The Defpom Forum, for RadioMods, S&M Software and Music by The Defpom

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Hey smokin....sorry if i misled you on my point(s), or maybe you just misunderstood the thrust of my post (prolly comb. of both..), but i wasnt questioning or even commenting on...your abilities, expertise level, how you went about anything, intentions, or any of the other points about the radio, et...

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Thanx for the reply smokinone. I can understand how locating & removing the source of the problem was a positive, restoring good sound. But i am curious as to how u concluded that the boards connections were not the source of the intermittent sound, esp since u said someth to the effect of movin...

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Hmmmm. Seems odd. I have always loved the 959 since its inception. I never noticed any issue such as this (at least not that i remember) & i have dealt w/many of them. (not disputing, just havent run into it). I'm sure i have checked the functionality & effectiveness of the anl/nb (cant reme...

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What is the "NF board referred to in this thread? Is it the "ANF/GNF" pcb? If so, is that a noise filter board, i.e., "automatic noise limiter/noise blanker/galaxy noise filter"?

Thx

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hey now, good find! seems we both had lots to say about the mode switch, early on, but who would think... ...it was replc'd & installed wrong?, AND (apparently...) ...you initially had no working spkr. with which to hear telltale squawking (lesson there..?) haha.. i'll bet you're spending extra ...

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sounds like it could be a clarif. mod, but you'd know better as i'm not looking at schem. if it's not a poor connect somewhere, then from what you've said so far, my guess is to look at coupling caps in final section. i mean, if i'm not mistaken, the radio does indeed switch into & does tx, and ...

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hmmm...well out of curiosity...it sounds like your speaking about the "component side" of the board, and saying the "gap" was too far, and you don't know how this happened....so i'm wondering...were they both "cut"....as in a hatchet job (mod) of some sort, or if not, a...

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hold the phone. i'd like to ask you something at this point. have you done anything to change the state of what you found? if not, i would ask you whether or not the broken connections are close enough the board to "make/break" connection with a flexing of the board? and if you have alread...

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hey challenger...i appreciate that alot! really. when i am doing all that longwinded "covering of the bases", so to speak, i'm not only doing it for my own benefit, but esp. in a case like this 148 problems thread, and with all the posts, i'm realizing at the same time, that others "s...

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yeah..chassis looks pretty familiar..i think i might have 1 or 2 of them kickin around. how you fixed for parts? and why bothering with...learning project or sentimental or collectors items? just curious. that schem. jpg. is useless in that format, to view, but maybe renders up in a better pic progr...

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ok..i guess i got confused a bit there...maybe cuz i saw the A (aussie?)and the B (on the end) and must've misread that page from that aussie site info you have...mkham or whatever that was...thinking i had seen the model you noted, as being 1 of that same bunch of chassis'. i remember when i 1st sa...

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ok cool...and do i underst correctly that the g.e. radio is approx same chassis?

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john..i'm pretty sure you do, but i want to make sure..you have what's avail. on this from vkham.com?

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john..i understand the 18 ch aussie radio deal, as i got myself up to speed on that aspect. so i assume radio is '77-'80 model. i'll tell ya..i've got alot of files & books, but could find no reference at all to any "phantom communicator". nor could i find any reference on cbtricks, no...

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i was about to suggest you checking out the mode switch, when i see you mention in your last sentence. i would clean mode switch, then "play with" switch to see if you can get any am rx or ssb tx action at all, if you haven't already tried that. and again, please flex pcb to see if you get...

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yes...but what's important to note is that the "issue" with the joint, is not necessarily the classic "cold solder joint"...there are numerous causes & resulting "bad joints"....in fact, ironically, i just walked in a couple of minutes ago from figuring out about 6 ...

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yes they did, thankyou. i posted my input.

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not familiar w/this radio...sounds like a euro model...probably has an american version...but i can tell from these 02a pll's you mention that these are very old radios, i think. do you have am tx? do you have ssb rx? sounds like more than 1 issue here. also, when you say no rx, do you mean no sound...

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johnno...you've been given alot of good advice here. only thing i would add at the moment is 2 things: 1, look at your schematics for "source voltages" listed in the tx sections. great, easy method of tracking a problem. if your schematics don't provide much of that, then i recommend "...

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johnno, i'd be more than happy to at least try to help, but you'll need to direct me to the 2 posts you refer to? this thread is 2 pages & i don't see your posts here. i'm not good at all on using the forum, so maybe you could post a link to, or repost a copy of...well wait..that method might no...

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thanks johnno. appreciate that. been a few months, so was surprised. and to be honest, i come back & reread my posts & see i'm way too longwinded with them. i keep trying to work on that. i think i may have in the meantime seen another one that needed a new pll, so keep in mind. and also, an...

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at my last post, i thought the case was closed on my two 148's, and indeed the 2nd one (the one that needed a new pll chip) is ok, but as my luck would have it, i guess i spoke too soon on the other one...the 1st one...the one i've been trying to get help w/here. i guess i got so excited, after all ...

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happy to report that i finally have figured out & fixed the problem, although how much of it i figured out is debatable..... i also repaired another similar boarded 148 (the modern ones are not all the same), which coincidently appeared (at first) to have the same problem, but as it turned out, ...

