| Author |
Message |
    
Im4jc
Junior Member
Username: Im4jc
Post Number: 48
Registered: 11-2005
| | Posted on Sunday, January 15, 2006 - 12:30 pm: | 
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I went to a cb shop to have the Schottky NTE 583/2sc2999 receive mod done to my Grant LT. He said he could do it, but it's not recommended. He said he has taken more of these mods out than put them in. He said that they are very succeptible to overload due to close proximity high power. He said that if someone has fire in the wire and is talking close to you, that it CAN and WILL blow out the diodes. He scared me away from this mod.
So, my question is: Is this true? I know that many of you on this forum are running this mod, and would probably have mentioned it if it was true.
But remember, I am always in RF nightmare environments where people think it's cool to fire up their sweet sixteen 50 feet away from me to dominate a truck stop.
P.S. Although the Grant LT has excellent receive, it still isn't as good as the S9. It has a higher noise floor. Sure it can pick out distant stations as copyable, but it's a bit hashier than the S9. I guess I was just spoiled by the best receiver on the market. That's why I want to do the Schottky mod. |
Bruce
Senior Member
Username: Bruce
Post Number: 3409
Registered: 9-2003
| | Posted on Sunday, January 15, 2006 - 1:58 pm: |
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BUNK ......
I have that mod and it dosn't cause overload as for fire in the wire my ham antennas are less than 20 foot away and nothing has burned yet .... |
Yankee
Senior Member
Username: Yankee
Post Number: 1053
Registered: 7-2003
| | Posted on Sunday, January 15, 2006 - 5:32 pm: |
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DITTO on the bunk, I have the mods. in my Grant XL, I run it as a base radio and I live less than a quarter of a mile west of Interstate 35 as it runs north and south in Oklahoma and I've yet to have an overload problem. |
Patzerozero
Senior Member
Username: Patzerozero
Post Number: 2263
Registered: 7-2004
| | Posted on Sunday, January 15, 2006 - 5:34 pm: |
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boy, Im4jc, whenever I say the S9 has the BEST receiver on the market, the **** hits the fan-BIG TIME!!!
a sweet 16 at 50' away has the potential to take out ANY radio's receive, modded or not.
as for taking out more then he's put in-DOUBT IT!!!
go ahead & put yours in....mine has survived the long island expressway, & many-a-trip past 1 of the big boys 'round here. just gotta be quick with the ole RF gain  & stay away from the 5kw & bigger crowd! |
Im4jc
Member
Username: Im4jc
Post Number: 51
Registered: 11-2005
| | Posted on Sunday, January 15, 2006 - 5:36 pm: |
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Thx Bruce. Anyone else care to give their 2 cent's worth? The more the merrier  |
Therealporkchop
Advanced Member
Username: Therealporkchop
Post Number: 536
Registered: 11-2002
| | Posted on Sunday, January 15, 2006 - 6:27 pm: |
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I've been doing that mod to Pat's favorite radios for years now. Everybody's I've done it to, like it and not one complaint yet.
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Im4jc
Member
Username: Im4jc
Post Number: 52
Registered: 11-2005
| | Posted on Sunday, January 15, 2006 - 6:35 pm: |
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Arrrgh...When I replied to Bruce, his was the only reply, then all of the others showed up, lol. Thanks all! I will do the mod.
Incidentally, this same tech had a recently calibrated Bird with a "swing kit", and I later found out (from 2 other shops) it was reading 2 watts low. Not a big deal when reading PEP, but HUGE when setting the radio's DK for an amp.
I won't go to him again.
So, I'm finding that it is difficult to find a CB shop that stocks the NTE 583's and the 2sc2999. I'll be passing a CB Shop the day after tomorrow, and I hope they have them. If not, I don't know where to get them. |
Patzerozero
Senior Member
Username: Patzerozero
Post Number: 2265
Registered: 7-2004
| | Posted on Sunday, January 15, 2006 - 9:14 pm: |
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www.rfparts.com has the 2999's. i got the diodes elsewhere last time, rf may have 'em too |
Im4jc
Member
Username: Im4jc
Post Number: 56
Registered: 11-2005
| | Posted on Sunday, January 15, 2006 - 9:36 pm: |
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Thanks Pat.
