| Author |
Message |
    
Flash463
| | Posted on Wednesday, November 27, 2002 - 4:02 am: | 
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galaxy 88 weak rx but strong signals come through, rf gain does not make any difference, all the way up or all the way down. any ideals? |
307
| | Posted on Wednesday, November 27, 2002 - 12:39 pm: |
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Yep..Common problem..Replace D-10 and D-11 (Germanium Diodes). There are a few current limit defects in Galaxy Radio AGC Circuits that sometimes "pop" one of these diodes. It will cause the "S" meter to stop working as well as distort RX...
307 |
2600
| | Posted on Thursday, November 28, 2002 - 2:04 am: |
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Uhh, sounds more to me like a front end problem in the receiver than one in the "back end", like D10/D11. The RF gain should still turn the already-weak receiver down if the AGC diodes are bad. He says turning it has no effect. If TR17 checks bad, D15 and D16 should get checked, too. They look (and check) like generic glass diodes, but these two are different. Don't know the ECG for them.
Sounds like one that pulled up too close to a BIG radio, like maybe parked at a truck stop, or stopped in traffic with your antenna two feet from Mr. KW when he keyed up. If the radio was turned off when it happened, or you were out of the truck, you'd never see the asassin. If runaway AGC is killing the receiver sensitivity, desoldering and pulling up ONE end (only) of R257 (2.2k) will bring back your noise level and channel chatter. Strong signals will now overload and distort if you leave R257 loose. If you see this, it won't fix the problem but would narrow it down.
73 |
307
| | Posted on Thursday, November 28, 2002 - 3:43 pm: |
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True..TR17 would be the next candidate. D10 and D11 seemed to be my guess , but it was my mistake to not ask if the "S" meter worked. I get about 4 in 10 with RX problems to be D10 and D11. I must be getting to old for this...
306.25 |
Flash463
| | Posted on Friday, November 29, 2002 - 3:00 am: |
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Pulled up one leg of r257 no difference. Could it be the switch on the rf gain. Have any ideals 2600? |
307
| | Posted on Friday, November 29, 2002 - 9:11 pm: |
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Flash , did you replace TR-17 yet just to see if the RX comes back to life before we go on...?
307 |
Flash463
| | Posted on Friday, November 29, 2002 - 11:11 pm: |
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Yes I did and d15 d16. |
Flash463
| | Posted on Saturday, November 30, 2002 - 2:37 am: |
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Ss8541 i did what you said and the rx did not come up. oh well |
307
| | Posted on Saturday, November 30, 2002 - 7:59 am: |
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Fash463 , email me direct , I will get you to send it down , I will fix it for you , "on me" to help you out..
tech307@copperelectronics.com |
2600
| | Posted on Sunday, December 01, 2002 - 2:55 am: |
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Time for an expert, sure enough. I predict that two or more parts will prove bad. If it's just one failure, the 'DIY' method will sometimes work. This is a job for someone who can pull all the usual suspects and catch all of them. If 3 things are bad, changing one at a time never gets you very far. If the problem is what the engineer types call a "single-point-failure", the "forum post" method can work. If it's caused by three different parts, the "hands-on" approach is a lot better.
73 |
307
| | Posted on Sunday, December 01, 2002 - 3:06 pm: |
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Flash463? , Are we on?
307 |
Flash463
| | Posted on Sunday, December 01, 2002 - 7:20 pm: |
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Sure, you the MAN. Whatever you think. Let me know. |
307
| | Posted on Monday, December 02, 2002 - 6:37 pm: |
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Email me direct and I will give it a shot...I like helping out when I can...
tech307@copperelectronics.com
307 |
Flash463
| | Posted on Tuesday, December 03, 2002 - 6:27 am: |
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Thanks 307. I'll try to send it soon. |
307
| | Posted on Thursday, December 05, 2002 - 10:25 pm: |
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Update!!! Radio is fixed , Yes it took me 1/2 hour but what can I say...The problem???
L-31 for starters was not soldered in.With a scope on the Antenna jack and +30dB Input , nothing out of L-31 , Simple fix and I might add "Common"
L-6 was open on the input side to TR-17. L-6 supplies the voltage to TR-17 so if it is not there it is like the RF gain turned all the way up.(turning TR-17 to minimum gain) Replaced L-6 and then found out every screw was turned (about 20 dB low in RX) Did a full alignment...she smokes now...
307 |
Flash463
| | Posted on Friday, December 06, 2002 - 6:05 am: |
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WOW, I knew you could do.Must I say you are the man. The boy that brought it over here said he had been messing around with it. Thats why he brought it over for me to use for parts, But when I looked at it I thought the radio looks to good to just tear apart. But I knew the MAN 307 could fix it. thanks a million. Paul |
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