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on the 200, i told you some things you could check for, in order to rule in/out what i suggested as possibilities...they were simple checks & didn't necessarily involve doing any smt work. the part about the mic possibility was real easy to check, but you didn't reply even as to whether or not y...

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you never answered the question about talkback, etc...
i'm curious as to whether or not you found/fixed the problem?....and if so, what it was..?

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rockhavenradio, back on 1-3-09, i posted (in response to someone telling me service man. was on cbtricks) that as far as i could tell, what they had listed there, was not the same as my radio, i.e., it showed ic4 as the old mb3756 switch/regulator, whereas my radio uses a 3pin 7809 reg. i went back ...

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yes, green rx light is lit.

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i've now replaced fet 1, as well. still no rx. trying to look at schematic & make some associations w/rx. replaced d65 & tr19. no change... also i should report that in my 1-7-09 post, i said that i detected a very lo-level "white noise" being generated from the radio & that it...

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i've done everything i could figure, plus what i've been advised to do. i posted all i did. could someone please help me further along with this process? hate the dead end...

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my experience with EL is that all radios with it are prone to this problem. and i've seen a high failure rate as well, at least with cobras anyway. i know that full lighting depends on perfect contact of the "layers" in the faceplate, that make up where the lighting comes from. i've seen s...

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i would 1st redo the solder joints in pll, vco sections & the regulator on the side.

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the 10kc switch does not function in that radio, after it has been converted. so that part is normal. i'm just guessing, but does it have talkback? the early models did not have factory t/b installed & had to be modified to have it. i'm thinking of the possibility that someone may have screwed s...

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likely you have checked already, but i have some stock mics that go w/that radio, that have something wrong with them, causing them to have very lo modulation. since that is unusual, i didn't realize it was those mics, for quite awhile. so just wanted to make sure you ruled out the mic. also, i don'...

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thanks 4 replying. tr44 is marked as an [S8550]. i could find no cross 4 that (to help me determine which is the collector). in the schematic, it's labeled as an [LM8550], but i can find no such listing for that either. in using my very quirky transistor tester (my good one was stolen), it appears t...

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could the person who runs this site please tell me if this is working or not?

i don't get what the problem is or what i'm doing wrong.

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at this point, my question is this: can some kind soul please tell me what i have said wrong, in my postings so far, that might explain why i am not getting any more responses from anybody?

i honestly don't understand why this is so...

thankyou for any replies.

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changed out fet2 & 3. was gonna change fet1 also, but broke it so didn't. still no rx. checked the 7809 reg. (it"s good) & the 1 on the back of the radio looks good.

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my pleasure. glad it went so simple.

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please need more help.

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the way you listed the colors should be the correct order for pins 1,2,3,4 - w,y,r,b.
looking at it from the inside, w/radio upside down, should be 1=top rt, 2=bot rt, 3=bot lt, 4=top lt. hope that helps.

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something to add, after yesterdays 'go at it'... while examining radio, i felt heat on chassis around area of pll, which led me to an overheated pll chip, very hot, obviously a short somewhere. the strange part about this, is that i had not done any work at all, in that area of the radio that would ...

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ok, thanks alot.

how bout it rick, or somebody...to please help me w/this?

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thanks loads for getting the schematic to me. & it's a high quality file also! i don't know what's going on for sure w/the numbers/letters & such... it's obviously not a 148gtl-f, as it says (in 2 seperate places), cuz a 148gtl-f is an old, 5 pin radio, although maybe that was sans the "...

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rockhaven radio, yes, that would be great, as i don't know, but i think i'm right about it being different than the rest of 148's. it would be appeciated. i don't know my way around this forum or it uses/how to's, etc., but as far as i can tell, can't you just "add an attachment"? when you...

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ok, i think you are talking about 2nd mixer (rx local oscillator outputs). as i was saying earlier, i don't know if this radios' circuitry/pcb matches with what is available on cbtricks, or i should say, a good enough match, because i'm pretty sure none of what 's on cbtricks is this board. if it is...

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ok, just came back from rechecking. there is indeed, no rx signal, am or ssb, but tx is fine, am/ssb/moduation. i have no true signal injector or generator handy, but i can say that an adjacent radio is putting no sound & no needle indication on it whatsoever, with respect to rx. the meter is go...

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rockhavenradio, thanks 4 reply. i'm quite sure that there's no rx on am & ssb. but i'm going to go right now & do a triplecheck, to make absolute certain, since i know it's a little easier to miss on ssb, than on am, the rx that is. i don't understand your wording on your 2nd line: "if ...

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timrim, are you saying that some of regulators are common to rx signal only? i don't know of that. (tx is good). also, what protection diodes are you referencing? and i may have misread something but it looks to me that the service manual you mentioned is not for model i have. at cbtricks, the 148gt...

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Radio Make and Model: cobra 148gtl PCB Number: "newer" 4 pin "made in china". (KEPC-332-E6) PLL Number: MMB8719 Test gear available: basic meters, dummy, freq cntr, dmm & anolog Symptoms: no apparent rx signal getting in. (no pickup at all, from an adjacent radio) no reading ...

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please, somebody...anybody....ch. conversion for this radio?
thanks

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