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Salty_bones
Junior Member
Username: Salty_bones
Post Number: 19
Registered: 5-2005
| | Posted on Sunday, February 26, 2006 - 7:48 pm: | 
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This linear did work good but now as soon as the linear is turned on it automatic keys down and will not unkey untill you turn the power switch off. Also you can talk when this is happens and its putting out power too. I would like to fix this myself and I don't think there is alot wrong with it. Also the 30amp or 35amp power supply is not working right, its really weak. I am not sure of that amps on the linear can't really remember but its one of those. Also this is a base linear. If anyone can help me that would be great.
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Hotwire
Advanced Member
Username: Hotwire
Post Number: 977
Registered: 1-2005
| | Posted on Monday, February 27, 2006 - 1:18 pm: |
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Heard of this before. Simple problem it could be RF getting into the amp, try a longer jumper maybe, but you say it happens as soon as you turn it on. I would bet its a bad keying transistor. I believe there is 2 of them I think. Little black transistors. A cheap fix and probably wise to replace both. 30 or 35 amp power supply is to small for a 500 watt amp if thats what you have. You need twice that to get even close to enough amps. Hope I could help. |
Salty_bones
Junior Member
Username: Salty_bones
Post Number: 20
Registered: 5-2005
| | Posted on Monday, February 27, 2006 - 3:27 pm: |
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I know its not the jumper it could be the keying transistor but I really don't have a clue. Do you know where they are and the numbers on them so I could find them? Would they be next to the relay? I was just talking on it one night and I heard the relay kick off but the fan and eveything was still on. I turned the amp off and then back on and it would just automaticly key down and wouldn't unkey untill I turned the power off. The linear is a Palomar delux 500 base linear and has a power supply to run other stuff with and its either 30amp or 35amp it says on it but I don't have it here at the house. Thanks for the reply. If you know what the transistors is that I need and where they are on the linear that would be great. I also already have it apart. Thanks guys. |
Hotwire
Advanced Member
Username: Hotwire
Post Number: 981
Registered: 1-2005
| | Posted on Tuesday, February 28, 2006 - 9:37 am: |
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Well Bones I know now that the power supply is built in so you should be ok. I never have owned any Palomar.
About the keying transistors. They are the only 2 transistors in the amp besides the 4 mrf455 pills. The transistor number for both is 2N2907A. I have no idea where they would be on the board but they should be black and sqaure with that number on them. They should look just like a radio final. Just a note Bones, I'm not a tech but I have learned a lot from some very knowledgeable and upstanding people outside and here in the forum. If anyone else has an idea what could be the problem with Bones's amp or you might think my info is not accurate please chime in. GOOD LUCK!! 73 |
Salty_bones
Junior Member
Username: Salty_bones
Post Number: 22
Registered: 5-2005
| | Posted on Tuesday, February 28, 2006 - 6:19 pm: |
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The 2N2907A TRANSISTOR are round and are a silver cap type. You think this is the problem? |
Bruce
Senior Member
Username: Bruce
Post Number: 3598
Registered: 9-2003
| | Posted on Tuesday, February 28, 2006 - 7:46 pm: |
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2907 is a pnp |
Hotwire
Advanced Member
Username: Hotwire
Post Number: 985
Registered: 1-2005
| | Posted on Wednesday, March 01, 2006 - 9:34 am: |
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WELL Salty Bones if you are confident then try to replace them with a new set and see what happens.
Bruce is telling us that it is a plug and play type transistor so you should be able to pop 'em in and go.
I have heard of this problem and fix before but again I am no tech. Being that they are the only other 2 transistors in the amp makes me believe they are they correct ones. Your wanting to save money by repairing the amp yourself and amp won't work now so what do you have to lose? Replacing the 2 is what I would do. Hope it does the trick. good luck and let me know what you get. |
Salty_bones
Junior Member
Username: Salty_bones
Post Number: 23
Registered: 5-2005
| | Posted on Thursday, March 02, 2006 - 4:21 pm: |
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So I need to replace the 2907? This is a Palomar Delux 35A linear and not an elite. It has 4 pills in it. Would that make any difference? Also I remember with this happen I was talking on it and the two fuses blew inside the linear and I replaced them with the same ones and this is when it started doing this. Thanks for the help on this I would like to get this thing working again. If you still think thats whats wrong let me know and I will see if I can find any 2907 pnp or is it the 2N2907A that I need? Do you think radio shack has this or do I need to order off of the net....Thanks again. |
Salty_bones
Junior Member
Username: Salty_bones
Post Number: 24
Registered: 5-2005
| | Posted on Saturday, March 04, 2006 - 5:11 pm: |
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I was looking at the linear today and it says Power Delux 35A on it and not Palomar. It might still be a palomar but not sure. Anyone knows if the above will fix this linear. Thanks for your time. |
Hotwire
Senior Member
Username: Hotwire
Post Number: 1011
Registered: 1-2005
| | Posted on Sunday, March 05, 2006 - 10:09 am: |
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I was hoping some other members would chime in but when it comes to amps you just do not know for sure unless you have it examined by a worthy tech. So it is a roll of the dice Bones. I have heard of the problem before and that was the fix. I got in here because nobody else did besides Bruce. Bruce is very knowledgeable in repair and if I was steering you wrong he would have schooled me I'm sure. The amp is non useable now so cross your fingers and give it a shot. A cheap fix. If that does not work ,well then you just have 2 new transistors in the amp is all. YOU CAN DO IT! And if thats not the fix I'm the one with egg on my face and Pat , Gorilla , Bruce ,and all the others will poke fun and send those little avatars laughing at me! 73 |
Salty_bones
Junior Member
Username: Salty_bones
Post Number: 25
Registered: 5-2005
| | Posted on Sunday, March 05, 2006 - 2:45 pm: |
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Ok...Thanks Hotwire. I will order the 2 2N2907A that I need and see what that does.
