2995DX,

[Number Three]

I have a heavilly-modded RCI2950DX here, and was wondering if the finals are stock, or yet one more modification. It has the EPT695014B sm Mainboard in it, but it instead of mosfets (as shown in most service manuals), it has bipolar transistors.
The 2sc2166 and a single 2sc1969 setup, as opposed to to the 2166 feeding dual 2sc2312's, as EPT used to.
I'm also curious to know if anyone else has heard of an RCI2995DX is labeled the "Genesis" from the manufacturer, or whether it was simply added by the the dealer/modder (one in the same shop).
This thing has been volted with a 15V@40amp switcher, accompanied by all the VR's required to back-down/ adjust the critical stuff back to normal.... Nice werk n all. Not complaining, just curious about that and the fact that the AM reg, driver and final were bad. I'm kind of concerned I will see this back here way more it should be. Yep... The alignment on this thing going to be a new experience for me.
I'd post this on some of the "shop forums" out there, but I don't want to embarrass the dealer/modder. Like I said, he did a very thorough job.

 

[Number Three]

I've concluded that the final stage is indeed an R&R Communications mod, and I now understand WHY. This is the way to go! Tho R&R chose to leave the briuck amp alone (as far as I can tell), They literally FIXED what I consider a major "factory defect" with those switching supply and AF devices.
After carefully studying schematic designs based upon the last line of Galaxies and first RCI's that used the biploars, I found all the needed data for understanding the circuit and the proper bias settings.I really like this mod, now that I understand it backwards and forwards... I will probably try to talk as many customers into removing the switching supply mosfets now used, with the old single final arrangement. That is, at least until the manufacturers come up with more stable, robust RF drive and final stage using purpose-built devices. Who knows if they will improve anything in the future, or not, but I look forward to a better idea coming from Ranger, Magnum etc.
The patient is still in "intensive care" waiting on NEW replacement parts as opposed to the "pulls" i used to get it working , but at least it werks now.

 

[hotrod]

unfortunely the bipolars are discontinued. what ever ones are outhere thats it.
far as mods go, im not sure. imho i think the factory settings seem to be a bit high
on finals that really arent meant to be driven like the old bipolar finals. might be wrong
here, but just my opinion

 

[Number Three]

True, RF Parts still has a huge supply of them, but they love them a bit too much. Luckily, I bought a BUNCH of C2166's when they went NLS. Digikey and other suppliers will give us a heads-up on devices we've purchased that are being discontinued, which gives us a chance to snap them up I wish I had that option when the C1969 production stopped. And until somebody decides there are bucks to be made by designing and tooling-up for some new devices made for RF applications, we are stuck using these unstable, unforgiving audio power and power supply mosfets in their place.
What's a guy to do? We don't have much choice.

 

[Robb]

Eleflow What's New?

www.eleflow.com

 

[hotrod]

True, RF Parts still has a huge supply of them, but they love them a bit too much. Luckily, I bought a BUNCH of C2166's when they went NLS. Digikey and other suppliers will give us a heads-up on devices we've purchased that are being discontinued, which gives us a chance to snap them up I wish I had that option when the C1969 production stopped. And until somebody decides there are bucks to be made by designing and tooling-up for some new devices made for RF applications, we are stuck using these unstable, unforgiving audio power and power supply mosfets in their place.
What's a guy to do? We don't have much choice.

i might be wrong on this but dont hf rigs like kenwood,icom ,ect use mosfets in thier radios
thought they been using them for years.and if im right these sound really decent
even if they only use the supplied mic. so why cant rci ,magnumect make thiers work
but then i may be wrong on all this.

 

[Number Three]

i might be wrong on this but dont hf rigs like kenwood,icom ,ect use mosfets in thier radios
thought they been using them for years.and if im right these sound really decent
even if they only use the supplied mic. so why cant rci ,magnumect make thiers work
but then i may be wrong on all this.

Well of course, most radio manufacturers now use mosfets exclusively and it is apples and oranges when I'm talking about this thing and the erf520 and the 2sb754's( or B827's) used -- and I'm not trying to single-out RCI, because RMItaly amps, RFX75 bricks ad nauseam do it too. And it would be fine if they held up as well as the old bipolars, and axe anyone who tries to keep them running -- often, they do not.

Not that those guys are the only ones. Ever try to keep drivers/finals in an Icom IC703? And you thought the "IC" stood for ICom? Makes me WISH i had an RCI cb radio, i tell ya. My whole point of this post was that they designed these stages to use high-speed switching, and AF amps in place of purpose-built mosfets, or "antiquated" biploars (unlike Icom, Yaesu, kenwood, motorola etc )... And I was lost big-time trying to git r done.
These designers and device makers just expanded their application data to include them. NOW they are considered "High Speed power mosfets".... Cute. They used to read "High-speed switching regulation applications for power supplies" when they first hit the market...
Still, if there weren't myriad stability problems and they were not so dang-touchy to bias-up, I would be 100% behind the practice. I surely wouldn't be trying to restore the mod done in a radio modified to run the old bipolars. I made a huge mistake treating this radio as stock, thinking I had the proper circuit setup, support component and bias data...Well, I did, but for an UNmodified 2995DX -- lotta good that did me. I got the bugga up and running, BTW, after resorting to bias data on the datasheets, voltages and component values to feed the bipolars along with the schematic data for an EPT360011Z mb!!
But i did this to myself thru asssuming i had the normal shop data to fix this turd. Well, kinda harsh to call it a turd, because it puts out a stable, cool 260W PEP on SSB now!
I want to keep that "turd" now instead of giving it back to the owner.