Hmmm. They have a $25 minimum order. That's alot of 2999's for a truck driver to have on hand, lol. Maybe I'll just have my local tech order them with his next order if I can't find them on the road this week. |
Kid_vicious
Senior Member
Username: Kid_vicious
Post Number: 1032
Registered: 9-2004
| | Posted on Sunday, January 15, 2006 - 10:58 pm: |
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im4jc,
leave it to a truckstop tech. to take OUT one of the best mods there is for these radios!
he is feeding you a line of bull. as a matter of fact, i am willing to bet that he totally misunderstood you and was thinking about the receive boost for the 2950 that really will make your radio susceptible to blowing the frond end out.
i use the NTE equivilents and have had great results.
for the diodes use NTE583
for the transistor use NTE107
they are readily available these days through mail order houses.
THIS IS A GREAT MOD!!!
matt |
Bruce
Senior Member
Username: Bruce
Post Number: 3415
Registered: 9-2003
| | Posted on Sunday, January 15, 2006 - 11:40 pm: |
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Pat ....... you know who has a SMALL supply of diodes and transistors ...... for CLOSE FRIENDS ..... |
Im4jc
Member
Username: Im4jc
Post Number: 57
Registered: 11-2005
| | Posted on Monday, January 16, 2006 - 2:03 am: |
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Matt. Shweeet! Chalk another one up for the mod. I will definately be doing it as soon as I can find a tech while on the road who has the parts. I trust you guys WAY more than the truckstop hack shops. It's your passion, not just your job |
Yankee
Senior Member
Username: Yankee
Post Number: 1054
Registered: 7-2003
| | Posted on Monday, January 16, 2006 - 12:24 pm: |
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It's best to stay away from the truck stop radio shops, most times they are highly over priced for anything they do.
Best to locate a real radio shop, which are far and few between.
Not long ago last year, I was in a truck stop shop here in Oklahoma, and I couldn't believe the prices he was charging. He has a $50.00 minimum charge just to put a radio on the bench to check it out.
I know of only one honest real shop in the Oklahoma City area. |
Im4jc
Member
Username: Im4jc
Post Number: 58
Registered: 11-2005
| | Posted on Monday, January 16, 2006 - 1:53 pm: |
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Yeah, I have had MANY bad experiences with truckstop cb shops. There are a few good ones, but I can't name them here |
Patzerozero
Senior Member
Username: Patzerozero
Post Number: 2271
Registered: 7-2004
| | Posted on Monday, January 16, 2006 - 5:08 pm: |
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bruce- |
Hollowpoint445
Senior Member
Username: Hollowpoint445
Post Number: 1012
Registered: 6-2004
| | Posted on Monday, January 16, 2006 - 10:07 pm: |
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This is one reason why I've never done the 2SC2999 modification to any of my radios. The potential for increased gain has little appeal to me as I normally run the RF gain of my radios at less than maximum anyway. The lower noise figure is what does appeal to me, but I wonder what it would do to the AGC range of the receiver. Does it increase or decrease it? I'd assume that it would decrease the range because the part itself has higher gain. The AGC of the MB8719 dual conversion chassis is excellent, and is one of the qualities that makes it the best receiver ever designed into a CB. I would hate to lose that quality. |
Kid_vicious
Senior Member
Username: Kid_vicious
Post Number: 1037
Registered: 9-2004
| | Posted on Monday, January 16, 2006 - 11:13 pm: |
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hollowpoint, all i can say is, try it.
its only one transistor, and the chances of you blowing out your front end in the half hour you'll be testing it for are slight; if any.
if you dont like it, just put the old one back in.
i doubt you will. the 2SC2999 simply has a lower noise figure than the 2SC1674.
its just a better part. not necessarily higher gain.
matt |
Im4jc
Member
Username: Im4jc
Post Number: 61
Registered: 11-2005
| | Posted on Sunday, January 22, 2006 - 1:13 pm: |
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Well, I did it All I can say is...man, what a difference. It's still not up to par with my S9, but very close. Thanks to all for the info.
The tech that performed the mod said he only saw a 2dB gain after the mod, but I say "nay, nay". The real world results are much better.
