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Message |
    
Chris2crazzy
New member
Username: Chris2crazzy
Post Number: 1
Registered: 10-2014
| | Posted on Wednesday, October 01, 2014 - 12:01 pm: | 
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i was talking locally on 10 meters while my phantom 500 was on idle mode aka on stand by so i turned my power up on my cobra 200gtl to 20 watts swinging 60 watts all while the amplifier was not being used now the amplifier wont key up but all tubes light up fan runs......... please help |
Charliebrown
Intermediate Member
Username: Charliebrown
Post Number: 376
Registered: 10-2002
| | Posted on Wednesday, October 01, 2014 - 2:27 pm: |
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It is in either your key up circuit board or your key up tube. Not all amps have the same key up. If yours is a tube simple fix. If it is your solid state circuit board it could be as simple as a switching transistor. Now that is just a guess on my part. Other's will help you out with more answer's. This should give you something to go on. Remember not all amp's are high drive and yours could require less drive. |
Chris2crazzy
New member
Username: Chris2crazzy
Post Number: 2
Registered: 10-2014
| | Posted on Friday, October 03, 2014 - 1:53 pm: |
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thanks charlie for your reply........ all tubes test out great and i was told it could be my keying circuit capacitor which is only rated at 4 watts even if your not keying the phantom 500 up........ wish it was a keying tube lol.... but i was told the part could be a NEC 1957 its a driver final for a cobra 29 ltd but commonly used in older tube amps........here is another part i found out today it could be as well 2N2904 PNP Bipolar... now thats commonly used as a keying transistor........if anybody else can help please do im no tec but wanna get back to my hobby thanks guys and charlie 73erds |
Press_man
Advanced Member
Username: Press_man
Post Number: 803
Registered: 5-2008
| | Posted on Tuesday, October 07, 2014 - 5:55 pm: |
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Check/have someone check all the caps, given the age of a Phantom you may have one or more leaking or a diode or resistor bad from overdrive. If you're not well versed in tube equipment, keep your heart thumping by, Committing No Entry! If you ever take a hit from tube equipment, you will never forget, if you survive.
An old friend had a Phantom 500 that ran great with a 4 watt input carrier and 12 watt swing and he always ran the Phantom on low and with 85% modulation in, he sounded like he was an AM broadcast station. His antenna was in a 100 ft tall pine tree.
I know of a good tube type shop, PM me if interested.
BTW, welcome to the forum.
73 Pressman
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Charliebrown
Intermediate Member
Username: Charliebrown
Post Number: 379
Registered: 10-2002
| | Posted on Monday, October 13, 2014 - 11:47 am: |
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To make sure you do not get a shock take a high wattage light bulb to the tube or capacitor to ensure proper discharge. Make double sure the discharge is complete for your safety. There are some that will use a solid wire or screw driver to do this but that can lead to the damage of these product's for it can cause them to ground out. Some have been lucky and not have damage but it is best to do the slow discharge. Press man is right once you get a shock you will not forget it and when in doubt take it to a tech. |
