| Author |
Message |
    
Jake
Junior Member
Username: Jake
Post Number: 47
Registered: 2-2002
| | Posted on Thursday, May 27, 2004 - 8:26 am: | 
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Is their a diod replacement or upgrade for my RCI2980 that will improve the receive to noise ratio like I've seen posted for the 2950,I think it's something like an in60p and to replace it with a nte583 scotkey(or something like that) D1,D2 ro D34,D35 anyway for my Rci2980 I hope this makes sense |
Highlander
Advanced Member
Username: Highlander
Post Number: 514
Registered: 12-2001
| | Posted on Thursday, May 27, 2004 - 2:18 pm: |
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Is it a 2980 or 2980WX?
The diode locations are different for each radio, they use different Main Boards-the 2980 uses the older EPT3600 board, the 2980WX uses newer EPT6900 board.
You replace the AM detection diodes with the shottky barrier diodes you mentioned, you can also do the Noise Blanker ones the same way to improve the NB circuit. You can also replace the RF amp transistor with a higher gain, lower noise replacement, I forget the number.
Copper Tech8541 did these mods to my Galaxy 2517 and I am very pleased with the results. |
Jake
Junior Member
Username: Jake
Post Number: 48
Registered: 2-2002
| | Posted on Friday, May 28, 2004 - 9:05 am: |
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highlander it's a RCI2980. and are the diodes that I mentioned the correct ones? Do both the 2950 and the 2980 use the same ones or have the same board?. |
Tech8541
Moderator
Username: Tech8541
Post Number: 205
Registered: 12-2003
| | Posted on Friday, May 28, 2004 - 10:37 am: |
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the diodes to replace are d1, d2, d24, and d23. replace tr17 with a 2sc2999. |
Highlander
Advanced Member
Username: Highlander
Post Number: 517
Registered: 12-2001
| | Posted on Friday, May 28, 2004 - 4:36 pm: |
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Jake, yes, that sounds like the right part number. I recommend the transistor swap, too. It really makes a difference. I no longer use squelch at all on AM, I just turn the RF gain to where the noise floor is just audible. When a real signal comes along, it comes through clear as a bell. |
Cm3885
Advanced Member
Username: Cm3885
Post Number: 514
Registered: 12-2003
| | Posted on Thursday, July 15, 2004 - 11:21 pm: |
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So id use NTE 583 shottkey diodes in place (D1 D2 D23 and D 24) of the stock diodes in my RCI 2980 Right?
If thats the case i cant find them anywere around here. Nobody has them in stock they are all out of stock on them and no one has an idea when they will get them... ARGH! |
Tech548
Moderator
Username: Tech548
Post Number: 133
Registered: 5-2004
| | Posted on Friday, July 16, 2004 - 4:45 pm: |
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Jake
To improve AM detection, change D-34 and D-35 from 1N60's to ECG583's. And by replacing D-1 and D-2 with ECG583's, this will give you a more effective noise blanker.
Tech8541 suggested changing TR-17 with a 2SC2999 to increase the receive gain. I don't have a reference in front of me but if memory serves me correctly, I believe the correct TR-number is TR-18, not TR-17. I hope someone can set me straight on this.
Anyways, the 2SC2999 transistor Tech8541 suggested is indeed a good one because of its higher gain and lower noise characteristics, "but" you will also have to re-adjust L-8 and L-9. The end results will give you a gain improvement of around 3 to 6 db with the same signal to noise ratio.
Jeff
Tech548 |
Cm3885
Advanced Member
Username: Cm3885
Post Number: 516
Registered: 12-2003
| | Posted on Saturday, July 17, 2004 - 10:43 pm: |
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Jeff RU talking about the 2990 NB anl receiver mod here?
D 34 and D 35 and D1 and D2 are in the 2990 aka RCI 2950 chassis old style board..
SS8541 mentioned the mods for the 2980 i think were you replace D 1 and D2 and D 23 and D 24..
Please clairify because im kinda confused..
CM 3885 |
Tech548
Moderator
Username: Tech548
Post Number: 154
Registered: 5-2004
| | Posted on Tuesday, July 20, 2004 - 12:46 pm: |
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Cm3885
I was refering to the original RCI (Non DX) board. Replacing D-1 and D-2 with ECG583's will give you a more effective noise blanker.
I am not familiar with any modification that calls for the removal of D-23 and D-24. Or am I missing something here. If you are refering to the DX Models, then I'm way off base and my previous post should be ignored.
I apologize for any confusion that I may have caused.
Jeff. |
Cm3885
Advanced Member
Username: Cm3885
Post Number: 535
Registered: 12-2003
| | Posted on Monday, August 02, 2004 - 2:30 pm: |
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Ok ive got the info for my 2990 older non DX verison. Now what i need are the parts that need replaced in my RCI 2980 older style. I think SS8541 said D1, D2, and D23 and D24 need replaced with ECG583s... I hope this info is correct.. Bad thing is, i cannot find ANY ECG583s or even substitutions ANYWERE here were I live.. No one has them.. |
Tech808
Moderator
Username: Tech808
Post Number: 3170
Registered: 8-2002
| | Posted on Monday, August 02, 2004 - 4:29 pm: |
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Cm3885,
Well you are in LUCK as SS8541 is Tech8541.
So Chances are he will see your post and be able to help or you can send him a note at:
Tech8541@copperelectronics.com
Hope this helps.
Lon
Tech808 |
Bruce
Senior Member
Username: Bruce
Post Number: 1419
Registered: 9-2003
| | Posted on Tuesday, August 03, 2004 - 7:10 am: |
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3885 I have some if you need them ( free ) |
Cm3885
Advanced Member
Username: Cm3885
Post Number: 552
Registered: 12-2003
| | Posted on Saturday, August 14, 2004 - 3:06 pm: |
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TY Bruce!!!!!!!!!! |
