Hi,

UPDATE:

Well it looks like I have evidence that the problem may be the final amp
or associated circuit. In the "Adjustment mode", I checked the idle current
(transmit SSB without modulation with a current meter in the power supply line
as described in the SM. For HF/50M and 144M against a "00" setting reference
(as described in the SM), the current was higher by the specified amount
compared to the "00" reference. However, for 430M, the idle current is the
same as the "00" reference, and it can not be increase (in transmit) to the
value specified in the SM. Rotating the adjustment dial, which shows a
change in the number, has no effect on the idle current.

I will not pursue this any further at this time. I am able to use
430 MHZ SSB, but at a lower power level (around 18W).

Thanks to everyone for your useful suggestions.

John N3AOF


On Wed, 13 Oct 2010 13:10:28 -0400, in sci.electronics.repair you wrote:

Hi,

I recently bought an Icom IC-7000 transceiver from the estate of a
"silent key". The UHF power output, although the radio is set to
"100 percent power" (all bands), puts out about 50 percent on the
UHF band. UHF watt meter indicates around 18 watts when it
should be 35 watts. Note: Other bands are just fine at 100 percent.

I downloaded the service manual from www.mods.dk and followed
the procedure to enter the "Adjustment" mode. However, I can not
change any settings beyond the "Total Gain (430)! My intention
was to increase the "100 percent" value, which is beyond the "Total Gain"
adjustments, to see if the power goes up. Note: I am using a proper dummy
load.

I couldn't find in the service manual or service manual addendum
any information regarding this issue.

By any chance, did you encounter the same situation?

Thank You in Advance, John N3AOF

PS, Remove "ine" from my email address

On Tue, 19 Oct 2010 12:41:23 -0400, wrote:

Well it looks like I have evidence that the problem may be the final amp
or associated circuit. In the "Adjustment mode", I checked the idle current
(transmit SSB without modulation with a current meter in the power supply line
as described in the SM. For HF/50M and 144M against a "00" setting reference
(as described in the SM), the current was higher by the specified amount
compared to the "00" reference. However, for 430M, the idle current is the
same as the "00" reference, and it can not be increase (in transmit) to the
value specified in the SM. Rotating the adjustment dial, which shows a
change in the number, has no effect on the idle current.

I will not pursue this any further at this time. I am able to use
430 MHZ SSB, but at a lower power level (around 18W).

Kinda looks like the RD60HUF1 RF output xistor might be toast. The
Vgs bias adjustment is a DC characteristic, and does not require any
RF drive to function. See Pg 2/7 which shows the Vgs to Igs graph. At
Ids=2.5A, Vgs should be 2.5 volts. You can measure that with a
volts-guesser by simply removing the bottom cover:
http://www.rfparts.com/pdf_docs/RD/rd60huf1.pdf
$29.20 from RF Parts.


--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558