Man, finding the NTE583's proved to be a nightmare, but I finally found them at a little electronic shop while on the road. I had to drop my trailer and bobtail into town. There was this little shop that had about everything NTE that you could imagine...and in stock to boot. I've never seen anything like it. Transistors, resistors, capacitors, diodes...all in the isles and ripe for the picking. It was pretty cool. |
Kid_vicious
Senior Member
Username: Kid_vicious
Post Number: 1077
Registered: 9-2004
| | Posted on Sunday, January 22, 2006 - 7:47 pm: |
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nice job!
what was the name of the store?
matt |
Im4jc
Member
Username: Im4jc
Post Number: 69
Registered: 11-2005
| | Posted on Monday, January 23, 2006 - 7:42 pm: |
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I just e-mailed it to you Matt |
Im4jc
Member
Username: Im4jc
Post Number: 70
Registered: 11-2005
| | Posted on Monday, January 23, 2006 - 7:45 pm: |
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I would really like to see an honest reply: "The lower noise figure is what does appeal to me, but I wonder what it would do to the AGC range of the receiver. Does it increase or decrease it?"
Any takers? |
Bruce
Senior Member
Username: Bruce
Post Number: 3452
Registered: 9-2003
| | Posted on Tuesday, January 24, 2006 - 6:49 am: |
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Ive done this mod in 3 radios a 2950, lincoln and a grantLT THEN used the LMR-1200 generator to see what it did the receiver was 6 DB BETTER and there was no increase in overload. |
Kid_vicious
Senior Member
Username: Kid_vicious
Post Number: 1110
Registered: 9-2004
| | Posted on Sunday, January 29, 2006 - 2:22 am: |
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i have been discussing the SK9975 diodes on another group, and after some checking; it seems that the SK9975 cross referrences to an NTE553. not 583.
can anyone verify that this is not a typo in the book?
i used the 583's. they work fine, but if 553 is the better part; i'll step up.
also, does anyone have a source for the actuall SK9975? (RCA part number)
i cant find any,
matt |
Inspector
Intermediate Member
Username: Inspector
Post Number: 159
Registered: 12-2001
| | Posted on Friday, March 03, 2006 - 5:12 am: |
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NTE538 are used and they cross-ref to 1N6263 Schottkey. And yes, replace your 2SC1674 with a 2SC2999...much better S:N |
Kid_vicious
Senior Member
Username: Kid_vicious
Post Number: 1251
Registered: 9-2004
| | Posted on Saturday, March 04, 2006 - 8:09 pm: |
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thats what ive found out too inspector; the 1n6263 is the real deal.
anyone know of a source for the 2SC2999 transistor?
matt |
Yankee
Senior Member
Username: Yankee
Post Number: 1089
Registered: 7-2003
| | Posted on Sunday, March 05, 2006 - 2:21 pm: |
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Matt, yes RF parts.
Carl CEF-357/CVC#9 |
Vanillagorilla
Intermediate Member
Username: Vanillagorilla
Post Number: 489
Registered: 4-2005
| | Posted on Sunday, March 05, 2006 - 3:02 pm: |
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Can I ask what exactly this mod involves? I feel pretty confident in doing it myself...IF I knew what TO DO!
Hank.....enlighten me?
CEF559
CVC#37 |
Patzerozero
Senior Member
Username: Patzerozero
Post Number: 2515
Registered: 7-2004
| | Posted on Sunday, March 05, 2006 - 4:27 pm: |
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you just unsolder the 3 legs of the 1674 at Q14 & replace it with a 2999(i got a bag of 'em...), THEN you take the 1674 & put it into Q19's spot, a 2sc945 that then finds its way in the trash bin .
if you look at the schematic for ANY CB, & follow from the antenna jack back to the 1st RF stage of the receiver, it USUALLY IS a 2sc1674, & can be replaced with a 2sc2999. HOWEVER, NOT ALL receivers respond as the receiver in the 8719 radios does. in some, the 2sc2999 just amplifies the noise to the point where if you listened long enough, you'd jump! |
Kid_vicious
Senior Member
Username: Kid_vicious
Post Number: 1261
Registered: 9-2004
| | Posted on Sunday, March 05, 2006 - 11:12 pm: |
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pat, have you ever tried using the 2SC2999 in the Q19 position too?
what happened?
