RCI 2990 Stuck in Transmit, please help

[BBB]

Just picked up a RCI 2990 base station. Got it home and it was working fine with a Turner Super Side Kick mic. Powered the 2990 back on for the second half of CRR, then plugged the Turner mic back in again (as I was using the mic on the Browning Mark III). The radio went right into transmit mode even with the mic un-keyed. Unplugged the mic and it still stayed in Xmit mode.

I have read that these radios based on the RCI 2950 are prone to CPU failures. This 2990 I have, is based on the Galaxy DX2527 radio with the DPT295042Z CPU board and EPT295013Z main board. The CPU board is the newer design with a capacitive memory back up not a battery back up.

I disconnected the connectors on the Mic jack pc board; problem still persists. Disconnected the connector to the linear amp board to disable it; problem still there. The radio display and transmit frequency is stuck on 27.115 and the push buttons for ANL, RB, SWR and Lock function along with the dimmer all with a normal beep. Pressing any of the others yields an error beep. The radio modulates properly when the PTT on the mic is pressed on all modes.

I see that the mic jack pc board PTT circuit connects directly to the CPU board and not the main board as with typical radios. Does anyone know what connector or wire I need to lift from the CPU board that goes to the main board that would be responsible for keying the transmit circuit on the main board?

I want to see if by disconnecting the signal from the CPU board to the main board switching for the transmit circuit if the radio stops transmitting. If the radio stops transmitting then the CPU may be at fault but if the radio still is still stuck in transmit, the fault probably lies on the repairable main board.

These symptoms resemble the CPU faults as noted on CB tricks with the exception of the fact that the radio's display is stuck on 27.115 (the last frequency I transmitted on normally) where the known published fault causes the rig to display 26.000 or 28.000. I sure hope it's just one of the keying transistors on the main board gone bad and not the CPU.

Maybe there is a CPU reset sequence I can try also if for some reason something got corrupted in there, but I don't know the procedure?

If the CPU is at fault I think I'm S.O.L, panic is setting in and I just lost the lottery -$$$ (unless someone has a good CPU board laying around)

Any help would be appreciated, Thanks. Here is the link to the schematics and such for the similar DX2527:

www.cbtricks.com/radios/galaxy/dx2527/index.htm

[BBB]

I believe that all these radios have a similar if not identical DPT295042Z CPU boards:

RCI 2990 base
RCI 2950DX
RCI 2970DX
Galaxy 22B base
Galaxy DX2527 base

The 2950DX service manual looks like it crosses as well except for the power supply and the amp in the 2970DX and 2990 of course.

Can you tell I'm already looking for possible donors?

[Sandbagger]

Apr 25, 2013 10:12:49 GMT -5 BBB said:

Just picked up a RCI 2990 base station. Got it home and it was working fine with a Turner Super Side Kick mic. Powered the 2990 back on for the second half of CRR, then plugged the Turner mic back in again (as I was using the mic on the Browning Mark III). The radio went right into transmit mode even with the mic un-keyed. Unplugged the mic and it still stayed in Xmit mode.

I have read that these radios based on the RCI 2950 are prone to CPU failures. This 2990 I have, is based on the Galaxy DX2527 radio with the DPT2950427 CPU board and EPT295013Z main board. The CPU board is the newer design with a capacitive memory back up not a battery back up.

I disconnected the connectors on the Mic jack pc board; problem still persists. Disconnected the connector to the linear amp board to disable it; problem still there. The radio display and transmit frequency is stuck on 27.115 and the push buttons for ANL, RB, SWR and Lock function along with the dimmer all with a normal beep. Pressing any of the others yields an error beep. The radio modulates properly when the PTT on the mic is pressed on all modes.

I see that the mic jack pc board PTT circuit connects directly to the CPU board and not the main board as with typical radios. Does anyone know what connector or wire I need to lift from the CPU board that goes to the main board that would be responsible for keying the transmit circuit on the main board?

I want to see if by disconnecting the signal from the CPU board to the main board switching for the transmit circuit if the radio stops transmitting. If the radio stops transmitting then the CPU may be at fault but if the radio still is still stuck in transmit, the fault probably lies on the repairable main board.

These symptoms resemble the CPU faults as noted on CB tricks with the exception of the fact that the radio's display is stuck on 27.115 (the last frequency I transmitted on normally) where the known published fault causes the rig to display 26.000 or 28.000. I sure hope it's just one of the keying transistors on the main board gone bad and not the CPU.

Maybe there is a CPU reset sequence I can try also if for some reason something got corrupted in there, but I don't know the procedure?

If the CPU is at fault I think I'm S.O.L, panic is setting in and I just lost the lottery -$$$ (unless someone has a good CPU board laying around)

Any help would be appreciated, Thanks. Here is the link to the schematics and such for the similar DX2527:

www.cbtricks.com/radios/galaxy/dx2527/index.htm

I had a 2950 once that did that, and a CPU reset fixed it.

