fatboy 2pill key problem

[airplane1]

hi, anyone know why a fatboy 2 pill would not unkey? it is a friends and he keys his mic on am and when he unkeys the amp stays keyed. It dont do this every time but intermitant. If he quickly rekeys the mic when amp is stuck it will unkey.

I told him to try lengths of coax but it wont help.

any suggestions welcome.

AP

 

[Moleculo]

Try replacing the relay and/or the keying transistor. It sounds like the relay is getting stuck. It could also be an RFI problem, but try the relay first.

 

[9C1Driver]

Mole has that nailed down. Once it's fixed have your friend double check how much he dead keys into the amp. Too much input dead key causes this. There is an e-bay seller, Swedisimpi or some crap like that, he recommends rediculous dead key levels for the fatboys he sells.

 

[mackmobile43]

the 2n222a is most likely shorted across and the 47mfd electrolytic is keeping the relay charged, change the 2n222a first and it cost only pennies.

 

[airplane1]

Thanks, I will check what he is dead keying into it and replace the 2n222a if I can find the thing. It was an am amp but when my friend got it they added a ssb switch. I dont know if it was done correct or not.

Thanks
AP

 

[TonyV225]

I remember one of my amps did that min was the damn keying transsistor

 

[Quiksilver]

Sometimes RF plays a part, as does jumper lengths. I had a similar problem with my T/S 500. A longer jumper solved the problem.
JMO

 

[airplane1]

Where is the keying transitor? is that what is a 2n222a?

thanks

 

[airplane1]

Ok, here is a little more info to help diagnose the problem. when it stays keyed it is not keyed totally, he can hear it receiveing but very faint till he quickly keys again and it unkeys and receive gets loud. It sounds like it is not unkeying all the way.

He is only feeding 4 watts in and getting about 150 or a little more out. I dont think he is over driving it, we tried different jumpers with no luck either.

once I find out the key transistor I will try replacing it.

 

[mackmobile43]

I remember one of my amps did that min was the damn keying transsistor

It may be some other numbers transistor but still functions the same and it's usually located near the input so-239 and the relay and it will have a diode across the legs of the transistor and possibly a 47pf electrolytic caps all tied to the relay.

It may be either the metal can style or black plastic.

 

[airplane1]

Thanks, great info and a pic makes it soooo much better.

 

[airplane1]

Well, put the new transister in and now it wont key at all. Anyone have a scematic for the fatboy 2 pill.

I want to trace everything and see id I can just set it back to am use only but dont know what parts were added to make it ssb compatable.

Here are some pics if it helps someone help me. the job these guys did is pretty bad. I dont even solder this bad and I am no tech.

I am trying to fix this for a friend who has very little money and needs help.

the shop who put the ssb switch in will not even try to help. they put it in and it has not been right ever since.

Thanks,
Airplane1

 

[High Voltage Mobile NJ]

it might be a relay to. i hope this helps.

 

[Dr_DX]

When he "unkeys" does the TX LED stay lit? If it doesn't, then what you have described sounds like a dirty contact on the relay when it is in the "open" position or RX position. Burnish the contacts and that should clear up.

 

[Dr_DX]

Looks like you need a diode across the relay coil too.