Icom: IC-208H problem

[KV8T]

Greetings,
I am experiencing a problem that just occurred this week with my IC-208H. No matter which band or what power level is selected it will transmit at that power level for a second then the power will cut back to 5 watts. It is acting like the high SWR protection is kicking in. Of course I have tried this on the bench connected to a dummy load to eliminate an antenna or power issue. I can get full output when in service mode but even after a factory reset it still cuts back to 5 watts. Has anyone else experienced this problem and does anyone know the solution. My phone call to Icom got me nowhere, of course they said just send it in. Any help would be greatly appreciated.
73 and best regards.
Mark (KV8T)

 

[n0zed]

Whats you power supply looking like , my 208 dose wonkey things if the voltage drops low or high .

 

[ShawnInPaso]

Have you checked the SWR?

Perhaps something else is in play that cannot be identified using the dummy load.

As you likely know from the user manual:

IMPORTANT! (for 55/50 W transmission):
The IC-208H is equipped with protection circuit to protect
the power amplifier circuit from high SWR (Standing Wave
Ratio) and temperature. When a high SWR antenna or no
antenna is connected, or when the transceiver temperature
becomes extremely high, the transceiver reduces transmit
output power to 15 W (approx.) automatically."

 

[K4EET]

<snip> I have tried this on the bench connected to a dummy load to eliminate an antenna or power issue. I can get full output when in service mode but even after a factory reset it still cuts back to 5 watts. <snip>

I've not had any problems with my IC-208H. For your situation, look at all of the common things between the "live" setup and the bench test. I agree with the comment on the power supply voltage. That is critical. You already did a reset but programming could still be an issue since that is also a common point. Any other common points? Perhaps a coax jumper between the rig and an inline wattmeter/VSWR meter? The antenna could be good but the jumper bad. If that is a scenario, try replacing the jumper to the radio. Finally, what else is common in the two setups? Sorry I cannot be of more help but I do hope you can find the common source for the problem. 73, Dave K4EET

 

[KV8T]

My apologies for forgetting to mention this. The problem was first detected in my car. I then bench tested it with my Astron 20 amp supply, same problem. Also different coax jumpers between swr meter and dummy load.
Thanks,
Mark....

 

[K4EET]

My apologies for forgetting to mention this. The problem was first detected in my car. I then bench tested it with my Astron 20 amp supply, same problem. Also different coax jumpers between swr meter and dummy load.
Thanks,
Mark....

Hi Mark, no problem... I have an Astron 50 amp supply and the Icom IC-208H in high power draws a shade over 10 amps. The specifications for 146 MHz state 12 amps at 13.8 VDC with a maximum DC voltage fluctuation of ±15%. Take a voltmeter and verify that both your wiring in the car and the Astron power supply at the radio's DC input connector is within specification. As for VSWR, do you have a male-male PL-259 connector so that you can attach the VSWR meter right at the connector to the radio? NOTE: Be sure to not stress the connection too much. Between all of us, we'll eventually figure this out. 73, Dave K4EET

 

[K4EET]

Hello again Mark,

In case you do not have a copy, here is a link to the Icom IC-208H Service Manual:

http://www.ko4bb.com/manuals/71.244.167.146/IC-208H_Service_Manual.pdf

Note that I have not looked at the service manual to see if it has any specific info on your issue as I am sort of busy right now with some school studies. Perhaps you or another reader could check out the manual's contents.

73, Dave K4EET