Intermittent Loss of Pre-Driver signal
IC-7000: Intermittent Loss of Pre-Driver signal
I've owned my IC-7000 for about three weeks, and it's now got an intermittent transmit fault affecting all bands.
The fault can be made to come and go when using the back of a small screwdriver to gently impact the PA Unit board in the pre-driver area of the board.? ? When the fault is on, I have TX signal at the gate of Q102, but no signal (or variable signal) at its drain.? ?The DC conditions on the gate and drain are consistently OK - regardless of whether the fault is present.? ?The TX signal at the drain of Q102 is highly variable between the fully working and fully non-working states.
Note:
All my measurements are being made at the components that I have access to from the bottom view of the PA Unit board.? ?To this extent, I must admit that I'm not making measurements directly on the pins of Q102 itself.
I'm currently attempting to isolate the fault, but do not know whether I'm looking for an intermittent open circuit condition, or an AC shunt path from the drain of Q102 to ground.
Has anyone here resolved a similar fault?? ? ?All tips gratefully appreciated.
With best wishes
Steve G4ALG
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IC-7000 with separation kit for sale
My IC-7000 is for sale. Includes new separation kit. Please email kc9c at yahoo for more information.
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Mark KC9C
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Interesting question, could anyone find information about the values ??of the IC-7000 Main Board L701 Transformer, the coil itself can't be found anywhere, so you have to do it if you don't happen to find something used.
T. Pentti OH5KOA
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Re: IC-7000 no rx and no sound out from speaker
Hi Geoff
While I wait for the parts to come in I thought to apply the recommended mods?
Also the pre driver transistor heat issue seems to be another issue with this radio
James?
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Re: IC-7000 no rx and no sound out from speaker
These cables are often handled inappropriately and the connecting end can lift the track
When pushed incorrectly into the pcb connector.
Yes, I would add the gate resistor for sure. It's seems to be hit and miss if these driver boards burn up. I had one that had worked fine for 10 years before it destroyed itself.
Geoff
On Thu, 14 Nov 2024, 10:04 James Tiberius via , <nono2212000= [email protected]> wrote: Hi Geoff
yes they are in a bad state - found bent contact strips on all cables. these cables are pretty weak and not well made.
I decided to pull the unit apart to check the driver board which is the original and from what i have been reading is prone to oscillation - do you think its worth while modifying with the resistor to prevent the oscillation occurring?
james
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Re: IC-7000 no rx and no sound out from speaker
Hi Geoff
yes they are in a bad state - found bent contact strips on all cables. these cables are pretty weak and not well made.
I decided to pull the unit apart to check the driver board which is the original and from what i have been reading is prone to oscillation - do you think its worth while modifying with the resistor to prevent the oscillation occurring?
james
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Re: shut down / restart on keying, now no power
Save the old, bad one. I’ll bet the connection was broken where you had the photo. Should be an easy fix and you have a spare.?
Tage
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On Nov 13, 2024, at 10:27, Tage Carlson via groups.io <tage_carlson@...> wrote:
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Congratulations.
Hello all,?
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Problem solved. I replaced the power supply cables and rig powered on.
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Thanks for all your help!
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73,
Colin N2TQT
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Re: shut down / restart on keying, now no power
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Hello all,?
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Problem solved. I replaced the power supply cables and rig powered on.
?
Thanks for all your help!
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73,
Colin N2TQT
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Re: shut down / restart on keying, now no power
Hello all,?
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Problem solved. I replaced the power supply cables and rig powered on.
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Thanks for all your help!
?
73,
Colin N2TQT
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Re: IC-7000 no rx and no sound out from speaker
Good move. These cables can produce weird faults if they are handled poorly. Make sure the small backup strip is in place on the new cables.
Looks like someone has been inside this radio then!
On Wed, 13 Nov 2024, 15:12 James Tiberius via , <nono2212000= [email protected]> wrote: Just an update-
still waiting for IC551 to arrive.
I had a look at the ribbon cables and they are not in the best condition so I ordered a new set from icom today - 60aud for 5 cables including gst and postage
james
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Re: IC-7000 no rx and no sound out from speaker
Just an update-
still waiting for IC551 to arrive.
