Looking for some advice on the main board? The service manual shows ept695011a mine is a 2005 model with the ept695014b? I'm assuming the alignment is the same? The only mod I see is the limiter has 1 leg lifted. I would like to do a few more mods to it, 1st is adding a second final all the components are present on the board except c228 470pf 50v and c290 560pf 50v this is according to the ept695011a board in the service manual the schematic doesn't show Q61 and no luck finding anything for the ept695014b board. Mine currently has a 2166 driving a 2312 I would like to swap in 2 1969's for the finals is this possible with adding the 2 capacitors. My next question is about the npc/ppe mod haven't done one on an smd board searching around the web I've seen some done at r292 (several different version) and I've seen some done by the am reg sb754 what is the best way of doing this type of mod the ones I have done to my galaxy is just lifting the resistor and adding a 1n4001 diode in line. The one I saw by the reg was a mosfet board in an rci X9, can't find anything for this board. Thanks any and all advice appreciated. (no bashing about the npc mod some like them some don't) I run them on all my galaxy radios with very good results if set up properly. Thanks Ira
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RCI 2995DX
- Thread starter ira parker
- Start date
You do have a 2995DX correct? The 2166 and 2312 are your drivers, the finals in that radio are a pair of Toshiba 2290’s. Those are 80 watt finals. There is no reason to mess with the drivers, you should be getting around 150 watts from that radio.
Ira.
Do us a favor and pull that little brown two conductor plug (most likely green and yellow wires going to it) that is just to the left of the mirror board by the driver and final. (i think its J22)
this will disconnect power to the amp portion and you can now see how much power your radio will make "barefoot".
once you see just how much power you are making in order to drive those two 2290's, you'll see why its a terrible idea to try to add a second final to this radio.
all you're going to do is drive those 2290's into self oscillation, overheat them, and probably pop them.
I have no idea whether or not the HG 2290's will work on that amp board without other component changes but i would say that the chances are quite high that you'll need to do a significant amount of experimenting in order to get them to work.
much better to keep the originals working as long as you possibly can.
remember that when you're making the power adjustments inside the radio, all you're really doing is increasing the drive to the amp.
a "2 pill" 2290 amp does not want any more than about a 2 watt deadkey, and if you're doing an NPC mod to the radio then you're already swinging 20-25 watts into them.
sure, you can add the final, turn the deadkey down to 2 watts, and then swing 35-40 watts into those 2290s and watch them get super hot in less than a minute of talking.
secondly, adding a second final is NEVER a straight forward process, and your chances of popping something are very high.
as for the NPC mod, the best way to do it, well really the only way to properly do an NPC mod is to use a scope so you can set the negative peak clipping where you want it. (around 95%)
so, first, align the radio and set the modulation to 100% using the scope, then get a 1K trimmer pot and connect it in series with a rectifier diode (oriented correctly! you can find images of the mod on google).
and strap those two parts across C258 which will be near the AM regulator.
now using a steady tone into the mic, key up and adjust the trimmer for full negative peak clipping without "flat lining".
now remove your diode and trimmer from the circuit and measure the resistance of the trimmer.
replace it with the closest value fixed resistor and you're all set!
LC
now
Do us a favor and pull that little brown two conductor plug (most likely green and yellow wires going to it) that is just to the left of the mirror board by the driver and final. (i think its J22)
this will disconnect power to the amp portion and you can now see how much power your radio will make "barefoot".
once you see just how much power you are making in order to drive those two 2290's, you'll see why its a terrible idea to try to add a second final to this radio.
all you're going to do is drive those 2290's into self oscillation, overheat them, and probably pop them.