Also another question about this liner is the 35A power supply that it has. Its not putting out enough power. Do you know what could be causing this. It has done it since I got it even when the linear part worked. |
Hotwire
Senior Member
Username: Hotwire
Post Number: 1024
Registered: 1-2005
| | Posted on Monday, March 06, 2006 - 5:41 pm: |
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Correct me if I am wrong. The amp has four 1446 transistors. 5 watts in 1 pill you get 90 watts. Two watt dead key 20 watts swing from the radio should get 360 watts total from the amp. Anymore input than that will produce poor performance and most likely over work the power supply. Dual final radio is not a good match for some amps that only need low drive, some may disagree but I learned by expierience.Even the big 2879 amps {exception customs} really do not have to have big drive to work clean. Now if you know better and have not been overdriving the amp then maybe the power supply is damaged. Try the power supply section of Ask the Tech. 73 |
Salty_bones
Junior Member
Username: Salty_bones
Post Number: 26
Registered: 5-2005
| | Posted on Tuesday, March 07, 2006 - 6:53 pm: |
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Yes thats the pills thats in the amp but the power supply runs other radios amps ect. and does not run the linear itself. When I first got the linear it was putting out like 20 volts but didn't know at the time and blew up a radio that I hooked it up to. I told the person that I bought it from what happen and they told me to ship it back to them and they would repair the radio and fix the 35A power supply. So when I got it back the radio worked fine but now the supply will not even hardly power a CB radio. I didn't want to ship it back because of the high shipping cost so they must be something in the linear that you can change to let it put out higher volts amps ect. BTW....I order them parts so I will know soon if thats what the problem was with the auto key down. Thanks |
Salty_bones
Junior Member
Username: Salty_bones
Post Number: 27
Registered: 5-2005
| | Posted on Sunday, March 19, 2006 - 1:17 am: |
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I got the parts in for the amp and will let you know soon if it worked or not. I would really like to have some help on the power supply on this linear. It has the 35amp power supply and I would like to run my mobile linears on it. I checked it earlyer and its putting out 22.6 volts. I need to know what is making it do this. Any help or ideas would be great.
Thanks again hotwire for all your help and I will let you know soon. |
Salty_bones
Junior Member
Username: Salty_bones
Post Number: 29
Registered: 5-2005
| | Posted on Sunday, March 19, 2006 - 6:18 pm: |
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Ok I got the linear to work so the 2 2N2907A worked for the linear auto keying on me. I now have another problem. On the low hi med switch I think something might have come off on it because I only have one power out put and they are a resistor right below the switch on the board that is not connected, its only connected to the board. I also think this is a Boomer 500 linear after doing some reading. Anyone know what causing this? Anyone have a pic of inside one of these amps? Thanks for any help. |
Hotwire
Senior Member
Username: Hotwire
Post Number: 1081
Registered: 1-2005
| | Posted on Tuesday, March 21, 2006 - 10:47 am: |
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Good Job Salty bomes! I'm glad to be able to help! I would have to look at the switch myself to try and diagnos it! Good luck 73 |
Salty_bones
Junior Member
Username: Salty_bones
Post Number: 31
Registered: 5-2005
| | Posted on Tuesday, March 21, 2006 - 4:14 pm: |
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The switch only has one resistor connected to it on the top post thats going into the board and the other two witch is Hi , Med has nothing connected to the post and its only working on one power setting. A picture of inside of one of these would be really great and I am sure it would not be hard to fix if I just knew where to hook the switch to the board.
Also when I use a volt meter to check the 35 amp power supply its putting out 22.6 volts . Man this thing is a pain. |