I had a look at the ribbon cables and they are not in the best condition so I ordered a new set from icom today - 60aud for 5 cables including gst and postage
james
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Band filter switching in pa board
Hi everyone,
i apologize if my first post can be off topic, but hope someone can give me an advice.
I have a working 7K's PA board , 2 rd100hhf1 and a driver board. I found also a empty 7000 body with fan (without front unit).
I would like to use this material for building a 1,8-50-mhz 100w linear for my Hermes Lite (5W out). What is missing is a control? interface for switching the different pass band filters and check the swr or power. I'll try to find a way to build something with a arduino or a Pi Pico but before starting i was thinking what must do this board. So i'm asking some guru in this forum if they can explain me , in detail, how the 7000 change the band and measure ros/pwr...
If the argumented answer point to a excessive complexity of the project i can think to swap those parts with some colleague.
Thanks in advance.
73
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EA8DJR LUCA
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Re: shut down / restart on keying, now no power
Might not pass a government inspection, but shouldn’t cause symptoms.?
Tage
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On Nov 11, 2024, at 19:02, Colin N2TQT via groups.io <colingee@...> wrote:
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Sorry, here's that photo. Note the red insulation worn away at the fuse connection.
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Re: shut down / restart on keying, now no power
Could be heat that has done that over time, suspect poor fuse connection 73
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On 12 Nov 2024, at 1:02?PM, Colin N2TQT via groups.io <colingee@...> wrote:
? Sorry, here's that photo. Note the red insulation worn away at the fuse connection.
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Re: shut down / restart on keying, now no power
Sorry, here's that photo. Note the red insulation worn away at the fuse connection.
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Re: shut down / restart on keying, now no power
Thank you all, vy much, for your responses. The first thing I did was examine the fuse cases. I received this radio from a friend and the power cables included seem to be OPC-025D, with a 6-pin connector on one end, used with a 6-pin to 4-pin adaptor into the radio. I saw that at one of the fuse case ends, the rubber insulation was gone from the wire, and the wire was exposed. Photo attached. Suspect, no? I'll replace this cable and see if that improves things.?
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I'll report back.?
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Thanks again!
73, Colin N2TQT
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Re: shut down / restart on keying, now no power
I had that problem some years ago. I was using a Samlex PS with fused wires and molex connectors. Very frustrating. I shotgunned it this way: use Anderson connectors, no inline fuses and sold the Samlex and use the little West Mountain Radio PS. I did not change the factory molex on the back of the radio. I just bought some connectors and made a little pigtail with the factory molex-type at one end and an Anderson connector on the other.?
Also, I want to add this was quite a few years ago and I got help on this group to solve the problem.?
73, Larry W7DGP
Enjoying my IC-7000 since 2007
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I have been trying to install version 2.6.1 and I get ?a failure message - can't find ".hamlib_settings". ?Should come with the WSJT program or do I need to find it somewhere? ?I'm using a Linovo Yoga cpu and a IC7000 with a Signalink.
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Thanks,
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Ed KE6SU
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Re: shut down / restart on keying, now no power
I've had this happen to me in the past. Fuse holder connections, power connections, even one time a defective fuse. The fuse read continuity with a meter on ohms but would not pass any current. I asked a professional radio tech if he had ever seen that B4. He replied, "yes, rare but I've seen it before" Bob W4JFA
Hi Colin, These things are ALWAYS caused by power input failure, which only shows itself when you transmit. There is a poor or corroded connection in your power supply leads. As the other posts have said, clean?every contact you can find, De-oxit?everything, and for final confirmation, attach your voltmeter to the power outputs of the 4 pin Molex ATU socket at the back, and watch the voltage?when you push the PTT. You'll find the pin-outs for that socket in the !C-7000's manual.
Good luck! 73 Dave? Reece????
ZS1DFR??? 083 270 6843
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My Hobby is Amateur Radio - ask me
for more details!
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View my star?
David-Fraser-Reece at RA12h43m14.15 -59deg24min15.9sec dec magnitude 11.03 in
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Regards,
Dave
ZS1DFR
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Re: IC7000 no HF power out but VHF/UHF ok
Signal level tracing with a 'scope is the way to go, looking at the levels in and out of the driver and to the finals.?
It is always possible that there is a problem past the finals as well.?
Sometimes you just have to drag out the test gear and take a look.
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Steve G4ALG
Edward Luers
Bob