If that doesn't work, you should try troubleshooting the PTT line and find out if/where it is being pulled low. It's possible that a bypass cap or some other component decided to short and pull the PTT line low. I assume that the CPU indicates that it's in the transmit mode (which would indicate a PTT short in front of the CPU). If the CPU doesn't indicate TX, then the PTT short is most likely after the CPU board.

Stick to old radios. All that "newfangled" CPU junk is just a problem waiting to happen. Why use a CPU when you can use a big ol' toggle switch. ;D

[BBB]

The red transmit indicator does indeed illuminate as soon as I turn it on. I'll double check if the CPU board triggers that LED.

Since this CPU board doesn't have the battery I'm thinking I may need to lift one of the storage caps leads to get it to reset.

Thanks for the reply.

["Doc"Hammer]

Hey Sparky, I have a 2950, but it uses a battery..It has other problems that keep it from working...the CPU board is good..you are welcome to it if you need it for parts..

[BBB]

Sincere thanks Doc Hammer. I'm not sure if it will cross to the main board or not yet. Maybe someone can clarify that?

I referenced the older 2950DX and 2970DX versions only because I saw that they use the same apparent non-battery CPU board with the non-SMT main boards on the CB Tricks schematics.

[2600]

The one symptom I haven't heard mentioned so far is the "TX" indicator on the display. The two letters "TX" appear on the display when the computer thinks the mike is keyed.

If you DON'T see the "TX" on the LCD display, there is hope. If it appears when you key the mike, and goes away when you release it, this suggests a problem in the radio itself, and not in the CPU.

The explicit plug that leads from the CPU board to the main board with the transmit function on it is poorly described in the manual. Pretty sure I have some bench notes at work on this.

I'll check back in when I find it.

And if the "TX" is always visible, with the mike unplugged, you're probably out of luck.

The CPU/display board from a mobile radio will work if it's modified a little. The pushbutton board's hookup in a base radio needs pins installed in the CPU where the mobile CPU has socket contacts.

Still has to be the correct version. Don't know how to adapt the older battery-backup CPU to work in the later-version radio that you have.

73

[BBB]

The TX does stay on the display. On another site it was suggested that I remove connector cn605 to see if it drops out of TX and it did. Then the radio receives correctly.

Thanks to 4-400 "unplug cn605 from cpu and see what happens, it has the command wire from the mic socket via the cpu then on to the echo board . You should have no tx when it is removed"

I pulled the CPU board and now see it's labeled (DPT295040Z) listed as "Early Production" on the Galaxy DX22DX page. Not (DPT295042Z) Don't know if that matters or not. The main CPU chip is the HD404818C89FS or YNRG2950SP.

On the bright side, the radio is stuck on 27.115 and I could rig a relay to the PTT to disengage the TX . I really hope I can get this radio going again, if not it will be my first real burn in the hobby

[BBB]

I have the DPT295040Z CPU board schematic, echo board, main board and interconnection diagram schematic if that would help in trouble shooting.

I think I'm understanding that if the CPU display reads TX all the time, there is an internal failure inside the large scale proprietary Ranger IC chip that cannot be corrected?

Coincidental (I think not) that this occurred immediately after I pulled the Turner SSK mic from the Browning and plugged it to the 2990's mic jack? I'm wondering if there was some kind of static charge left on the Turner mic or if the mic transferred an EMP from the open mic adapter that was on the Browning's mic jack.

I read of another possible incident of a CPU failure of a 2950 based radio when the person had a operational Browning in close proximity and switched mics. Isn't there a decent amount of un-sheilded voltage present on a Browning Mark III's open mic socket?

If this is the case, operators beware of having a powered Browning Mark III near a powered 2950 based radio

[2600]

I think I'm understanding that if the CPU display reads TX all the time, there is an internal failure inside the large scale proprietary Ranger IC chip that cannot be corrected?

That's what it sounds like to me.

If the Browning were plugged in to the wall, but NOT grounded, you could maybe hurt something by touching the ungrounded Browning with one hand and the metal body of the mike with the other hand, maybe? There is enough AC leakage current on the chassis of an ungrounded Browning radio to cause mischief with the sensitive input pins on the RCI computer. Your body has a low enough resistance to feed that leakage current where it could cause trouble. Seems to me the mike would have to be wired wrong for the RCI radio to do this, but who knows?

A customer was sitting in front of his Galaxy DX2527 one night when a lightning surge jumped from the landline phone on his desk to the radio's D-104. That radio was stuck on transmit from then on. He ended up buying about five used CPU/display boards salvaged from mobile radios before finding one that worked. The sharper horse traders know about this problem and will salvage the CPU from a mobile radio that has other problems. Just no easy way to tell if it's any good once it's pulled from the "donor" radio.

I have been threatening to come up with the few thousand bucks it would take to develop a "drop-in" replacement CPU/display for the 1995-1999 "problem" radios. Figured a 7-segment LED display would be an improvement over the original LCD.

