to the relay.


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45, North Florida

 

[wavrider]

It blocks the receive when turned on. What do i need to look for?

A technician maybe?

 

[ExitThirteen]

A technician maybe?

Agreed.



~Cheers~

 

[Robb]

Check the switch too . . .

 

[Zman]

A technician maybe?

Please no snarky remarks, I was looking for a few hints...
if i can fix it myself im better off...

 

[Mudfoot]

https://www.youtube.com/watch?v=0VCQfyqw4M8&feature=youtube_gdata_player

 

[Zman]

Whatever............ if you have a good answer to help me then ok if not then don't reply, OK?

 

[wavrider]

Whatever............ if you have a good answer to help me then ok if not then don't reply, OK?

Try an ohm meter. if you know how to use one for checking the transistor.

 

[Zman]

Try an ohm meter. if you know how to use one for checking the transistor.

Uh yeah.... I DO know how to use one! Geeeez!!!!:angry:

 

[wavrider]

Uh yeah.... I DO know how to use one! Geeeez!!!!:angry:

Then why are you asking for help in fixing the preamp?

A simple ohm meter will verify if the transistor is good or bad, that is assuming you know the difference between a PNP and an NPN.

You can also stop sending me PM.

I do not have a problem, you are the one with the many broken pieces of equipment, not me.

This is a forum open to all so please post your findings IF you ever get the pre amp fixed so others can gain knowledge.

 

[9Lives]

I don't know that particular preamp but it's pretty typically a single transistor gain stage. Start on one end and work your way out. See if the relay works. It's there so that when you turn the amp off you won't transmit into the collector.
After that I would test the collector for voltage. If it has none then work you way to the power. If all that's good, work your way from the output jack to the base. Check the base for some kind of bias voltage. If all that's good go to the emitter.

I didn't read the symptoms in your description it just looked like they were giving you a hard time. They're giving you a hard time just bc its a single transistor lol. People forget pros were noobs at one point. I think a preamp is actually a good place to start!
Check this out dude. If all else fails, figure out which components are the circuit and replace all damn 6 or 7 lol

 

[The Mad Scientist]

Agreed. Everyone has to start somewhere and slapping one in the face for asking questions no matter how "stupid" somebody thinks it is, is just not cool.

The last post gave some good information. A little time and patience will tell you if either the transistor is bad and, or if the realy is stuck open.

However there are other possibilities as well...i.e. running to much power through that pre-amp. It would also help to look for burned traces or cooked components.

Good luck to you.

 

[9Lives]

Yea, im willing to bet it's that relay. Before I understood why they use one on the preamp I put one in an amp I built. I found out when I turned off the amp and the receive faded. I was like ooooooooo.

If you think about it, there's not really a such thing as a dumb question unless you don't find the answer. That discouraged me so bad when I started tinkering. This forum was actually better about answering some of my "dumb" questions.

 

[TonyV225]

Im also gonna say start at the relay which Im going to say is most likely your culprit. Its most likely stuck thus not switching back to recieve. You can lightly tap on the relay and see it it clicks back over to recieve.

Sometimes the relay plastic cover or housing can be pulled off or removed and you can clean the relay with contact cleaner