I have no idea whether or not the HG 2290's will work on that amp board without other component changes but i would say that the chances are quite high that you'll need to do a significant amount of experimenting in order to get them to work.
much better to keep the originals working as long as you possibly can.
remember that when you're making the power adjustments inside the radio, all you're really doing is increasing the drive to the amp.
a "2 pill" 2290 amp does not want any more than about a 2 watt deadkey, and if you're doing an NPC mod to the radio then you're already swinging 20-25 watts into them.
sure, you can add the final, turn the deadkey down to 2 watts, and then swing 35-40 watts into those 2290s and watch them get super hot in less than a minute of talking.
secondly, adding a second final is NEVER a straight forward process, and your chances of popping something are very high.
as for the NPC mod, the best way to do it, well really the only way to properly do an NPC mod is to use a scope so you can set the negative peak clipping where you want it. (around 95%)
so, first, align the radio and set the modulation to 100% using the scope, then get a 1K trimmer pot and connect it in series with a rectifier diode (oriented correctly! you can find images of the mod on google).
and strap those two parts across C258 which will be near the AM regulator.
now using a steady tone into the mic, key up and adjust the trimmer for full negative peak clipping without "flat lining".
now remove your diode and trimmer from the circuit and measure the resistance of the trimmer.
replace it with the closest value fixed resistor and you're all set!
LC
now
First off I want to thank you both for your inputs, addressing the concerns I was thinking about. Now let me rephrase some of my terms and thinking. 2995dx is a stand alone transmitter with a stand alone amp built on the back so I call the 2166 a driver and the 2312 the final in the radio, the 2290's are just an external amp driven by the radio. I put switch and a indicator light in so I can run either with or with out the amp. The radio is new to me so it gets a full body cavity search. Inspection showed only 1 leg of q43 lifted at the junction of r208/217 rendering vr17's function out. Next was a check up on the alignment of the radio using the service manual that's available for this model (695011a) board mine is the 695014b any information on this exact board is like searching for hen's teeth! So proceeded with the alignment with what's available and the amplifier in the off mode, the alignment procedure clearly depicts this as a dual final radio in the biasing of the pa section .10 driver .50 and .50 for finals? Hence my question about adding the 2nd final. Initial tuneup resulted in 5.25 watts dead key with rf power at max, 1 watt at minimum with 12 watts pep am either position, 14 watts ssb either position so on to the biasing .10 driver .30 final held the key for additional 15 seconds and it would only pull up to .40 so the final may be weak. Put the amp back inline and reset the high and low rf power high 45watts, low would only go down to 2 watts with vr and front variable at minimum. Amp on 2 watt dead key 5 on the mic gain was at 100% mod 80-90 watts pep but had some distortion, increased dead key to 5 watts mod up to about 110% 90 -100 pep 110 on ssb cleaned up the distortion. So shut the amp down and rechecked the radios output rf power at low 0 watt dead key rf power at high 3.75 watt dead key, low would swing 9 watts pep but very swipey high would swing 11-13 pep clean so I believe it's under driving the 2290's I've seen many of these radios do 150 plus and stay clean and cool. So before I look into the dual final setup I'll pull the 2166 and 2312 and test them if they're weak might replace the 2312 with a 1969 then do the npc mod and see what i get and yes I set the neg. peaks with the scope. The dual final setup still has me scratching my head, could be one of the revisions between the 11a board and the 14b gonna have to do some digging on that. Sorry about the long post but sometimes the more info the better. Once again thank you for your thoughts and input. Ira
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The 2312 is a stronger final then a 1969. The 2995DX never had dual driver finals. The reason the board has the slots for another final is that board is probably also used in the 2950 that did at that time have dual finals. Here is some good stuff for this radio.
Yes that's the alignment service manual I'm using, I did find the ssb apc quite low at 9 volts so brought that up to 12.5 volts rf power at max boy what a difference ssb will now peak 150-160 pep and it brought am up. I tried to set am apc at 6 volt rf power at max but it was way to hot when I went back to low power setting dead key was over 20 watts readjusted for a 2 watt dead key on low with vr15. vr19 is all the way down I'm seeing about 130 pep am, I can bring the dead key up to 5 watts and she swings 150 pep am. I wouldn't think the ssb apc would make that big of a difference on am but it sure as heck did. so I went back and checked the voltage on tp8 on am high power is 3.25 volts and low power is .85 volts that's a long way from the 6 volts the manual calls for on the apc vr15. I think the service manual needs a good tune-up and alignment on it's information. LOL All in all I think it's good after a through alignment that's when I found the ssb apc volts being low, so I'm going to do the npc/ppe mod so I can run the lower dead key for my amp and get the modulation back under control with the limiter being clipped it's a little ugly on the scope even with the mic gain backed down. A fella could go bald trying to use that manual and I don't have much left. Once again thanks for all the help. Ira
P.S. got a fan kit coming and a 40amp switching power supply coming for it, think I got a good deal for 250$ she's really clean and the original box and all the paper work.