Still haven't come up with the bucks to make good on my threat.

Makes me wonder how many I'd sell.

But cool ideas are a dime a dozen. What's really rare and precious is the resources to make an idea real.

But if I went to borrow the money, that's the first thing they'll ask, is how many of them I would sell.

Hard to tell. Too risky to take out a mortgage for it.

73

[40sx]

I had a similar event happen to me with my Galaxy Saturn Turbo about ten or fifteen years ago. The only thing I did was to plug a different microphone into the four pin adapter cable I had going to the Galaxy. The microphone was not defective nor its wiring. The microphone was a Turner Super Sidekick. I believe the radio went into the TX mode immediately. After much troubleshooting I ended up getting a new CPU board for the radio. The radio works fine to this day, even using that same Turner Super Sidekick.

Dennis

[Sandbagger]

May 1, 2013 8:06:13 GMT -5 BBB said:

The TX does stay on the display. On another site it was suggested that I remove connector cn605 to see if it drops out of TX and it did. Then the radio receives correctly.

Thanks to 4-400 "unplug cn605 from cpu and see what happens, it has the command wire from the mic socket via the cpu then on to the echo board . You should have no tx when it is removed"

I pulled the CPU board and now see it's labeled (DPT295040Z) listed as "Early Production" on the Galaxy DX22DX page. Not (DPT295042Z) Don't know if that matters or not. The main CPU chip is the HD404818C89FS or YNRG2950SP.

On the bright side, the radio is stuck on 27.115 and I could rig a relay to the PTT to disengage the TX . I really hope I can get this radio going again, if not it will be my first real burn in the hobby

Time to wire up that "Big ol' toggle switch"...... ;D

[BBB]

"Time to wire up that "Big ol' toggle switch"...... ;D "

THAAAAAT'S RIGHT! Thanks all for the assistance.

Luke.... resist the dark force of the Black Faced Radio

[BBB]

Good news. A donor CPU board was found and I swapped it in and she's back on the air. It wasn't totally a drop in, but no soldering was required.

In my case the donor needed to be a '95 or later 2950 or 2970 non-DX. Thanks Operator Ron!

I then took the donor "push button board" and trimmed off the mounting pins that attached it to the donor 2950 CPU board. I did this in such a way that the pins remained rigid due to the fiberglass board still utilized ( insert band saw here)

Next I slid the pins back thru the donor CPU board's connectors. These pins now protrude thru the other side of the CPU board long enough to slide the 2990's original "push button board" cable connectors on to. That's the difference between the two CPU boards, the "push button board" cable connectors. This is due to the 2990 having the push buttons lower on the radio's bezel as where the 2950 has the push buttons right under, and mounted to, the LCD display. All the others CPU connectors are the same.

Since they are no longer indexed (keyed) like the original wire connector sockets were, take special care as to also note how the 2990's push button board wire connectors are oriented as they fit onto the new donor CPU pins. I put a dab of glue on the side of the connectors to keep them from sliding off the new pins.

Note, both small black jumpers are used on the 2990 so make sure the donor has both in place on the CPU board. Label all the CPU connectors prior to removal.

I can put some photos up later if anyone's interested. Thanks for all the information ;D

[Sandbagger]

Jul 15, 2013 23:48:06 GMT -5 BBB said:

Good news. A donor CPU board was found and I swapped it in and she's back on the air. It wasn't totally a drop in, but no soldering was required.

In my case the donor needed to be a '95 or later 2950 or 2970 non-DX. Thanks Operator Ron!

I then took the donor "push button board" and trimmed off the mounting pins that attached it to the donor 2950 CPU board. I did this in such a way that the pins remained rigid due to the fiberglass board still utilized ( insert band saw here)

Next I slid the pins back thru the donor CPU board's connectors. These pins now protrude thru the other side of the CPU board long enough to slide the 2990's original "push button board" cable connectors on to. That's the difference between the two CPU boards, the "push button board" cable connectors. This is due to the 2990 having the push buttons lower on the radio's bezel as where the 2950 has the push buttons right under, and mounted to, the LCD display. All the others CPU connectors are the same.

Since they are no longer indexed (keyed) like the original wire connector sockets were, take special care as to also note how the 2990's push button board wire connectors are oriented as they fit onto the new donor CPU pins. I put a dab of glue on the side of the connectors to keep them from sliding off the new pins.

Note, both small black jumpers are used on the 2990 so make sure the donor has both in place on the CPU board. Label all the CPU connectors prior to removal.

I can put some photos up later if anyone's interested. Thanks for all the information ;D

So for those of us keeping score, you now have 2 working 2990's?

[BBB]

Yes, I'm submitting to the dark side One now repaired 2290 (non-DX) I got off of the local Ham.

The other is the loud and proud Grumpy Memorial 2990DX Transceiver.

[cbrown]

Good for you. I too had a weak moment and bought a 2995 back in 2004. It's a nice radio. And so far no problems. Love it on SSB.