matt |
Al_lafon
Intermediate Member
Username: Al_lafon
Post Number: 184
Registered: 3-2005
| | Posted on Monday, March 06, 2006 - 9:55 am: |
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Hello i had ordered some 2SC2999's and the outfit
sent me 2SC3402 inaplace of what i ordered. I have tryed them in two of my radios both had no ears after mod receive was very low. I see you need to retune the if coils just be fore and after this did not help so i am going to can this
part and get the 2SC2999. in retuning i just need a little bit of this right? |
Patzerozero
Senior Member
Username: Patzerozero
Post Number: 2525
Registered: 7-2004
| | Posted on Monday, March 06, 2006 - 10:43 am: |
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yes kid, NOISE!!! too much amplification of EVERYTHING! i guess the 2sc1674 is 'just right' for SSB rcv.
a couple possible problems, al, i've gotten 2999's that just showed NO DIFFERENCE as compared to the 1674 i pulled out. i've gotten some that have not neccessarily shown 6 db gain(based on what should be a 1 S-unit gain in signal, without test equipt), but have at least shown a noticeable improvement of readability-on known signals, & using a detuned, low powered walkie talkie left keyed up out in the yard that showed LOW SIGNAL on rcv with either dummy load or secondary antenna attatched.
are you positive you installed the transistor facing the right way? the radio WILL receive, extremely poorly, with the transistor in backwards.
as for retuning, i explained above how i do it. if i see ANY noticeable increase, i just leave it alone. if i feel i should touch the coils, nudge L4 & L6 just a hair in each direction for loudest signal/highest meter reading, then lightly touch L5 to see if any further improvement.
lastly, i've used a known, working 2999 that showed little if any increase in a particular radio that already had exceptional receive qualities. |
Kid_vicious
Senior Member
Username: Kid_vicious
Post Number: 1266
Registered: 9-2004
| | Posted on Monday, March 06, 2006 - 9:45 pm: |
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thanks for the clarification pat.
seeing as the NTE107 has slightly lower gain than the 2sc2999, do you think this might be a suitable replacement?
both 2sc2999 and 2sc1674 cross referrence to an NTE107.
al, they messed up your order. that transistor you got has built in resistors for some purpose; im guessing its not the right one.
i cross referrenced it on NTE's site, and it should have come back as NTE107, but it came back as NTE2355.
they either accidentally or purposefully gave you the wrong part.
matt |
Gumpit
New member
Username: Gumpit
Post Number: 7
Registered: 11-2005
| | Posted on Tuesday, March 07, 2006 - 6:23 pm: |
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If you look at the datasheet for the 2sc2999 there are 3 different ones.With 3 different gain. You want the one with the "e" not the "d" there is one more that falls in the middle.But "e" has the highest gain. |
Kid_vicious
Senior Member
Username: Kid_vicious
Post Number: 1274
Registered: 9-2004
| | Posted on Tuesday, March 07, 2006 - 10:54 pm: |
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interesting randy, can you give me the site where you found this?
matt |
Hollowpoint445
Senior Member
Username: Hollowpoint445
Post Number: 1128
Registered: 6-2004
| | Posted on Wednesday, March 08, 2006 - 9:50 pm: |
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Randy - I don't see any difference listed on the data sheet for Power Gain or Noise Figure, just a different set of numbers for DC Current Gain. Is that what you're referencing? |
Dondg
New member
Username: Dondg
Post Number: 3
Registered: 1-2006
| | Posted on Saturday, March 11, 2006 - 11:48 am: |
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how can i do this mod to the galaxy dx 2527
for better receive is there a site for this mod
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Patzerozero
Senior Member
Username: Patzerozero
Post Number: 2546
Registered: 7-2004
| | Posted on Saturday, March 11, 2006 - 2:59 pm: |
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you can find this transistor in ANY radio if you have the schematic. find the 'antenna jack' on the schematic & follow it to the 1st rf amp stage. the way 90% of the radios today have their schematic drawn, the XMIT section of the schematic is to the 'lower right side'. the antenna jack is to the 'lower left side', & the 1st rcv rf amp stage is 'above the antenna jack at the top of the page', or '2nd line down'. that is not merely coincidence, but just how close in design most CB's & exports are today.
