Icom: ICOM 7610 and LDG 1000PROll tuner

[kf8iv]

I roasted the internal fuse on the 7610. Put a new one in and it fixed it.

However, my LDG 1000proll tuner wont turn on with the power from the LDG IC-PAC. I thought it was the cable, so I got a new one. Still doesnt power on. I check the voltage at the end of the cable and I am only getting like 5-6 volts. I need 12 to run power the tuner. Anyone know what the problem is? I am assuming when I roasted the fuse, I may have popped a diode or something. If anyone knows where its located as I my skill is limited (but feel confident I change it out if its in an easy location).

Any help appreciated.

Ryan KF8IV

 

[AK9R]

Could be a bad connection on the 4-pin Molex connector. Take a close look at the pins in both the connector and the radio.

 

[kf8iv]

Checked it. Looks good. When I hook it up to a separate 12v supply, the tuner fires right up.

 

[n3pm]

There is a discussion on the IC7610 io group concerning this issue.
It's under "No power to external tuner".
Mike N3PM

 

[kf8iv]

Ok. Thanks. I just requested approval to become a member. Hopefully I can get this thing fixed.

Ryan KF8IV

 

[AK9R]

I wrote this up in response to a question in one of the IC-7610 Facebook groups. It may help here:

K9EQ wrote a detailed description of how the AH-4 works several years ago which you can find here: AH-4 Tuner – HamOperator

Here's another useful source: Icom Tune Control Plug - KC2WI

The pins on the 4-pin Molex connector are 1 KEY (nearest the pointy end of the plug/jack), 2 START, 3 POWER, 4 GROUND.

If you connect a voltmeter between pins 3 and 4, you should see radio supply voltage (approx. 13.8 volts DC).
ETA: With the radio turned on.

You can check continuity of the LDG adapter cable. Between pin 3 of the Molex plug and the center pin of the coaxial power plug going to the LDG tuner, you should see near 0 ohms. Between pin 4 of the Molex plug and the barrel of the coaxial power plug, you should see near 0 ohms.

This is the tuning process:
1. When the radio requests a tune cycle, the radio asserts the START line.
2. The AH-4 CPU resets and starts running its program. When its ready, it asserts the KEY line.
3. When the radio sees the KEY line being asserted, the radio transmits a carrier at about 10 watts RF.
4. The AH-4 starts tuning and removes the START signal.
5. If the AH-4 achieves a match, it drops the KEY line. When the KEY line is dropped, the radio stops transmitting.
6. If the AH-4 doesn't get a match, it "flashes" the KEY line. The radio sees this and indicates that the tuner isn't tuned.

 

[kf8iv]

Thanks for info. I am only getting between 4-6v DC on the power line at the molex connector. Its really strange. I wonder if something shorted inside the radio?

Was hoping I wouldnt have to send it out if at all possible.