You stole it for that price, especially if it's the version with the 2290 amp board! Set it up right with no hack mods and She's a keeper.
yeah definitely a good price for that radio!
on the service manual, that's just the ranger way. they intend that manual to be used with every iteration of that board/radio and they just expect the tech to know how to interpret it.
i work on quite a few of these radios, but i really only see the newer ones with the mosfets in the radio and the built in amp.
i can tell you that these new boards do not like the NPC mod much, and an operator who is long on the key will most likely eventually pop the final, which can also take out a few other parts.
if you are dead set on adding a second final, don't change them to 1969s. get a matched set of 2312s either the originals if you can find them, or the HGs if you can't.
if the two finals are not matched you stand a good chance of one of them doing most of the work and the other not holding up its end of the bargain.
be aware that not every part that could possibly be in your radio is on the schematics and jumpers are not shown.
LC
on the service manual, that's just the ranger way. they intend that manual to be used with every iteration of that board/radio and they just expect the tech to know how to interpret it.
i work on quite a few of these radios, but i really only see the newer ones with the mosfets in the radio and the built in amp.
i can tell you that these new boards do not like the NPC mod much, and an operator who is long on the key will most likely eventually pop the final, which can also take out a few other parts.
if you are dead set on adding a second final, don't change them to 1969s. get a matched set of 2312s either the originals if you can find them, or the HGs if you can't.
if the two finals are not matched you stand a good chance of one of them doing most of the work and the other not holding up its end of the bargain.
be aware that not every part that could possibly be in your radio is on the schematics and jumpers are not shown.
LC
Hey LC, I have got her running right with the single final so I'm not messing with making it dual. Operator error on my part I'd just done a quickie touch up on the alignment for initial testing, went back through it and found the ssb apc was quite low at max power after adjusting it up to 12.5v bias to 2312 came on up to .50 now has good pep ssb 150-160w it bumped 200 at first so I backed down some, it also brought am up 2w dead key 120-130 pep 5w dead key 150-160. I don't volt the finals with the npc mod one mishap with rf power knob bye bye finals!!! On the old boards I've always upgraded the reg and companion part 817/1012 runs way cooler. Just wasn't sure if these smd boards could handle it, I remembered seeing sp5it's post on the mod he was upgrading q67 but not the reg? Hence the other post but he's volting the finals and I'm not so it will be sb817/2sa1012 1n4148 and the resistor (value not yet determined) 40amp power supply and the fan kit. My thinking has always been like a car good tune a few performance parts she'll run 140mhp but as a daily driver she'll run cooler, cleaner and better mpg at 60-80 mph with a little pep left in the tank for a mustang every now and then. As always thanks for your input. Ira
Look at this setup on the bottom side of the board I believe it accomplishes the same thing as the jumper on c258 much easier on bottom of the board. Yeah nay maybe? What's your thoughts. Diode to collector sb754 resistor to plus side of c260.
ive seen it done that way.
it does put you on the wrong side of R293, but its only a 15 ohm resistor.
however, i seem to recall that when i tried doing it that way, i could not get the negative peaks "down" far enough meaning i couldn't get past about 75% "negative modulation" for lack of a better term.
so i removed the NPC resistor and went with just the diode.
this improved it, but i don't think i ever got the negative peaks to the 90-95% that i wanted.
sure is convenient to do it this way though!
LC
it does put you on the wrong side of R293, but its only a 15 ohm resistor.
however, i seem to recall that when i tried doing it that way, i could not get the negative peaks "down" far enough meaning i couldn't get past about 75% "negative modulation" for lack of a better term.
so i removed the NPC resistor and went with just the diode.
this improved it, but i don't think i ever got the negative peaks to the 90-95% that i wanted.
sure is convenient to do it this way though!
LC