anyway, in the case of your 2527, the part should be labeled as either Q or TR 17. HOWEVER, depending on the preceding & after circuitry, it is possible that the 2sc2999 swap will only make more of a mess by amplifying NOISE as well as signal. 8719 chassis are famous for being able to use this mod exceptionally well. other types of radios do not have such satisfactory results. only way to know is to try it. be very careful with the soldering iron & you can swap the 2sc1674 back in if the noise is unbearable. |
Gumpit
New member
Username: Gumpit
Post Number: 8
Registered: 11-2005
| | Posted on Sunday, March 12, 2006 - 9:46 pm: |
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If you do a google search on "2sc2999 datasheet" you will see the 3 different values for the dc gain.I have no idea what this means but the ones I Got from fox international "E" seem to work better than the ones I got in auction #9106226389 "D". But if you want to try them anyway.The person I got them from in the auction said he has more.The 1n6263 work great.Personally I wouldn't use an NTE # I have had nothing but problems with NTE parts...I just did this mod and timed it. 16 minutes once the iron was hot.And I am not a tech.But I can solder enough to have built the_mod several times.I think this is an easy enough mod for anyone who can solder and use desoldering braid ;) |
Yankee
Senior Member
Username: Yankee
Post Number: 1099
Registered: 7-2003
| | Posted on Monday, March 13, 2006 - 12:48 pm: |
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After doing the two transistor swap on my Grant XL, I have noticed much quieter receive and some what of a gain increase. so I for one can say that these two mods do work, on the radios the likes of the Grants and Cobra 148 GTL, 2000 GTL.
Carl CEF-357/CVC-9 |
Allan
Member
Username: Allan
Post Number: 85
Registered: 2-2006
| | Posted on Monday, April 24, 2006 - 9:25 pm: |
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Pat sez...3 legs of the 1674 at Q14 & replace it with a 2999, THEN you take the 1674 & put it into Q19's spot, a 2sc945 that then finds its way in the trash bin....
Pat.... Finally getting around to doin' this mod on the 95(Trashy), but you were the only one in the archives to mention taking the 2sc1674 and moving it to 2sc945s spot. Can't remember where for sure, but I ran across the duties of these two transistors, and the 2sc1674 is a RF amp oscillator, and the 2sc945 is used for low speed switching in the 95(Trashy). Zer a difference?.. Will the round one fit the square hole on this rig, or omit it on this go-round??? Oh, no mention on changing the diodes (D1, D2, D30, & D31 on mine) in the NB circuit to hush it summore. I used the 1n5711 schottky... |
Patzerozero
Senior Member
Username: Patzerozero
Post Number: 2775
Registered: 7-2004
| | Posted on Friday, April 28, 2006 - 4:03 pm: |
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the 2sc945 is in the SSB detector circuit. i guess the swap just helps 'find' the 'weak' SSB signal that is not a steady carrier as it would be on AM. off the top of my head, i think the schottky swap on the 8719 is 1,2,21,22, but, anyway....ALL the 8719 mods seem to improve the radio OR at least not cause any detrimental effects. some radios respond differently then others, which may just be a case of general condition/state of tune or align. |
Allan
Member
Username: Allan
Post Number: 88
Registered: 2-2006
| | Posted on Friday, April 28, 2006 - 9:22 pm: |
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Roger that... Hey, the 5-6 bucks I spent on the parts and 20 minutes install was worth the effort. It is better on the receive, just not what the extremists claim. I'll give it a week or so, and touch up the L-8 coil to skim off any annoying hash, so long as it doesn't knock my ears back too far. Thanks, 00 for the reply.....Enjoy your weekend.................. |
Wildrat
Advanced Member
Username: Wildrat
Post Number: 862
Registered: 12-2003
| | Posted on Sunday, April 30, 2006 - 8:18 pm: |
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Can the old SS gold face 3900 have it's receive modded? |
Allan
Intermediate Member
Username: Allan
Post Number: 103
Registered: 2-2006
| | Posted on Sunday, April 30, 2006 - 9:11 pm: |
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It's a (RCI) Ranger. Don't see why not. |
Kid_vicious
Senior Member
Username: Kid_vicious
Post Number: 1497
Registered: 9-2004
| | Posted on Sunday, April 30, 2006 - 10:18 pm: |
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yes!
not sure of the part numbers, but i know pat is!
if he doesnt see this, try PMing him.
matt |
Patzerozero
Senior Member
Username: Patzerozero
Post Number: 2797
Registered: 7-2004
| | Posted on Sunday, April 30, 2006 - 10:27 pm: |
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the superstar 3900 uses the old ept3600XXX galaxy board. probably labeled 'TR' instead of 'Q', its transistor is #17. try it. some just increase noise, some work as intended. |
Bruce
Senior Member
Username: Bruce
Post Number: 3784
Registered: 9-2003
| | Posted on Sunday, April 30, 2006 - 11:28 pm: |
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check the receiver rf stage if it is a 2sc1674 YES it can..... |
Patzerozero
Senior Member
Username: Patzerozero
Post Number: 2804
Registered: 7-2004
| | Posted on Monday, May 01, 2006 - 4:03 pm: |
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in some radios with the early galaxy board(pluto, super, II, texas star radios, & some superstar) swapping in the 2999 makes the noise as well as the signal LOUDER. just have to try it. |
Allan
Intermediate Member
Username: Allan
Post Number: 107
Registered: 2-2006
| | Posted on Monday, May 01, 2006 - 8:59 pm: |
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Bruce. You mentioned a LMR-1200 generator used on 3 separate model applications in this thread. (about half way up) Said the receiver was 6 DB BETTER and there was no increase in overload. What's a LMR-1200 generator? Did a search, but gave up after 20 something pages (ugh) of partly matched words. Can you enlighten us, radio god? |
Bruce
Senior Member
Username: Bruce
Post Number: 3790
Registered: 9-2003
| | Posted on Tuesday, May 02, 2006 - 7:08 pm: |
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We have 2 of them at the shop very old pushing 20 years but very nice ..... |
Bruce
Senior Member
Username: Bruce
Post Number: 3790
Registered: 9-2003
| | Posted on Tuesday, May 02, 2006 - 7:06 pm: |
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OOPS IFR-1200s
 |
Mrbigshot
Member
Username: Mrbigshot
Post Number: 68
Registered: 2-2005
| | Posted on Sunday, June 25, 2006 - 2:28 am: |
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sorry for digging up an old topic but could someone please tell me the location of the ECG583 diodes should go in a uniden grant xl. d-numers would be helpfull, also where do i install the 2sc2999? i know what im replacing but i am hoping there is a number so i can find it much faster.
thank you |
Kid_vicious
Senior Member
Username: Kid_vicious
Post Number: 1841
Registered: 9-2004
| | Posted on Sunday, June 25, 2006 - 10:48 pm: |
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replace TR14 with 2SC2999 (3/4 way to the back of the radio closer to the left side of the PC board)
remove TR19 and put the transistor you just removed from TR14's spot in TR19's holes. (TR19 is just to the right of TR14 by a few inches)
replace diodes D1,D2,D21,D22 with NTE 583's.
retune receiver portion of radio.
matt |
Mrbigshot
Member
Username: Mrbigshot
Post Number: 69
Registered: 2-2005
| | Posted on Monday, June 26, 2006 - 12:27 am: |
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i dug around and found the locations, i will post them here in case anyone else is wondering
for the receiver, replace TR14 with a 2sc2999 or NTE 107.
replace TR19 with the old TR14. (2sc1674)
replace D1, D2, D21, D22 with NTE583 diodes. |
Dirtyharry
New member
Username: Dirtyharry
Post Number: 1
Registered: 1-2007
| | Posted on Sunday, January 21, 2007 - 3:40 pm: |
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HI FOLKS, I DID THE MOD WITH THE 2SC2999 TO MY CHIPSWITCHED PRESIDENT LINCOLN, IT PULLS IN SIGNALS NOW LIKE A SUPER CHARGED MAGNET, & WITH THE SAME NOISE TO SIGNAL RATIO.HIGHLY RECCOMMENDED IN MY OPINION!! |
Patzerozero
Senior Member
Username: Patzerozero
Post Number: 3460
Registered: 7-2004
| | Posted on Sunday, January 21, 2007 - 9:43 pm: |
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Q101, a 2sc1674, maybe 1-2" from the mrf477 final transistor, between ft101 filter & L101 tuning coil. |
